LilRoush

Don't need to. Most understand it already.
If the IRS is the end all of rears, the question needs to be asked:

Why to the Cobra guys swap them out so often? Hum...

As for the weight issue. My car is 54/46 right now with a SRA. If I go 5 link, it will be just as close to 50/50 as you would be with an IRS... so that's not a point to compare.

And TJ, when you compared cost I love that you post the DEAL for the IRS (if you look around) and then average or off the shelf prices for SRA parts. A bit one sided at all?

sn95_331_GT_ yellow

see plenty of IRS's for around $4-500 up here, so its not really a deal...

and the Cobra guys swap out the IRS when they go DRAG racing, so do all the import guys, hell my buddies RX7 has an 8.8" in it, an idiot could figure out that solid rear > halfshafts for 6000rpm launches...

Bpohlman13

Half of the people say that the sla will cost more and half will say that the IRS will cost more to run in high hp cars. They really cost the same amount. FOr the SLA, you need better control carms and a built rear end. On an IRS you need better bushings. If you want to do really well with both in the straight, you also need better tires. The only reason cobras change to SLA, is because they are making a hardcore drag racer that they usually trailer to the track anyway. Most of the time, you can find someone willing to do a straight up trade. So the initial cost is the same.

A few weeks ago I saw a ~700rwhp 04 cobra with the IRS still in it. All it had was a rear brace and was running low 7s in the 1/8th mile. Just saying.

If he wants a comfortable ride and something he can take to an autocross track one day and a dragstrip to the next, the irs can do it well for the hp he has and hp he is planning on having in the future.

LilRoush

That first part is exactly my point. He posts buying used IRS parts (far cheaper than going to Ford and ording a new OEM IRS), but then posts the new full list price for SRA upgrades, when all it takes is a little forum searching and you get slightly used parts at half price.

I've seen just as many SRA Mustangs doing well at open track events as IRS. If the IRS is as great as some seem to THINK it is, there would be more IRS open tack Mustangs. My experience stays the same: well built SRA > modified IRS on the track (not strip).

Harryman2002

That's not the whole point. Fully built SRA vs fully built IRS are pretty much equal on the track but the IRS rides much better on the road so for someone who drives their car on the street and track the IRS is more practical.

stangalator

I just got done with my IRS swap, full tilt boogie bushings, OEM cobra bilsteins, eibach springs and a bf brace. Handles like nothing else even with 315mm sumis. Launches are better then my stock SRA too. Sometimes people forget that with the ~75 extra pounds the IRS brings you loss ~75 pounds of unsprung weight which I would trade any day of the week!

Do the swap, the IRS is better for every aspect of driving other then pure drag racing period.

crash

do it! It makes driving the car soo much better. You rarely go to the track anyways. You can build a car for turns and still do decent at the strip, but it doesn't work the other way around. If you're patient then a steal can be had.

LilRoush

So you've ridden in both to compare?

Harryman2002

Uh not fully built of both but my car has had an IRS and SRA and Im sorry but something that is essentially a stick with a wheel on each end is not going to embarrass a more sophisticated suspension set up. Plus soldier isn't looking to make his car an all out race car so he would be better off with a better ride quality and improved handling instead of just improved handling.

LilRoush

Calling a 5 link a "stick with a wheel on each end" is like calling the IRS a stick with a wheel on each end that is broken in the middle.