Ilya, 4.55
- Thread starter JChoice
- Start date
Hello Everyone! I'm back from my extended vacation and business trips. Sorry for not responding.
I still have the 4.55 sitting in my trunk. I've been so busy I haven't even had time to install it. I'm going to be working every weekend this month, so looks like I'll have to be waiting until Feb. to do this.
It's tough having that sitting in your car and not being able to install it for so long.
I still have the 4.55 sitting in my trunk. I've been so busy I haven't even had time to install it. I'm going to be working every weekend this month, so looks like I'll have to be waiting until Feb. to do this.
It's tough having that sitting in your car and not being able to install it for so long.
Interesting thread.
One of my hypotheses about NSX gearing for a while has been that stock gears + 4.55 is better than short gears + 4.235, because in the former case, you end up with much shorter 4th and 5th gears, which seems like it would make a huge difference in the, say, 90 to 150mph accelleration range (like coming onto the straight at SIR). I'd love to see a numerical analysis of kind of accelleration between stock gears + stock R&P, stock gears + 4.55, and short gears + 4.235.
(other premises of that hypothesis are that the driver doesn't mind higher revs on the highway, and that stock + 4.55 is better in 1st, and almost as good in second and third).
I really see where Ken is coming from saying it really doesn't seem worth it to upgrade gears (unless, of course, you're building a racecar, and you need the different gears), because the cost/performance ratio isn't favourable. However, the one variable is transmission health. For example, if you have to open the tranny anyway, because you blew a snap ring, or your synchros are dead, or whatever, it's not really clear whether you should go ahead and spend an extra $2000 on shorter gearing while it's open, or save that $2000 toward your Basch Boost kit, or a Dali triple-plate carbon fiber clutch, or beer, or something else.
Also, on the question of time-to-speed... I think everyone else has touched on this pretty well, but I kinda liked the way I thought of it. =) Namely, the clock doesn't stop ticking during upshifts. However, common sense dictates that you're not accellerating during shifts, therefore, people can conveniently ignore time taken to shift when building a perception of speed. Therefore, from a purely visceral evaluation of fun with no concern of stop watches, a 4.55 ring an pinion is about 12% (4.55-4.062 / 4.062) better than 4.062. =)
Of course, when they line up next to the person that spend their $2000 on a 70-shot RM Nitrous kit, they won't be having so much fun.
-Mike
One of my hypotheses about NSX gearing for a while has been that stock gears + 4.55 is better than short gears + 4.235, because in the former case, you end up with much shorter 4th and 5th gears, which seems like it would make a huge difference in the, say, 90 to 150mph accelleration range (like coming onto the straight at SIR). I'd love to see a numerical analysis of kind of accelleration between stock gears + stock R&P, stock gears + 4.55, and short gears + 4.235.
(other premises of that hypothesis are that the driver doesn't mind higher revs on the highway, and that stock + 4.55 is better in 1st, and almost as good in second and third).
I really see where Ken is coming from saying it really doesn't seem worth it to upgrade gears (unless, of course, you're building a racecar, and you need the different gears), because the cost/performance ratio isn't favourable. However, the one variable is transmission health. For example, if you have to open the tranny anyway, because you blew a snap ring, or your synchros are dead, or whatever, it's not really clear whether you should go ahead and spend an extra $2000 on shorter gearing while it's open, or save that $2000 toward your Basch Boost kit, or a Dali triple-plate carbon fiber clutch, or beer, or something else.
Also, on the question of time-to-speed... I think everyone else has touched on this pretty well, but I kinda liked the way I thought of it. =) Namely, the clock doesn't stop ticking during upshifts. However, common sense dictates that you're not accellerating during shifts, therefore, people can conveniently ignore time taken to shift when building a perception of speed. Therefore, from a purely visceral evaluation of fun with no concern of stop watches, a 4.55 ring an pinion is about 12% (4.55-4.062 / 4.062) better than 4.062. =)
Of course, when they line up next to the person that spend their $2000 on a 70-shot RM Nitrous kit, they won't be having so much fun.
-Mike
The R&P was sold to me by a chap with a 600+ HP Turbo NSX. His 1/4 mile times were suffering because of having to upshift to 4th gear with the 4.55 R&P. He wanted the stock gearing back.
