Making a Panther Platform Vehicle Handle ... Crown Victoria, Grand Marquis, and Town Car

The following article is aimed at making a Panther Platform vehicle handle better.

Who is X Racer (Author)?

X Racer has raced, wrecked, broken parts & bones till he is now "X" Racer. X Racer may not be the one to listen too on much more than how to break something or wreck it. But since you are, X Racer is me. My father even took my first wheelchair away from me because he thought I would kill myself in it. It could have been the ramp to ramp jumps or it could have been doing wheelies down the road at 25 mph. I did not mind as I had worn the tires off it in about 2 months. Wheelchairs were never engineered to carry that much plaster of paris. Anyway, the devil lured me into wanting to go fast. So I raced MotorCross, Hairscrambles, Enduros, Trials, AutoX and some flying competition. We want even talk about the fast women. If I was not racing, I was playing Football, Wrestling or Boxing. I have been kicked out of every Go-Kart track in Panama City. I have also been kicked out of half the Water Parks I go to for going to fast. Along the way I learned a bit about racing and Orthopedic Doctors. Between all these mechanical toys, I learned how to repair them, weld them, modify them, and then break them again. Now that I am older, more mature, and laid back, I bought a 92 Crown Victoria and now my current 99 Grand Marquis. These cars should carry me well threw my slower years. During my first AutoX race in the Grand Marquis, I blew away 1/3 the participants in a nearly stock, full treaded tir,e land yacht after waiting nearly 15 years since the last AutoX. Don't even ask me what happened at the last Auto X. You are supposed to do better each time.

Handling and what is it. So you want to make your Crown Victoria, Grand Marquis, or even Town Car handle better. Good, it is not that hard. But first what is handling? Smooth ride, quiet ride, high cornering limits, good steering response, confidence inspiring, stop watch says its fast, 0-60, 60-0, 1/4 mile times, low vibration, traction, and many other words describe

Hi! My name is Sarah. I am here to help X Racer show you how to handle the curves and bumps. Along the way, I hope to teach him how to spell and use proper punctuation.

handling. Racecar handling and a smooth quiet ride tend to conflict. We are lucky with modern cars because they give both better than ever. If you go to modifying your car, you are shifting the compromise that the engineers picked. Engineers are not wrong or right with the settings they chose. There is nothing wrong with shifting the compromise to satisfy your taste. Just remember, you rarely get something for nothing. I will try to let you know the pros and cons of each modification. It is a lot like an old radio with a treble/bass knob. No one can walk up, set it and say, "This is the only correct position". It is personal. We are talking about a handling Vs ride. Sometimes you can get a lot of handling with little trade off in ride. Some modifications give very little handling and kill the ride. Many of the modifications listed do very little to the ride by themselves, but start adding them all together and you may be making big changes. Many of us bought our CV/GMs for the smooth quiet ride. Many for the safety, spacious interior, 6 seats, and more. Only you can decide how much handling Vs ride you want. My wife says her car is stock and it will stay that way. She says I ruined my cars ride. I love my car's modifications and most of us on Crownvic.net/.org do. I promise to do one thing here and that is give you the Pros and the Cons so you can make an informed decision.

Tires:

The tires are your only connection between the road and your vehicle. No one part of your car can influence handling more than tires. First lets put a hole in the old fiction tale that wide tires put more rubber on the road. When you put 34 pounds of air in a tire, you do not pull out a scale and weigh 34 pounds of air to pour into your tire. It means 34 pounds per square inch of pressure. No more and no less. The front and rear of our CV/GMs weigh about 2200lbs and 1800lbs respectfully. That would be 1100lbs for each front tire and 900 lbs for each rear tire. 1100lbs divided by 34psi would be about 32 square inches. If your 225 width tire were about 8.7" wide, the contact patch would be about 3.7 inches long. 3.7" x 8.7" x 34psi = 1094lbs. Close for rounding off. A wider tire, say 10", would have a contact patch 3.4" long. Obviously you would have to reduce the square inches of rubber in contact with the road because of tread groves. All this math means one thing and that is, wide tires only change the contact patch shape. And yes, this does affect handling.

There are only three ways to increase rubber on the road. Lower your air pressure, increase the vehicle's weight, and go to racing slicks so there is no tread cut out. Tires have an ideal air pressure for peak performance. Lowering the tire pressure will only hurt traction. Increasing the vehicle weight is a BIG no no! That only leaves race slicks and that is illegal, dangerous, and useless in the rain. You are now 0 for 0 on increasing the contact patch. Well not really ... I left you an out with "ideal tire pressure". We will come back to this.

Many of us have put wide tires on and noticed a big improvement. Was it the width, or was it the tire compound, cord material and layout, and the profile?

Lets go straight to the number one influence on tire traction since obviously it is not tire width. Here it is... "Tire Design". Tire companies design their tires for a purpose. The best dry weather paved road tires are classified as "Max Performance" tires. Next are "Ultra Performance" tires and last are "Performance" tires. Please reread all the conditions. That was dry weather & paved roads. Not rain, snow, or off road. "Max Performance" tires have nicknames such as gumballs, Auto-X tires, DOT race tires, and such. They are purpose built for racing. They ride rough, they are noisy, expensive, dangerous in the rain, and have very very short life spans. A highway tire typically is rated around 600 to 700 on wear. These tires typically run around 50! That is 1/12th to 1/14th the time! Like I said they are for racing only or for the rich on sunny days. They also need a special break in to work their best.

