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Discussion Starter · #1 ·
So the old girl is getting the motor rebuilt after I blew up some pistons - planning on it being stronger than ever. I am also going to be putting some MT E/T Street Radials on the back so I can finally hook up and have some fun.

This got me thinking though. I am pretty sure the TKO600 is not the next thing to break, but the IRS I have concerns. With 500-550 HP, sticky tires and an IRS should I be careful with that? It is your standard ford 8.8, 3.73s and 28 spline axles. If I launch it hard off the line am I just asking for something to break, or with so little weight it should be okay.

Obviously anything can happen, but anyone with experience with such a setup I am all ear and willing to learn.

Thanks everyone.

-Ryan
 

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Pro FFR Builder and Moderator
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14,785 Posts
Breaking a half shaft would probably be the most likely. I have broken a few over the years road racing so doing a hard launch would put a lot of stress on them.
 

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Pro FFR Builder and Moderator
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I think Mike Forte has some upgraded shafts. They run about $1200 a pr.
 

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FFCobra Fanatic
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Ryan,
If you run MT/ETs outback, be very carefull when you start some hard launches! I've run ETs on the street & strip for a few yrs. now, and they really HOOKUP! I love my MT/ETs. They help to get hp to the ground in our lite cars. Too much traction might be hard on IRS? Just saying--
Have fun & be safe--
Butch

PS
ETs will still spin with your amount of hp!!!
3:73 is WAY too much gear IMHO
 

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FFCobra Fanatic
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5,533 Posts
Hey Ryan,
You probably dont need to really drop the clutch at 4500 and powershift to run a fast ET. With the power you are making, you should be able to ease it out of the hole, shift fast and run in the low 11's high 10's. The next question would be if you have all the safety equipment to satisfy your local track. If your running 1/8 mile you may not need all the same things as for 1/4 mile because you wont see the same speeds. One thing that will break IRS components real quick is wheel hop. Hopefully you have upgraded to poly mounting bushings for the front ears. That will help a lot. Quad shocks can be retained depending on tire size but I am not sure of their effectiveness in IRS applications because IRS doesnt suffer from the same axle wrap a solid axle does. Good Luck with it and take some time to get used to your new power before letting it fly.

Mike
 

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Albany ny
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410 Posts
I would look up The Drive Shaft Shop for stronger axles. Someone here told me it was about $750 for bullet proof axles. They say axles are available in levels to handle up to 1,400 hp! However you may not get that with 28 spline diff.
 

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FFCobra Craftsman
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Also ask Forte about a limited slip unit, trueTrac,Torsen, for the IRS that allows 31 spline axles. I have truetrac in my solid axle w/ 31 splines but IRS would be different.
 

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The driveshaft shop axles I bought for $750 are rated to 550hp. They have higher rated axles but cost more,I think around $1200.

I would change before failure. They will break with the amount of hp and tires you have. It's a known weak link and only a matter of time.
 
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