Would love some opinions on 4.55 R&P upgrade only

[sjs]

Two more references to "the dreaded RPM drop". A few months back during one of the many discussions on this topic, I posted a chart of the actual acceleration of a stock 5-speed. That chart quite conclusively supported the assertion of others that the weak acceleration in 2nd has almost nothing to do with falling off the power band, and everything to do with the taller gear yielding less torque multiplication and therefore less acceleration. That still means a shorted second, shorter R&P, or both will "fix" it, but not because of the difference in RPM.

This same concept is precisely why I am quite confident that unless you are at a track where you can run out of gears, the lower R&P will more likely help more than hurt. It's simple physics. The car will always pull harder at a given RPM in a given gear than it will with a taller R&P for the same reason it pulls harder at 75-80 MPH in second than it does in third. It's mostly the gearing, not the power band. Sure, with a shorter R&P you may find a corner or two where the gearing is just wrong, but that's always the case. And as I said before, there are narrow MPH ranges where acceleration is less because you are now in a higher gear, but that's minor compared to the gains over the broader range. So, without considering a specific track and corners, I still say that the lower R&P will most often help. It seems very straightforward.

The "short"/close gears are a little less certain especially at a track where 5th gear is used a lot because they move the big hole up there. However, I would still bet on them helping in most cases because so much time is spent in the lower gears. Do both, and then it may get questionable at big fast tracks.

 

[nsxtasy]

isn't it safe to say that the 4.55 R&P is the one change will help in nearly every way except for top speed?

No.

There are two points that people often ignore:

1. Shorter gearing (and we can use the 4.55 R&P as an example) improves acceleration WITHIN THE SAME GEAR, but may hurt acceleration at certain road speeds. sjs understands this, when he notes that acceleration with the 4.55 R&P is better 0-35, but is worse from 35 to 40. That's because with the stock gears, you can stay in first gear, with shorter gearing and better acceleration, than with the 4.55 R&P, where you would be forced to be in second gear, with longer gearing and worse acceleration than the stock first gear.

This can have a big effect on the street as well as on the track. For example, on some turns on some tracks, you would be forced to upshift with the shorter R&P, whereas you could stay in the lower gear with the stock gearing.

The second point that so many people miss is that shorter gears give the perception of helping more than they do. That's because you reach redline faster (so you see the tach revolve faster) and you reach the louder, upper part of the revband faster. But, that happens at a lower road speed. Once you take away the decrease that happens at the speed after upshifting, the net gain isn't anywhere near what it feels like it is.

Bottom line of all this is what Bob (1BADNSX) is saying. Shorter gears help at some speeds, hurt at others. Overall, their net benefit is as shown in the charts.

 

[Exotica]

Originally posted by nsxtasy:

...shorter gears give the perception of helping more than they do. That's because you reach redline faster (so you see the tach revolve faster) and you reach the louder, upper part of the revband faster. But, that happens at a lower road speed. Once you take away the decrease that happens at the speed after upshifting, the net gain isn't anywhere near what it feels like it is.[/B]

Since perception is reality (except on the track where results are what matters) - at the very least, shorter gears should improve the "fun Factor"!

[This message has been edited by Exotica (edited 04 November 2001).]

 

[DanO]

I put the short gears and 4.23 r&p on my car a few years ago $3,200. Personally, I don’t think they’re worth the $. IMO, the shorter gearing increases the fun factor a bit on the street (but a tall 2nd gear is also fun at 60-80 mph) and I bet the short gears/r&p are mandatory for a good autocrossing car. But, in general they hurt as much as they help at the track and I’ve been to several (of the same) tracks with both OEM and my current gear set. The reason I put them in is because “everybody” was raving about them at the time on the main NSX list and Bob hadn’t made his table yet so guys like me were convinced they made this HUGE difference so a bunch of us put them in and raved about them mostly because we just spent 3k on a marginal upgrade and were too embarrassed to admit the truth. On average, at the track there is no difference between OEM and other gear sets/R&P. On the street I bet a 4.55 will be a HUGE difference, especially on those long highway drives to/from NSXPO <g>. When I drove from Michigan to CA for NSXPO I wished I had the OEM r+p because of engine noise at highway speeds and I think the 4.23 only adds ~200 rpm.

