Detroit area live axle ponderers

[postban]

I talked to Greg at Detroit Speedworks last night while I was dropping off my car for clutch replacement.

They will do a live axle/exhaust/driveshaft swap for $250 per car as long as it is "whole units". Meaning catback for catback and axle for IRS, no fancy stuff or disassembly. That is with you supplying all parts or having the donor car driven there.

This post is purely for discussion, not recommending anything, just relaying information.

There several unsavory factors that he mentioned;
1)According to him the driveshafts do need to be switched. Out with the aluminum one, in with the steel GT one. Or buy a new FRPP aluminum one?

2)Also it is a $major$ pain to keep the Cobra brakes calipers. Swapping them is not included in the $250.

3)You need a new catback (up and over type)

4)I forgot to ask if the gears were the same. Don't want a 3.27 rear gear after the swap, neither does my GT friend want my 3.55's. Are they switchable from 8.8 to IRS? I know it is easy but trying to keep this as cheap as possible.

Only thing I am sure of is the catback. The rest I need to investigate.

Also, Bushings, shocks, drag radials, stiffer springs are all a total waste, nothing stops the hop except rolling out slow and then slowly applying power (IRS= I Race Slow):fm:

 

[MidLifeC]

Here's another question to ponder: Do you need 31 spline axles with the power you need?

If you you have to switch gears, would you consider a different ratio? 3.7, 3.9, or even 4.1?

Good luck with the swap.

 

[Snakebite]

Hmmmmmmmmmm...:dw: ...all this info to digest.

How about another thought...Would it be better to install higher performace half shafts, input shaft, and anti hop bushings / suspension upgrades on our current set up?

Cost, driveability, performace, and re-sale value are all factors to consider with a project like this.

There is no doubt that a live axle set up is "best" for drag racing applications...but at what cost?

 

[postban]

Originally posted by MidLifeC
Here's another question to ponder: Do you need 31 spline axles with the power you need?

If you you have to switch gears, would you consider a different ratio? 3.7, 3.9, or even 4.1?

Good luck with the swap.

Have had several guys state the a standard 220RWHP GT live axle will live behind my 440ish RWHP setup. They say blown GT's with standard rears can see mid 11's. They caution that repeated trips down the 1/4 with hard launches on slicks will shorten it's life though. I would only use DR's

You can upgrade to Moser or Strange 31 spline setup for $525-600 for the axles/pinion flange.

I don't want to change gears. 3.55 seems right. I like 2200rpm at 80. Drag racing is another story, having to hit 4th 100 ft from the timing lights is a drag. I guess if I could go 3.73 and have the speedo corrected it would be something to try.

 

[postban]

Originally posted by Snakebite
Hmmmmmmmmmm...:dw: ...all this info to digest.

How about another thought...Would it be better to install higher performace half shafts, input shaft, and anti hop bushings / suspension upgrades on our current set up?

Cost, driveability, performace, and re-sale value are all factors to consider with a project like this.

There is no doubt that a live axle set up is "best" for drag racing applications...but at what cost?

Bushings had only minimal effect, they let you out of the hop sooner if you ease off. If you stay in it, you hop like they were stock. DANA is a live axle swapper and he made some very interesting comments.

Originally posted by Dana
I think I remember that thread, but can't seem to find it now.
The problem is that the entire IRS setup in the Cobra's is weak, relatively speaking, from the axle flanges to the differential.
The half shafts are breaking everywhere. Replacing them with heavier, stronger ones is not the answer. Neither is putting bigger stubs on the ends of the half shaft because they are still using the the aluminum carrier. The side gears and housing would have to be changed to allow bigger stubs in the differential. And you still have the cast aluminum housings and covers which are also breaking under the current level of stress.
The only way that this would ever work is to design an entirely new IRS setup. One that would fit into the Mustang, but still be strong enough to handle 800 HP or so.
I would love to see it happen, but I don't think it would be economically feasible for anyone but the manufacturer to do it.
Dana

from this thread------------->straight axle swap?

I believe JB talked to him in Bowling Green for a bit.

Some guys claim lowering/different springs is the answer. Some guys claim 18" wheels help.

Take a look at this thread too, http://www.modularfords.com/forums/showthread.php?threadid=5545

All I know is I cannot use the car in a seeemingly normal (agressive) way from the line. Furthermore my problem is most solutions being offered are by coupe guys, very few vert owners have fixed the IRS issue.

 

[MidLifeC]

What about this?

http://cart.kennybrown.com/ProductCart/pc/viewPrd.asp?idcategory=136&idproduct=428

IRS Cobra Forward Torque Brace
SKU: KBP-29600
Heavy Duty Performance Upgrade for '03 Cobra

 

[postban]

Originally posted by MidLifeC
What about this?

http://cart.kennybrown.com/ProductCart/pc/viewPrd.asp?idcategory=136&idproduct=428

IRS Cobra Forward Torque Brace
SKU: KBP-29600
Heavy Duty Performance Upgrade for '03 Cobra

Possibility.....

We need a guinea pig or put the link in the Terminator forum. Still have fragile halfshafts and housings tho....

$149 for that brace plus $800 for upgraded halfshafts is doable if it does what it promises.

 

[postban]

http://www.svtperformance.com/forums/showthread.php?postid=675054#post675054

 

[postban]

Got a little more info to ponder. Heavier springs are not the answer either. Going from my 470 rates to coupe 600 rates would delay the start of hop momentarily but also make the force of the the hop more severe. I am surmizing that is why more coupes are going through halfshafts than verts.

I am going to get the differential bushings and see if that makes a diference, possibly investigate further the MM IRS brace.

Also was told that the action of the hop is side to side. Both wheels do not come up at the same time. It is sort of left-right-left-right alternating grip and slip. If you can slow or abate the start of that oscillation (diferential bushings/brace) you get in at the where the hop starts. The differential bushings are at the front of the hop system, whereas the IRS bushings are at the end of the hop cycle.

Damn I hope my swag is on............:idea:

 

[MidLifeC]

Another source of good info:
http://www.svtperformance.com/forums/showthread.php?s=&threadid=40845&highlight=irs+brace