Ultra Performance Tires:

Now, that 99.9% of us were just talked out of "Max Performance" tires, lets go to the next category. "Ultra Performance" tires are full treaded and normally perform very well in the rain. The tread wear ratings run about 180 to 280. Not great on wear but that is the price you have to pay for performance. Also some of them ride rough and are noisy. www.tirerack.com has excellent write ups and comparisons. Spend some time at this great web site when it is tire time. High performance tires tend to handle better, have better steering response, more neutral handling, more forgiving, more confidence inspiring, better rain performance, brake better, accelerate better, and flat out corner harder. You buy a lot with your money here! This is the first spot to not be skimpy with your money if you want good handling.

Plus sizing has been proven to help handling while maintaining the stock gearing, ride height, speedometer accuracy, and overall handling characteristics. The lower profile tires used in plus sizing helps reduce slip angles, improves steering response, and they corner harder on smooth roads. Using the stock wheels and low profile tires, will lower the car, drop your gearing, improve steering, improve cornering power, reduce wheel weight and rotating inertia,

Rocket Couch ++sizing

and throw the speedometer accuracy off. My old 245x50x16 tires dropped the gearing the equivalent of going from the stock rear end ratio of 3.55 to a 3.70. The speedometer was off about 3 mph by the time I am running about 70 mph till corrected with a performance chip.

When it comes to ride, anything that firms up the tires will also hurt the ride. That includes performance level, plus sizing, profile, rim width, etc...

As you firm up the sidewall with wide rims and/or the short sidewalls used in low profile tires, the tires ability to grip on rough roads may be reduced instead of improved. Our solid rear axles tend to aggravate this problem. The vast majority of pavement is not that rough. Just be ready the first time you see ripples in the asphalt. That means slow down. Good shocks help offset this.

Next:

For the next step in making your car handle, you need to decide what part of handling is important to you. For most of us, it would be confidence inspiring and fun cornering. Sway bars normally win with no contest. But the stock swaybars are not too bad on the HHP cars and our stock shocks are soooo soft. Do shocks first if you have HHP bars and then swaybars or flip a coin. It is close.

Shocks:

Bilstein HD shocks are the only reasonably priced shocks that work on CV/GM cars. There are many shocks that do wonders for other cars. They just don't work on ours. The part numbers are:

Bilstein HD front P/N B46-1495 Bilstein HD rear P/N B46-1496 They run about $65 a piece. Better shocks will help braking power and acceleration off the line on even smooth roads. It will also help cornering power and tire wear. Don't expect night and day changes on these improvements. Expect night and day on these: no more float, confidence on rough roads is way up, much better bottoming resistance, much tougher to

I like a firm ride ! Let me hold those big shocks while you tighten things down.

belly the car into the ground. Here is the down side. Your passengers will not sense the much improved handling that the driver will notice, but they will notice the much firmer ride. The stiffer ride opinions have varied widely amongst CV/GM owners. Bilstein shocks may not be consistent on their dampening. This may be an area where people vary a bit with seat of the pants judgement. Even though there is no consensus on how Bilstein shocks affect the smooth stock ride, we all agree it was worth the money. You definitely get used to it. I have one advantage over others and that is my wife also has a 99 Grand Marquis HHP. I can do back to back comparisons to a stock GM. That way my slipping memory does not get off base.

Here are the specifications on dampening rates in lbs. for both standard Bilstein shocks that are virtually the same as stock and HD Bilstein shocks:

B46-1497 Comfort, Front 1240 compression, 1040 rebound (Close to stock)
B46-1498 Comfort, Rear 1000 compression, 470 rebound (Close to stock)

B46-1495 HD, Front 3090 compression, 2000 rebound
B46-1496 HD, Rear 1750 compression, 850 rebound

So you say you want Max Performance from your Bilstein shocks. Call up Energy Suspension and order polyurethane shock mount bushings. This will help tie the wheels down even better. Notice how all real race shocks use spherical bearings. Polyurethane give near metal to metal results with less vibration and noise and unless there is rotation in the joint, it will not need lubrication. Two people have done this. One said the ride was much rougher and the other could not tell a change. I'm sure that helped you.

Very often people ask what other shocks do better (stiffer) than stock for less money than Bilstein. Years of knowledge from the hundreds of CV & GM enthusiast has lead to the following list:

Gabriel LT (1 driver) $18-$20

Edelbrock IAS (There is very positive feedback on the newest models and all say they are not harsh) $??

Ford PI (1 driver felt it got most of the float out) $22

End of list.

Don’t ask about Marauder shocks. They will not fit. Marauder shocks should have the perfect blend of ride and control. They rear shock mounting points have moved to the outside of the frame.

Ok, for more money what is there. You are now stepping into new territory. The only place left to go are separate rebound/compression, low speed adjustable & reshimable shocks. No one has gone there to our knowledge with CV/GMs. There is only potential for improvement and I believe it is there in transit steering response. Long ago, experts believed shocks had little control on cornering. Wrong. Around 91 or 92 Indy race cars learned about the shocks offroaders have used for centuries. In recent years Auto-X racers have adopted this technology too. We are talking about separate low/med/high speed dampening, one way shim stack dampener and other spy stuff. You may also need someone with a shock dyno that knows how to use it and knows how to tweak all those springs, washers, orifices, and whatever. When you turn the wheel hard the car leans, weight shifts, tires take a set in slip angle, and more. The inside turn shocks must extend while the outside shocks compress. This takes time and there forth we call this transit cornering. It also gives the shocks time to work. If we set the shocks with different rebound and compression settings, we can momentarily shift weight to wheels different than what the springs and swaybars would do. With our big cars the front tries to push with a quick jerk of the wheel. With shock tuning we could get the right tires working harder and faster. Unless you are rich, an Auto-X racer, or just want an all out handling CV/GM, then you would most likely find the extra work, money, and possibly ride harshness a disappointment for what you get back. If you are still with us, then go to Koni shocks web site. Just remember that you want dual adjustment for both rebound and compression. There are also other shock manufacturers. Research it. Don't expect big changes, just the ability to fine tune.