I did not notice any gas mileage differences when I switched.

Bob, what’s the rpm difference between OEM, 4.23 and 4.55 r+p at 80mph in 5th gear?

So, in my opinion, the short gears / R&P are marginally good if and only if:

1) One is looking to have a little more spirit on the street at the expense of cruising comfort (R&P)
2) autocross
3) drag racing

I like your idea of just changing the R&P as it mitigates the cost somewhat; the expense will be a car that is not as fun to take on long highway drives.

For the track, I think I’d rather spend my money on other things like brake pads and a nice bratwurst lunch.

YMMV,
DanO

 

[1BADNSX]

Originally posted by sjs:
Two more references to "the dreaded RPM drop". A few months back during one of the many discussions on this topic, I posted a chart of the actual acceleration of a stock 5-speed. That chart quite conclusively supported the assertion of others that the weak acceleration in 2nd has almost nothing to do with falling off the power band, and everything to do with the taller gear yielding less torque multiplication and therefore less acceleration. It's simple physics.

Yes, it is simple physics, but your statements are misleading. Power, torque, and RPM are all related. The equation in any physics book is:

Power = Torque x RPM x 2 x Pi

Therefore you can not claim it "has nothing to do with falling off the powerband". Let me explain by giving an actual example.

From dyno data road horsepower and crank torque at 8000 RPM is 236 HP and 154.9 lbft. At 4500 RPM the results are 157 HP and 183.3 lbft.

In a stock geared 91, the RPM drops from 8000 to 4500 when you shift from 1st to 2nd. Your point is correct that the torque multiplication of the gearing changes from 4.06 (R&P) x 3.071 (1st gear) = 12.47 to 4.06 (R&P) x 1.727 (2nd gear) = 7.01. The torque to the road went from 1931.6 lbft (154.0 x 12.47) to 1284.9 lbft (183.3 x 7.01). The torque dropped 33.5% and this is what you feel as the dreaded RPM drop.

But you said it has nothing to due with power, but they are related and the exact same thing can be proved with power. The power before the shift was 236 HP and 157 HP after the shift. Yes, a 33.5% reduction. In fact, it is easier to determine shift points and acceleration due to power than torque because you don't have to make the adjustment from crank to tire (torque multiplication). The power is self adjusting with gear changes because as tire torque is higher than the crank, the tire RPM is lower than the crank.

Originally posted by sjs:

This same concept is precisely why I am quite confident that unless you are at a track where you can run out of gears, the lower R&P will more likely help more than hurt. So, without considering a specific track and corners, I still say that the lower R&P will most often help.

Not true. For some tracks it will help, others it will hurt. This is why racecars with easily changed final drives do not always run the shortest gearing. They pick the best final drive for each track.

Originally posted by sjs:

The "short"/close gears are a little less certain especially at a track where 5th gear is used a lot because they move the big hole up there. However, I would still bet on them helping in most cases because so much time is spent in the lower gears. Do both, and then it may get questionable at big fast tracks.

Yes. Tracks where the short gears have to upshift to 5th will kill this setup because of the hole (RPM drop) to 5th gear. But, no, you can not say it will most likely help in the lower gears without knowing the corner exit speeds of the track.

Jimbo, I didn't know the C5 weight and I just used what the original poster quoted.
A 91 NSX weighs 3010 lbs fully loaded with fuel and fluids. Therefore my estimate of 3200 lbs with a driver is reasonable.

Dano, The RPM for either 5-speed in 5th gear at 80 mph with different R&P's is shown below.

R&P RPM@80mph
4.06 3440
4.23 3584
4.55 3855

The higher RPM during highway cruise would be the biggest negative for the 4.55 R&P with a 5-speed. The 4.55 with a six-speed would be nice if you could afford it!

Bob


[This message has been edited by 1BADNSX (edited 04 November 2001).]

 

[ilya]

***The higher RPM during highway cruise would be the biggest negative for the 4.55 R&P with a 5-speed. The 4.55 with a six-speed would be nice if you could afford it!***

Very true. I would love to do it this way, but it really is too much for me right now.
I got a great deal on the 4.55 so I'm going for it. I'm sure it will make driving around town more enjoyable. I tend to go with quieter exhausts so hopefully that will help a bit on the freeway. I'm a real wuss when it comes to getting speeding tickets so I rarely cruise over 70 on the highway here.
I'm still under 25 and my great insurance rate relies on me keeping my good driver status.

