I have the most stupid question you guys have ever heard. Is the redline on a FD 8K or 7.5K? I 'm pretty sure it is 8K and it beeps at 7.5K. I usually shift at 7.5K but is there any power after that with the stock twins? I haven't gotten my car dynoed yet so I was just curious.

 

I haven't taken my car to the track or anything yet because it is too cold too right now. But according to the dyno test that SCC did a few years back on their project RX7, they said that the peak is right around 6500rpm and then drops off, so I would think that around 6500rpm's would be your best bet but I'm not sure on the gear ratios and such in each gear. Anyone feel free to jump in here and correct me.

Memphis

 

the redline is 8K. power with the stock twins starts to drop at around 6800-7000.

 

I shift @ 7.5 because you can actually feel the power drop off right after that.

 

i shift @ 7,000 rpm

 

depending on mods to your car, will affect your shift points, so that it drops you back in the fat part of the torque curve. My car with a hi-flow cat would drop off considerable at 6600 rpms, so I would shift at 7k, so I'd end up back in the fat part of my torque curve. Now with a resonated midpipe, hp starts to taper off at 7300 rpms, so I take it up to red line now jsut for the fun.

hi-flow cat - hp at 6600 rpms - 315 at 12psi (running a little too rich)
hp at 7000 rpms - 280
hp 7500 - 260

mid pipe hp at 6600 rpms - 318 at 12 psi (running a little too rich)
hp at 7000 - 320
7500 - 311

it all depends on the car and mods done to it.

Tim Benton

 

In first gear, I shift at 8500...after that, I shift at 7500...

 

I've obtained my best drag-racing time by shifting in this manner:

1st gear: 8k rpm (kinda hard to shift before this....)
2nd onwards: 7k rpm.

I've noticed that if I shift above 7k rpm in any gear, my trap speed and ET worsens. For my car, this seems to be the optimum shift point.

My car has the basic boltons: PFS I/C, intake and PMS; Pettit downpipe and HKS sport catback. I usually run 13 psi boost at the drag strip.

 

I remember reading/hearing that you should shift 500 rpm's after your peak power point. But the only way to know for sure is to take your car to the strip, and try various shift points.
Brad

 

My car has a hi-flo cat so I'd imagine the power will drop off quicker than with a midpipe. I'm running non-sequential so I wonder if that would affect my power up high..I'm getting dynoed in a month so I'll know what my curves look like.

 

http://www.ricemobile.net/HPvsTQ.htm

styk33's page has some good info

quote:
So, we wish to maximize the acceleration of the vehicle by selecting the most advantageous shift rpms. Some simple physics (above) and little algebra (spreadsheet of you choice) will show us how to obtain maximum acceleration. I will not explain formulas in any real detail, but the math is simple: (trans ratio) * (torque @ rpm) ==> plot vs. speed for each gear examine the graph ... where the lines cross is the optimum shift point (simple linear interpolation).

At the drag strip in the real world, one may need to deviate from this slightly to obtain the best time. for example, in a bone stock RX-7, the above analysis would have you to shift to 4th at about 97MPH. This would produce the best overall acceleration (if we were interested ingetting to 130) but in fact this shift occurs just shy of the finish line and hurts ET. The better plan for the RX-7 is to hold 3rd all the way to the finish line, winding to 8000 rpm. This will sacrifice speed to save ET.

 

I shift at about 4k and never go WOT. I also have too many mods for my factory ecu and dont want to risk anything till i can upgrade