Sport Side

iTrader: (6)

Is a shift extension, the rpm, that the motor falls to after a shift?

When buying a stall converter with the correct shift extension, you want it to match the current rpm that you fall to after a shift. Is this wrong?

ex. Shift, 5669rpm
rpm drops to: 3229rpm

when picking a new tq converter, i would want a shift extension of 3229?

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The way, I had always seen it, was. Dyno your motor, and pick the shift extension by the torque curve.

Someone guide me, please. Perhaps, explain shift extensions while your at it

Predator answered some of my questions (thank you), but I'm still a bit confused.

Thanks guys,

Kyle.

DrkPhx

iTrader: (15)

Yes, that is what a shift extension is described as and no you do not want the same shift extension as stock. You want it higher which keeps the motor in the stronger part of the power band for a longer period which results in the car "pulling" stronger. Picking a converter based on the dyno curve is good.

Examples:

My old converter - Yank Y3200 shifted at 6300 rpms, shift extension was 4200 rpms.

My new converter - TCI 3800 shifts at 6500 rpms, shift extension is 5150 rpms.

So when I run the quarter mile the only time the motor see less than 5150 rpms is from launch to the 1-2 shift (before the 1/8 mi), after that it's in the sweeter part of the powerband for most of the run which results in a better ET. This compared to a stock converter which spends a fair amount of the same run in the lower part of the powerband catching up.

I'm no expert, but these are obervations I've made over time based on my car's characteristics. I hope this helps.

cliff notes: higher shift extension = stronger pulling car/truck and better ET.

Sport Side

iTrader: (6)

thank you sir.

thats what i thought, but i was a bit confused after some reading earlier.

anyways-

is there a method to figuring out the exact shift extension you will need given your power band?

Ragtop 99

iTrader: (7)

In theory I would argue that you want your shift extension to land just a few hundred rpm behind max HP. That way you stay near max HP the entire rest of the way down the track. However, getting a converter not to stall outrageously high, be efficent, and achieve that high a shift extension is nearly impossible. The other tradeoff is that a long shift extension tends to make for a looser feeling converter.

Therefore get the stall you need, at an acceptable looseness, with the most extension available given those criteria. If racing only from a roll, pick the most extension you can get at an acceptable looseness.

Sport Side

iTrader: (6)

Alright, that sounds good.

Thank you ragtop.