The track is only an occasional luxury and something I do for fun when time and money permits. When it's time to get serious, I agree that I may have to rethink gearing. Until then, it's more about fun factor and low end power. I can still have fun at the track, but I'm not competitive enough to start worrying about tenths yet.

Now I just need to find a nice used set of headers to complete my system

They don't seem to come up very often.




[This message has been edited by ilya (edited 04 November 2001).]

 

[sjs]

Originally posted by 1BADNSX:
... Not true. For some tracks it will help, others it will hurt. This is why racecars with easily changed final drives do not always run the shortest gearing. They pick the best final drive for each track. ... Tracks where the short gears have to upshift to 5th will kill this setup because of the hole (RPM drop) to 5th gear. But, no, you can not say it will most likely help in the lower gears without knowing the corner exit speeds of the track.

If you read my posts carefully you will see that I made that point more than once, and was speaking in general terms which I always hate to do but sometimes can't avoid in such a discussion. I never said 90%, just most likely, which is to say better than 50/50. All that said, again, I would start with the shortest R&P I can for a given track without running out of top gear in the fast bits, then try to fine-tune from there for the idiosyncrasies of that track, assuming I'm a serious racer with a variety of gear sets and R&Ps. So, if you want to play the odds and already know what the fastest part of the track is like so you won’t run out of top gear, yes, always bet on the shorter R&P as the place to start because it will more likely help than hurt unless you already know something about the corners to suggest otherwise.

As for your calculations, they look OK as far as they go but as with most things in life you can't really identify and account for all the variables. Perhaps my biggest error was stating that it's simple physics because there are also other factors involved. But the big one you left out is quite simple. With the stock 2nd gear you suffer the RPM/torque/HP loss for only a small fraction of a second before you are back up to the same RPM range you would have been with a shorter second gear. How much time can you save/lose in that one or two tenths? (answer: not much) By contrast, you continue to reap the mechanical advantage across the entire gear. How much time can you save/lose the rest of the way through the gear? (answer: relatively speaking, a bunch) So, that already makes it 90% or more a matter of gearing. (I'll let you run the calculator.

)

It's been many years since I played with such calculations, partly because they always fall short of reality. So here's a dose of that. Even if you say that your calculations were only intended to explain the sensation of a big power hole in second at the moment you shift, I still contend that it is mostly gearing. If you measure actual acceleration in second gear at WOT starting from about 4k, you will see that it does not increase significantly as you pass through the range of RPM where you would normally land after an 8k shift from 1st and on up to the point you would hit it with lower gearing. The difference is very small, (which I've often said is the real beauty of VTEC)and again, it lasts only a small fraction of a second. Linking this back to my prior post, "the dreaded RPM drop" is mostly fiction, or at least incorrectly named which amounts to the same thing in this case because people continue to believe that 2nd sucks due primarily to falling out of "VTEC range". Simply not true. Both math and measurement show otherwise.

The other problem is, people have different ideas and measures of performance. What works best 0-60 is probably not the same as what works best in the 1/4 mile, and what works best at one track is likely to be different than the next. If your favorite thing (as mine was as a kid) is racing people from a 60 MPH punch on the highway but sometimes you get stuck doing it from a little higher, then the stock gearing is great. If you're into stoplight to stoplight racing (I never was) then stock gears suck. The NSX was never intended for either of course, but that's another story.

[This message has been edited by sjs (edited 04 November 2001).]

 

[DanO]

Originally posted by ilya:
The track is only an occasional luxury and something I do for fun when time and money permits. When it's time to get serious, I agree that I may have to rethink gearing.

You won't need to rethink gearing at the track with the 4.55...it will work just fine, better at some tracks than the 4.06 and worse at others but not enough to worry about for the kind of track driving we do.

DanO



[This message has been edited by DanO (edited 04 November 2001).]