Notes for installation on all shocks: Take it easy on the lower front shock bolts. There are no nuts ... just the thin soft stamped sheet metal lower control arm. I learned the hard way. The top nuts use a 9/16" wrench or socket. The top of the shock can be held with a #9 spoke wrench or a ?/?" wrench. To speed up removal, you can cut the plastic guards, slide them down, and vise grip the shaft so you can remove the nut. If you take this short cut, the old shocks are history. Also use penetration oil a few days before work. You will cuss the access to the rear shocks upper nut. It requires a long wrench and you can turn it very little. This will require a lot of patience (beer).

Swaybars:

Next are swaybars and Addco is the only one there for us. The part numbers are:

Addco front swaybar #509 1 1/4", about $90

Addco rear swaybar #650 1", about $90

Energy Suspension ENS-9-5165G 1 1/4" "C" clamp w/grease, $13.95

Energy Suspension ENS-9-5161G 1" "C" clamp w/grease, $13.95

New front end link - ENS-9-8124G x2, 3 9/16" $13.95

Addco/Energy Suspension endlink bushings for rear - Package of 8, $7.95

98 Stock rear bar ?" next to Addco's 1"

I can help you stiffen the ride.

"crownvic96" Without Addco Swaybars. Not to bad, but room for improvement.

Addco quality is satisfactory and the results are always very worthwhile. Everyone has been glad they did this upgrade. They are very modestly priced. Addco increases the front bar roll resistance about 52% and 71% for the rear over the 98+ HHP bars and more on the rest. This is done with a 1.25" front bar and a 1" rear bar. So far 100% of us have mounted our bars on urethane or polyurethane bushings. The ride will noticeably tighten up. This is more noticeable on rough roads. You can always substitute some of your old rubber endlink bushings with the urethane/polyurethane bushings till you get the ride you want. I have never heard of a person complaining about the ride with 100% rubber. You can still get about 75% of the improvement with all rubber. Nothing does more to make hard cornering fun than swaybars. The tire wear improves, tire squeal changes to a growl, and the car stays much flatter in the turns. You do get some improvement in cornering power. This is the one handling modification that puts more smiles per turn than anything else.

The stock 98+ HHP bars are not too bad with stock tires. Just replacing the stock bushings with urethane/polyurethane helps some and does not change the ride. This is very cheep with a modest improvement. Cost is about $37 if you hunt around.

Mounting is done with either Energy Suspension polyurethane bushings or Addco urethane bushings. With either you only want the "C" clamp bushings with grease fittings. Only Energy Suspension comes with them, but they also have them without so be careful which ones you order. With Addco, you will have to drill, tap, and cut a grove. If you do not have grease fittings, you will soon hear the dreaded dry bushing squeak. Addco tends to be over priced with their mounting hardware. They do have a good deal on the endlink bushings. These can be bought at Advanced Auto Parts and other parts shops. Do note that Ford's rear "C" clamp is not a conventional two bolt set up. Some people have drilled and tapped for a second bolt. Some have inserted a 3/8" spacer under the urethane/polyurethane bushing and reused the stock "C" clamp.

This requires that a grease fitting mount be drilled and tapped. Also the grease fitting will need to be long threaded as the Ford's "C" clamp has a reinforcing ridge running down the middle creating a gap. Energy Systems rear "C" clamp will not bolt up without modifications. Addoc's will bolt up but it does not have grease fittings. We have one known failure with this "C" clamp. No matter what the rear will require some work or risk the dreaded dry urethane squeak from lack of lubrication. Suspension friction = poor ride and handling.

Addco has in the past forgotten to add all the instructions. They have had fatigue problems with the stock front endlinks. They now have a new front endlink that bolts to the lower "A" arm. There is an existing unused hole in the arm. The hole is punched so the edge is very sharp for the plastic bushings. I would recommend grinding the ridge down and adding a small radius to the hole. The link is ?" long.

There is a down side to Addco's endlink replacement. The following is a quote from a Ford engineer on their ball jointed link directly connecting to the spindle:

” We attach with a ball link directly to the spindle since 1991 Town Car. We call this a 1-1 stabilizer bar attachment. It is much much more efficient than attaching to the lower arm with rubber insulators, like some do, and we did for years. Of course the ball attachment is more expensive, but the effects on steering response and transient roll control are dramatic."

The Ford engineer was very confident on the durability of their endlinks. Still, safety comes first.

Because of the data making the stock endlink desirable, a letter was sent to Addco to verify the problem. Here is the reply:

Dana,

I have not heard of any problems we have had with endlink failure. I have asked around the office and no one seems to have heard anything either. I'm not sure who sent you information indicating there was a problem but as far as I know there isn't one.

Let me know of any further information you can get me and I will do the same.

Dan Osborne / Vice President of OEM Operations
ADDCO Mfg. Inc.
1596 Linville Falls Hwy.
Linville, NC. 28646
Phone: 800/621/8916
Fax: 828/733/1562
e-mail: dosborne@addco.net

A second E-mail was sent with the original installation sheet. With no reply, I spoke to Dan Osborne on the phone.3-26-02. Dan is now saying not to use the stock front end links. He could not expand on the change in his response.

Don't ask me what to do. This has left me a bit confused too. These are the facts as they are.

The PI CVs have clearance problems with the front Addco bar because of the oil cooling lines. I have not looked at the PI models to see what the problem is. If the stock 1 1/8" bar clears, why would Addco's 1 1/4" not? Well the word back to me is the arms have a different bend. Energy Suspension does make tall mounts as well as standard. Also the endlink height could be adjusted some. Maybe between the two, it can be done. I would think that the oil lines could be rerouted. I don't have a PI so I don't know. Do NOT mount just the Addco rear bar alone! That would make the car tend to spin. This is especially true in the rain. This is not theory as several people have reported their cars handling dangerously with only a heavy duty rear bar. Addco says this too and so will I.

