Which Ring and Pinion for Track only car

[ncdogdoc]

Just put a deposit on my second NSX! I will be making this one a track only car. The clutch is about gone, so while I have the transmission cracked open, was wondering what everyone thinks about the different R&P's when used on the track. I have wandered throught the FAQ, and have read many other posts, but would like to get a few ideas from those that track extensively what the real difference in the gearing makes.

------------------
Gary Yates
1995 Red/Tan

 

[nsxtasy]

It's probably not going to make a huge difference, either way. It will help acceleration in any particular gear, but will hurt acceleration on any track where the lower shift speeds force you to upshift to a higher gear.

The main advantage of shorter gearing is at lower speeds, not at track speeds where you are (or should be) doing a lot of upshifting and downshifting.

 

[maomaonsx]

NSX-R 4.23, because you can then use the ATS LSD. It's more suitable for track than the stock LSD.

------------------
George W
Porsche 996 for sale!

 

[ACR_Motorsports]

For your track car, I would recommend the 4.23 Type-R R&P if it is NA. The ATS LSD would be really nice along with an Exedy Clutch.


Disclaimer: We sell/distribute the Exedy NSX Clutch.

Originally posted by ncdogdoc:
Just put a deposit on my second NSX! I will be making this one a track only car. The clutch is about gone, so while I have the transmission cracked open, was wondering what everyone thinks about the different R&P's when used on the track. I have wandered throught the FAQ, and have read many other posts, but would like to get a few ideas from those that track extensively what the real difference in the gearing makes.

------------------
www.acrmotorsports.com / 949-929-8973

[This message has been edited by ACR_Motorsports (edited 01 November 2002).]

 

[Jimbo]

Gary,

Congrats on your 2nd. What year, color, specifics?

Seems like 4.23 is the choice for the R&P.

Makes sense.

Obviously, Honda gave this a great deal of thought and also decided upon the 4.23 for their Type-R.

-Jim

------------------
1992 NSX Red/Blk 5 spd #0330
1991 NSX Blk/Blk Auto #3070 (Sold)
1974 Vette 454 4 spd Wht/Blk
1976 Honda Accord 5 spd, 3 door Blue/Blue
1977 Honda Accord - Custom - Under Construction
1986 Chevy Suburban
http://homepage.mac.com/jimanders/PhotoAlbum1.html

[This message has been edited by Jimbo (edited 01 November 2002).]

 

[Jason Weaver]

You dog!

I knew it was coming!Private me with all the details.

------------------
Jason

 

[sjs]

Nice! I've been wrestling with the fact that I really should part with one of mine in the spring. Part of me really wants to do the same as you, or even go GT2 with it (knowing full well that I wouldn't be spending enough on it to be competitive) I just keep telling myself I only need one for the street and that my track time should be focused on racing the 510 for another season. Still, it's very tempting...

Well, have fun!

 

[ScienceofSpeed]

I've found the 4.23 to be a really big aid on the track compared to stock geared cars in corners where you can't be in the right gear (and downshifting would put you mid corner at redline). Difference between stock geared NSX to 4.23 or 4.55 equipped NSX on the same track is noticeable. I agree, 4.23 gives you more options for a track car, and is also less expensive ($852.32 vs. $1695.00 from ScienceofSpeed).

Cheers,
-- Chris



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

 

[nsxtasy]

Originally posted by ScienceofSpeed:
I've found the 4.23 to be a really big aid on the track compared to stock geared cars in corners where you can't be in the right gear (and downshifting would put you mid corner at redline). Difference between stock geared NSX to 4.23 or 4.55 equipped NSX on the same track is noticeable.

But that's only on the same track. As Chris points out, you might have one track where, with the stock R&P, you "can't be in the right gear (and downshifting would put you mid corner at redline)". However, there might be another track where the speeds in the corners are slightly lower, so that the exact same phenomenon occurs with the 4.23 R&P. You can choose one R&P that will be better than another for any particular track. However, if you drive a variety of tracks, you will probably find that a given gearset is better on some tracks, while a different gearset is better on others. That's why it doesn't make a huge difference which R&P you get. (Although there may be an advantage of one R&P over another if you're trying to optimize your gearing for one particular track.)

