Short Gears and R&P 4.23

[1BADNSX]

Nope.
I think this mod should be good for your exit speed when you come out of a corner

For road course performance, changes to gearing are very track specific and not very productive. Below are a few examples of different corner exit speeds and how much time it would take an NSX to cover a certain distance after starting the straight-away at that exit speed. Different gearing combinations are shown with positive numbers represented as time saved (good), but many cases achieve negative results due to the speed bands where performance is diminished. As you can see the overall gain is very low even for the most beneficial cases.

I race against many guys (in an M3, not an NSX) who do not understand this and they think lower gearing is always better as long as you don’t run out of RPM. This is not always the case and gearing is a very ineffective use of modification dollars, especially on a road course race track.

Bob

 

[docjohn]

I have spoken about my experience with shorties and 4.55 before,and this thread is about the 4.23,which I have not driven,my gut tells me I might like it better

 

[nsxtasy]

Below are a few examples of different corner exit speeds and how much time it would take an NSX to cover a certain distance after starting the straight-away at that exit speed. Different gearing combinations are shown with positive numbers represented as time saved (good), but many cases achieve negative results due to the speed bands where performance is diminished. As you can see the overall gain is very low even for the most beneficial cases.

What an excellent analysis tool! Thanks for posting!

 

[LJSB]

Nice charts 1BADNSX.

Like I said, I'm not a track guy (I'm a poser :biggrin: ) and wouldn't know from experience how these gears work on the track. Your charts really do make your point being the type of track would make or break this mods cost effectiveness in terms of real return.
Again, nice job.

On the street at lower speeds, like the first two charts, as I drive, it would seem from your chart that this mod does exactly what I've been feeling and that is a snappier response. I expect the reason they sell these gears in Japan models and not here in the US is, as I've read, due to the difference in the typical roads found in the two countries. The performance models with the 4.23 R&P again may be with the tracks of Japan in mind.
This mod isn't a supercharger but for the way I drive on the street it is a nice tweak. Perhaps it is not a lot of bang for the buck but I like it and would do it again. I like the feel.

One thing I did notice is that the charts seems to show that the 6 speed has a great balance.
Thanks.

 

[RacerX-21]

Here’s my take on the subject- if I needed to pick one set of gears between;
Stock, short gears, or a combination with the three common sets of ring and pinions; I would run the short gear set with the OE ring and pinion. It has had the best average gearing for the tracks you will encounter. This combination is far better for road racing then OE, and if you’re driving on the street it will still have the same final drive ratio. (Another factor- I’m told that the aftermarket ring and pinions are less durable then the OE when used with high horsepower). The short gears even your ratios and bring them lower from 2nd to 4th. 1st and 5th stay the same. The ring and pinions lower everything, making 1st unusable, and you still have the poor 2nd gear transition. A combination of short gears and the R&P bring your gearing way too low. Of course every track is different but I think this is the best average… especially if you also run on the street. More transmission info can be found here http://www.dalmotorsports.com/shows.asp (#16)

 

[goldNSX]

I've played a little bit around with an Excel-spreadsheet. Unfortunately I can't load it up. So it's only a gif. pm me if you like the full spreadsheet to play with it. It supports mph and kmh. I'm not sure if all numbers are correct. The goal is to show (or not) fun-factor with different setups. I know that some of the setup will be good in the fun-factor-point of view but are even slower overall compared to stock. Thanks to 1BADNSX for the helpful input with the diagrams. :wink:
As I'm not racing my car, the fun-factor is far more important. Still not decided.

 

[docjohn]

Nice discussion,I think I may try the oe r&p with the shorties next go round.

 

[goldNSX]

here are the ratios I used

 

[TurboLexus]

Here’s my take on the subject- if I needed to pick one set of gears between; Stock, short gears, or a combination with the three common sets of ring and pinions; I would run the short gear set with the OE ring and pinion.

That's what i've got, pretty happy with it. Seeing as how I drive at fairly high speeds on the parkway from time to time, I felt I was already reaching as high an rpm as I wanted to see, I don't think i'd be happy with a 4.23 ring and pinion, let alone a 4.55, and i'm curious if those that have the CT R&P feel comfortable keeping the motor at such elevated rpm's for extended periods when driving into triple digits, as I wouldn't. Behaviour on the track was a secondary concern for me as this is also my daily driver...but Rob's evaluation confirms what i suspected. Good thread.
- Jon

 

[goldNSX]

The Excel spreadsheet above can be downloaded from http://www.reuschsoftware.ch/short_gears.zip

Greetings,
Thomas

 

[goldNSX]

1BADNSX, do you have some graphic analysis with starting points at 20 or 30 mph? It would be very helpful for my driving conditions.

