I prefer the IRS, but I also have love for the straight axle. I think of it like this if you car come factory with a straight axle or you really into DR'ing then stick with or go to a straight axle. Then get rid of that 4 link crap by add a Torque Arm with either a Panhard Bar or Watts Link and dropping the upper control arms. I personally think the IRS when built right is the better choice for a badarse streetcar though. You can run much higher spring rates without diminisioning the ride quality and not all roads are smooth.
Am I Crazy?
- Thread starter BlownAway03
- Start date
This is what is great about these cars. You can do whatever you like to your car and it will perform well weather it be Drag/street/open track/AutoX. Different strokes for different folks. The Solid rear is alot cheaper and stronger. With that being said I'll keep my IRS and Mod it until its strong enough for what i need. If i wanted to cut low 60' like Jake and dip my term into almost 9's i would get a SRA too.
lol at the people who STILL think the IRS is better than a SRA at road racing.
I don't RR, but on the streets the IRS is most defanently better handling than a SRA. Sure a SRA can be made to handle great, but the properties of a IRS are better for most everything other than DR'ing. IRS = less brake dive, more suspension travel, much stiffer spring rates, a lot less unsprung weight, and when one wheel is effected by something the other wheel doesn't have to move with it. I can apply alot more power exiting a turn with my IRS than I've ever been able to do in a SRA Mustang. Griggs and most other suspension companies use SRA's because thats what 99% Mustangs were/are sold with so thats what they've spent their time and money developing even before the IRS Cobra came out. They also race them on ideal tracks.
lol at people who act like the charactoristics of a SRA are better than a IRS for handling. Also lol at the people who claim the IRS's geometry is way off, but then act like the SRA's geometry is so right on a Mustang built on a Foxbody based platform Mustang.
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I lol at lol.....:lol:
thats where your wrong. As i said above, the perfect example of proof the SRA is better than the Mustang IRS, is the Griggs Racing Gr40, its actually for sale on ebay for 45K which isnt bad considering it can out handle porsches. :beer:
^ Sorry guy but I've owned both with modded suspensions and have had plenty of friends with SRA Mustangs and its defanently IRS > SRA on the street. The IRS is much more predictable and forgiving and doesn't have the quick, surprising oversteer that 4link Mustangs have. A Griggs GR40 suspension car cost about 13 or 14K in parts so it better handle good which it does. I gareentee you that if the full Mustang lineup was released with the IRS back in 1979 and the 99 Cobra got a SRA that the IRS would have the aftermarket rear suspension on lock and people would be talking about how much of a turd the SRA was compared to the IRS except at DR. Like I said Griggs, Steeda, MM, Agent47, etc are going to push what their R&D has spend time and money to develop. There are several examples of IRS car that seem to handle high end exotics pretty well also. Look at Bruces 2000 Cobra R for example.
Again don't get me wrong, I understand that a SRA car can handle great, and if I get another Foxbody based car with a SRA it will keep it and probably get the MM torque arm and panhard bar treatment, but still I say IRS > SRA for handling on the streets.
Again don't get me wrong, I understand that a SRA car can handle great, and if I get another Foxbody based car with a SRA it will keep it and probably get the MM torque arm and panhard bar treatment, but still I say IRS > SRA for handling on the streets.
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Have you ever had a conversation with bruce griggs about the irs. The man has a one track mind, if it's not his suspension he doesn't want to discuss it. Asked him about the lightning and he didn't want to say what worked and what didn't work just that a tq arm and panhard bar was the best. He never tested an irs so how could you it's better.
Isn't that a oxymoron, rides nice and racecar:shrug:
Just cause it can out handle some porsches doesn't mean it's proof. My corolla can out handle some bmw's with less experienced drivers ..... so it must be better ..... i don't think so. So how much faster is an sra then a irs .... a few tenths???
My thoughts
Ride quality and cornering ability are definitely more refined in the cobra compared to my old gt, but my favorite part of the IRS is watching people who know everything* about cars, look underneath and tell me that Mustang never came with IRS stock. Worth to prove gear heads wrong from time to time.