 

[ScienceofSpeed]

Ken --

I would disagree, I think this would hold more true to transmission gear ratios than rear end gear ratio.

The small difference in RPM at the same speed in two otherwise identical cars (one with stock US 4.026 R&P and another with NSX-R 4.23 R&P) approaching the same corner will be far outweighed by the ability of the car with the 4.23 being able to accelerate faster, especially at lower speeds, exiting the corner.

For example, the two cars entering a corner at 100 mph in 3rd gear will only have a difference of about 300 RPM between the stock US and 4.23 gearing. This small difference in RPM on a car like the NSX with so much usable rev range is minimal.

When Honda designed the NSX-R R&P, they didn't arbitrarily pick 4.23 as a rear end gear ratio. They were limited to the dimensions of the ring and pinion gears to be able to keep the same basic transmission, so they could only go up or down a number of teeth (which is why there are no R&P's between the stock 4.026, NSX-R 4.23, and Comptech 4.55. I think Honda did their homework, and determined the 4.23 was optimal for performance and track driving.

I think what you are saying is very applicable to transmission gear rations though, just not R&P.

Regards,
-- Chris

Originally posted by nsxtasy:
But that's only on the same track. As Chris points out, you might have one track where, with the stock R&P, you "can't be in the right gear (and downshifting would put you mid corner at redline)". However, there might be another track where the speeds in the corners are slightly lower, so that the exact same phenomenon occurs with the 4.23 R&P. You can choose one R&P that will be better than another for any particular track. However, if you drive a variety of tracks, you will probably find that a given gearset is better on some tracks, while a different gearset is better on others. That's why it doesn't make a huge difference which R&P you get. (Although there may be an advantage of one R&P over another if you're trying to optimize your gearing for one particular track.)

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

 

[nsxtasy]

Originally posted by ScienceofSpeed:
I would disagree, I think this would hold more true to transmission gear ratios than rear end gear ratio.

Chris,

It can happen just as easily with the R&P. Differences are slight, and any particular track can favor the stock R&P or a higher-ratio one.

Let's take as our first example a racetrack with a lot of corners that you apex at 75 mph. This is the kind of turn that you referred to in your first post. With the stock NSX gearing, it probably doesn't pay to downshift to second. So you take the turn in third. With the 4.235 (or 4.55) R&P, you also take the turn in third. The higher numeric ratio R&P gives you an advantage because it accelerates faster in third than the stock R&P in third.

Let's take as our next example a racetrack with a lot of corners that you apex at 65 mph. Here, with the stock NSX gearing, it does pay to downshift to second. So you take the turn in second, accelerate out, and you get some nice acceleration past the track-out point and the first part of the straight, before upshifting to third when you run out of revs at 81 mph. With the 4.23 (or 4.55) R&P, it doesn't pay to downshift to second, because - just like the first example - you run out of revs too soon, at 77 (or 73) mph, which you hit before the track-out point. So you take the turn in third. Here, the stock R&P gives you an advantage because it accelerates faster in second than the higher numeric ratio R&P in third.

So, it depends on the track. On some tracks, the stock R&P will give you better acceleration than the higher-ratio R&P does; on others, it will be vice versa.

Similarly, as you go down the straights, you will have portions of the straights where you are accelerating faster with the stock R&P, and other portions where the higher-ratio R&P will give you better acceleration.

Here's one more way of showing this. On many tracks, let's say you spend a lot of time accelerating and decelerating between 60 mph and 120 mph. These is a very typical speed range on many tracks. I have chosen it because it includes two upshifts regardless of which R&P you use. Let's compare acceleration time from 60 to 120 mph. With a '91 with stock gearing, that acceleration takes 12.85 seconds. Add the 4.235 R&P, and it takes 12.84 seconds. Add the 4.55 R&P, and it takes 12.68 seconds. As you can see, the differences in acceleration at these higher speeds among the three R&P gears are quite minimal. Compare those with a hypothetical mod that adds 15 hp, which reduces the 60-120 time to 11.89 seconds, and you can see that the gearing differences are slight. The decrease in 60-120 time in going from the stock R&P to the 4.55 is about the same as doing a mod that adds 2 horsepower.