The increase is questionable for what it costs retail, but at the deal I received it will be worth every penny in regard to fun factor.
Then again, with the cash offers I've had for it since it came into my posession... it's been tough not to sell it on the spot and make some money.
I have a baby on the way and there is an outside chance I may sell it to put some more money in the bank. Then again... there's no rush. I've had to fend off the buyers ever since I got it.
No offers yet you vultures. I promised Larry first dibs if I do, and he wants it bad for that price.
Every time I get sensible and decide I should sell it.... I visit the shop and get all fired up again!
[This message has been edited by ilya (edited 07 January 2002).]
The increase is questionable for what it costs retail, but at the deal I received it will be worth every penny in regard to fun factor.
Then again, with the cash offers I've had for it since it came into my posession... it's been tough not to sell it on the spot and make some money.
I have a baby on the way and there is an outside chance I may sell it to put some more money in the bank. Then again... there's no rush. I've had to fend off the buyers ever since I got it.
No offers yet you vultures. I promised Larry first dibs if I do, and he wants it bad for that price.
Every time I get sensible and decide I should sell it.... I visit the shop and get all fired up again!
[This message has been edited by ilya (edited 07 January 2002).]
Are you sure you don't mean he was hitting 5th gear? 3rd gear with 4.55 runs out at 101mph, which you can hit with a stock NSX in the quarter. 4th gear runs out circa 125mph, which I'd hope he'd be able to surpass with 600hp....
-Mike
I'd love to see a numerical analysis of kind of accelleration between stock gears + stock R&P, stock gears + 4.55, and short gears + 4.235.
stock + stock / stock + 4.55 / short + 4.235
0-10 MPH 0.71 0.63 0.68
0-20 MPH 1.46 1.30 1.40
0-30 MPH 2.16 1.91 2.06
0-40 MPH 2.84 2.53 2.72
0-50 MPH 4.05 3.87 3.90
0-60 MPH 5.31 4.98 4.96
0-70 MPH 6.59 6.15 6.12
0-80 MPH 7.98 7.99 7.98
0-90 MPH 10.16 9.76 9.68
0-100 MPH 12.30 11.74 12.04
0-110 MPH 14.71 14.60 14.75
0-120 MPH 18.16 17.66 17.83
0-130 MPH 22.27 21.52 21.68
0-140 MPH 27.64 27.86 28.81
0-150 MPH 37.78 37.02 39.82
¼ mile 13.67 13.43 13.48
stock + stock / stock + 4.55 / short + 4.235
0-10 MPH 0.71 0.63 0.68
0-20 MPH 1.46 1.30 1.40
0-30 MPH 2.16 1.91 2.06
0-40 MPH 2.84 2.53 2.72
0-50 MPH 4.05 3.87 3.90
0-60 MPH 5.31 4.98 4.96
0-70 MPH 6.59 6.15 6.12
0-80 MPH 7.98 7.99 7.98
0-90 MPH 10.16 9.76 9.68
0-100 MPH 12.30 11.74 12.04
0-110 MPH 14.71 14.60 14.75
0-120 MPH 18.16 17.66 17.83
0-130 MPH 22.27 21.52 21.68
0-140 MPH 27.64 27.86 28.81
0-150 MPH 37.78 37.02 39.82
¼ mile 13.67 13.43 13.48
Those are all 0 to whatever. You're never going from 0 on a racetrack. I'd really like to see, say, 70 to 150.
It is interesting to note, though, that starting at 0-100mph, the short + 4.235 starts to lose badly to stock + 4.55, and once you get to 0-150mph, it starts losing even to the stock tranny. All that would tend to back up my hypothesis.
Would it be valid to assume that the 0-150 time minus the 0-70 time equals the 70-150 time? If so, we'd get:
70-130
15.68 stock
15.37 stock + 4.55
15.56 short + 4.235
70-140
21.05 stock
21.71 stock + 4.55
22.69 short + 4.235
70-150
31.19 stock
30.87 stock + 4.55
33.70 short + 4.235
Now, what to make of those numbers.... Hrm. First of all, it shows that I'm right, the short + 4.235 does, in fact, lag quite a bit at the higher speed ranges compared to stock + 4.55, and in fact, stock period.
