Make payments with PayPal - it's fast, free and secure! registry | CVN on Facebook | tech | news | email login Make payments with PayPal - it's fast, free and secure!


Welcome to CVN - Your Panther platform headquarters!


Custom Search


Topic Options
#4102040 - 03/17/21 07:28 PM Alternatives to MMC drive shaft
young831 Offline
n00b

Registered: 01/21/21
Posts: 30
Loc: Santa Cruz County, California,...
So search is failing me. I want to shorten my gears, and I was reading that it's recommended to get an MMC drive shaft because of the higher critical speed and better balance, but it looks like remaining MMC shafts are rarer than hens teeth these days. Is there any alternative aftermarket drive shaft that would have the same or higher critical speed that's more available and priced reasonably?

Thanks
_________________________
2009 P71, 6 years as a NorCal cop car, 5 years as a NorCal cab, and a few months with me.
------
Other vehicles I've driven a while:
2002 Honda Accord Coupe EX-V6
2008 BMW 328i SULEV
2011 Smart Fortwo Pure

Top
Links
#4102046 - 03/17/21 08:19 PM Re: Alternatives to MMC drive shaft [Re: young831]
dixiebandit69 Offline
5.4 Club
Member

Registered: 01/17/12
Posts: 318
Loc: Texas
How low do you want to go with the gears?
How fast are you going to drive the car?
_________________________
2007 Grand Marquis LS: 5.4 swap, 9.9:1 compression ratio, Comp XE268s, NPI pistons, PI heads ported by me, Accufab upper plenum, 75mm DBW throttle body, Factory PI intake with Chinese spacers, CVPI dual exhaust, CVPI torque converter, CVPI air-box and zip tube, J-Mod, 3.55 gears, FMS Trac-Loc differential
17" Dorman CVPI steelies, BFG Comp T/A 255/45 R17s

Top
#4102050 - 03/17/21 08:47 PM Re: Alternatives to MMC drive shaft [Re: young831]
Davidzq Offline
Climber

Registered: 01/19/15
Posts: 519
Loc: Seattle, WA
The aluminum driveshaft your p71 has is fine.
The MMC is a little better though.
2000 p71s received them, so check your local junkyards.
_________________________
David Hensley
Member of Northwest Panthers Car Club

2008 P71, Norsea Blue SAP
-Message Center cluster retrofit
-Towncar Signature L heated power seats
-Long overhead console
-Compustar remote start/security

Top
#4102062 - 03/17/21 09:51 PM Re: Alternatives to MMC drive shaft [Re: dixiebandit69]
young831 Offline
n00b

Registered: 01/21/21
Posts: 30
Loc: Santa Cruz County, California,...
Originally Posted By dixiebandit69
How low do you want to go with the gears?
How fast are you going to drive the car?


I'm thinking 3.55 or 3.73 gears. As for speed, ADTR has this to say for 16" wheels:

CVPI Aluminum Driveshaft 4.10 = 116mph
CVPI Aluminum Driveshaft 3.55 = 132mph
CVPI Aluminum Driveshaft 3.27 = 145mph
CVPI Metal/Matrix Driveshaft 4.10 = 133mph
CVPI Metal/Matrix Driveshaft 3.55 = 154mph
CVPI Metal/Matrix Driveshaft 3.27 = 167mph

I'm guessing the critical speed is going to be lower for the 17" wheels my car has now, or 18" I'm considering going to?

As for top speed, goal is 150mph but I'll probably never use that. I'd like to keep the factory 130mph limit, but I'd feel uncomfortable with a top speed under that, but I could live with 115 or so. There's a chance I run this car at some track events, and I've had to use speed to avoid a road rage problem before.
_________________________
2009 P71, 6 years as a NorCal cop car, 5 years as a NorCal cab, and a few months with me.
------
Other vehicles I've driven a while:
2002 Honda Accord Coupe EX-V6
2008 BMW 328i SULEV
2011 Smart Fortwo Pure

Top
#4102066 - 03/17/21 10:14 PM Re: Alternatives to MMC drive shaft [Re: young831]
ClayBelt Offline

Over the Hill

Registered: 04/03/18
Posts: 1736
Loc: Leon County
Yeah your aluminum driveshaft will be enough
_________________________
There’s a right way, a wrong way, and a janky way to fix something; I don’t usually have the brains or the money to pick the right way.

2001 Chevrolet Tracker LT “Featherbrick” - 6/2016-10/2016 - SOLD
2005 Toyota 4Runner SR5 “Panzer” - 8/2016-4/2018 - SOLD
1966 Ford Thunderbird “Fordy McFordface” - 11/2016-2/2020 - TRADED
2005 Buick LaCrosse CXS “Jumba” - 2/2017-2/2018 - SOLD
2010 Mercury Grand Marquis LS “Touge Sofa” - 4/2018-?
1990 Mazda Miata “Little Boy” - 5/2019-10/2019 - SOLD
1986 Ford Mustang SVO “Touge Fox” - 2/2020-11/2020 - TRADED
1978 MG Midget 1500 - 11/2020-?

Top
#4102088 - 03/18/21 09:23 AM Re: Alternatives to MMC drive shaft [Re: young831]
Davidzq Offline
Climber

Registered: 01/19/15
Posts: 519
Loc: Seattle, WA
Rim size does not effect speed. Tire size is what matters.
235/55)17 are about the same size as 225/60/16. There are many similar sizes for 8s and even 20s.

