Shifting

[JekylandHyde]

Staying on throttle while shifting is not as bad as launching the car ... you are basically doing the same thing: increasing revs before engaging the gear.

However, when you launch, you are "shocking" the system and you have to get everything moving.
At least when you WOT shift everything is already moving .... especially the wheels.

If you watch my in-car drag footage you will hear that the 3rd->4th shift is smoother than the others.

[TeamFL1]

umm power shifting at the highest point of torque...........so power shift if ur highest torque peak is at 3,500rpm????????? wouldn't reving it all the way to the redline and shift be better tha power shifting at 3,500, if ur rve limit is at 7,600rpm???

[JekylandHyde]

TeamFL1, actually neither is correct

You do not want to shift at the torque peak for mazimum acceleration. And not all cars should be taken to redline either.

To find the ideal shift point you need to know your gear ratios and your torque (dyno) curve.

[CBFryman]

Shouldnt you shift to where your RPM's will land right where your power band starts? Thats how i do it.

[JekylandHyde]

You maximum acceleration will come from staying in the thickest part of your power band across all of the gears you are using.

This is why you need to know the power band and the gear ratios.

It does you no good to shift at peak torque in one gear if you drop well below the powre band in the next gear. Conversely, it does no good to shift at redline in every gear if your power band does indicate that you are making significant power to redline.

[CBFryman]

That is what i was saying. Example.

The Manual Tranny i am most used to driving is my moms Nissan Truck...well not the most high performance but when i fell like some get up and go this is how i shift.

I dont really "launch" because i dont drag but hey if i was i would hold the RPM's at about 3,500. Ive mesed around and any higher and i get wheel spin and any lower and i bog down a bit.
i bring the RPM's up to 5,200. This is where the engine really stops making power and the RPM's just creap up. it makes peak HP at 4800 (wow, lol 148 at the crank) but it hits its power ban late 3,000's. The gears are pretty evenly space but from 1st to 2nd at this RPM i usually get about 1500-1800RPM drop placing me at right at the bottom of the power ban. 3rd the truck really shines its short and the RPM's only drop 1200-1500 so i can bring it up to about 5,000-5100 and be put right back in a good ban. 3rd to 4th (im usually getting pretty fast now, around 70, much faster and im going faster than i want to go in a truck) i usually shift at about 4,800 then put it up into over drive.

[TeamFL1]

Originally Posted by JekylandHyde

TeamFL1, actually neither is correct

You do not want to shift at the torque peak for mazimum acceleration. And not all cars should be taken to redline either.

To find the ideal shift point you need to know your gear ratios and your torque (dyno) curve.

so if you car has very close ratios, you shift at the reline?

[JekylandHyde]

That would depend on your power band.

Example: The stock MR2T's turbo runs out of breathe above 5500 rpms and the redline is 7200 ... so not much worth racing to redline for even with close gears!

[buymeabmwm3]

http://www.cyberstangs.com/autocalc/...hiftPoints.asp