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Re: Do any of you---->

yes you could look at the peak power (and peak rpm) - which will tell you what the mph and finish line rpm will be, then select the gear (according to tire ht.).
 

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Re: Do any of you---->

I dyno all of mine. It first breaks in the motor rather than in the car. Then you can make changes and see if they really are good or bad. And finally and most importantly it tells you peak power and torque which is required for proper gear, tire and converter setup. To me it is always worth it.
 

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Re: Do any of you---->

<------- have your engines dynoed to determine what the optimum rear gear/stall converter/trans will be for 1/8-1/4 mile racing?
I don't bother with mine since its a street car that just makes a few passes down the track every now and then for the last 5 years :D
 

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Re: Do any of you---->

What point would be optimal for the stall and gears~Would it be peak torque rpm for the stall and peak hp rpm for the gear? Seems like I've seen somewhere (maybe speedtalk) that optimal convertor is 500 rpm over peak torque and optimal shift point and trap rpm is 500 rpm over peak hp.
 

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Re: Do any of you---->

i think thats 500 below peak TQ and 500 after Peak HP, but really the shift point would be determined by where the recovery RPM is at gear change. I think this is why the 500 over peak HP. For example if you shift at peak HP and after the shift your rpm drops to 1,000 below peak TQ then you are losing momentum ect.
 

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Re: Do any of you---->

We dyno most of our engines (not all), but determining the best gear ratio is a side benefit, not the primary reason. The power peaks from the dyno certainly give you the opportunity to maximize the area under the curve when picking shift points and rear gear ratios. Note, we're 3-pedal racers so we never worry about the converter stall speed, just change the launch rpm chip.
 

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Re: Do any of you---->

but really the shift point would be determined by where the recovery RPM is at gear change. I think this is why the 500 over peak HP. For example if you shift at peak HP and after the shift your rpm drops to 1,000 below peak TQ then you are losing momentum ect.
Great post. IMO this is more important in many ways than just using the numbers to pick conveter and gear. It's using those numbers to make the most out of your combo...gear, converter, tire, etc.

I take the dyno results and build a spread sheet to calculate where my drops are going to be so I'm launching at peak torque and my shift points drop me down to peak every time.
 
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