Tranny/Syncro/ShortGears+R&P+BBSC Questions

[ub2slw]

Since I've owned the car, I could not downshift into first if traveling more that 25mph. I have always assumed that it was a "lockout" feature that prevented excessive wear on the syncros. This weekend I went to put it into first and ground the gear. (I may have been above 25mph)

However after reading the replies at the bottom of the article here http://www.nsxprime.com/ubb/Forum1/HTML/002327.html I think I may need to replace the syncros. Unless there IS a lockout on the tranny that maybe needs to be fixed (yeah, right!)

So…Is there a lockout? (umm, I think I already answered that)
How difficult is it to remove the tranny?
Have any of you replaced your syncros?
How competent should I be to even attempt this job? (Scale 1-10, 10 being take it to Acura)
Should I look for a used 6-speed Tranny?

Bright side: I'll probably take this opportunity to install a 4.55 R&P. I am VERY interested in doing everything myself, however, funds are available for a professional to do it. I enjoy the satisfaction (and saving $) of doing it myself, I just don't want to get in over my head.

P.S I'm still planning on going the BBSC route, should I do shortgears as well?

 

[Jimbo]

In my opinion most mechanically inclined people with auto experience with the proper equipment (lift, tranny jack) could remove and replace a transmission, but I would not attempt to open up a tranny and replace synchros, etc, unless I had a fair amount of internal transmission experience. I personally would shop it out.

As far as short gears are concerned... I just had short gears installed (along with a 4.23 RP) by Mark Basch and I highly recommend both with qualification. I also highly recommend Mark too!

My qualification is based on how you drive and use your car. If you mostly track your car there might not be any benefits and there might be a downside. Others have discussed this at length and you can do a search and find those posts.

If, however, you're like me and do most of your driving on the street in a mix of road conditions, the short gears make a big difference. The standard 5 speed gears have a big ratio jump from 1st to 2nd and it makes that shift annoying. There's a big BOG when you make that shift and it makes for a more jerky shift and it's harder to match the revs for a smooth transition.

The short gears solve that problem. When I first got my short gears my first inclination was this was how the tranny should have been all along.

Big driveability difference.

I also found that the 4.23 RP helped make the car seem lighter and more nimble in all the gears. As time goes on, you'll get used to the difference but I have no doubt that the car accelerates quicker and you feel that acceleration in normal street driving.

I'm not particularly interested in tenths of a second here or there, nor am I interested in drag racing or street racing. I understand and concur that the actual performance differences might be modest, but I do find the driveability changes to be noticeable and significant.

And I think most people who have gotten the short gears and R&P would agree.

Hope this helps.

-Jim

------------------
1992 NSX Red/Blk 5 spd #0330
1991 NSX Blk/Blk Auto #3070 (Sold)
1974 Vette 454 4 spd Wht/Blk
http://homepage.mac.com/jimanders/PhotoAlbum1.html

[This message has been edited by Jimbo (edited 09 September 2002).]

[This message has been edited by Jimbo (edited 09 September 2002).]

 

[FuryNSX]

Originally posted by Jimbo:
And I think most people who have gotten the short gears and R&P would agree.

Yeah, I do. It's also not all about the numbers for me, and my driving enjoyment significantly increased after the work was done.

------------------
1995 NSX-T
1999 3.2TL
2001 Odyssey
1992 SC400

 

[TampaBayNSX-R]

I have the BBSC, six speed and 4.55's and the car is a blast to drive!

 

[nsxtasy]

ub2slw,

Since you live in an area with a very active chapter of the NSX Club of America, you might want to go to one of the club meetings and see if an owner with the changes you are considering might let you try driving his car, to see how you like it.

You're also fortunate to live in an area with a dealer with a lot of NSX experience. If you do decide to have the work done by a professional, you've got a great place to take it to.

 

[ub2slw]

Are/would you consider Short gears? With the superchager wouldn't it be advantageous to have the taller gears? (i.e with the added torque, short gears aren't AS important)

Originally posted by TampaBayNSX-R:
I have the BBSC, six speed and 4.55's and the car is a blast to drive!