See Bada Bing's web page on installation with some great pictures. Thanks big guy!

http://home.swbell.net/jorem/addco_sway_bars.htm

Some people have reported that Addco uses a poor grade of steel. This may be true and would help explain their low prices. However all steels have the SAME spring rate. Using a lower quality steel would only be a problem if you twist the bar to its yield point or close. If Addco's bars were reaching the yield point, I would think it would be only a short time till they break. You just can not bend steel back and forth with out it very shortly breaking. I just don't think our cars have enough suspension travel to twist the bars to their yield point. Besides, Addco are the only ones there for us and we have never had a problem.

Rim widths:

This comes second to tires on pure cornering power. Radial tires are sensitive to rim widths and they DO respond to it. Wide rims speed up the steering response noticeably! A wide rim is a great foundation for the tire. This is especially true with heavy cars. I believe it also lowers the optimum tire pressure. Lower tire pressure means more rubber on the road. You should also get better tire wear. If you research the tire you are buying, you should have found the approved rim widths. Sometimes you will see wording like, "Recommended rim width". This may be true, but is only true when keeping it conservative on ride. It really should say rim width used for tire measurement and many do this. For maximum cornering power, reduced slip angles, best steering response, pick the widest rim width. The ride will degrade noticeably. This happens mainly on sharp edged bumps. You should notice very little with normal road bumps. For most 245 x 50 x 16 tires the max rim width would be 8.5" and for 245 x 45 x 17 tires this would be 9". This is an additional 1.5" to 2" over the stock 7" rims. Where are you going to put it? On the inside you have an upper ball joint that hits first and in the turns it is the front swaybar. It only gets worse with 255 tires. The rule of thumb says overall width goes up .4" for every additional 1" of rim width. If I wanted performance over looks, I would go with 225 tires over 245 or 255 if it meant loosing rim width. It helps that much. You ask how wide it best for cornering power? The width of the tread is a good rule of thumb for the width of the rim for max performance.

There are two down sides to a wheel too wide (exceed recommended rim width). First the cornering power will start to diminish. Second the flexing of the sidewall will move down closer to the bead. The bead area is thicker and will not tolerate this well. Heat will build up and the tire may fail! At the same time if the rim is too narrow, the flexing will move up to the tread area. Again the rubber is getting thick and heat will be generated. Excess heat can cause tire failure. The manufacturer's guide lines for approved rim widths should work fine. Use the recommended rim widths and everything will be fine. That also means that even the widest recommended width should not be too wide for maximum cornering power. Maximum cornering power hits typically when the rim width matches the tread width.

The heavier a vehicle is, the more important it is to have a good foundation for the tires. Our cars are very heavy compared to sports cars.

On the down side, rim width has a direct affect on the ride. Also the rims will be moving out from the protection of the tire. It will be easier to scrape a rim on a curb. If you have scuffmarks on your rims now, then this may not be a good idea. My mom's car is a great example for not needing wider rims. Lol! That is something to think about before loaning out your car.

Here are some Tire Manufacturer links on this subject.

Dunlop:

http://www.dunloptire.com/tiretech/?article=tire_width.txt

If all those tire size numbers did not register, click here for tire numbers 101.

http://www.howstuffworks.com/tire2.htm

Scrub radius:

X Racer, you got me all dirty ... Now you have to scrub me too!

This is also called Kingpin offset and Pivot Radius. This is simply the distance from an imaginary line drawn through the ball joints till it hits the ground and the center of the tire.

This imaginary line is what the tire pivots around when you turn the wheel. Most of the time it is 1" to 1.5" inches on rear wheel drive cars. It is also the leverage the wheel has against the wheel in your hands. Think of it as a wrench 1" to 1.5" long trying to fight you when driving. The good thing is you should have a second wheel on the front of your car balancing things out. Every time one wheel hits a deep water puddle and pulls on the wheel, this is the lever pulling against you. Same thing for brakes that pull. It is also what gives you much of the "road feel" sensation when driving. Why are you telling me all of this? Because on most cars all the added rim width will have to go to the outside. Going to a 17" x 9" rim may add at most 1" to the scrub radius. This is a 100% to 67% increase. The wrench just got longer. Every water puddle will pull twice as hard.