 

[1BADNSX]

Originally posted by sjs:
But the big one you left out is quite simple. With the stock 2nd gear you suffer the RPM/torque/HP loss for only a small fraction of a second before you are back up to the same RPM range you would have been with a shorter second gear. How much time can you save/lose in that one or two tenths? (answer: not much)

The reason the RPM dropped so much in the first place is due to the lower mechanical advantage of the stock second gear and it doesn't change as long as you are in second gear, not a fraction of a second. But I do agree that it is not that big a deal. As I said earlier it accounts for about 0.2 seconds 0-60 mph.

Originally posted by sjs:
By contrast, you continue to reap the mechanical advantage across the entire gear. How much time can you save/lose the rest of the way through the gear? (answer: relatively speaking, a bunch) So, that already makes it 90% or more a matter of gearing. ]

Now I assume you are now talking about the R&P. If so, you don't always have an advantage because at many speeds, a car with taller R&P could have been in the next lower gear yielding an overall advantage. A point you keep ignoring.

Originally posted by sjs:
It's been many years since I played with such calculations, partly because they always fall short of reality. So here's a dose of that.

Professional teams use computer simulations to determine gearing before they arrive at the track. In fact, gearing advantages or disavantages are so small that they have to be calculated because you would be unable to duplicate equal laps on the track with only changes to the gearing.

Originally posted by sjs:
If you measure actual acceleration in second gear at WOT starting from about 4k, you will see that it does not increase significantly as you pass through the range of RPM where you would normally land after an 8k shift from 1st and on up to the point you would hit it with lower gearing.

No kidding! You had to measure this? The measured acceleration will always match the geared torque curve exactly minus aerodynamic drag proportional to velocity squared and rolling friction. Look at any NSX torque curve and you can tell what the acceleration curve will look like in any gear. And yes, the VTEC holds the torque curve nice and flat, therefore no gain in that particular gear, but that doesn't mean that dropping the RPM was OK because it was caused by a gear with lower torque multiplication to begin with.

I think Dano summarized it best:
"So, in my opinion, the short gears / R&P are marginally good if and only if:

1) One is looking to have a little more spirit on the street at the expense of cruising comfort (R&P)
2) autocross
3) drag racing"

I strongly agree with this and Ken's comments.
Bob




[This message has been edited by 1BADNSX (edited 04 November 2001).]

 

[JickedOut]

Ok Ok Ok... Here it is on paper.
My car is a 91 with the 4:55 ring an pinion.
I also have the Dali chip(more RPM) and I'm running 275/35/18....
This afternoon I went out with a radar gun and this is what I got...

At 80 mph in 5th I'm turning 3750 rpm.
1st gear at 8000 rpm = 41 mph
1st gear at rev limiter = 43.9 mph
2nd gear at 8000 rpm = 73 mph
2nd gear at rev limiter = 78 mph
3rd gear at 8000 rpm = 103 mph
3rd gear at rev limiter = 109 mph
4th gear at 8000 rpm = 133 mph
4th gear at rev limiter = 139 mph
5th gear at 7500 rpm = 155.5 mph

The road I was on was a 2 lane farm market road and I was out of road for any more speed..
At 7000 the car really started to slow down on it's pull. To top it out will take alot of road and some time.
You guy's with the stock gear I don't think can pull 5th out without some serious mods or a whole lot of road...
How often do we run 155+ anyway?

I can see no disadvantage to the 4:55....
If this gearing bothers you at cruz speed maybe you need a cadilac with a big overdrive. And what about when the local jick brain wants to race through town, 1st 2nd and 3rd are all that matters... I need all the help I can get these days!

 

[sjs]

Sorry guys, I can't leave it at this.

First, let's recall what the basic issue is. I stated that the "the dreaded RPM drop" was not the cause of the sudden drop off in acceleration when you shift to 2nd in a stock 3.0 5-speed. The phrase in question and ones like it are intended to attribute this phenomenon to the engine falling below "VTEC" range and thus having less HP than you would if by some means you were to enter 2nd at a higher RPM. (This could be achieved by a lower second gear, a lower R&P, shifting out of first at a higher RPM, or any combination of these.) What this is not about is the inherent large drop in RPM that accompanies any up-shift. Rather, the point I made speaks to the impact of the comparatively small difference in RPM due to specific gearing selection, which is to what "the dreaded RPM drop" refers. If a change in gearing accounts for about 0.2 seconds 0-60, then the HP loss attributed to "the dreaded RPM drop" (below the level of a slightly lower gear) is only a tiny fraction of that. I think you agree with me on this, so perhaps the real problem here is that you are not aware of the common belief among many that the acceleration hole is caused by falling below "VTEC" range, and that lower gears solve this by keeping you in "VTEC" range. That, as I have seen again and again, is what people typically mean with phrases like "the dreaded RPM drop".

