Input shaft limits

bigbadfox

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I'm kicking around the idea of putting a 2.2 KB on my 03 Cobra and I would really prefer not to have to mess with the input shaft. My goal is around the neighborhood of 600 RWHP and i'll be keeping street tires on it. From what I understand the general limit of the shaft is 500 RWHP but it won't see any hard launches with sticky tires. Do you think I would be in the clear?
 

stal94gt

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odds are you will be fine with the 10 spline input shaft, but when the time comes to swap the clutch i would replace it along with the tob sleeve.
 

Bdubbs

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Seems like hit or miss. Some break them with 450rwhp, while others are 600+ with zero problems.
 

Tims97SVT

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As long as your on the stock clutch it may live. If you put a more aggressive clutch in it will kill the stock input.
 

black 10th vert

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I am running a Whipple at 17psi with stock clutch and input shaft. It's all in the driver inmo. If you are extremely hard on the car powerbraking it every chance you get, powershifting constantly, drag style launches on slicks, etc., you will break it even on a stock Eaton. If you just like to go fast, but not necessarily beat the car to death, then it will live. That being said, I agree with stal94gt, when it's clutch time then you would be foolish not to put in better hardware "while your in there".;-)
 

sidewayscoupe

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x2, the key is the clutch.

Even my brothers 92 coupe (heads, s-trim, bolt ons) was fine for years. We put a badass clutch in the car he broke the 10 spline shifting it into 3rd on the street.

Anything north of 450 is a gamble with a grabby clutch.

As long as your on the stock clutch it may live. If you put a more aggressive clutch in it will kill the stock input.
 

bigbadfox

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I forgot to mention that I have a spec stage 3 and it's pretty grabby. I'm kicking myself for not doing the shaft while I was in there but the flywheel was broke and I didn't have the money to do all that I wanted.
 

sidewayscoupe

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Yeah that really sucks.

We had just put his back together for the Dream Cruise last year and he made it 300 miles before twisting his up..... Keeping a budget in mind during a build is always important but it would have been cheaper to do it right the first time.

Oh well it will be even stronger this year.

noboost92coupe.jpg

3550inputshaft2.jpg

3550inputshaft1.jpg


I forgot to mention that I have a spec stage 3 and it's pretty grabby. I'm kicking myself for not doing the shaft while I was in there but the flywheel was broke and I didn't have the money to do all that I wanted.
 

Jimmysidecarr

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Above the power level mentioned above, it's all about the shock load.

Wheel hop, clutch drops with good traction, power shifts, hair trigger grabby clutches that have less damping.
Any of these things or or any combination of these things can destroy the input shaft, diff cover and axles.

Sticky tires on the stock clutch and input shaft with zero wheel hop will tolerate quite a bit of power without breaking anything.

Road race/ open track/ HPDE type events don't shock the drive line much at all, depending on the driver.
 

Brutal Metal

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Just like T-5 tranny's and stock half shafts, there is no set HP level where breakage occurs, like Jimmy said shock and an aggressive clutch can reek havoc!
 

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