That brake job that was over due will be twice as bad. Our cars appear to have good room on both sides. CV/GM cars have some of the poorest road feel and the strongest power steering units around. I don't think we have too much worry about. The only time I was mildly disappointed in the scrub radius change was when I jumped from a 5" wheel to an 8" wheel with manual steering. You should be able to add 1" more rim on both sides keeping the scrub radius the same if you use nearly the same offset. Where do you get the data to mount wider wheels? All any tire shop will do is add all the width to the outside and it is your problem if it hits the fenders. Most front ends are tight on the inside anyway so their brainless method is right most of the time. Can you tell me what clearance you need? Sure, here is the formula. Just factor in the tire coefficient of friction that generates the cornering forces that compress the rubber "A" arm bushings, bows the spindle, twist the frame, flexes your wheels, and off sets the tire on the rim that air pressure and rim width also affects. It's just that simple! Ok, it is too complicated with to many variables. Adding it all to the outside is safe except for the fenders. 8" rims appear to be very safe on our cars. With a nearly stock offset, 9" rims should work with 245 tires. Most likely 255 tires will squeeze by. Several people have used up to 275 tires on the rear. I am not sure what rim width they used. Wider rims do affect the overall tire width. Obviously it has no affect on tread width. If you want to go wider, ask yourself, "am I ready to flare my fenders to make the tires and wheels fit if there is a problem?" I am not talking about 5" fiberglass flaring like some road racer with tires 12" or wider. I am only talking about folding the inner lip and then maybe a body man massaging and extra inch or so into the metal, if anything is even needed. I have done this before and it is no big deal. You will also be widening the track width and this tends to help cornering power. "If" you feel the increase in the scrub radius adversely affected the handling, then you can tighten things up. Many wheels companies machine the center section of the wheel down for different offsets. Check to see just how much they approve. Second, place some clay on the tight fitting areas. This would again be the upper ball joint and the swaybar. The swaybar only hits in full lock turns and is not sharp. This should do little harm if they bump from time to time. Just don't crank the wheel with a lot of pressure at full lock. When it stops turning that is it and let up. The ball joint is the key, but don't trust me. Get in there and look around. It could be the brake calipers. Anyway pile the clay on and go for a drive. Hit the roughest and hardest turns you know of. When you are done, measure how thick the clay is. You could do this with the stock wheels to see just how much room you have with the fenders. Just remember that the tire only moves over half the rim width you are adding and the center bulge only moves .4" for every 1" of rim width over the wheel used to make the tires measurements. This is listed with the approved rim widths. This peak bulge is not at the edge of the tread. It is even further away from the fender. Also do not eye ball the fender clearance. The top of the tire is pulled in by the shorter top "A" arm giving even more clearance. Adding say 1 degree or more negative camber will also add fender clearance. Clean the parts and with a little luck the clay will stick. Once you know exactly how much room you have, take the wheels to a machine shop and machine the mounting flange down to your new specification. Keep the changes small or go buy a new wheel with a different offset. Spacers are frowned at, but up to a 1/4" is safe with longer studs. Don't forget, if you are testing with a tire with a lower performance level than you plan to use in the future, deflections may be less. The "Watts Link" used on 98+ CV/GM cars does a better job of locating the axle laterally. Obviously this means on pre 98 vehicles you will have to have more clearance or replace the control arm bushings with polyurethane to firm things up.

Ok, is there anything you do know for sure? Yes, on stock 15" x 7" 10mm offset wheels (pre98s), 255/50/15 tires will fit with some slight dragging on the swaybar and the plastic by the footwell, but only at full lock. With 255/50/16 tires with stock 7" wheels (98+), other owners say they clear. My 245/50/16 tires on stock 16x7 10mm offset wheels cleared until the Addco front sway bar was installed. It took awhile, but plating is wearing a tad. Again this is only at full lock. We have a few members who have used the 17"x8", 25mm offset Mustang Cobra wheels with 1/4" spacers. Mustang wheels normally do not fit without spacers. Cobra wheels are 17" in diameter and 8" and 9" in width. With stock 16" wheels, it looks like we have 1.75" of clearance on suspension parts. You should not have any problems with 8" width wheels, 9" may be tight and I highly recommend 17" wheels on any car with 98+ brakes. I have yet to find a 16"x9" wheel that will fit. Currently I am running Ford Cobra 17x9 wheels with 1/4" spacers. More on this four paragraphs down.

The Tire Rack (www.tirerack.com) has a 16x8 wheel for our cars. Cheap, easy, and you know it fits.

The stock wheels use a 10mm offset and the new appearance package Crown Victoria's use a 12mm offset. The max backspacing appears to be 5.5" that will fit.

If this is not complicated enough, a college did a study on the affect of scrub radius on cornering power. They designed a custom adjustable spindle so that they could play with the scrub radius and not affect any other measurements. They took it all the way to a negative scrub radius. Their test showed that the cornering power went up a full 0.1G with a negative scrub radius over about a 1.5" scrub radius. Remember they adjusted the scrub radius without changing the track width. Adding track width normally improves the cornering power. I noticed that the skid pad was very very tight. I would guess near full lock on steering. Also the test were done with a SUV. Still 0.1G is a big jump. They said nothing about the stability on the highway. The old school of thought is that wheels that widen the track help cornering. This makes you think about it twice. Once again, this data does not lead to a clear answer. I never said I knew everything and if someone claims to; RUN!

Ford Cobra 17" x 9" wheels and Kumho ECSTA Supra 712 245/45/17 tires:

As of June 2002 I have not found a wheel under $1000 each that is 9" or more and will fit our cars. That does not mean it does not exist, but I searched for months. I did find a 16x9 wheel with a near perfect offset that would work on any pre 98 car. Even though it will mount a 16" tire just like a stock98+ CV/GM stock wheel, the inside wheel diameter will not clear the 98+ brakes. The only thing I have found is 17x9 Cobra wheels with 1/4" spacers. I would think twice about using replica Cobra wheels. They tend to weigh more and if you ever dent/damage a wheel, you have no guaranty the company will be around for a match. Ford will be here tomorrow. Also the best price on each is very close. Tire Rack had the best deal at the time of my purchase. The Cobra 17x9 wheel and tire added 5lbs per wheel over the 16x9 wheels I found. Even these were about 9 to 10lbs over the 16x7 HHP wheels with near bald tires. Obviously, this is no way to improve your 1/4 mile times. Also the extra weight is toward the outside of the rim. This is a modification for handling and not for acceleration. Even with 1/4" spacers, the offset is a tad less than stock. Between new full treaded tires and less offset, you can feel that the steering is lighter. It was light enough to begin with. I chose Kumho ECSTA Supra 712 245/45/17 tires. They are not the best Ultra performance tire. But they are near the top. I did compromise a tad to gain better tire wear, reduced noise, wet traction, and ride. A 50 profile tire would keep the diameter closer to stock. The Cobra center hole is perfect for our cars. The hub that fits into the hole is rather short. I have concerns as to if the two even touch with the 1/4" spacers. A 1/8" spacer may work. I need to pile some clay in a few places and see just how much room I have. I would highly recommend longer studs any time you use a spacer. Summit should have longer wheel studs.