 

[Jimbo]

UB,

The short gears generally refer to the spacing of the gear ratios in the 5 speed tranny. There's not as big of gap between the 1-2 shift with the short gears. I don't see this having much to do with your decision to get a supercharger or not.

The numerically higher ring and pinion (i.e. 4.23 or 4.55) might have some implication.

However, the NSX, even with any supercharger is not particularly known for its stump-pulling torque figures. It just depends on how dramatic you wish your acceleration to be.

I've driven in a BBSC-equipped NSX with 4.55s and it was very fast and the shifting/redlining also happened VERY fast. I'd probably go with the 4.23s as they seem to be a nice compromise.

The 4.23 are also Honda parts and there has been some reports of gear noise with the 4.55s.

-Jim

------------------
1992 NSX Red/Blk 5 spd #0330
1991 NSX Blk/Blk Auto #3070 (Sold)
1974 Vette 454 4 spd Wht/Blk
http://homepage.mac.com/jimanders/PhotoAlbum1.html

 

[ScienceofSpeed]

In order to shift at 25mph to 1st gear, you need to rev match. Depress the clutch pedal, and blip the throttle with your foot speed the engine to the resulting engine speed that will result in 1st at 25mph, and and shift into gear.

You can see the short gears and final drive gears here:
http://www.scienceofspeed.com/products/drivetrain_performance_products/NSX/gears_LSD.asp

regards,
-- Chris

------------------
Revolutionize your NSX with ScienceofSpeed
www.ScienceofSpeed.com | [email protected] | 877-863-4520

 

[nsxtasy]

Jim's right. The gearing is separate from the supercharger.

Taking that into account, there's no particular advantage in doing both upgrades at the same time, other than saving you a drive over to the dealer. So, you might want to consider, for example, doing the supercharger now, and then, afterwards, if you feel like you want a little bit more oomph, doing the gear changes.

Another strategy would be to wait until you need the clutch replaced. Replacing the gears at the same time as the clutch would save you from having the labor to open up the transmission performed twice.

Also, if you are considering the short gears and the R&P, you should do them the same time as each other, again to save from having the labor to open up the transmission performed twice.

 

[ScienceofSpeed]

The gear noise of the Comptech 4.55 R&P is a thing of the past. The gear teeth have micro channels that retain tranny oil to properly lube the gears. I have had the 4.23 and 4.55 in my car, and there is no difference in driveability or noise between the two.

I have the 4.55 now, and it's a blast. Driving it reminds me of when Dan Aykroyd and Chevy Chase walk out of the g-simulator in "Spies Like Us".

-- Chris

Originally posted by Jimbo:
UB,

The 4.23 are also Honda parts and there has been some reports of gear noise with the 4.55s.

-Jim

------------------
Revolutionize your NSX with ScienceofSpeed
www.ScienceofSpeed.com | [email protected] | 877-863-4520

 

[Jimbo]

Chris,

That's good news. If I would have known that at the time my decision would have been more difficult.

-Jim

------------------
1992 NSX Red/Blk 5 spd #0330
1991 NSX Blk/Blk Auto #3070 (Sold)
1974 Vette 454 4 spd Wht/Blk
http://homepage.mac.com/jimanders/PhotoAlbum1.html

 

[TampaBayNSX-R]

Originally posted by ub2slw:
Are/would you consider Short gears? With the superchager wouldn't it be advantageous to have the taller gears? (i.e with the added torque, short gears aren't AS important)

I have a good friend who has a '94 BBSC powered NSX, like me, but his has about 40,000 fewer miles on it. He has the stock five speed tranny and clutch. Our cars have dynoed on the same dyno within a few hp of one another yet my car is decisively quicker due to the difference in gearing.

