I already did that. Shift right before you hit the rev limiter. This will maximize the averaged HP of each gear.

The power or tq on any of these engines does not go down low enough (as you approach redline) to justify a short shift.

You don't want to shift into the engines max TQ. You want to shift into the max average HP. To the engine, TQ and HP are interchangable because of gear shifting. So the objective is to keep the engine at max HP. Gears will take care of the TQ.
When I did this analysis, I put all the dyno data into excel to find exactly what and where everything happens with the power curve.

For example, if you short shift by 500 RPM, you cut out the average power of the last 500 RPM and replace it with the average power of 500 RPM at the bottom of the next gear. At a lower RPM range with a lower power.

And the average power at the bottom of the next gear is much lower than the average power of the top end of the previous gear.
I hope I'm being clear here.


Dont trade higher HP for lower HP by short shifting. Stay as high as you can on the power curve.

 

When I sealed my box, I used simple pipe foam insulation from the hardware store. The long sticks of foam with a slit down one side. It has an adhesive on the inside that is exposed when you pull off a clear tape.

Just put that around the circumference of the box that runs near the engine compartment chassi and it will block out a lot of the exposed areas.

 

Anyway you can post a pic of this Tony, I'm gonna try it when my Stillen box gets here.

 

Sorry, I don't have the pics anymore.

 

Tony is it possible that the results are different on a non-revup because of the power drop off at the end? I did gain over 1mph at CSW by shifting 6700 on the tach, from 3rd to 4rth, instead of 7300rpm. Unfortunetly i haven't ran since that 1mph gain on my very last run.

 

Tony,

Thanks for the clarification. Your explanation makes perfect sense. I already knew what shift points would give me the best result, but I didn't completely understand why. (You've taken care of that for me).

.

 

From my 50+ runs at the drag strip, I seem to gain 1.5 MPH trap speed by shifting at 7100-7200 from the 3rd to 4th as opposed to shifting at 6800.

1st & second are always redlined.

But then again, I have a revup. So I honestly can't say what the best shift points are for he non revups.

Have you consistently gotten a 1mph gain by shifting at your stated shift points or was it a one or two time experiment?

.

 

Just once and that was my very last run. I haven't ran 1/4 mile (at the track) since that very last run.

 

fall/winter right around the corner!!!

 

You'll have alot of room for experiments the next time we have a private drag event

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^yup!

 

Do you have any dyno plots you can post?

 

Red line was the exact power that i was making during that 1mph gain by early shifting. The blue line is my current power.

 

Here is the reason why not to short shift.

The blue lines represents the RPM range of 3rd gear when you shift at redline.
The redline represents the RPM range of 3rd gear when you short shift by 500 RPM.

When you short the top of the gear that you are leaving, you end up at a lower RPM of the gear you are entering.

So when you short shift, you are trading area "A" of the power curve at ~270HP for area "B" of the power curve at ~225 HP.

...not a good trade.

 

this is the exact explination i was looking for thanks tony! That is why i shift as deep as i can with out bouncing limiter on my non revup with the limiter set at 7200rpm.