That's a lot of details, but how did it perform? The steering is noticeable more tight and a tad lighter. Cornering power is way up. The tires will not squeal until clearly over the edge. It is more of a whooshing sound in the turns. The back and front end used to have different ideas on what they wanted to do. Now the rear end follows the front with absolute precision. It is now boring to drive because it is so easy at normal speeds. You feel like you have less control on speed as the car no longer responds to the throttle much. What I mean is if you take you foot off the gas when turning hard, she will not slow down nearly as fast. The scrub is greatly reduced. This is free HP. Less scrub means that if you screw up and get to hot in a turn, you are in real trouble. Plus the speeds are way up. A public road can no longer be used to the limit even when no one is around. The speed is just to fast. With the old set up, you only had to hold on for a few seconds and the speed would scrub off fast. The ride is much rougher on sharp edged bumps. Rounded bumps are virtually the same. It is almost the same amount of ride change as when the Bilstein shocks were installed. If your butt meter likes it smooth, then stick with a 8" max width rim and no lower than 50 on the profile of the tire. The ride is still very quiet. Many people say some of the very best of the Ultra Performance tires tend to be noisy. Tire Rack post owner’s opinions good or bad. The ride Vs performance with this tire/wheel combination is not as favorable as expected. The body rubber mounted on the frame does a great job of reducing any harshness that modification can cause. Evidently, you can push this rubber too far. My butt meter is at its limit on harshness. Our cars will never be race cars so me there is no reason to totally kill the ride. But I am getting a little older. Someone in there 20's may say, "What’s next?" But at the very beginning I said much of this is personal and subjective.

I have played with the tire pressure some. Dropping the air pressure to34psi front and 32psi on the rear seems to be helping and I feel both ends take a better set at the same time in a turn.

Alignment:

Camber: For peak cornering power, cars need negative front camber. If you are wearing the outside edge faster than the rest of the tread, then this is a win win improvement. With our cars, you most likely have a suspension problem if you are wearing uneven. Especially with a 98+ car. They take abuse very well. While adding negative camber helps cornering by keeping the tire flatter when the car leans, it also increases the camber change when using the brakes hard. You may loose a tad in braking. For peak performance, most radial tires like 2 - 3 degrees of negative camber. Most street cars run 1/2 - 1 degree as a reasonable compromise. If you are wearing the outside edge, then keep cranking the camber in. Cornering power will go up and uneven tire wear will go down. It also may be time for HD swaybars and/or "A" arm bushings if you are wearing the outside edge badly. 98+ CV/GM cars handle hard cornering with even tire wear. Thank you Ford.

Even the rear tires like camber. If you are ready to go 100%, you can torch the top of the rear axle making it warp. This is how many NASCAR and other solid axle race cars add about .75 degrees camber to the rear. Anything more and you have to modify the axle splines. Also bearing, axle, and differential wear goes up. This would make this modification rather drastic with little return. This would be cool for a dedicated Auto-X car and not much else. That eliminates about 99% of us.

How much gain in cornering power does 0.5 to 1.0 degrees camber give you? If you can find the data, then let me know. Experts only say it helps. Handling is part science and part art. Every vehicle and tire will be different.

Toe-in: Our cars are slow to initiate a turn. Setting less toe in will help. I have tried toe out before and the car (not a CV/GM) was still fairly stable. Wide tires tend to add stability too. Going toe out is a trial and error method. The car may become darty, and braking may be more unstable. Front end condition and tires can have an affect. Experiment with caution is the only advice with toe.

Castor: Castor adds stability and helps with straight line stability. It also affects trail. Trail is the same as on bicycles and motorcycles. Castor is more like the fork angle. Just like with two wheel vehicles, increased castor and trail increases stability. It also may slow down turning. With four wheel vehicles, it adds negative camber to the outside tire as you turn the wheel. This can help keep the tire flat in the turns and or help add the negative camber needed for maximum cornering power. Trail changes with castor changes. There are no separate adjustments except for casting/forging your own spindles.

Tire loads Vs Traction:

This makes all the difference in the world to cornering power! Lighter is better. If you take a tire and apply a 500lb vertical load, you would likely find it could handle a 500lb side load. That would be the same as turning 1G! That would be great. Now if you place a 1000lb load on the same identical tire you would hope to get the same ratio and get a 1000lb side load. Nope! It would be closer to 850lbs or about .85G. That is no where close. Our tires are running about 1100lbs on the front and about 900lbs on the rear empty! Yes they are big cars! From hear it goes down hill.

Weight shifting:

Our cars sit a tad high and we get a fair amount of weight transfer from the g force of a turn. You could easily transfer with good tires about 80% of the weight. Lets play with some numbers. Take a 3950 lb Grand Marquis with 12 gals of fuel and a 200lb driver and CV/GM's 55%&45% front to rear weight split. This would place about 1858 lbs on the outside front wheel and 1520 lbs on the rear! The inside tires would be running about 464 lbs and 380 lbs. Note the rear inside wheel weight of 380 lbs and then think of trying to put power down threw an open differential. Can you say wheel spin! This is just an example and we do not have any real data to show real weight transfers and which end of the car is doing the most roll resistance. This is controlled by the sway bars, springs, track widths, and more, but then taken away by frame flex. Many front wheel drive vehicles lift the inside rear wheel right off the ground in a turn. Porsche rear engine cars tend to lift the inside front wheel off the ground. This shows how cars react when the front to rear weight bias is way off 50/50. The best performance with a given tire is when all four tires work evenly and at the same time. However, racing has shown weight distribution close to 40% front and 60% rear on rear wheel drive works best. The fact that our inside tires are very lightly loaded and can withstand higher G loads as shown above, does not make up for the highly loaded outside tires that we know can not corner hard. Not even close with say 20% of the weight in their corner. The poor performing 80% of the weight or whatever will dominate.

