IRS to Solid Axle Conversion - TCCoA Forums
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post #1 of 7 (permalink) Old 06-29-2004, 08:20 AM Thread Starter
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IRS to Solid Axle Conversion

Has anyone done or know anyone whom has done an IRS to solid axel conversion on and MN12?
Foe those who many think the 01+ Cobra conversion kit will work on our cars, it will not come close to even remotely fitting.
I have talked with GKN and to get a set of axles for my IRS build up and to get a set of axles that will hold up to what ever you throw at them for as many runs as you could ever want to go will be in the neighborhood of $3600!!!!! Even then, the guys from GKN said that it is not 100% they will hold up.
I have an appointment with a race shop to get my car looked at and see what it would take to have the IRS ripped out and the Solid axel put in. I know that I am going to need a new fuel cell, since the fuel cell that comes on our cars encases the drive shaft.
The guy doing the work for me and does custom work like this all the time and comparative to other cars I have seen him do, this will be nothing for him.
I just wanted to know if any one has done this before and if any one had any tips

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post #2 of 7 (permalink) Old 06-29-2004, 08:36 AM
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Here's my take on this: If you're going to build a drag car, spend the money on a "drag car". Starting with an MN-12 and then spending the money, time, and effort to do that type of conversion is IMHO wasted on a boat the size of a T'Bird. And you're going to have something that hasn't been done so it might not work. Are you willing to drop the coin on something that might not hold up or transfer weight properly?

Again, I don't want to start an argument, buy you're talking about an awful lot of fabrication work on a car that you can't even buy subframe connectors for anymore.

And are you realistically going to put enough power through the rear end to break a set of Raxle's half shafts?

I've learned (the hard way) over the years to sit down and take a realistic look at the expectations vs. finances... It can be an eye opening experience.

But go for it and post pictures.

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post #3 of 7 (permalink) Old 06-29-2004, 11:16 AM
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I have looked into tubbing the Cougar, and I believe the cost would be very similar to just have it changed to solid axle. I was quoted $2500 just to build the steel subframe in the rear. The you have to price your rear-end, 4 link bars, and everything. I'd agree it would only be worth it if you were going to make a full drag-car, gut, tub, and tube chassis. There are plenty of people putting a lot of HP through the IRS. Make sure you get a guarantee that the chassis will pass NHRA tech to a certain time before you get started, that's the only way you are going to know you get a quality job. The guy who's building my chassis for my drag car has the inspector come look at the chassis after every step to insure that he won't have to redo it, and that It'll tech to 7.50's in the quarter. If a builder is not willing to include NHRA certification in his price, then he's not the one to be working on my car, I've seen too many cheap backhalf jobs break exactly that, the backhalf. Either that, or the first time they get to the track, the car is so uncontrollable, because the suspension geometry isn't right, that they have to almost start over again.
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post #4 of 7 (permalink) Old 06-29-2004, 07:32 PM
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I have no idea what your power or 1/4 mile goals are, but the fastest street legal MN12 on this site uses the factory IRS an has gone 11.10 @ 123.88 mph on it.

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post #5 of 7 (permalink) Old 06-29-2004, 09:35 PM
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Coy Miller also uses the factory IRS, and runs right around where EECDOC does. I'm sure EECDOC is going to pass his 11.05 real soon though.
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post #6 of 7 (permalink) Old 07-13-2004, 10:47 AM
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I was poking around some forums and saw this thread:

Its for a an '03 Cobra but says their all customized, maybe give them a call if anyone is interested.
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post #7 of 7 (permalink) Old 07-13-2004, 11:13 AM
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The problem with that is that all Mustangs, Cobras, GTs and V6's all start out with the same unibody. That means the brackets are on all the cars, so it's as easy as bolting a solid axle in a Cobra. The MN12/FN10 series never had a solid axle in any car, so there is no such monster on our cars, it would have to be a total custom job.
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