Transmission Limits

[len3.8]

Anyone explored the limits of the NSX's transmission @ high hp?
Say a 6spd with 4:55
Not planning on going over 500-550hp, I'm not drag racing. I will be tracking the car. I don't baby the car, but I am not into just dropping the clutch either.
But I am still concerned about the trans.

Thanks

 

[MiamieNeSeX]

Aren't there weaker links before the transmission that would give out first? I think it was discussed before by AndyV.


Armando

 

[len3.8]

I read Andy's post, It did not state any findings, it's talking about what he suspected. I don't think his transmission is finished being rebuilt. Also he is not anywhere near 500hp at the wheels.
That is why I was specific with the HP rating, I know that there are others on the forum running those #'s, or there going to be running those #'s, I just wanted to hear some of them chime in.
That is the only reason I started a new thread.
Thanks

 

[MiamieNeSeX]

How are you going to get to that HP? Fi and nitros shot? Or just FI?

Armando

 

[len3.8]

FI

 

[Turbo NSX]

CV joints and axles have broken before the tranny. I haven't heard of anyone splitting the case yet from HP.

 

[Yellow Rose]

I read Andy's post, It did not state any findings, it's talking about what he suspected.

After four-plus weeks, I should get my car back today or tomorrow. There have been some expected and some not expected discoveries inside the transmission. I've begun drafting my post.....stay tuned. I agree with TURBO, there are no known records of split cases; however, internals are a different story. Jeez, just when I got my CC balance within reason.

 

[KGP]

I've begun drafting my post.....stay tuned.

Hopefully you have a few pics? Looking forward to your findings.

 

[ncdogdoc]

I have heard that the Comptech 4.55 is not as strong as either Honda R&P. This is second or third hand from Realtime.

I would think the synchros would get the most abuse, with the actual gears second. Really depends on how well you heel and toe I think.

JMHO, as I "only" have 250hp.

edit: With this much HP, why do you even need the six speed. I know it is nice around town, but on the track, you will not use the extra gear with that much HP and torque. Save some money, as the five speed and associated gears are much cheaper to come by. YMMV.

 

[len3.8]

Thanks NCdoc...
I am not buying a 6spd, I already have it as my current setup.
I had heard the same as you about the weakness of the 4:55, you are right inline of why I was asking. I appreciate all the responses.

 

[AATA]

With 500+HP and a 5-speed we've run 2 track events now with no problem at all. I have also heard that the 4.55 are weaker. The 6 speed are more likely to fail with high HP than the 5 speed, but the 6 speed diff is much better. HMMM better diff/replace tranny? If you heel toe correct and give the synchros time on upshifts everything should be OK. If you treat the tranny well it will treat you well.

 

[sjs]

Aren't there weaker links before the transmission that would give out first? I think it was discussed before by AndyV.


Armando

Sure, the half shafts for example, but doesn't alter the question about the transmission. According to what we've heard from early high HP car owners like David, Gerry, and Factor-X, the 5-spd is pretty darn tough even when used for drag racing. I haven't heard any reason why the 6-spd is any different, although there seems there may be an issue with non-OEM ring & pinions in either.

Of course now we have Andy's case which will be very interesting. I would contend that the real abuse is more from mid-range torque than peak HP, and compared to some of the monster turbos I would think that Andy's car is comparatively gentle in that respect.

 

[AATA]

With 500+HP and a 5-speed we've run 2 track events now with no problem at all. I have also heard that the 4.55 are weaker. The 6 speed are more likely to fail with high HP than the 5 speed, but the 6 speed diff is much better. HMMM better diff/replace tranny? If you heel toe correct and give the synchros time on upshifts everything should be OK. If you treat the tranny well it will treat you well.

Well, as an update to this...on our 3rd race at Infineon I was in first place when the differential went out on the last lap. Not sure about the details as it just happened this last weekend, but there is fluid everywhere and no power to the left tire. The car started shaking violently and clunking really load. The car still shifts fine. The tranny is the original 5 speed with approx 65k. Anybody have any experience with some of the aftermarket diffs. I plan to use either the 6 speed diff or one of the aftermarket diffs. Any recommendations are welcome.

 

[sjs]

Well, as an update to this...on our 3rd race at Infineon I was in first place when the differential went out on the last lap...

Congrats on a strong showing before it broke! Would you remind us of which sanctioning body and class you run under?

I guess I'm a bit surprised to hear that it failed in a road race considering the abuse they have survived at the drag strips. Had you shimmed the LSD or was it all stock? Please let us know what you learn when it comes apart.

 

[Andrie Hartanto]

Trev was visitng in Sears Point running in Super Unlimited in NASA.

I got a video of me passing him in my civic.


After he broke the tranny


Seriously, the car is super fast. He is new to the track and to the car, and can only get faster.

I'll get the video up soon.

 

[sjs]

Andrie, second overall in a civic? Must be some mean ride!

 

[Andrie Hartanto]

Steve,

I got first overall in the civic on Saturday race starting from P30, due to transponder problem in qualifying

I posted the vids in track report forum

 

[AATA]

The diff was all stock. We just finished getting the car together and knew that the diff was the weak link. I will keep you updated on the status once it is disassembled. I do have a great video of Andrie sideways with the rear tires off the track and the front tires on flinging mud everywhere in turn 6 at Infineon. It was a nice save! I will try to get that to you soon Andrie.

 

[Kip Olson]

limits

Hi, I have broken two 4.55 r&p's I am now using the 02 nsx-r r&p with no issues in a 6 spd. Good luck.

 

[len3.8]

Re: limits

Hi, I have broken two 4.55 r&p's I am now using the 02 nsx-r r&p with no issues in a 6 spd. Good luck.

Kip can you elaborate on how you actually broke the r&p's?
Were they under high horsepower conditions?
Were you drag racing with them? Roadracing?

 

[sjs]

Also, were the broken ones in a 5-spd, and if so were they CT?

 

[Andrie Hartanto]

Kip do track driving in road course. And Kip's car has about 400Hp at the wheel.

The problem with the Comptech 4.55 if you have high power motor. I heard the old design, the noisy ones are much better in handling the HP. Comptech had to change the design to get the gears much quiter because of customers complaint. In result, they loss some of the strength as well.

We are interested in sourcing another 4.55 for the 6 speed, if we can get enough people interested. This one will be good for over 500HP. Price will be around $2K each, depending on how many actually get produced.

 

[Kip Olson]

Andrei is correct, I do track events and the car is at 400 rwhp. It also has 300 lbs of torque. This combo did not work for me. Comptech suggested the honda gear and I purchased it from Dali. The ring gear was always the problem. I was also using S-03 tires at the time. I am now running comptech pro suspension and racing slicks and have done quite a few hard track days on this setup and have had no issues. I did notice the gear ratio change between the two and still prefer the 4:55 gear ratio over the NSX-R gear but there is plenty of power to push me around. By the way, Comptech was 200% supportive in dealing with these issues, and the the diff. assembly required parts from other year cars due to the inside ring gear teeth are straight cut versus the helical cut in U.. 6 spd transmissions. Good luck and let me know if I can help further

 

[len3.8]

Thanks Kip, Andrie, SJS. I really like the 4:55 gear as well.
I will seriously have to consider the gearing though, after hearing some of the issues you guys are explaining.

 

[len3.8]

Kip when you re-done your differential, were you able to buy the parts from Comptech for the rebuild? What FI system do you have on your car? Nice numbers by the way...