Perhaps the definition of the core phrase in this tiff is the real problem? I suspect that we are in fact on pretty much the same page here, but started with that different perspective. But since it was my statement that was questioned it's up to me to clarify and define the terms I used. If your number of posts are any indication of how long you have followed this board, you may not be as keenly aware of the common misconception at the root of this as am I. Time and again people blame the 2nd gear bog on the wrong thing (falling a few hundred RPM too low and thus off the more aggressive cam lobes), and then when they observe that a lower 2nd or R&P yields a higher RPM, and it then feels much stronger, it appears to support their theory so they add 2 + 2 and get 6, believing that getting up on the higher lobes was what made the difference when in fact what they feel is mostly the increased torque multiplying from the lower gears. (No offense intended to them, it's an understandable mistake.)

I feel like I've said at least a dozen minor variations of the same thing now. Sorry, but apparently I'm still fishing for one that communicates the intended meaning.

So, when I see that reference come up repeatedly, I try to address it, as do others. I think if you go back and re-read my posts you will see that this is exactly such a case.

By the time I concluded that this might be just a misunderstanding, I had already addressed many of you most recent comments. I've decided to leave my remarks below because I think they may help to clear things up for anyone we have unintentionally confuse by all this.

Originally posted by 1BADNSX:
The reason the RPM dropped so much in the first place is due to the lower mechanical advantage of the stock second gear and it doesn't change as long as you are in second gear, not a fraction of a second. But I do agree that it is not that big a deal. As I said earlier it accounts for about 0.2 seconds 0-60 mph.

My point was, and remains that the sudden sense of poor acceleration when you hit 2nd is the gearing, not the engine RPM falling too low and thus being off the power band compared to a lower 2nd or R&P. (Refer back to your math showing a 33% drop in power and comparing it to the similar change in gearing to show that they play equal parts in this phenomenon.) The fraction of a second I mentioned is the time before you get back to the higher RPM that the lower gear would have yielded at the shift, in addition to the gearing. From that point on it's only a gearing issue.

Originally posted by 1BADNSX:
Now I assume you are now talking about the R&P. If so, you don't always have an advantage because at many speeds, a car with taller R&P could have been in the next lower gear yielding an overall advantage. A point you keep ignoring.

Clearly you have forgotten my earliest posts. It was I who first made exactly that point. But no, I was not specifically talking about the R&P. Since the effective ratio of 2nd is lowered with either mod, the fundamental point remains true, more torque multiplying through the entire gear. The difference in the two mods (or a combination of them) is their inherent tradeoffs and when or if you pay back what you gained. That of course depends on other factors such as whether or not you will need to up-shift before reaching the next corner or completing a 0-X run etc. Again, not relevant to this discussion.

Originally posted by 1BADNSX:
Professional teams use computer simulations to determine gearing before they arrive at the track. In fact, gearing advantages or disadvantages are so small that they have to be calculated because you would be unable to duplicate equal laps on the track with only changes to the gearing.

True, but irrelevant. I think I said serious racers, not mega-dollar professionals. For the rest of us, gearing choices at a new track come from a combination of asking others, guessing based on what the track looks like, and trial and error on the track itself. None of which has anything to do with my point or this discussion. What is relevant are the points I already made. Until you know (by whatever means) the specifics of each corner, the smart move is to use a gearing combination that is just manageable for pulling away in first, and will just about max out at the fastest part of the track. If you have the luxury of different choices for all the intermediate gears then you space them out logically for acceleration in the most used ranges until you have more information about specific corners. ( I feel like I'm stating the obvious, but I keep catching flack. )

Originally posted by 1BADNSX:
No kidding! You had to measure this? The measured acceleration will always match the geared torque curve exactly minus aerodynamic drag proportional to velocity squared and rolling friction. Look at any NSX torque curve and you can tell what the acceleration curve will look like in any gear. And yes, the VTEC holds the torque curve nice and flat, therefore no gain in that particular gear, but that doesn't mean that dropping the RPM was OK because it was caused by a gear with lower torque multiplication to begin with.