Thanks in advance,
Thomas

 

[LJSB]

Another factor- I’m told that the aftermarket ring and pinions are less durable then the OE when used with high horsepower

Peter Cunningham, famous Real Time ex-NSX driver said the same thing at a NSXNE tech session at Lime Rock 2002.
I don't know if he used the stock or the 4.23.

One important point is that the 4.23 R&P IS OEM. It was sold in Japan and came in the NSX Type R, 5 speed models. It is only available here through importing vendors like SOS or Dali.
As I understand it, in Japan all the 5 speed cars were sold with the short gear set.
For more info see the FAQ:
http://www.nsxprime.com/FAQ/Performance/gears.htm

 

[LJSB]

Nice discussion,I think I may try the oe r&p with the shorties next go round.

When and if that happens and, you want to sell the 4.55, let me know. :smile:

 

[RacerX-21]

Peter Cunningham, famous Real Time ex-NSX driver said the same thing at a NSXNE tech session at Lime Rock 2002.
I don't know if he used the stock or the 4.23.

One important point is that the 4.23 R&P IS OEM. It was sold in Japan and came in the NSX Type R, 5 speed models. It is only available here through importing vendors like SOS or Dali.
As I understand it, in Japan all the 5 speed cars were sold with the short gear set.
For more info see the FAQ:
http://www.nsxprime.com/FAQ/Performance/gears.htm

Thats a good point about the two OE ring and pinions. In 2002 Peter ran a 6-speed with the stock R&P.

 

[1BADNSX]

1BADNSX, do you have some graphic analysis with starting points at 20 or 30 mph?

I have the raw data for all the speeds, but when I wrote the NSXDriver article, I didn't plot below 30 mph because even the slowest road course hairpins are faster than 20 mph. Below are the 30 mph and 90 mph graphs.

Bob

 

[LJSB]

1BADNSX,

I don't understand some things about what your graphs represent.
I know I might seem a little slow but I sincerely don't get it.
Help me to understand.
Are the illustrations for 4.23, 4.55, 4.23 +short gears, 4.55 +short gears all with the 5 speed 3.0 and the six speed, 6speed 4.55 with the 3.2 motor?

Also as I understand, the graph begins with all at 30 mph but what gear and rev?
It would seem that both gear choice and rev number could make a dramatic impact on the results.
I'm sure I'm missing something that may be obvious to you but sometimes I'm a bit slow :redface: and, not just in my car if you get my drift. :smile:

Please explain.

 

[Hrant]

I am with Joe on this one.

Based on my readings, I thought the 6 speed (presumably in 3.2L) was the "best overall" given all the conditions described except for over 70 mph. Or did I miss something too

Edit: The clarification below by 1BADNSX is quite helpful, and yes we are all excited about this thread and its potential. But let me push the envelope in here. First, again unless I am missing something, don't the graphs confirm that for a 3.0L the 6 speed (without the 4.55) is better overall except over 70 mph?

Secondly, if the 6 speed is this good for 3.0L then wouldn't the 6 speed with 3.2L be even better because of the added torque on the low end and higher HP on the upper end? If so, then just curious what improvements does one get from the Type R gearing on a 3.2L over the baseline - theoretically speaking?

 

[1BADNSX]

1BADNSX,

I don't understand some things about what your graphs represent.
I know I might seem a little slow but I sincerely don't get it.
Help me to understand.
Are the illustrations for 4.23, 4.55, 4.23 +short gears, 4.55 +short gears all with the 5 speed 3.0 and the six speed, 6speed 4.55 with the 3.2 motor?

Also as I understand, the graph begins with all at 30 mph but what gear and rev?

The graphs only compare gearing changes and this particular comparison is for a stock 3.0 engine with a vehicle at 3200 lbs with driver. The other NSX Driver article specifically looked at acceleration differences from a standing start and compared weight and horsepower changes, in addition to gearing changes. But making changes to horsepower or weight in this example would totally pollute the data, so they are all held constant.

