Japanese Short Gears Top Speed?
- Thread starter Redeye
- Start date
not really the question here, but:
changing the R&P (from OE 4.06) will REDUCE the top speed, right?
- 4.23 (JDM Honda NSX-R) -- lower
- 4.55 (Comptech) -- even lower
Tradeoff between more rapid acceleration versus top speed
New top speed should be of the order of 4.06/new R&P, assuming nothing else changes (e.g., taller rear tires).
[This message has been edited by cojones (edited 06 August 2001).]
changing the R&P (from OE 4.06) will REDUCE the top speed, right?
- 4.23 (JDM Honda NSX-R) -- lower
- 4.55 (Comptech) -- even lower
Tradeoff between more rapid acceleration versus top speed
New top speed should be of the order of 4.06/new R&P, assuming nothing else changes (e.g., taller rear tires).
[This message has been edited by cojones (edited 06 August 2001).]
A higher R&P will lower top speed.
A long time ago, I was told this, which made a lot of sense to me:
Stock gears --
Take your right hand, and face the palm down. Each finger represents a gear. Notice how the thumb and pointer have a 'gap' in the 'powerband'?
Japanese gear set --
Take your thumb and bring it closer to the pointer finger while moving everyone except the pinky justa little. Now you have the Japanese 'short gear ratios'.
Higher r&p (Comptech, NSX-R, etc.)
Take your whole hand, and move it a bit right on an x axis of the 'powerband'. This results in acceleration which will result in your being at a higher RPM at the same speed of a stock car.
Hope that makes sense.
-- Chris
------------------
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A long time ago, I was told this, which made a lot of sense to me:
Stock gears --
Take your right hand, and face the palm down. Each finger represents a gear. Notice how the thumb and pointer have a 'gap' in the 'powerband'?
Japanese gear set --
Take your thumb and bring it closer to the pointer finger while moving everyone except the pinky justa little. Now you have the Japanese 'short gear ratios'.
Higher r&p (Comptech, NSX-R, etc.)
Take your whole hand, and move it a bit right on an x axis of the 'powerband'. This results in acceleration which will result in your being at a higher RPM at the same speed of a stock car.
Hope that makes sense.
-- Chris
------------------
www.ScienceofSpeed.com - Click for more info
www.NSXClassifieds.com - The internet's only exclusive NSX Classified site!
New top speed should be of the order of 4.06/new R&P, assuming nothing else changes (e.g., taller rear tires).
I'm not sure that that's true.
It's certainly true for the top speed in all the gears where you can go to redline, since the road speed at redline changes by that ratio.
However, if the top speed occurs before redline in the top gear - and I believe it does, in the NSX - then it's possible that the top speed does not change in the same ratio as that of the two R&P gears.
[This message has been edited by nsxtasy (edited 06 August 2001).]
I'm not sure that that's true.
It's certainly true for the top speed in all the gears where you can go to redline, since the road speed at redline changes by that ratio.
However, if the top speed occurs before redline in the top gear - and I believe it does, in the NSX - then it's possible that the top speed does not change in the same ratio as that of the two R&P gears.
[This message has been edited by nsxtasy (edited 06 August 2001).]
What about the speedometer? Does any of this mess up the measurment of true speed.
No.
I think changing wheel size is the only way to mess up the speedometer???
The speedometer and odometer will change if you change the outer diameter of the tires.
If you get bigger wheels but get a tire size that keeps the outer diameter the same size, the speedometer won't change.
No.
I think changing wheel size is the only way to mess up the speedometer???
The speedometer and odometer will change if you change the outer diameter of the tires.
If you get bigger wheels but get a tire size that keeps the outer diameter the same size, the speedometer won't change.
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nsxtasy is correct. If a stock 5-speed NSX had enough power, it would be at about 186 MPH when it hit redline in 5th gear. But since top speed is drag limited and not redline limited, the 4.23 and even 4.55 gears do not reduce top speed in direct proportion to the gearing changes. It would only be in direct relation if your top speed were redline limited in every case.
With the 4.23 the redline limit would be around 178 MPH, which means you are still drag limited because the stock car doesn't have enough power to go quite that fast.
Exactly how fast? Since you're changing where in the power band you are relative to speed, and peak HP is about 1000 RPM below fuel-cut, it is somewhat complicated to calculate your new drag limited top speed. I'd estimate your drag-limited top speed would be very close to stock with the 4.23 R&P - somewhere in the lower 160s. Anyone who wants to do the math, feel free.
With the 4.55 you are redline limited at 166 but again you're changing where in the power band you reach a given speed. I would guess that you'd be drag limited to the mid 150s or so. Again, feel free to do the math.
With the 4.23 the redline limit would be around 178 MPH, which means you are still drag limited because the stock car doesn't have enough power to go quite that fast.
Exactly how fast? Since you're changing where in the power band you are relative to speed, and peak HP is about 1000 RPM below fuel-cut, it is somewhat complicated to calculate your new drag limited top speed. I'd estimate your drag-limited top speed would be very close to stock with the 4.23 R&P - somewhere in the lower 160s. Anyone who wants to do the math, feel free.
With the 4.55 you are redline limited at 166 but again you're changing where in the power band you reach a given speed. I would guess that you'd be drag limited to the mid 150s or so. Again, feel free to do the math.
