quick96z28

If i were to be putting out about 400RWHP, how well would the IRS hold up?? I am talking about drag racing it with probably nothing no more stickier that nitto drag radials and stock gears.

thanks guys

trav

WillieD

It is recommended to get a harrop diff cover to strengthen it up at that point. The real weak point is the driveshaft followed up by the half shafts. The only replacements I have seen is from BMR and they are very pricey$$$

Solobarictahoe

Well just look a bmr low 10s on the irs but with there driveshafts and hlf shafts you can get the gto rippin

BADBIRD2000

Actually, BMR just recently had to swap in a 9" conversion in place of the IRS, but they are laying down some serious hp with nitrous.

Jake99SS

There is a company that makes a 9" conversion so you can keep the IRS.

BADBIRD2000

Actually, i think THAT'S what BMR got. They had to get it from the Aussies.. took awhile to get it. I haven't been to their shop since they got it put in...Can't wait until they go back to the track...

quick96z28

what do you guys thing the horsepower and 1/4 mile limit is for the stock IRS?? I ask because in my area, the GTO's are as low as $24,000!! My girlfriend has always thought they were cool, but the prices have always been out of reach. Now they are finally down to where they should have been. My camaro runs a 12.9 @112, and wants to get her GTO to atleast match me. Will the IRS hold up to some 12.7's on nitto drags?? I dont want to have her spend all she has on this car, we mod it a little then we turn her rear end to dust and she ends up shelling out more money that she doesnt have. Thanks for the input guys!

trav

GTPprix

I dont see what not 12.7 is really nothing, even for these rear ends hehe.. Lower than that is anyones guess..

CSiJason

Their are a few people over at LS1GTO.com running low-mid 12's on the stock drivetrain. Also, an automatic is softer on the drivetrain than a manual. Assuming you get an auto (which will be slightly slower to begin with but easily 'fixed' with a little higher stall converter and LS1Edit) it might be pretty fast while being streetable and 'girl driveable' still.

FlyinGTP

iTrader: (1)

Well the diff in a gto is a dana 44 and the c4 guys had a similar unit that held up to a ton of power some even in the 10's. There are also a lot of of aussies putting down some serious power in monaro's and commodores with stock irs. Difftechnic's is an aussie company that makes all sorts of parts for the gto/monaro setup. There the ones who have the 9inch irs conversion kit along with upgraded halfshafts. So far i've seen 1.7 60ft's on MT ET street drag radials and my irs is still functioning other then haveing some axle bolt loosening issues. I have a totally stock a4 too, they seem to be a bit more gentle on other drive train components.

gtodoug

iTrader: (1)

You can certainly get the car into the 12's just be careful. I'm in the low 400hp range now and having a ton of drivetrain issues. I've almsot got them all sorted out now but it's been a chore.

The stock driveshaft seperated in the front part at a weld. This caused a clinking noise in the driveshaft.

Then the driver's side cv axle spider broke causing a bind you could feel. We caught this one before it tore through the casing.

The posi unit let go. This one took a while to track down.

As far as going to the track, the car has maybe 25 passes down the track. Most in the high 12 sec range. When I finally made it back to the track with the DR's I got some light clutch slippage so the best 60' I could muster was a 2.1. The best time to date is in my sig 12.7@113.xxmph. I've since added LT headers, 3.91 gears, and a retune. On the street this setup rocks, however the drivetrain didn't like the new power with DR's and the new gears.

I've since replaced all of the drivetrain with the exception of the posi unit which is in transit. I'm hoping to bottom out in the low 12's at 115-116mph. Wish me luck!

brent eb02

i ran 12.4 with no problem

Rhino74

iTrader: (1)

You ran 12.4 with just a Converter and a Cam???
Wow. That must have been a really high stall and a really crazy cam, and I assume you were on slicks of DRs, right? That's still incredible. Ever get on a dyno?

brent eb02

my converter is a very streetable ss3800

the cam is slightly larger than a 02 zo6 cam like 207 217 on a 117 lsa its more of a turbo grind than anything

dyno #s are 325 rwhp and 325 rwtq

i had bfg drag radials and ran 12.4@108 mph

tuned by cartek!!!


now its a completly different car

its now a monster with the sts turbo!!!!!! should run low 11s with 540 rwtq

gtodoug

iTrader: (1)

But that is an automatic. Nice times by the way.........for the 6 speed guys once you are making some power and slapping some DR's or slicks on hold on tight to your wallet. There are about a half dozen guys I can think of with driveline issues from busted posi units to driveshaft problems, to torn cv axles. All 6 speeds. It's just harder to get the power down to the ground without breaking something.

Rhino74

iTrader: (1)

Does using true street tires avoid these problems by creating slippage instead of breakage of can you still break things during the 1-2 shift?

mr2guru

iTrader: (16)

On actual street tires you're gonna be hard pressed to break things. The tires will go up in smoke before anything gets too stressed.

I'll stay away from drag tires until I have $$$ for driveline upgrades....until then, hello high traps AND high ETs lol

DZmedia

HIGHWAY RACER FOR LIFE!!!!!!!!!!!!!! or untull i get about 10k to upgrade my driveline.

sb427f-car

You're talking the 9" gear set with the outputs still being to a halfshaft correct? Then again the drive and half shafts would be the weak links.

sb427f-car

Where are you from? 05s or 04s?