It's not that there's anything wrong or worse with a 4.235 R&P or a 4.55 R&P; there isn't. IT JUST DOESN'T MAKE MUCH DIFFERENCE in actual, measurable performance gain.

[This message has been edited by nsxtasy (edited 03 November 2002).]

 

[NSXTC]

Im gonna have to agree that it depends on the track, and how you drive on that track.

For example, you might get fast enough on a certain track that you are always hitting the redline well enough before the braking zone that you have to back off (and lose speed) but you dont't have enough time (or it's not worthwhile) to upshift.

In such a scenario, you'd actually want a taller R&P combo, so I have to say that yes, it does ultimately depend on the tracks you run and how you run them.

This is why you see so many club racer guys with a box full of different gear ratios. The fast guys take copious notes as to what setup and gears they run at each track.

But with the NSX, we really can't so redialy change R&P ratios, at least not with a typically modest club racing budget.

So, if I had to pick one ratio, Id probably go with the 4.23, noting the reasons Chris mentioned, and knowing that it's probably better to shift more than you want, instead of constantly being too low in the RPM band, and being prevented from putting the maximum power to the ground.

------------------
All My NSX'es Live in Texas

[This message has been edited by NSXTC (edited 03 November 2002).]

 

[Jimbo]

I'm going to have to agree with Chris...and Honda.

Somehow, I don't think that Honda's engineers just flipped a coin on this one.

-Jim

------------------
1992 NSX Red/Blk 5 spd #0330
1991 NSX Blk/Blk Auto #3070 (Sold)
1974 Vette 454 4 spd Wht/Blk
1976 Honda Accord 5 spd, 3 door Blue/Blue
1977 Honda Accord - Custom - Under Construction
1986 Chevy Suburban
http://homepage.mac.com/jimanders/PhotoAlbum1.html

 

[sjs]

We've been here before, and I said then as I do now that given no specific information about any particular track or corners, the slightly shorter R&P is the better bet for a one-size fits all. This time Chris and others have explained it well, and even nsxtasy's points help to make the case IMO. It does vary by track, and driver ability to enter/exit corners at the limits. It is for that reason that I would take the constant benefit of better torque within a given gear over the possibility of needing to make an extra shift, particularly given the broad power band of the NSX means that there are comparatively few shifts at many tracks to begin with.

That said, I wouldn’t judge the potential cost/benefit to justify the mod unless the car was used in truly competitive events, and even then it would probably not be very high on my list unless experience at my "home" track(s) indicated it.


[This message has been edited by sjs (edited 03 November 2002).]

 

[nsxtasy]

Originally posted by sjs:
It is for that reason that I would take the constant benefit of better torque within a given gear over the possibility of needing to make an extra shift, particularly given the broad power band of the NSX means that there are comparatively few shifts at many tracks to begin with.

Based on my own track experience (well over 100 track events including many as instructor), I would disagree that there are comparatively few shifts with the NSX compared with other cars. It's possible to drive it that way, but not for maximum performance.

The NSX does indeed have a very broad power band, due to its flat torque curve. This means that it can be driven in a wide range of speeds in a single gear. For example, on most tracks, you can drive a stock '91 5-speed in third gear on virtually the entire track. However, for maximum performance, you can improve lap times by doing a lot of upshifting and downshifting. This is something that comes with experience, and is not necessarily recommended for beginner track drivers who might find the additional shifting to be a distraction and are not usually overly concerned about eeking out every tenth of a second in lap time while they are just starting out.

Let's take GingerMan Raceway as an example:

Gingerman has a lot of turns where you need to slow to 60-65 mph to take the turn. The straights (2-3, 3-5, 6-7, 10-11, 11-1) are all medium-length, so at the fastest you may get up to 110 mph or so entering turn 11.

On this track, a beginner can drive a stock five-speed NSX in third gear all the way around the track, while learning the track and learning the performance of the car. However, for an experienced driver, I have found that it is worthwhile to take all the turns (except turn 4, which is flat out) in second gear, to have the benefit of the extra acceleration powering out of the turn. Doing this, I run out of revs and upshift to third on all five straights, and downshift again at the entrance to the turns at the end of those straights.

