• Protip: Profile posts are public! Use Conversations to message other members privately. Everyone can see the content of a profile post.

Final Drive noise with high HP

6 January 2009
Cincinnati, Ohio
How long will it take 4.55 R&P to fail @ 500+hp?

The answer is immediate failure with 80 dyno miles.

Sooooooo......Before it grenades and destroys the tranny the car is shut down. I'm trailering it home this weekend and will make this fix here.

Do I:
Go back to 5 spd
Leave 6 spd and go to a different R&P
Do something else

I could really use some input here. My month long turbo install turned into an agonizing 5 month whole motor build extravagonzo. Now immediate final drive issues.


I have no personal experience but i'm going thru a trans build as well. All the "experts" i've talked to tells me the 5spd is stronger. For your application i'd go with 5spd and go from there.

You have a 4.55 Comptech R&P unit? Perhaps the OSG 4.4 is stronger.

You know who has a lot of experience here? Call Nick @ Applied Motorsports in San Diego. Please share what you find out too :)
Personally I have found short gears to be worse on cars with more HP.

I say stock 5 or 6spd.
Short gears are great for stock or high HP builds. Depending on what part of the power band you want to stay in between shifts (i.e. close ratio gears).

A short final drive is not so great for high HP builds that are track (road course) or street driven. The shortest R&P I'd like on a high HP build is probably the 4.235 R final drive.

A 1/4 car can benefit from a really short final drive especially if you've got some DOT slicks on there. It's brutal on the R&P though.

Obviously there's no right answer. Lots of folks have varying opinions on this subject.
Last edited:
Can not believe it failed that quick..

Long gears in turbo is what I have always heard. However the 6 speed in the silver turbo car I had was a blast.

I would keep the 6 speed and do a different R&P
Last edited:
I would do the os giken 4.06 lsd.

Not only will it hold the power and let that 550hp get to the ground in a turn, It is the stock ratio so you will not have to shift ever 2 seconds.
Sorry to hear about the gears. I hadn't seen this post prior to my mentioning that the gears should be changed. I have had the 6 speed with stock gears in my 98 with over 600 RWHP and no issues with over 25K miles. I don't baby my car. I know that Woody has also had over 600 RWHP with his 6 speed and stock gears. I would therefore recommend keeping the 6 speed and going to stock gears. Don't know that going to the OS Giken or ATS gear sets would be any better than stock.
Thanks all for the quick recommendations.

Well, stuff happens. However this is a pretty awesome community which will help get it together.

So, I have a great motor build courtesy of Cody @ LoveFab. But I got the wrong final drive.

Shad @ Driving Ambitions has got a R&P at a very fair price and will ship it Monday for Thursday delivery to...

...Brian at Source 1 Automotive. He's booked Friday AM for me to swap out the very girly 4.55 for a stock one. Probably good that I did not get a chance to drive the car with the old final drive so I'll start fresh with the stock unit.

Headed north with a great (obviously) friend, his truck and enclosed trailer to bring my baby back.
Last edited:
I wish I had found this out sooner. I had 4.55's in my car with 470+ hp and on my sixth lap (yes the first 5 were me warming up and getting squinted with the car) boooom the 4.55 r and p fail. I picked up a new stock six speed tranny and am very happy to be back to stock. On the track, at least my home track, I had to use an extra gear due to the gearing ratio. All I have to say is the 4.55 gearing is like putting sand in your motor. It will cause failures. Run away. Go to a stock six speed and good luck.
This interests me greatly.

Anybody else? I would build in some extra time in the final drive replacement process to realize an appreciable increase in r&p strength.
Yes, this is on my trans build list. The company is local to me and it's cheap insurance. I'm not sure if the duburring is worth it but it sure would be nice.

I'm in the process of trying to figure out exactly what should be coated. I don't think it's cost effective to simply go to town on all the parts. If I recall they treat the bearings too but talking to LarryB the NSX trans bearings rarely even wear out. shrug..
SourceNSX here in Cincinnati removed the transaxle and installed an OEM 6 spd R&P this weekend. LoveFab said that the existing final drive was bad and was in the process of failing after a one hour dyno engine break-in session.

Upon removal and inspection of the Comptech 4.55 final drive there was nothing wrong with the existing unit.


I could go on and on about my experience but it is incredibly comforting to have a competent NSX specialist here to help me get my car sorted back out. LoveFab gave me back a car that is far from where it should be given the time and expense invested and Brian (along with his gifted tech Justin) is proving to be an invaluable resource to get closer to where 18K and five months should have already gotten me.