best acceleration

[thescreensavers]

Horsepower @ RPM 280@6200

Torque @ RPM 266@2750 (foot-lbs)

If I could control when the car shifts..ect for max acceleration what would be the best to shift at?.

6200 is redline.

 

[overst33r]

Need to see a dyno to tell you specifically. More than likely the car makes power all the way up to redline, or close to it, so it would be optimal to shift there to put yourself into the best position for the next gear.

 

[Demon-Xanth]

The idea is basically you want to get as much torque as possible coming from the rear wheels. If you took a dyno chart, and converted it to rear wheel torque (not HP) vs. speed for each gear, you'd see the lines cross. Those crossing points are where you should shift. HOWEVER, there are exceptions. In my Dakota, if I were to do a 0-60 run I'd wind out second gear to avoid the 2-3 upshift. (normally at about 50MPH) And in the 1/4, I take 3rd further to avoid the 3-4 upshift. (would otherwise shift at 80 instead of the 90 trap speed)

Given your numbers, I'm guessing you're best off rather close to redline.

 

[iamwiz82]

Take your dyno then multiply that by your absolute gear ratio (final drive x transmission gearing) for each gear. Overlay each graph and the points where the lower gearing cross the higher gearing is when you should shift, optimally. Obviously this isn't always correct as a shift point might be 40 feet from the end of a quarter mile run and would slow you down versus just wringing it out a bit more.

 

[thomsbrain]

If max horsepower is at redline, then that is almost certainly where you will want to shift, assuming a relatively constant power curve. All else being equal, the max power RPM is where you will get maximum acceleration.

This doesn't apply to your example, but for some cars, max power comes before the redline. For those cars it may make sense to shift before the redline. In those situations, iamwiz82's explanation makes sense if you want to be exact. If you don't want to get that technical, just try to shift at a point that roughly balances the swing of RPM's above and below peak power as you move from gear to gear, so that you hover as closely as possible to the peak HP RPM.

 

[daw123]

Does your car have 4 wheel drive? There is no point having max. torque/power if it just spins the wheels.

I know on my car, the turbo kicks in about 2,700 RPM and the power band is 4-5,000 RPM and after that the power curve is not as steep, but it will keep on accelerating (at quite a pace) through the red line (at 7,000 RPM). I don't generally redline it (I can only think of two instance where I've gone beyond the redline) and I usually change before this at 6,500RPM under hard acceleration. Then again, my car has 4 wheel drive and I have never been able to spin the wheels, even from a standing start under hard acceleration.

 

[thescreensavers]

Originally posted by: daw123
Does your car have 4 wheel drive? There is no point having max. torque/power if it just spins the wheels.

I know on my car, the turbo kicks in about 2,700 RPM and the power band is 4-5,000 RPM and after that the power curve is not as steep, but it will keep on accelerating (at quite a pace) through the red line (at 7,000 RPM). I don't generally redline it (I can only think of two instance where I've gone beyond the redline) and I usually change before this at 6,500RPM under hard acceleration. Then again, my car has 4 wheel drive and I have never been able to spin the wheels, even from a standing start under hard acceleration.

it is an 4x4 and actually redline is at 6800

ty for the replies so far