autoluder

I'm thinking about doing a auto to manual conversion and was just wondering if it would be better or not to put a vtec tranny on a Si since the gears are shorter, and the Si powerband is more lower end to midrage. Or would it be better to just put an si tranny on?

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Black 93 SI CAI/H/E, AEM CAM gears, jacobselectronics wires, 2.5" drop (sprint springs, kyb shocks), neuspeed front upper strut tower bar, no name rear strut tower bar, chrome dc sports lower rear tie bar, thermal R&D exhaust, DC Header. 17's currently with dunlap sp901's.

autoluder

Just for the record, I raced a Si manual that had a underdrive pulley, shortram intake, and a header, and short shifter, and I beat it. I don't know though if it was because he had stock tires and spinned them too much on his launch or he is just a bad driver? But if hes manual he should of beaten me or caught up, but i stayed about 10 feet ahead of him the whole time. And was pulling a little too.

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Black 93 SI CAI/H/E, AEM CAM gears, jacobselectronics wires, 2.5" drop (sprint springs, kyb shocks), neuspeed front upper strut tower bar, no name rear strut tower bar, chrome dc sports lower rear tie bar, thermal R&D exhaust, DC Header. 17's currently with dunlap sp901's.

Paul H22

4th Gen
--H23a/Si - H22a/VTEC
----M2S4----M2F4
1 - 3.307 - 3.307
2 - 1.857 - 1.950
3 - 1.320 - 1.360
4 - 1.034 - 1.071
5 - 0.812 - 0.870
FD 4.266 - 4.266

The Si has a slightly longer geared transmission in every gear. I would recommend the VTEC tranny for some more pep. It's not going to make a huge difference. Both will work fine for you.

Your car is so close to the performance of your friends that it was just a driver's race. Meaning whoever drove better, shifted better etc, is teh win.

Modifications don't always determine the winner.

LudemanDan

I have a stock Si and I'd rather have the Si tranny than the VTEC. With the Si, you're already shifting pretty often in the lower gears when you're gunning it. The H23 revs up to 6500 rpm. The VTEC tranny is designed for a car that revs up to 7400 rpm, and if you put that tranny in an Si you would have less distance after taking off (from any speed) before you have to shift. Plus your freeway gear will suck and therefore your gas mileage and your top speed will too.

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"The only thing that needs adjusting is the nut behind the wheel."

Redline05

Stock SI = awesome tranny

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autoluder

Thanks for the input guys.

Yea i forgot vtecs rev higher than Si's, but how is a tranny designed for a higher redline....

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Black 93 SI CAI/H/E, AEM CAM gears, jacobselectronics wires, 2.5" drop (sprint springs, kyb shocks), neuspeed front upper strut tower bar, no name rear strut tower bar, chrome dc sports lower rear tie bar, thermal R&D exhaust, DC Header. 17's currently with dunlap sp901's.

LudemanDan

In other words, since you have less flexibility in the engine (H23), you need more flexibility between the gears (Si tranny). A tranny with gears not so closely spaced gives you more flexibility in each gear. A tranny with closely spaced gears (H22 tranny) on an engine that redlines at 6500 rpm means you're always coming up on a shift point. Does that makes sense?

Edit: Personally, I've thought about getting a VTEC engine and keeping the Si tranny. The Si tranny has the same gearing as the 5th gen Prelude, which as you know is VTEC. You'd be slower in the 1/4, you get a little more run time in each gear and a better freeway gear.

Dan

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"The only thing that needs adjusting is the nut behind the wheel."

autoluder

thanks, guess i would just go with matching tranny to motor, makes the most sense.

My other thoughts were to chip my ecu to change shift points and redline for the auto, since there are no shift kits for jap auto trannies.

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Black 93 SI CAI/H/E, AEM CAM gears, jacobselectronics wires, 2.5" drop (sprint springs, kyb shocks), neuspeed front upper strut tower bar, no name rear strut tower bar, chrome dc sports lower rear tie bar, thermal R&D exhaust, DC Header. 17's currently with dunlap sp901's.