Tranny issue, should I get 6 spd or 5spd???

[Siulonbow]

Hi,

I recently find out that my new NSX falls into the snap ring range. I am debating whether I should go with a 6 spd tranny. I have asked mechanics, they recommended me to stay with 5 spd, and get a short gear and OS Giken LSD/4.44. If I use the car mostly for street use, would it be better to get a 5 spd?

1) I would like to know how much would it cost to fix the snap ring?

2) Is there a big difference in rpm when crusing on the freeway in the 80mph with 4.44 rear diff. (5spd vs 6 spd)?

3) Is it a good investment as in personal enjoyment if i get the Gilken LSD? The car might not see a lot of track, but should i get the Gilken anyway because I heard from my friend that ppl have problem correcting the tail. They ended up total the car because the tail swings out and hard to correct.

Please let me know what you think? Thanks

 

[4AU4LIFE]

Unless the snap ring has failed on you I don't see why you would need to do it unless you just want to. There are many cars in the affected range(myself included) that have many miles of enjoyable driving.
I believe the gears in the 6 speed are a little shorter anyway so doing that swap will automatically give quicker acceleration but higher rpms to go along with it.
I would imagine 4.44 gears running 80 would be turning ~4500 or better.
IMO, drive it till it breaks and then do the change if you feel like it is needed. Just because your trans is in the range doesn't mean it will fail.

 

[nsxtasy]

1) I would like to know how much would it cost to fix the snap ring?

If you don't already have to have your transmission serviced, then you will need to spend 8-12 hours to open up the transmission, plus about $800 for the parts (upper transmission case plus snap ring), for a total of roughly $2000-2500, give or take.

However, if your transmission is being serviced anyway, then it's just the $800 cost of the parts.

This is why many owners with snap ring cars just keep driving them, while making sure they have read up on the symptoms of the snap ring failure. If the snap ring doesn't fail - and in some cases, it will never fail - there's no harm done, and no cost involved. If it shows the failure symptoms (loose shift knob into second gear, etc), and you park it immediately, at that time you can spend the $2000-2500. If you wait until you need transmission service anyway - until a clutch replacement, or synchros, or a gearing swap - then at that time it will only cost the $800. Like 92NSX, I would just keep driving a snap ring car and not worry about it, and do it if and when it fails or your tranny needs servicing.

Incidentally, here are 1/4 mile times with the most common gearing setups, for an otherwise stock '91 NSX:

stock 5-speed 13.67 seconds
short gears 13.56 seconds
4.55 R&P 13.43 seconds
short gears and 4.55 R&P 13.38 seconds
6-speed 13.56 seconds

IMHO those slight differences in acceleration times don't justify the cost of buying a whole new transmission or of opening the transmission up. But if you want to do it, those are the numbers.

 

[Siulonbow]

I am still thinking about the 6spd vs 5 spd. After putting the fujitsobo header into the car, i feel that I wasn't able to test the car's full potential. At first gear, the car feels fast after 4K, but after I upshift, I have to wait until it get back to the vtec range. If i redline at 2nd, I would be hitting 80mph. I wouldn't be able to test the header because I can hardly get to 80mph driving around LA.

I have thought about getting short gear and OS gilken LSD/4.44 for the 5 spd, but i don't want to lose the enjoyment cruising in the city (higher rpm due to 4.44 lsd). Then I come to another idea, which is to get a 6 spd tranny with 4.44 LSD. This route will cost more, but am not sure if it's worth it. I have seen a lot of NSX owner switch back to 5 spd after installing 6 spd. I have tried to search around the board, but wasn't able to find previous post that is similar to my scenario now. What do you think?

 

[BD]

I am still thinking about the 6spd vs 5 spd. After putting the fujitsobo header into the car, i feel that I wasn't able to test the car's full potential. At first gear, the car feels fast after 4K, but after I upshift, I have to wait until it get back to the vtec range. If i redline at 2nd, I would be hitting 80mph. I wouldn't be able to test the header because I can hardly get to 80mph driving around LA.

I have thought about getting short gear and OS gilken LSD/4.44 for the 5 spd, but i don't want to lose the enjoyment cruising in the city (higher rpm due to 4.44 lsd). Then I come to another idea, which is to get a 6 spd tranny with 4.44 LSD. This route will cost more, but am not sure if it's worth it. I have seen a lot of NSX owner switch back to 5 spd after installing 6 spd. I have tried to search around the board, but wasn't able to find previous post that is similar to my scenario now. What do you think?