The starting point for each speed is whatever that particular combination would allow for proper gear selection. You asked about the 30 mph graph. In that case, they all/could be in 1st gear and the only difference is for the R&P. The engine would be at 5137 RPM for all the cases with 4.06 R&P (stock, short, and 6-speed), while the 4.23 R&P would be at 5352 RPM, and the 4.55 R&P would be 5757 RPM. This is why the first 100 feet or so of this particular graph shows no difference for many of the gearing permutations.

Yes the 6-speed with 4.55 R&P will win most general comparisons. But it comes with a price tag. What I hope most folks notice is that gearing only makes a few 10ths difference (sometimes in a bad way), while tires/suspension can be 2 to 6 seconds each, and you all know the driver has the biggest influence.

Bob

 

[LJSB]

First off I want you to know I am impressed by the ability to represent this in the manner that you have. Well done 1BADNSX. I am envious and couldn't do it and wish I knew how.
At thirty miles an hour, with the short gears and 4.23 R&P I would think it to be more advantageous to raise the revs to hit hard into the next highest gear say second gear. If both stock and short/4.23 went into second at the same rev it should be in favor of the latter. This would seem to me to be the character advantage of the short/4.23 setup though it would in theory fade as the starting exit speeds went higher. I can't say for sure having not the stones to have been done this say at 80 mph on the track with other folks trying to beat me on the exit. You have. Me, I just watch. :smile:Chicken that I am. :redface:

Even .1 of a second per corner per lap translates into a good lead rather quickly.

 

[goldNSX]

I have the raw data for all the speeds, but when I wrote the NSXDriver article, I didn't plot below 30 mph because even the slowest road course hairpins are faster than 20 mph. Below are the 30 mph and 90 mph graphs.

Bob

Excellent graphs, Bob. Thank you very much. I think I'll go with the shorties and the 4.23 R&P with the following reasons with the following priority:
1st: the shorter second gear helps me to accelerate from 30 to 60 (leaving a village) or 50 to 65 (overtaking) or 20 to 60 (climbing up a hill with slow corners). I can go to second at 50 mph with 5700 rpms which help me much to overtake sunday drivers.
2nd: For starting points above 60 mph I'll take the third gear starting with 5000 rpm.
3rd: I know it's for the fun factor only, but this is very important to me as I don't race my car
4th: It's still OEM quality and durability
5th: I'll take the slower gearing above 80 mph into account but these speeds are only 0.1 percent of my driving routes.
6th: Comfort/noise at 80 mph is ok as the rpms don't climb very much.

Disadvantages or things to work at:
Fuel consumption
Tire wear due to traction problems with the Eibachs
Exhaust noise, in fact very linear in my case
My mechanic must agree on the 4.23 R&P to install it

Why the 4.23 R&P: I don't think it's a breakthrough, but for the speedlimits we have and the overtaking situations I face it's a little bit better than the shorties alone. And it will help me in slow corners climbing up a hill. The 4.55 would force me to shift too early and the rpms at 80 mph would be too high. Finally if's the gearing of the 92 Type-R.

Thanks for everyone. I'll let you know as soon as it's installed.

BTW: HAPPY NEW YEAR!

Greetings,
Thomas

 

[Onsoku]

Any updates?

 

[goldNSX]

Any updates?

Unfortunately Honda Europe can't find the oil pump gear. Maybe they never used it here. All other parts are ready for install. I think I'll have to wait till mid or end of April. I'll let you know.

Greetings,
Thomas

 

[goldNSX]

Finally the parts are ready for install which will happen next week.

Greetings,
Thomas

 

[ATERPAK]

You should love it. I loved mine. I also installed a new clutch with a lightened flywheel and that really helps to get things going. Still I would love to get Comptech's supercharger for that final kick in the pants feel. If you didn't know already the demand for the supercharger is extremely high. They are on back order I believe on the order of 18 units. Glad to see things are moving for them on this item.

 

[Onsoku]

You should love it. I loved mine. I also installed a new clutch with a lightened flywheel and that really helps to get things going. Still I would love to get Comptech's supercharger for that final kick in the pants feel. If you didn't know already the demand for the supercharger is extremely high. They are on back order I believe on the order of 18 units. Glad to see things are moving for them on this item.

Mine is at Applied Motorsports. I'm getting a Centerforce clutch, NSX-R gears and the 4.23 installed. Still waiting for CompTech to send the s/c...I guess there really is a backlog then! That most likely happened from the group buy in Feb.