Lets see what we can do to balance the traction. Try to imagine a car with only one large sway bar at one end and nothing at the other. Most all the weight transfer would be carried by the sway bar end and it would be massive or even 100% as in cars that lift a wheel. The non sway bar end would have both inside and outside tires working together with nearly the same load. Guess which end will have the most traction. Yep, the non swaybar end. This is how we tune our cars. If one end of the car is loosing traction before the other end, we can shift the traction. Our cars are heavy in the front and lighter in the rear. About 55/45. They also come with a rather large front swaybar. Our rear track width is about 65.3" Vs 63.4" on the front. All of this tends to make the front push. Addco bars are 40% stiffer in the front and 70% in the rear. This will shift the traction from the rear to the front so that all four tires are working more evenly. We call this a balanced car when both ends work equally. The bars also keep the tires flatter on the road by reducing body roll. This all adds up to more cornering power. The stiffer rear bar also transfers more weight off the inside rear wheel making it tougher to accelerate out of a turn. Our cars are not all that powerful so the wheel spin is not much worse than the stock set up before Addco. Our CV/GM cars have a big problem with frame rigidity. The same body on frame with rubber mounts that makes our cars so smooth and quiet also lets everything flex. It is hard to adjust a sway bar and get the chassy to respond because the frame flexes instead shifting the weight like we wanted it to. Again, a Panther platform car will never be an ultimate sports car. Just better if you want it to be.

So what if you go threw a turn so hard that nothing is left to put power down threw an open differential? You are going so much faster than the other guy that he will never catch up. The only real fix is a limited slip of some sort.

Adjusting the cars balance

If the car is pushing (to tight, understeering) to much, try the following:

More front tire pressure

Less rear tire pressure

Smaller front swaybar

Softer front swaybar mounts

Larger rear swaybar

Stiffer rear swaybar mounts

Wider front tires

Wider front rim widths

Shift weight from the front to the rear

Use softer front springs

Use stiffer rear springs

Use softer front shocks

Use stiffer rear shocks

Widen the front track

Narrow the rear track

Use a softer compound tire on the front.

Use a harder compound tire on the rear

Reduce the roll axis angle by lowering the rear center of roll (rear is normally higher than front)

Reduce toe in on the front (toe out may be unstable)

Add more front camber

Reduce scrub radius (may only work on tight turns)

Reduce kingpin angle without increasing the scrub radius (only works on tight turns)

If the car is oversteering (loose, trying to spin) too much, try the following:

Do everything the opposite as shown for understeering. If that does not work, lift your right foot a tad off the right pedal.

Reducing weight shift in the turns, Ride Height, Springs:

Obviously we have learned so far, that anything that reduces weight transfer in a turn and helps all four tires work together in a turn will also help cornering power. The easiest way to reduce weight transfer in a turn is to lower the car. The air ride rear suspension cars are easy. Just loosen the ride height sensor, slide it over away from the differential, and retighten. Done. This is only on the rear on some of our cars. They all have coil springs on the front.

With springs there are two ways that are cheap. The easiest is to cut the spring down. The problem is it will also make the spring stiffer. If you cut 1" worth of spring you may only get 3/4" lower. 1/2 to 1 coil is about all you can get away with on our cars. This is a bit of trial and error. Just go slow because you can not add back what you cut. One member reported about a 2" reduction in ride height with 1 coil cut. He also felt the ride was noticeably stiffer. He strongly recommended starting at 1/2 a coil to start with. He said that the camber adjustment was maxed out during the realignment.

The second method is to use the same spring compressor that you used to remove the spring. Compress the spring as far as you can. Then place it in your oven at 450 degrees for say about 10 minutes. Remove and recheck the length. You did measure it before baking it? Keep increasing the time till you get the desired results. There is no data on baking time. So go slow or risk messing up a spring. This is a great way because the spring rate does not change. It is also a trial and error method. Again, go slow. The toughest part is getting the left and right the same. Just make sure you compress the left and right springs the same and use the same oven time. They should come out the same. If not just cook a tad more on the long spring. The low 450 degree temperature will not alter the heat treatment. Some people use a torch directly on the springs while on the car. This is a BIG NO NO. It also gives the oven method a bad rap. Jumping from 450 degrees to about 1500 degrees or more will mess up the metal grain structure, temper, heat treatment, or whatever you want to call it. The oven method will not change the spring stiffness and there forth no ride change.

The third method is to spend your hard earned money on after market springs. Most after market springs are stiffer. Same or close to a cut stock spring. Increasing the spring stiffness is one of those modifications where the handling increases very little, but the ride takes a big dive. Remember that stiffer springs work similarly to stiffer swaybars. It can change the balance of understeer and oversteer.

I would NOT lower a CV/GM without much better shocks and HD swaybars. Car lean and weak shocks can use up most of the suspension travel leaving you little for the bumps in a turn. You do NOT want to ride your bump stops in a turn! This will kill your car's handling. Some people try stiffer springs to stop bottoming and dragging the car. Offroaders use compression dampening in the shocks as the primary method for bottoming control. This is catching on with street vehicles. Both stiffer springs and stiffer shocks reduce bottoming. But stiffer shocks hurt the ride less. Stiffer springs will kill the ride. For maximum traction, you always use the softest spring you can use. Again, Bilstein shocks do a great job at this and they are matched to the stock springs. Stiffer springs may throw off the rebound setting Bilstein designed. Just don’t know. Here comes the down side again. When you lower a car using the springs, you change the "A" arm geometry. This may hurt the handling more than you helped it. Not often, but it can. Also you are loosing some of your compression travel. Hopefully, better shocks and swaybars will keep this in check. It has on mine and other CV/GM drivers.