The NSX is really no different in this regard than most other cars. With the NSX, the ratio between the two gears being shifted on the track (2-3 and 3-4, and for tracks with a REALLY long straight, 4-5) is roughly 3:4, which is similar to most other cars. At some point, with the variation of speed on a track, there is a time when it makes sense to upshift and downshift. Granted, there might be a track somewhere that has a relatively narrow range of speed that JUST fits into a single gear, but that could be just as true for such a track with any other car. As long as the speed varies enough that it brackets the optimal shift points, you will get a benefit from shifting the NSX just as much as any other car with similar shift points. And, regardless of torque curve, most cars have gears that are similarly spaced with a 3:4 ratio, more or less.

However, I agree that the NSX can be driven with less shifting, for those not solely concerned with minimizing lap times.

 

[sjs]

We're certainly not talking about inexperienced drivers droning around to learn the line here. Still your points are valid, but they address an "also" rather than the main issue. Interestingly, your explanation of why more shifts is not necessarily bad may apply similarly to the selection of the shorter R&P. In your sample track, how often are you within a few hundred RPM of redline prior to braking for the next turn? Even if that occurs, how certain are you that the sum of time saved in all the other acceleration zones is not greater than the time lost to a shift or even feathering the throttle for an instant before braking?

And of course, Gingerman is not necessarily typical of what ncdogdoc can expect in his area.

 

[nsxtasy]

Originally posted by sjs:
Still your points are valid, but they address an "also" rather than the main issue.

Agreed.

Originally posted by sjs:
Interestingly, your explanation of why more shifts is not necessarily bad may apply similarly to the selection of the shorter R&P.

Sure.

Originally posted by sjs:
In your sample track, how often are you within a few hundred RPM of redline prior to braking for the next turn?

Not very often - primarily at turn 10, where the higher ratio R&P might force you into fourth gear. However, the higher ratio R&P would probably prevent you from taking advantage of second gear in some of the turns. For that reason, GingerMan is a track where the stock R&P will be best.

Originally posted by sjs:
how certain are you that the sum of time saved in all the other acceleration zones is not greater than the time lost to a shift or even feathering the throttle for an instant before braking?

At GingerMan, quite certain that it will achieve better lap times. But also reasonably confident that the difference won't be huge.

However, that is only for this particular track and the NSX gearing setup, and might not be true at another track or with another car. For example, the Integra Type R has shift points at 60 and 90 mph. With that car, it doesn't pay to downshift to second anywhere, and you don't gain much if anything with a brief upshift to fourth at the end of the straights, so you're just as well off leaving it in third all the way around.

Originally posted by sjs:
And of course, Gingerman is not necessarily typical of what ncdogdoc can expect in his area.

Of course not.

However, the main points remain that (1) some tracks will favor one R&P, others will favor another; and (2) either way, the differences between them won't be huge - almost certainly less than any power-adding mod.

 

[nsx1164]

Originally posted by ncdogdoc:
so while I have the transmission cracked open, was wondering what everyone thinks about the different R&P's when used on the track

In this situation you MAY also want to also consider the close-ratio JDM gearset (aka "short gears") if working with a 5-speed tranny.... IMO they offer a more significant change than a 4.06/4.23 R&P ratio.

Which is "faster" depends on a number of factors, many already discussed above and in other threads... which is "better" for you may also depend on a number of other factors,

Interestingly enough, Honda went with 4.23 for both the C30A (older) NSX-R and the newer C32B NSX-R

 

[sjs]

Originally posted by nsx1164:

In this situation you MAY also want to also consider the close-ratio JDM gearset (aka "short gears") if working with a 5-speed tranny.... IMO they offer a more significant change than a 4.06/4.23 R&P ratio.

I think that's an equally tough call. The biggest "selling" point for those gears seems to be narrowing the gap between 1 & 2, the reality/perception benefits have been much debated. Since the 1-2 shift is not of interest on almost any track then it is irrelevant. 2-3 is slightly closer, but "close" is not a problem with the NSX unless you have a very highly modified NA engine with a comparatively narrow power band. (I don't know of any other than full race.) 2, 3, 4 are also lower than the stock gears but as with the R&P, the benefits/drawbacks may vary. Also, I think the 3-4 shift is significantly wider than stock (as a % change) which may (very) slightly offset the fact that they are shorter.