Nice. But to my amazement, I think you have just agreed to the only point I was trying to make!!!

So do we agree, or do we need to take this outside?

 

[nsxtasy]

I think we agree.

I understand and agree with sjs's point about the VTEC range and dropping out of the VTEC range being a myth.

In addition to his excellent explanation for this myth (the fact that acceleration worsens so much when a downshift puts the engine out of VTEC range, when in fact it's the big difference in gearing that causes the poorer acceleration), there is another reason why people THINK there is better acceleration in VTEC than below the VTEC range. You can hear the engine get louder when the additional cam lobe kicks in at the VTEC crossover point. This creates the PERCEPTION (there's that concept again) of additional acceleration at higher revs. In fact, what VTEC does is keep the torque curve flat as revs rise (flat torque curve = constant acceleration) instead of dropping as it otherwise would. A year or so ago there were some g-meter plots posted on this board that illustrated this very well. Where's the Forums Nazi when we need him?

 

[Exotica]

My question is a little off topic...but is the short gear setup on the 5 speed at all similar to the first 5 gears on the 97+ models? Meaning, aside from the additional HP on the newer models, does the 6 speed gearbox offer similar performace as the short gears on the older models?

 

[1BADNSX]

Originally posted by sjs:
So do we agree?

Yes, except for a small misconception of my example showing the drop in power and torque to the road being equal. I wasn't trying to show it was half torque multiplication and half power. I was trying to show that the two are equivalent. Geared torque is effectively power when determining acceleration. Because they are related through RPM, claiming the drop in acceleration is due to power or torque is not possible, they are directly related. Because of this the nice thing is you don't have to go through the hassle of determining the torque multiplication change after a shift. All you have to do is compare the power before and after the shift and you will get the same answer.

Bob

 

[nsxtasy]

Another possible (but wrong) inference that someone may make is thinking that more power = more acceleration.

Power is a good measure to indicate the optimal shift points (shift where the power before the upshift equals the power after the upshift, or at redline if it never drops off that much like on our cars).

However, torque at the wheels (engine torque times gearing minus drivetrain losses) is the force that provides acceleration. Within a single gear, the torque curve shows how your acceleration varies as you move up the revband. In the NSX, the torque curve is relatively flat, which means that acceleration within each gear is roughly constant (even though power rises steadily).

[This message has been edited by nsxtasy (edited 05 November 2001).]

 

[smoore]

i was to believe that the 4.23 and the short tranny gears was the best all-around set up for the nsx

 

[nsxtasy]

Bottom line is that there isn't that much difference among any of these setups - and so changing setups may not be worth the money.

That doesn't mean the short gears aren't better than stock - they ARE better than stock (slightly, not dramatically). The six-speed is even better than the short gears, though.

 

[ak]

iLya, maybe you can get a hold of Gtech meter and do baseline run VS after mod run. Best way to settle any argument I say.

 

[ilya]

Not a bad idea. It won't prove anything conclusively as there are too many factors. However, if I can get 5-10 good runs in before and 5-10 after, it would be interesting to see the overall impovement in times (if any). It would at least show how much time 'I personally' was able to take off with the upgrade to my NSX.

I'll see at the next meeting if anyone has one of these available.

 

[sjs]

Originally posted by ak:
iLya, maybe you can get a hold of Gtech meter and do baseline run VS after mod run. Best way to settle any argument I say.

Please, don't rely on the snap-shot approach of a G-Tech, which is better than a stopwatch from 0-x, but still a very narrow view of what's happening. If necessary, I'll ship you my G-Cube so you can record the real-world acceleration curve before and after

 

[ak]

Originally posted by sjs:
Please, don't rely on the snap-shot approach of a G-Tech, which is better than a stopwatch from 0-x, but still a very narrow view of what's happening. If necessary, I'll ship you my G-Cube so you can record the real-world acceleration curve before and after

I'm just suggesting a cheap and easy method that can be used to capture the feel of the mod in some numbers that we can understand. If you can do more detailed and accurate measurements, i'm all for that.