There is a forth way to lower your car. Just buy low profile tires with the stock diameter wheels. This will lower your car, gear her down for better out of the hole power, increase braking power, improve the sprung to unsprung ratio, the tire profile is lower, the steering response is better, the control arm geometry is unchanged taking the risk out there, the rotating inertia is reduced, and you will still have full compression travel in the suspension. Wow! For the down side, smaller diameter tires will lower your gas mileage just the same as if you changed your rear end ratio. The same thing happens to the speedometer. And just the same, you can buy a new speedometer gear and/or burn a chip to bring the accuracy back in line. Also anytime you use low profile tires, the rim is closer to the ground. This will degrade curb and pothole damage resistance. Last, the car will be lower when the bump stops are reached.

And you thought we were out of methods. Lol! Here comes #5. Another trick is to replace the frame to body rubber mounts with a stiffer and lower mount. This will hurt the CV/GMs great ride. This method also ties the body and frame together adding rigidity. This helps a lot when it is time to use sway bars and shocks to tune the car's balance. This is rather extreme for most of us. This method keeps your ground clearance and suspension geometry the same. Note: The gas lines pass between the frame and body by the drivers side rear wheel. Check for wiring, engine, transmission, etc... clearance and interference problems first. You could say forget the bushings all together and bolt the two solid. I have noticed that all large trucks lay a piece of wood between the frame and body. I would think this was to keep from rubbing metal on metal. Also welding lumps and such could be imprinted into the wood Vs steel that is not so good at it. Kind of like a gasket making up for irregularities. 95-97 Impala owners have gotten great results in handling by messing with the body to frame bushings. No, CV/GM owners have messed with these mounts to date. This would be new ground to break for us.

If you do lower your car using the springs, expect the alignment to change. You should find more negative camber. That will help cornering and most likely cause uneven tire wear.

The track width also plays an important part of the weight transfer. Making the car wider helps. The only real option is with wheel offset and width. The down side on scrub radius is covered under wheel widths. The only other way is custom control arms and spindles. Can you say $$.

Anything to get weight off the front will help. Remember that the more even the tire weights, the better their performance. More rear weight also helps acceleration off the line and braking potential if you readjust the bias. Moving the battery to the trunk will shift a little under 1% of the weight and lower it and get it out of the heat so it will last longer. Pre 98 cars have aluminum bumpers that may weigh less. We have not compared to know. Exhaust systems have been upgraded to improve power and they tend to be much lighter. Trailer hitches add weight. But, I have things to tow and that adds 40+or- lbs to a bad spot. A mini spare can knock off 15 to 20 lbs. Mustang Cobras use a light weight mini spare that may work on our cars.

Spring and ride height data from Ray Bones. Great work Ray!

From Ray Bones:

The spring rate is different (HPP = 102 lb/in, base air spring is 89 or 75 depending on year). They are a direct plug in for each other, ie no vehicle modifications required. HPP springs have a firmer ride and are harsher. Handling will be a little different.

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Spring rates for the pre-03 non-HPP CV (P73/74) - Front=440 Rear=130

Spring rates for the pre-03 CV PI (P71) - Front=700 Rear=160

Spring rate for the pre-03 HPP - Front=560 Rear=Air 102

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Base air springs EN & FN 1990 -1997 (75 lbs/in) Cream piston and cream cap, HPP air springs all years (102 lbs/in) - black piston and cream cap, Base air springs 1998-present (89 lbs/in) cream piston and black cap.

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Aprox. rear metal to metal travels at curb.

Jounce Rebound
Base = 5.5 3.9
HPP = 5.1 4.3
Police = 6.3 3.1

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Mercury Marauder uses the HPP rear air springs. Front springs are 325 lbs/in (do not compare directly to older cars spring rates due to different motion ratios). Shocks have much more effective damping than the older car you are talking about. Also Mercury Marauders have less suspension travel in order to protect package space for the larger tire/tire package.

Slip angle:

When we turn the wheel we assume the tire contact patch turns with it. However our tires are very flexible with the massive weight they have to support. When we corner, the contact patch is turning a different direction than the wheel. We call this the slip angle. It does not mean we are sliding on the pavement. This is easy to see in a parking lot. With the engine running, stand outside your open window. Apply pressure to the steering wheel till you can see the wheel turn. Then release. The steering wheel and rim will spring back in place. Keep doing this till the tire contact patch slips. If the tire slips, the steering wheel will not return to its original position. This is the maximum slip angle for your car. At least in the parking lot with no weight transfer. Anouther way is to go to a large empty parking lot. Turn the wheel to lock. Now make a slow turn. Keep speeding up and note that the car keeps making larger turns. You have not moved the steering wheel, and the tires are not sliding. Yet the side loads are reducing the effective steering angle making for a bigger turn. Just say slip angle.

Engineers make sure the front lets go first for safety reasons. That also means that the front slip angles are much greater than the rear. When we add Addco swaybars, the slip angles are much more even. We get a slip angle on the front tires by turning the wheels. So how does this work in the rear? The whole car must turn side ways to get a slip angle. When Addco added about 70% more roll stiffness to the rear bar Vs 40% for the front, they induced more slip angle on our rear tires. This does mean you will go threw a turn more sideways. Lets say it was 5 degrees before we upgraded the bars.