Having said that, the short gears aren't for everyone. For those who do alot of commuting and stop/go duty on a regular basis the rapid shifting may become bothersome. I enjoy the short gearing as it allows me to run the car in VTEC more frequently. For example, with my six speed, 4.55 setup I enter VTEC at around 45mph in second gear...a speed that is legal on many streets in my town. With the stock 5 speed setup I wouldn't reach that until probably 60mph...a speed that I can only achieve legally on the interstate.

 

[Jimbo]

Tampa,

When you say "short gears" I assume you're talking about the 4.55 ring and pinion.

This might confuse some people because most of us use the term "short gears" to identify the tranny gear set and not the final drive R&P.

Just a minor semantic point for clarity.

-Jim

------------------
1992 NSX Red/Blk 5 spd #0330
1991 NSX Blk/Blk Auto #3070 (Sold)
1974 Vette 454 4 spd Wht/Blk
http://homepage.mac.com/jimanders/PhotoAlbum1.html

 

[len3.8]

Originally posted by Jimbo:
Tampa,

When you say "short gears" I assume you're talking about the 4.55 ring and pinion.

This might confuse some people because most of us use the term "short gears" to identify the tranny gear set and not the final drive R&P.

Just a minor semantic point for clarity.

-Jim

Isn't he tallking about the shorter gear stack? I have the 6spd comptech trans and the
4:55 R&P , And the comptech SC. The car pulls very fast and hard when I want it to.
I love it on the track. When you guys aree talking about short gears you are talking about gear stacks correct?
Len
n9s5x-t

 

[nsxtasy]

All NSXs contain two different kinds of gears. There is a selectable set of forward gears - four of them in the automatic, five in the five-speed used in '91-96, and six in the six-speed used since '97. One of these forward gears is in use any time the car is being driven forward. (There is also a single reverse gear.) There is also a "ring and pinion gear" (or "R&P"), also known as a "final drive gear", and this is also in use any time the car is being driven forward. So there are actually two gears whose ratios are being used to change the number of revolutions from the crankshaft, to the rear axle.

Any gear can be "shorter", meaning that its ratio is a higher numerical value. However, the term "short gears" has a specific connotation for the NSX. The NSX five-speed was sold in North America and Europe with a certain set of gears. The NSX five-speed was sold in Japan with a set of gears which had a different ratio for second gear, third gear, and fourth gear; these three gears were shorter than their counterparts sold in other markets. Some owners have chosen to replace those original three gears in their five-speeds with the three gears sold in the Japanese market; hence the term "short gears" for the NSX is usually used to refer to those three gears, the ones that were used for NSXs sold in Japan. AFAIK there is only one set of the six gears available for the six-speed.

Two versions of the ring and pinion gear are available for the NSX; both are shorter than stock, but neither is usually referred to by the term "short gears". All NSXs sold in North America were sold with a R&P with a 4.062 ratio. Honda makes a R&P with a 4.235 ratio that was originally in the 1991-94 NSX Type R sold in the Japanese market. Comptech makes a R&P with a 4.55 ratio.

[This message has been edited by nsxtasy (edited 10 September 2002).]

 

[len3.8]

Originally posted by len3.8:
Isn't he tallking about the shorter gear stack? I have the 6spd comptech trans and the
4:55 R&P , And the comptech SC. The car pulls very fast and hard when I want it to.
I love it on the track. When you guys aree talking about short gears you are talking about gear stacks correct?
Len
n9s5x-t

NXSTACY , Is the first gear usually not changed because it is welded to the mainshaft? If I understand you correctly, You are saying that there is only one set of
gears for the 6spd? If so, does Comptechs racing trans have a custom gear stack that is
not readily available for public sale?
Because I know that the 6spd in my 95 does
not run out like the 6spd in my friends 98 with the same 4:55r&p.
My car has a custom gear setup, as I am told
unless I was BS'd. But it does feel totally different than my friends.
Anyone that wants to chime in and knows let me know.
My transmission case just has Comptech stamped on it. Not any kind of Factor #'s at
all. The mechanic that worked on it just asked me how did I get the trans.
Len
n9s5x-t

 

[Inquisitor]

So let me get this right. An nsx from Japan has these "short gears" that the US and Europe have to change to, yet a Japanese nsx can still change the R&P to 4.55 from Comtech. A Japanese nsx-r has a R&P of 4.23 already so a normal nsx can still upgrade to the 4.23 R&P.
Presumably the nsx-s will have the same setup as the nsx-r.

