Shifting

[Reaper948]

OKAY OKAY....
So my friend tells me this

Shifting when You're only looking at 0-60.......................
Solamente.......u shift up as soon as u reach the torque band.......

As opposed to shifting before redline.....

what do u motorheads think

[SergntMac]

I'm not sure I'm getting your question, Reaper, but maybe it will help if I page back through my own history and explain what I do in the 0-60 race, or any spontaneous stop-light challenge.

I've always believed the "red-line" was the point where maximum performance has been exhausted. Reach your red-line, and you have all the motor has to give in power. Push past the red-line has no benefit in the race, and it puts the motor at risk. Many of my cars over the years redlined well before the danger point, but a few missed shifts also cost me a few mains when I was a bow-tie BB fan. I don't think it's really changed much today.

Understanding that, my MM redlines at 6000 RPM, visually, on my tach. No sense in pushing past that, though the motor has seen 6500 RPM a number of times.

Before I added my chip and gears, the ECM would shift out about 4200 RPM under WOT, well before I exhausted the powerband in the higher gear. Back then, I would manually shift at 6000 RPM and the car was much faster. However, I also missed this mark a few times, and caused a delay in hitting second. The power flattened out for almost a full second, almost like a pause, and that's not good in any race, eh?

After I added my chip and 4:10, the program changed. Under WOT, the chip shifts out by itself at about 5750 RPM. Again, I can hold it back until 6000 RPM, but I don't feel any more from the last 250 PRMs. Since Dennis knows more about these things than I do, now I just leave it in drive and let the chip do my shifting. Under WOT, I feel a full use of the powerband, and no risky missed shifts. The 5750 RPM was confirmed in two dyno tests, and you can see on the graph, that max power has been achieved.

Under less than WOT conditions, maybe just your casual spirited driving stuff, I can hold the higher gear by toying with the accelerator, and most of the time, keep the RPM in the powerband with little difficulty. Under normal grandpa conditions, the shifts are early, but still sure and certain. That factory "slushiness" is history with the chip.

My bottom line is, let the chip and gears do their thing, tough enough driving this b**ch wide open.

Well, didn't mean to run on, hope this helps you.

[nomad]

Thought this might be the place to stick this in.When my dealer installed my chip, he told me TWICE, to be careful not to hold too long in lower gears at full throttle as chip bypassed rev limiter!:(
Any truth to this:help: :confused: Thanks!

[Mark McQuaide]

I noticed that, shifting manually from 1 to 2, the tranny "bangs" second gear and barks the tires, but letting it shift itself it's smooth. I assume there's some programming there that backs off a bit during the shift to smooth things out. This would lead me to believe you would get quicker 0-60 times shifting manually. Any thoughts on this?

[Reaper948]

Thanks for the answer Sarge, Youve answered other questions Ive had about the car....

Arite lemme make it clearer.......Max Torque comes in our car at about 4300 right?...Lets say we had a manual transmission too...........so when dealing with the best 0-60 performance on our car........would we shift up every gear whenever we hit 4300? or would we just wait 'til redline?........this Volvo guy has a S80 T6 in his car, and he has Tiptronic in it too... he wanted to prove to me that shifting at your max torque would give you the best 0-60.........I beg to differ.... thoughts?

[RF Overlord]

Reaper:

There are far too many variables in this equation...whether to shift at torque peak, somewhere after TP, or at redline is dependent on the gear ratio spacing, for one thing...with gears that are too far apart, shifting at peak torque may then drop your RPM down too low, and the car will have to recover...in that case you would shift a little after peak...closer ratios may allow you to shift at peak. Shifting at redline would depend on how close the redline is to the torque peak, and how quickly torque falls off after peak, in addition to the ratio-spacing issue. I don't think it's a one-size-fits-all thing...different cars will require different shifting methods to produce optimum performance...shifting at max torque may indeed be best for your buddy's Volvo, but not necessarily for your hypothetical 6-speed Marauder...

[smith5365]

I was taught years back to rock back and forth around the peak as I went up through the gears through 4th on my GT-350. How to find the peak and determine where to shift? Dyno the car. As stated above, every car is different and the best way to learn before you hit the track is from a dyno. Then try slight variations at the track. Since I road-raced, getting into and out of corners was my passion. Learning how to down shift, use brakes, and then come out was the key. Never did learn well enough which is why I never made the big SAAC events.

[cyclone03]

If the trans has proper gear spacing and the engine torque and horsepower peaks are known,for maximum accelleration you want to shift at the HP peak and the RPM should land right on the torque peak.
Now if the gear spacing isn't right you want to shift above the torque peak and have the RPM drop back to the top of the torque peak.
I think this is why when our transmissions shift automaticly it shifts at differnt RPM's depending on which gear it's in.