Possible to Build 8.8 IRS Safe for 1400hp?

[1siksl]

Hello everyone I know technology is always changing and companies are always creating new products. I've done a little bit of searching but alot of the answers are years old...

I have a Cobra 8.8" IRS that i've had probably for 8 years now from a previous car build. Currently I am building a Turbo Street Car that is planned to produce about 1350hp to the wheels. Would anyone know is it possible to build the 8.8" IRS up to 1400hp and if so could you recommend the company for the parts? Thank you very much for helping me save time and figure this out!

 

[zredfire04]

you'll likely have to buy high end half shafts. the driveshaft shop or gforce are the likely vendors for those. you'll benefit from getting rid of the rubber bushings in the suspension as well. most people will point you to full tilt boogie for their bushings, but maximum motorsports has some and there is always polyurethane if you want to go that route. you'll also need the reinforced diff cover.

i doubt it needs to be said, but i'm putting it here anyway...if you dead hook with that power, something is going to break. i don't think there's such a thing as a bulletproof irs at that power level.

 

[roy_1031]

Nothing's ever safe with these cars. Especially the wallet.

 

[CobraBob]

I know you said that this will be a "street" car, but at 1350rwhp how much street time is it really going to see. If it's minimal, and if you plan to spend a good deal of time at the track, why not just go with a solid rear setup?

 

[tt335ci03cobra]

•strengthen the unit by eliminating deflection
•delrin. Aluminum. Done. At that power level, you cannot compromise for poly. Poly is great for a daily driven street car making 500-700whp. Delrin and aluminum will perform better at those power levels but be louder/ride more tightly.
•Detroit trutrac
•ford racing diff cover
•level 5 s2's. Or plan on replacing stock units often enough. $250 vs $1500. The axle shafts will break if there is deflection and force. You can have unubtanium shafts and still snap em like a toothpick if it's hobbling in a loose area.
•luck. You'll need lots of luck.
•tires: slicks. Wrinkle walls. Deflection in the sidewall is great. If the tire absorbs the twisting force, and the irs is tight and locked in place, you won't break pieces often.

 

[2DXTRM]

•strengthen the unit by eliminating deflection
•delrin. Aluminum. Done. At that power level, you cannot compromise for poly. Poly is great for a daily driven street car making 500-700whp. Delrin and aluminum will perform better at those power levels but be louder/ride more tightly.
•Detroit trutrac
•ford racing diff cover
•level 5 s2's. Or plan on replacing stock units often enough. $250 vs $1500. The axle shafts will break if there is deflection and force. You can have unubtanium shafts and still snap em like a toothpick if it's hobbling in a loose area.
•luck. You'll need lots of luck.
•tires: slicks. Wrinkle walls. Deflection in the sidewall is great. If the tire absorbs the twisting force, and the irs is tight and locked in place, you won't break pieces often.

exactly what was said above!

 

[keith89]

an even better option would be to just do delrin control arm and differential mounts. Ditch the IRS MOUNTS and fabricate mounts to bolt directly to the chassis. It's been done for road racing with excellent results. I would love to do this but it's beyond my fabrication skills at the moment. It requires measuring and properly welding mounts that bolt directly to the frame in place of the stock provisions to eliminate the bushed mounts. Of course NVH will go up but it's one less area for flex.

 

[Nightmare302]

There is ZERO reason to build a "1350rwhp" mustang and put an IRS behind it. It will never break because it will never hook. At that power level a truetrac won't hold either. You need to be looking at 9 inch rears with spools. You are borderline at the level of needing pro gears. "Street" and 1350 rwhp don't match. Be realistic with the build and goals.

 

[keith89]

There is ZERO reason to build a "1350rwhp" mustang and put an IRS behind it. It will never break because it will never hook. At that power level a truetrac won't hold either. You need to be looking at 9 inch rears with spools. You are borderline at the level of needing pro gears. "Street" and 1350 rwhp don't match. Be realistic with the build and goals.

I agree. I just figured I'd throw in my 2 cents for theory sake.

 

[lucheski]

Lookup Mr95gst - Nicholas Shortridge

He is over 1450rwhp running a Built T56/RAM Twin Disk/ Built IRS/DSS LVL5's

IMO you can't keep the stock IRS Half-shafts at higher power levels because of the 28 splined outer hubs. I'm only at 800rwhp and I twisted the splines on the outer hubs which are only 28 Splines. The DSS or Gforce Axles have 31 spline outer hub which is needed IMO at the higher power levels.