IRS to SRA....the whole shabang

rotor_powerd

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This is a rather vague statement and I was wondering if you could elaborate on exactly how the chassis engineers at Ford botched the IRS installation in the Mustang? Sounds like you have some insights on this topic some of us are unaware of.

The rear end is a bunch of stuff out of the parts bin, with a "We got to make this fit" subframe around the whole assembly holding it in the car. Nothing about the rear end is "engineered," it was made to put in the car to say it had independent rear. It doesn't take a rocket scientist to look at the ghetto ass IRS in the car to come to that conclusion.

If they wanted to do it the right way, the Cobra unibody would not be identical to a V6 Mustang unibody. But hey, if you're happy with a rigged IRS vs. no IRS, more power to you. Fact is, the SRA will always work better in this chassis because it's what was engineered for this chassis.
 

CPViolation

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I don't see a diff cover brace.
Wheel hop is the destroyer of IRS and half-axles.

If you install Derlin bushings, sub frame connectors and a cover brace it should take care of the wheel hop. The brace has nothing to do with wheel hop, it's just good insurance from pumpkins like yours.
Never upgraded to level 5 half-shafts either... A waste of $1,000.00
Jeff
 
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03cobrarocks

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dont most people like steeda and maximum motorports use sra in their auto cross cars anyways... Due to the weight savings and if you just do the right suspension its just as good?
 

CPViolation

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dont most people like steeda and maximum motorports use sra in their auto cross cars anyways... Due to the weight savings and if you just do the right suspension its just as good?

All I can say is, any car worth its weight has independent rear suspension.

SLA=Weight savings, easy to set-up.
IRS Great ride, expensive to get it right, all around better unless you drive in a straight line.
Griggs is a major pimp for SRA... Keep the cash flowing.

Jeff
 
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rotor_powerd

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IRS is great, yes.

The IRS that was rigged into these cars, not so much.

You are the reason why it's in the car. "Any car worth it's weight has IRS." That's Ford's motivation to have IRS in the car, because it's perceived as "more advanced" or "better." It's a real shame, because it could've worked out great for them if they hadn't cut so many corners with it.
 

CPViolation

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IRS is great, yes.

The IRS that was rigged into these cars, not so much.

You are the reason why it's in the car. "Any car worth it's weight has IRS." That's Ford's motivation to have IRS in the car, because it's perceived as "more advanced" or "better." It's a real shame, because it could've worked out great for them if they hadn't cut so many corners with it.

Do you really believe that?
IRS is not a buzz word
I've owned a '96 Cobra and the '04.
There is no comparison stock for stock.

Ford did ok with the IRS but like you said lacks. A few bucks it becomes magic.
The '96 had awful bumpsteer, the SRA felt like t was travailing across state lines.
I bought both cars brand new.
Jeff
 
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rotor_powerd

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Take the cost of an IRS diff brace and give the SRA control arms that aren't made of wet noodles. No more side to side slop. Problem solved.
 

mu22stang

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Roto, your opinion of the IRS seems to have transformed as of late. Since you dropped in the SRA, you've been brainwashed!!!

To be honest though, both systems from the factory have and are compromises. In fact, the SN95 chassis in general is one huge compromise. Cost, NVH, cool factor, and performance all played their part in how the two suspension geometries were implemented in their time. Also, we can't forget both systems weren't designed for race cars; they were designed for street cars. As soon as you at an ounce of power, all bets are off.

BUT, the stock '03/'04 IRS is by far the best SN95 rearend from the factory.
 

Black Sex

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Ford should have taken a page out of GM's book and took a look at the Corvette IRS. That seems to be a good quality IRS. They ahve been using it for how many years now? I dont hear of too many people having problems with those, and the axles are alot better. JMO
 

rotor_powerd

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Ford didn't need some funky leafspring IRS like the 'Vette, they just needed to not half ass the one in the Cobra. Look at Supras, RX7's, 240's, etc. etc. from 15 years ago..... all have great IRS's. It's not like the technology wasn't around, Ford just didn't put in the time, money, research, etc. into doing it right.
 

geoffw

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If you drag race, definately go SRA
If you road race or autox, sell your cobra and buy a vette.

Im a good problem solver ;)
 

yellowgt02

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I love the IRS. It handles way better than my 02 GT with a SRA does. My only mods to the IRS so far are Diff Brace and H&R Race, and good tires to keep the hop away.

The car handles awesome when I want to take some hard corners, and I can hook it up at the track on ET Streets, and cut low 1.6x 60fts on Stock Half Shafts.

I eventually plan on doing Bruce's kit, as it seems to be the one to go with for bushings.
 

rotor_powerd

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This is only good advice for people that live their lives 1,320' at a time! ;-)

That's funny, I've seen F150's clean up at autocrosses against Vette's, P cars, etc. etc. etc. before. SRA and leaf springs..... oh man, I'm surprised that thing could even make a turn without falling apart!
 

ac427cobra

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That's funny, I've seen F150's clean up at autocrosses against Vette's, P cars, etc. etc. etc. before. SRA and leaf springs..... oh man, I'm surprised that thing could even make a turn without falling apart!


Let me guess, that's a 4,700# Lightning cleaning up on those 3,300# Vettes in the autocrosses!!! ;-)
 

mu22stang

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Some of you are getting a bit out of hand here. If you've never driven the IRS to its limit, your opinion doesn't matter...at all. How much do you actually know about engineering a suspension? How many of you actually were a part of the design process, in the meetings, on CAD machines, running calculations, etc. for the suspension on ANY vehicle? Get a grip.

The blind gospel of the SRA continues, but I'm not surprised by how many jump on the band wagon. Compare the number of SRA Mustangs to IRS Mustangs from the factory and you see the reasoning behind the huge aftermarket and overall complacency with upgrading the SRA. I, for one, have driven both and love the communication I get from this supposedly crappy IRS. If you are willing to open your eyes, read this (post #64) and tell me how poor the IRS performs in comparison to a fully built SRA on a real track.
 

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