As far as your speed goals, you're on a long and expensive road. There aren't many panthers that'll teach 150, it's going to take a lot of mods.
P71s with 3.55 are usually limited at 119. But without the limiter, 135 is about all you'll get out of the stock motor.
_________________________
David Hensley
Member of Northwest Panthers Car Club

2008 P71, Norsea Blue SAP
-Message Center cluster retrofit
-Towncar Signature L heated power seats
-Long overhead console
-Compustar remote start/security

Top
#4102240 - 03/20/21 02:04 AM Re: Alternatives to MMC drive shaft [Re: Davidzq]
young831 Offline
n00b

Registered: 01/21/21
Posts: 30
Loc: Santa Cruz County, California,...
Originally Posted By Davidzq
Rim size does not effect speed. Tire size is what matters.

Thanks, that's good info.

Originally Posted By Davidzq
As far as your speed goals, you're on a long and expensive road. There aren't many panthers that'll teach 150, it's going to take a lot of mods.
P71s with 3.55 are usually limited at 119. But without the limiter, 135 is about all you'll get out of the stock motor.

This car I'm probably going to stop modifying at FBO. It's cool to know what kind of speed you can get. I'd be satisfied with keeping the original 130 top speed, I just wouldn't want to have it be below like 115 or 120.
_________________________
2009 P71, 6 years as a NorCal cop car, 5 years as a NorCal cab, and a few months with me.
------
Other vehicles I've driven a while:
2002 Honda Accord Coupe EX-V6
2008 BMW 328i SULEV
2011 Smart Fortwo Pure

Top
#4108312 - 05/09/21 01:21 PM Re: Alternatives to MMC drive shaft [Re: young831]
hkerekes Offline
Member

Registered: 09/19/20
Posts: 102
Loc: NC
i have 3.27 in our road race crown vic with a oem 1996 steel drive shaft. We have been 115-120 ish and have had no issues so far. The speedo was buried at 120 but i know it reads high.

Top
#4110560 - 05/26/21 12:19 PM Re: Alternatives to MMC drive shaft [Re: young831]
hkerekes Offline
Member

Registered: 09/19/20
Posts: 102
Loc: NC
Well i was wrong, we had the steel driveshaft vibration beat two brand new seals to death. Now we have a leaking tailshaft and differential.

3.27 gears and 100+ mph in the heat is where it would happen.

Top
#4110894 - 05/28/21 08:33 PM Re: Alternatives to MMC drive shaft [Re: hkerekes]
dixiebandit69 Offline
5.4 Club
Member

Registered: 01/17/12
Posts: 318
Loc: Texas
Originally Posted By hkerekes
Well i was wrong, we had the steel driveshaft vibration beat two brand new seals to death. Now we have a leaking tailshaft and differential.

3.27 gears and 100+ mph in the heat is where it would happen.


Did you change the output shaft bushing?
_________________________
2007 Grand Marquis LS: 5.4 swap, 9.9:1 compression ratio, Comp XE268s, NPI pistons, PI heads ported by me, Accufab upper plenum, 75mm DBW throttle body, Factory PI intake with Chinese spacers, CVPI dual exhaust, CVPI torque converter, CVPI air-box and zip tube, J-Mod, 3.55 gears, FMS Trac-Loc differential
17" Dorman CVPI steelies, BFG Comp T/A 255/45 R17s

Top
#4110930 - 05/28/21 11:16 PM Re: Alternatives to MMC drive shaft [Re: dixiebandit69]
hkerekes Offline
Member

Registered: 09/19/20
Posts: 102
Loc: NC
Originally Posted By dixiebandit69
Originally Posted By hkerekes
Well i was wrong, we had the steel driveshaft vibration beat two brand new seals to death. Now we have a leaking tailshaft and differential.

3.27 gears and 100+ mph in the heat is where it would happen.


Did you change the output shaft bushing?


Every bushing, bearing, and seal in the entire driveline had less than 20 hours on it. It definetly was the steel driveshaft vibrating, granted we were hitting 125 mph so im not too mad. The trans seal is a joke to change and im going with a long boot but the differential seal isnt so easy.

I am looking for a 3.45 8.8 gearset to swap in and cant seem to find one. 3.55 only gets us 132mph at 6200 and we are not far from that at all. 3.45 gets us 136 which is probably safe.


Edited by hkerekes (05/28/21 11:17 PM)

Top

Who's Online
6 registered (Old_Guy_Stu, ClaySmith, bluejay_32, Hoov, GoldPanther, 1 invisible), 52 Guests and 94 Spiders online.
Key: Admin, Global Mod, Mod
Shout Box

Top Posters (30 Days)
bluejay_32 108
Old_Guy_Stu 92
Dmblanch 76
a_d_a_m 52
RF_Overlord 47
GM_Guy 44
Moby_Vic 38
SocalSam 35
Tenevic_P71 31
Ponyguy 31
Member Spotlight
Member Since: 11/13/19
Posts: 377





Copyright 2000-2015 by Crownvic.net and Steve Spaulding. All Rights Reserved.
The photographs, graphics and data contained in this Web site are the properties of the contributors, or Crownvic.net and may not be used without expressed written consent.
Crownvic.net is not affiliated with the Ford motor company.

Happily consuming the fuel saved by Prius owners!