Purely a theory question regarding hp/torque & gear changes during racing
#31
Rennlist Member
Yep, thats pretty much it.. there can be some variations of this, based on HP curve shape, but generally, this is the best way to maximize acceleration, regardless of what the torque in any gear "feels like" or "seems like" based on a falling HP or torque curve.
because, at any vehicle speed, if you have more HP available at tha speed, you will accelerate at a faster rate. ths goes for comparing acceleration of your own car in different gears, or another same car you are racing against with an entrely different engine. (e.g. the Viper vs GT3 example i often show, both with 450hp, but one with 2x the engine torque of the other, accelerating at the same rate at any spot/speed, on the track!)
#33
The original question is from a "never been tracking a car" type of guy. The correct answer is " You will almost allways experience more acceleration by staying in ther lower gear longer even though the torque curve is past it's peak." This is due to the mechanical advantage of the lower gear. While many exceptions exist, the exceptions are negledgable for a beginner.
#34
Rennlist Member
The original question is from a "never been tracking a car" type of guy. The correct answer is " You will almost allways experience more acceleration by staying in ther lower gear longer even though the torque curve is past it's peak." This is due to the mechanical advantage of the lower gear. While many exceptions exist, the exceptions are negledgable for a beginner.
When you start racing, its always redline (max rpm possible for your comfort zone), unless you are doing it in a part of the track that would not benefit by it.
anyone that thinks that short shifting before redline, is better because the engine is just making "noise" at that falling part of the torque curve, is providing incorrect information. as you say, almost always, staying in a gear to mechanical limits will maximize HP-seconds and acceleration overall.
#35
Rennlist Member
Simple question, simple answer.
Look up a dyno chart for your car, you want hp vs. rpm (not torque).
Shift at the point such that the hp at that point equals the hp you'd have at the rpm in the next gear. If this doesn't happen before redline, shift at redline.
You can't argue with math.
Look up a dyno chart for your car, you want hp vs. rpm (not torque).
Shift at the point such that the hp at that point equals the hp you'd have at the rpm in the next gear. If this doesn't happen before redline, shift at redline.
You can't argue with math.
#37
Race Director
one huge factor I forgot to mention is how reliable the engine will be near redline....most modern engines are fine...but spending lots of time near redline WILL reduce its service life......especially in engines designed for street cars..... Of course a properly built race engine solves most of these issues.....but generally speaking when you turn UP the rpm....the lifespan on the engine goes down....
I can't remember what the rebuild interval is got 997 Cup cars.....20 hours?
I can't remember what the rebuild interval is got 997 Cup cars.....20 hours?
#38
Rennlist Member
Simple question, simple answer.
Look up a dyno chart for your car, you want hp vs. rpm (not torque).
Shift at the point such that the hp at that point equals the hp you'd have at the rpm in the next gear. If this doesn't happen before redline, shift at redline.
You can't argue with math.
Look up a dyno chart for your car, you want hp vs. rpm (not torque).
Shift at the point such that the hp at that point equals the hp you'd have at the rpm in the next gear. If this doesn't happen before redline, shift at redline.
You can't argue with math.
one huge factor I forgot to mention is how reliable the engine will be near redline....most modern engines are fine...but spending lots of time near redline WILL reduce its service life......especially in engines designed for street cars..... Of course a properly built race engine solves most of these issues.....but generally speaking when you turn UP the rpm....the lifespan on the engine goes down....
I can't remember what the rebuild interval is got 997 Cup cars.....20 hours?
I can't remember what the rebuild interval is got 997 Cup cars.....20 hours?
#39
one huge factor I forgot to mention is how reliable the engine will be near redline....most modern engines are fine...but spending lots of time near redline WILL reduce its service life......especially in engines designed for street cars..... Of course a properly built race engine solves most of these issues.....but generally speaking when you turn UP the rpm....the lifespan on the engine goes down....
I can't remember what the rebuild interval is got 997 Cup cars.....20 hours?
I can't remember what the rebuild interval is got 997 Cup cars.....20 hours?