Now, the reason I'm thinking about this is because of straights at race tracks. Say you exit turn 14 at Road America at 70mph (at the track out, which is fairly reasonable if I remember right, I'm sure Ken can correct me here). Then you've got a hill followed by a straight (someone help me out on how long that straight is). So what I'm not sure is how the above numbers would translate into how much time would elapse from the track-out of turn 14 to the braking point for turn 1. I can only imagine the hill makes 3rd gear performance that much more important, though. Plus, when you're talking about distance, and not MPH, the faster you're going at any given point in time, the more distance you're covering, so even though time-to-speed numbers might not be that different, the different setups might actually differ a lot more when time-to-distance is considered. Short + 4.235 is getting to 96mph quickly, but then hitting 4th and staying there 'til 130-something, where it goes into a painful 5th gear. While the stock + 4.55 is getting to 101 quickly, then getting to 125 quickly, and then hitting 5th which isn't TOO much taller than stock 4th and still pulling strong. Then still, the stock tranny is pulling hard in 3rd until 114mph, then pulling fairly well to 140mph where it's most certainly run out of track (I was hitting 130-something with headers and exhaust on stock tranny before I felt like I needed to brake).
Common sense says that when trying to cover a certain distance, the faster you get to any given speed, the faster you'll get to the end point. The stock gearbox has an advantage to 140mph because it can stay in 4th where the other two setups need 5th. Short + 4.235 puts up a fight to 130mph, because it can stay in 4th where stock + 4.55 needs 5th.
As far as shifts, going 70 to 140, stock shifts 2-3 and 3-4, while the other two do 3-4 and 4-5 (they're both low 70mph redlines in second, so it's certainly worth starting in 3rd). When talking about time-to-distance, the time taken to shift at 80mph hurts a LOT more than the time taken to shift at 125mph.
I think what really, really hurts the short + 4.235 setup is the huge amount of time spent in 4th gear, followed by the near-stock 5th gear (which starts at 130-something instead of 141).
*sigh* I wish I just had 3 cars with 3 different trannies so I could test this all in the real world.
-Mike
[This message has been edited by grippgoat (edited 07 January 2002).]
It is interesting to note, though, that starting at 0-100mph, the short + 4.235 starts to lose badly to stock + 4.55, and once you get to 0-150mph, it starts losing even to the stock tranny. All that would tend to back up my hypothesis.
Would it be valid to assume that the 0-150 time minus the 0-70 time equals the 70-150 time? If so, we'd get:
70-130
15.68 stock
15.37 stock + 4.55
15.56 short + 4.235
70-140
21.05 stock
21.71 stock + 4.55
22.69 short + 4.235
70-150
31.19 stock
30.87 stock + 4.55
33.70 short + 4.235
Now, what to make of those numbers.... Hrm. First of all, it shows that I'm right, the short + 4.235 does, in fact, lag quite a bit at the higher speed ranges compared to stock + 4.55, and in fact, stock period.
Now, the reason I'm thinking about this is because of straights at race tracks. Say you exit turn 14 at Road America at 70mph (at the track out, which is fairly reasonable if I remember right, I'm sure Ken can correct me here). Then you've got a hill followed by a straight (someone help me out on how long that straight is). So what I'm not sure is how the above numbers would translate into how much time would elapse from the track-out of turn 14 to the braking point for turn 1. I can only imagine the hill makes 3rd gear performance that much more important, though. Plus, when you're talking about distance, and not MPH, the faster you're going at any given point in time, the more distance you're covering, so even though time-to-speed numbers might not be that different, the different setups might actually differ a lot more when time-to-distance is considered. Short + 4.235 is getting to 96mph quickly, but then hitting 4th and staying there 'til 130-something, where it goes into a painful 5th gear. While the stock + 4.55 is getting to 101 quickly, then getting to 125 quickly, and then hitting 5th which isn't TOO much taller than stock 4th and still pulling strong. Then still, the stock tranny is pulling hard in 3rd until 114mph, then pulling fairly well to 140mph where it's most certainly run out of track (I was hitting 130-something with headers and exhaust on stock tranny before I felt like I needed to brake).
Common sense says that when trying to cover a certain distance, the faster you get to any given speed, the faster you'll get to the end point. The stock gearbox has an advantage to 140mph because it can stay in 4th where the other two setups need 5th. Short + 4.235 puts up a fight to 130mph, because it can stay in 4th where stock + 4.55 needs 5th.