 

[matteni]

Here is the link inside our FAQs (at the top of this page) that has the information you are looking for. You can also do a search and get opinions on how people felt about the cost and benifits of doing this.
http://www.nsxprime.com/FAQ/Performance/gears.htm

Welcome and good luck!

------------------
Nick M

91' Red/Black with Many Mods
99' Honda Odyssey with Many Kids

 

[nsxtasy]

Originally posted by len3.8:
Is the first gear usually not changed because it is welded to the mainshaft?

No, the first gear is not changed because the first gear sold in the Japanese market is the same (has the same ratio) as the first gear sold in other markets.

Originally posted by len3.8:
You are saying that there is only one set of gears for the 6spd? If so, does Comptechs racing trans have a custom gear stack that is
not readily available for public sale?

I have never heard anything about a Comptech six-speed before. I don't know anything about the gears or the gear ratios. I wonder whether it contains the stock gears along with Comptech's 4.55 R&P and their clutch, but I don't know for sure.

However, the six gears in the stock six-speed are closely spaced, so they don't suffer from the relatively wide gap between first and second on the American/European five-speed. It's a nice set of gears and I'm not sure how it could be improved.

Originally posted by Inquisitor:
So let me get this right. An nsx from Japan has these "short gears" that the US and Europe have to change to, yet a Japanese nsx can still change the R&P to 4.55 from Comtech. A Japanese nsx-r has a R&P of 4.23 already so a normal nsx can still upgrade to the 4.23 R&P.

That's correct.

 

[len3.8]

Thanks.
I seem to have a different gear stack.
1st and 2nd are the same.
3rd-6th have been changed. Again as I have been told privately. I will definately check into this.
Appreciate the help.

 

[ScienceofSpeed]

There is only one mainshaft/countershaft gearsets available for the 6-spd.

The only option for the 6-spd is a 4.55 final drive ring & pinion gears.

Cheers,
-- Chris

------------------
Revolutionize your NSX with ScienceofSpeed
www.ScienceofSpeed.com | [email protected] | 877-863-4520

 

[TampaBayNSX-R]

Originally posted by Jimbo:
Tampa,

When you say "short gears" I assume you're talking about the 4.55 ring and pinion.

This might confuse some people because most of us use the term "short gears" to identify the tranny gear set and not the final drive R&P.

Just a minor semantic point for clarity.

-Jim

Jimbo,
Yes, you are absolutely correct. I have the 4.55 ring and pinion with the 6-speed tranny. Sorry for the confusion.

 

[sjs]

Back to the downshift issue. No, there is no "lockout" as such, just the natural resistance of the synchros. Once you beat them (press too hard/fast) you get the grind. This does not mean you need to replace that syncho, yet, you're just asking too much of it. They are mean to make up for modest RPM differences as in a normal upshift or gentle downshift, not allow you to jam it in at any speed. You can’t get that and smooth too.

As Chris said, if you insist on downshifting to 1st at 25 (not sure why you would unless autocrossing) you need to match revs between the engine and the input shaft of the transmission. However, I think half of the story was left out. Reving it with the clutch pressed in will bring the engine up to the right RPM for your velocity and lower gear to be selected. That will prevent the sudden "engine braking" where the car slows abruptly when you let the clutch out as if you hit the breaks, but it won't bring the input shaft up to match engine speed so you aren't doing anything to take the load of the synchros. You'll still find the shift difficult and wear the synchros. For that you must pause in neutral, let the clutch out, blip the throttle, press the clutch back in, shift down to first, and let the clutch out. That's the often discussed "double clutch" and you should feel no resistance at all in the shift, else you missed the revs. It sounds slow, but when practiced and done well it happens in a blink.