When to shift in relation to peak power and gears - Ford Mustang Forums : Corral.net Mustang Forum
 
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post #1 of 7 Old 04-16-2016, 10:51 AM Thread Starter
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When to shift in relation to peak power and gears

I've got a 393w that makes peak power at 5400 rpm, it's a really small streetable cam, I'll be upgrading at some point but for now I've added a progressive nitrous setup to help with some more power. I'm running 26" drag radials and I've also swapped the 3.55's for some 4.10's. I'm curious at what RPM should I shift the car, it's an Astro A5, is it ok to rev past the peak power at 5400 in order to keep the car higher in the RPM's and not run out of gear at the finish? The track I run at is 1/4 mile. Is it ok to rev past peak power, would the nitrous help it out at the higher rpms, I haven't had a dyno run with the nitrous yet.

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post #2 of 7 Old 04-17-2016, 03:30 PM
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If your making peak power at 5400 I don't see why you would need 4.10 gears...

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post #3 of 7 Old 04-17-2016, 05:36 PM Thread Starter
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I'm swapping cams real soon, in the mean time I may run the car with the current cam so I'll have a baseline to see the improvement.
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post #4 of 7 Old 04-17-2016, 10:37 PM
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What did you run in the 1/4 with the 3.55 gears?

What cam are you going with???
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post #5 of 7 Old 04-18-2016, 09:22 AM
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Any rpm/gear calculator would be a good estimate on what you need. But you stick as much gear in the car that the RPM limiter will allow. What is your limiter set at?

As far as shift points, on average you want to shift the car around 500 rpms past peak. After the gear change this will put you back at the beginning of your power band. Remember during the run you want to put down the highest "average" rwhp to get the greatest acceleration.

-Mark

98 red cobra (N/A 5.4)
[email protected] (1.59 60')
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post #6 of 7 Old 04-26-2016, 08:49 AM
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I have found that the torque curve is more important than the horsepower curve meaning that you want to shift from one gear to another when the torque curve is high or at it's max. On yours I am guessing that the torque curve is at it's max from 3500-5000 so you would shift so that the gear you shifted into will be from 3500-5000 and ride that out until next shift which will put the engine between 3500-5000
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post #7 of 7 Old 04-26-2016, 09:39 AM
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I'd be looking at a 6k shift point and 6500 cross. That is if power doesn't fall off a cliff past peak. This would be without nitrous.
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