Welcome to the Fujitsubo family. The reason your lower RPM range is hurting is due to the design of the header, it has a rather large diameter piping that you loose some back pressure. Short gears or six speed will definitely make a world of difference.

Another good thing about six speed is, you will be able to save some gas, probably not significant enough, but the saving will be there.

 

[davidf]

6 spd.:wink:

 

[Ponyboy]

Don't know about any "tail correction" problems with the OSG but I don't think it's a good recommendation for mainly street driven NSXs. The OSG has a pronounced chatter that can be a bit unsettling (and even embarassing) in slower corners (like street corners).

I'd go with the 6 speed. Or maybe even the 5 speed with short gears and the 4.23 final.

 

[Siulonbow]

I remember a few years back on Prime, there was a page where they have analyzed the gearing and the gearing of 5spd and 6 spd transmission. Can anyone send me the link?

A few years ago when I was looking for a NSX, I have test drove a CTSC NSX with short gear and 4.55 RP. Back then, I remember the car rev really fast, but I am not sure if it's due to the 4.55 R&P or the CTSC. I wondered if anyone can input their thought about have CTSC with short gear/4.23 or 4.55 or 6 speed tranny. Thanks again.

 

[CDX_NSX]

I remember a few years back on Prime, there was a page where they have analyzed the gearing and the gearing of 5spd and 6 spd transmission. Can anyone send me the link?

http://www.nsxprime.com/FAQ/Technical/gearratios.htm

 

[JeffShoots]

Hi,

I recently find out that my new NSX falls into the snap ring range. I am debating whether I should go with a 6 spd tranny. I have asked mechanics, they recommended me to stay with 5 spd, and get a short gear and OS Giken LSD/4.44. If I use the car mostly for street use, would it be better to get a 5 spd?

I think you should get a NEW 6-speed AND an OS Giken for the 6-speed from me :biggrin: The best setup all around. I just drove TiDaves car a few weeks ago with this setup. It's great. I love the OS locker and the short gears. The locker will "set" on a long apex and you just get grip, grip, and more, GRIP.......on THill with R888 tires you throttle through the long turns I love it

I have both and can install the OS Giken if you want for a great price. All parts are NEW in box Trans from Acura and OS Giken 4.44 from SOS.

PM me if interested.

 

[omega2]

I remember a few years back on Prime, there was a page where they have analyzed the gearing and the gearing of 5spd and 6 spd transmission. Can anyone send me the link?

A few years ago when I was looking for a NSX, I have test drove a CTSC NSX with short gear and 4.55 RP. Back then, I remember the car rev really fast, but I am not sure if it's due to the 4.55 R&P or the CTSC. I wondered if anyone can input their thought about have CTSC with short gear/4.23 or 4.55 or 6 speed tranny. Thanks again.

I have a type R final drive(4.23) with the short gears and the CTSC. The final drive and short gearing upgrade is the best bang for your buck upgrade for the 5 speed with a NA 3.0L engine. The stock gearing for the 5 speed is too tall for the amount of power the stock engine puts out. As far as which causes the engine to rev faster, it is really both. If you are planning on keeping the horsepower under 400 rwhp, then the short gears and type R final drive are great complimentary upgrades to the CTSC at 7-8.5 psi.

 

[nsxtasy]

The final drive and short gearing upgrade is the best bang for your buck upgrade for the 5 speed with a NA 3.0L engine.

Absolutely not true. In terms of the improvement in acceleration versus the amount of money spent, you will get far greater "bang for your buck" with power adders such as exhaust and headers, as well as with whatever weight reduction steps you are willing to do.

The stock gearing for the 5 speed is too tall for the amount of power the stock engine puts out.

As a blanket statement, that is also not true; it really depends on where (what speeds) you want the best acceleration. The stock gearing has a fairly wide gap between the lower gears, particularly between first and second, but have nice, closely-spaced upper gears. The short gears reduce the spacing between first and second, but widen the spacing between the upper gears. If you're looking for better acceleration in the 40-70 mph range, the short gears will help, but if you prefer better acceleration above 70 mph (such as on racetracks), the closer spacing of the stock gears in that range is actually preferable.