As far as shifts, going 70 to 140, stock shifts 2-3 and 3-4, while the other two do 3-4 and 4-5 (they're both low 70mph redlines in second, so it's certainly worth starting in 3rd). When talking about time-to-distance, the time taken to shift at 80mph hurts a LOT more than the time taken to shift at 125mph.
I think what really, really hurts the short + 4.235 setup is the huge amount of time spent in 4th gear, followed by the near-stock 5th gear (which starts at 130-something instead of 141).
*sigh* I wish I just had 3 cars with 3 different trannies so I could test this all in the real world.
-Mike
[This message has been edited by grippgoat (edited 07 January 2002).]
Would it be valid to assume that the 0-150 time minus the 0-70 time equals the 70-150 time?
Yes.
Say you exit turn 14 at Road America at 70mph (at the track out, which is fairly reasonable if I remember right, I'm sure Ken can correct me here).
Sounds about right.
Then you've got a hill followed by a straight (someone help me out on how long that straight is).
Actually, that's ALL the straight - from the exit of 14 to the braking point of 1. It starts level, then becomes dramatically uphill until you cross under the pedestrian bridge, then it's not sloped as sharply by the time you reach the start-finish line.
My '91 is stock (except for brake rotors, pads, and cooling ducts). I downshift to second for the braking zone of 14, then upshift twice going down the straight. I get up to around 140 when I enter the braking zone for 1, then downshift to third.
Of course, different gearing setups will be better for different tracks. Road America is relatively unusual because the straights are so long, much longer than most other tracks. A gearing setup that's good at Road America might not be good at a track where the turns are closer together.
[This message has been edited by nsxtasy (edited 07 January 2002).]
Yes.
Say you exit turn 14 at Road America at 70mph (at the track out, which is fairly reasonable if I remember right, I'm sure Ken can correct me here).
Sounds about right.
Then you've got a hill followed by a straight (someone help me out on how long that straight is).
Actually, that's ALL the straight - from the exit of 14 to the braking point of 1. It starts level, then becomes dramatically uphill until you cross under the pedestrian bridge, then it's not sloped as sharply by the time you reach the start-finish line.
My '91 is stock (except for brake rotors, pads, and cooling ducts). I downshift to second for the braking zone of 14, then upshift twice going down the straight. I get up to around 140 when I enter the braking zone for 1, then downshift to third.
Of course, different gearing setups will be better for different tracks. Road America is relatively unusual because the straights are so long, much longer than most other tracks. A gearing setup that's good at Road America might not be good at a track where the turns are closer together.
[This message has been edited by nsxtasy (edited 07 January 2002).]
Yeah, I know it's all the straight, but I see that hill as being kind of a special case, so I wanted to mention it separately.
OEM Yokos are stickier than what I was running, and you've got a lot more practice on that track, and you were probably also going a LOT deeper in the braking zone, so that makes sense compared to what I was doing.
At Seattle International Raceway (now known as Pacific Raceways, http://www.pacificraceways.com,) however, it's actually even more dramatic. You apex the last turn (I think it's 9 without the chicane) at probably 90mph (more on race tires) and then you're flat-out for more than quarter mile as you go onto the straight, and then you're STILL flat-out through turn one (much like Road America's kink, only not as tight, with more runoff, with the added fun of a pavement dropoff and going over a rise, and going a good 30-40mph faster), before you climb on the brakes for turn 2. At my one event there, I was hitting 140mph, then gently slowing down to about 120 for turn one, which means I would have easily been going 145-150 if I were on race tires and kept it flat through turn 1.
Of course, that track layout will only exist for the rest of this year, and then it remains to be seen what the new layout will be like. The maps I've seen make it look like it should still have a very high-speed straight.
Portland International Raceway also has a lot of high-speed stuff.
As does Bremerton, which I'll probably never go to, since it's just an old runway and taxi strip where they set up some cones and fire extinguishers.
So anyway, for the tracks near me, 70-130+ is fairly important. Not to mention the first and second gear benefits of the 4.55 for autocross.
But still, I think this thread has convinced my that even if I need to open my tranny for maintenance, the money that could be spent on gears is probably better spent on nitrous or seats or a supercharger or track time. And that's before you take things like highway tolerability into account.
-Mike
[This message has been edited by grippgoat (edited 07 January 2002).]