So, I’d say that’s another doubtful value.

 

[huckster]

this is all theoretical for me--no personal experience. but logically it seems like there would be very little difference, as i think someone else said, one of the least impactful changes you could make. IMO, this would probably be my last mod, if i ever could justify doing it at all. I'd want an installed sc first to see how that effected my shift points on specific tracks, along with any other gofast mods, then would evaluate the r&p.

 

[Jimbo]

Well, I think in Gary's case the situation is different. He's in a position to easily make the change since he's having other work done.

-Jim

------------------
1992 NSX Red/Blk 5 spd #0330
1991 NSX Blk/Blk Auto #3070 (Sold)
1974 Vette 454 4 spd Wht/Blk
1976 Honda Accord 5 spd, 3 door Blue/Blue
1977 Honda Accord - Custom - Under Construction
1986 Chevy Suburban
http://homepage.mac.com/jimanders/PhotoAlbum1.html

 

[DanO]

Originally posted by nsxtasy:
At GingerMan, quite certain that it will [the stock R&P] achieve better lap times. But also reasonably confident that the difference won't be huge.

Like Ken, I also have put in a few hundred (or is it thousands

) laps at Gingerman; I have driven my own car with both the stock gears/R&P and with short gears/4.23. I have also driven the other NSX’s there with stock gears/4.55 and with the 6-speed. I agree with Ken and all others on this thread that there may be advantages/disadvantages of different gear ratios at different corners at different tracks, but the difference in overall lap time is mostly negligible. It may be next to impossible to figure out what is the single “best” compromise combination for all the tracks that you plan to run.

Tires and brakes are WAY more important than gears and I’d even take a 5-pt. harness over a specific gear set. Speaking of tires, rear tire circumference is also significant variable in this equation. If this is a track-only car then will you have big rubber in the rear? If so, this can increase your final “gear ratio” (sometimes significantly), which therefore may make the 4.23 R&P a good choice.

DanO




[This message has been edited by DanO (edited 04 November 2002).]

 

[Andrie Hartanto]

Depending on your tire size you use for the track, you might want to use 4:55.

If you use 275/40/17 or similar size tires for the rear of the NSX, this will negate the 4:23.

 

[ncdogdoc]

Thanks for the input guys. I have decided to stay with the stock '92 R&P. Will be installing a Dali ACT rebuilt clutch with JUN lightened flywheel (not exactly my first choice, but for the money quite a deal!) I do think that the ~$1g cost of the R&P could be better spent on suspension and lightening the chassis. I just bought a plastic hatch from SoS, and I am actively searching for the right seat for my fat ass! I am shooting for a final weight of 2400-2500 pounds, maybe less. Will keep everyone updated as I hope to pick up a set of Longacre scales for this project.

Suspension is still a question. I have the Comptech Koni/Eibach setup on my Targa now, and really like it. Had planned to pull it this winter and have Koni revalve and convert to dual adjustability, but may just leave it on the red car and shop for something else on the white car. Would love to find someone's used Penske, Moton, JRZ setup, but will likely go with Tein or Koni, possibly even the H&R setup. Not sure yet.

Will probably just run 15/16 wheels (I have three sets!) with both Hoosiers and Kuhmos depending on weather. Will use the stock brakes with Carbotech Panther Plus until Cobalt comes out with something better (listening Andie?). I have Project Mu floating hat disks all four wheels, and I was very pleased with the rotor temps in TX, up to 150 degree F cooler than other cars with OEM rotors and race pads (mine ran 250-350 degrees). I am working on some sort of underbody tray/splitter for the front, still not sure what to do with the rear. Just bought Quicksilver's wing, will see how that does.

BTW, it is a 1992 White with black interior, around 100,000 miles mostly stock. I will have many, many stock parts to sell very soon so e-mail me with your wants and needs and see if we cannot help each other out.
[email protected]

------------------
Gary Yates
1995 Red/Tan

 

[Andrie Hartanto]

Hi Gary,

if you are looking for a good suspension, get the Comptech pro series. It is the best suspension I ever tried by far. It is totally different Koni than the off the shelf koni yellow.