Ride quality and cornering ability are definitely more refined in the cobra compared to my old gt, but my favorite part of the IRS is watching people who know everything* about cars, look underneath and tell me that Mustang never came with IRS stock. Worth to prove gear heads wrong from time to time.
yikes! I hope those people dont consider themselves "car people" :lol:
Dave Royce driving a MM IRS disagrees with you. See post #64 here:
http://www.svtperformance.com/forums/open-track-racing-203/544615-cobra-irs-vs-solid-axle-3.html
FWIW
:thumbsup::coolman::beer:
It's nice to see a quantitative review of the two side by side by an experienced unbiased driver. His opinion towards the two is exactly how I feel towards them: they both have their strengths and weaknesses but clearly the IRS is a better choice for all situations.
There are way too many people on these forums that preach the solid axle endlessly that are not qualified to make an accurate assessment of either. I think people that really hate on the IRS are people that had it completely stock, which obviously everyone agrees is far from perfect. My IRS is fully built and I absolutely love it! I've never experienced wheel hop in my car and some people refer to this heavily as a fatal problem with the IRS.
Like I've said before, the IRS is clearly superior technology and I will never get rid of mine.
My reason for wanting to switch to a SRA is because its cheaper to beef the SRA up than it is to beef the IRS up.
I've probably got about $750 or so invested in parts to beef up my IRS. They include Bruces complete IRS bushing kit, MM rear tie rods, and a Billetflow IRS brace. DSS halfshafts aren't unneccessary. Infact if someone were to give me some lv5's I would not run them and would sell them.
Swapping over to just a regular Mustang GT's rear axle will probably cost you atleast that much, when you factory in exhaust, control arms, the rearend itself, etc, etc, much less converting it to an expensive, beefed up SRA.
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Well a very rough mental calculation, I was considering:
IRS:
lvl 5 - 1500
bushings - 600
brace - 200
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thats about 2300 bucks
SRA:
rear end - free if trade
axles - 250
control arms - 300
bracing - can do myself
_________________
650
I would love to keep the IRS, and I'm probably uneducated about it, but I have been reading various threads and most people are just biased towards one side for one reason mainly autox - irs, drag - sra type of thing.
I herd/believe the level 5 halfshafts aren't going to stand up to any torque like a SRA axle would. I realize right now with my mods (not many) I don't even need to beef up the IRS much as it is, but I like to plan for the worst and the last thing I want is to snap a half shaft and have to get the car towed home. With a SRA it sounds much safer.
I have considered using street tires though so it will break traction before the torque shears the shaft in two, would that work out?
Is there anyone who has a 700+ rwhp mustang that can launch on the IRS without snapping it like a twig that hasn't dropped many thousands of dollars into beefing it up?
Oh another consideration is I have the 99-01 IRS which is much less beefy than the 03/04 one is also.
I'm really interested in learning more about this though, above wasn't explaining why your "wrong" more like why I believe the SRA is the best choice for me.
Also, I'd like to add that keeping the IRS from snapping is more important than a faster 60' time. Thats why I suggested street tires which have less traction would slip before the half shaft breaks.
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L-5's are a waste of money for 90% of the people buying them.
Your $2,300 IRS mod just went to $800. :read:
You'll retain a true Cobra as opposed to a cross bred Cobra/GT.
FWIW
so your saying an upgraded IRS will handle all the power you throw at it from a dead hook automatic transmission?
i am in this predicament now, as i have a whipple, auto and want to keep my IRS, as i drive my car a lot on the street, but am worried that if i go from digs, or take it to the track i will surely break something in the IRS.
i have also been told/read you can make a solid handle every bit as well, with the right suspension mods.
i am in this predicament now, as i have a whipple, auto and want to keep my IRS, as i drive my car a lot on the street, but am worried that if i go from digs, or take it to the track i will surely break something in the IRS.
i have also been told/read you can make a solid handle every bit as well, with the right suspension mods.
everything breaks....but I mean guys run in the 7s and 8s with solid axles. the irs will take it for a while imo but mid 9s to low 10s seems to be where all the level 5 breakages have occured.
The IRS has limits, just as a stick has limits. By going with an automatic, you'll most likely be able to run somewhere in the 700 RWHP range and be ok. With a manual trans, 600-650 RWHP+, launching at 5k is what kills the IRS.
750 RWHP, launching at 5k will kill an 8.8 SRA. You're looking at 9" territory then.
FWIW
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