 

[DanO]

Originally posted by JickedOut:
Ok Ok Ok... Here it is on paper.

What exactly are you trying to prove with your experiment? Speeds at redline have been on paper for years.

This afternoon I went out with a radar gun and this is what I got...

Or you can use a calculator and the table at www.nsxprime.com/FAQ/Technical/gearratios.htm to more accurately figure out speed & RPM with different gear ratios and R&Ps without a radar gun and the risk of an expensive speeding ticket. I admit that using a calculator is not as much fun, but it provides the same "paper" results

I can see no disadvantage to the 4:55

Um….disadvantages:
1) Expensive
2) Marginal price/performance ratio (comparred to Basch SC

)
3) 3855 RPM at 80mph in 5th
4) Possible increase in fuel consumption
5) Hard to uninstall
6) May hurt resale value
7) Questionable advantage at road courses
8) Limits top-end speed
9) Increased engine wear

Advantages of 4.55:
1) Faster than 4.06 R&P from 0mph to X (where X is less than 168)
2) Probably much better at the autocross course then stock R&P
3) More zippy feeling on the street
4) Cheaper than short gears

If this gearing bothers you at cruz speed maybe you need a cadilac with a big overdrive.

This may be your taste now, but keep in mind that your taste may change over time and the R&P is a difficult mod to undo. For example: after a few years of loving the loud RM exhaust on my NSX, my tastes changed and I no longer wanted to hear that loud rumble in the cabin when cruising down the highway; it was easy to change out the exhaust-—the R&P is not easy to change out.

And what about when the local jick brain wants to race through town, 1st 2nd and 3rd are all that matters

If all that matters is being faster than a "jick brain" (whatever that is) from a stoplight in a straight line, then you are correct, the 4.55 R&P is for you! And so is a Supra boosted to 30psi with 50 decals and a 4” exhaust pipe. Most NSX enthusiasts don’t care about 0-60 times. We’ve never had a 0-60 or drag race at any of our NSXPOs, but we do have hundreds of people who sign up for the road courses! Therefore it’s wise to remember these people when we offer advice.

Remember that our audience here is big and diverse and what we write can influence people’s buying decisions. Almost every performance modification has an upside and a downside and I think it’s our responsibility to report both with all or our modification reports. That way, people can make a more informed purchasing decision.

I also have the Dali chip(more RPM)

The Dali chip is a good mod with to do with the short gears and or short R&Ps because it extends the range a bit. The downside is that running over factory redline could grenade your engine. If you use the Dali chip and drive the car hard then I’d suggest keeping your engine in topnotch condition.

DanO
’92 w/Short gears and 4.23 R&P and Dali chip

[This message has been edited by DanO (edited 05 November 2001).]

 

[ilya]

***Um….disadvantages:
1) Expensive
2) Marginal price/performance ratio (comparred to Basch SC )***

I agree with you here too. I was not ready to spend that kind of money. A SC or turbo would have been the choice for me.

I got very lucky in that one came up for 1K plus my stock ratio. I'm doing the clutch soon anyway, so for an extra grand I have a 4.55R&P. Didn't want to pass that up.

As long as FedEx doesn't lose the package I sent. It wouldn't be the first time. I put the value of the stock 4.06 R&P I sent at 1K dollars.

I don't drag race on the street. It's more for personal enjoyment and amusement. Also for the occasional club drives we have.

 

[DanO]

Ilya, are you going to change the torque on the LSD while you're in there? Most people who upgrade the R&P also increase the torque on the LSD for better cornering (at the expense of tire wear). You may want to consider giving Mark B a quick call to get his advice on this subject as he gave a pretty good talk about this at the seminar this year at XPO.

DanO

 

[ilya]

I am now that you mentioned it.

Larry Garcia will be doing the work so I will see what he usually does. I don't mind increased tire wear if there is an improvement.
As long as it's not too much and I don't break an axle.

Was there any minutes or writeup on the discussion Mark B. had? I would definitely love to read about it. It would make a good addition to the FAQ too.