Vtec vs Si gearing - Honda Prelude Forum

Kango · 08-08-2003, 04:51 PM

I found the difference in gear ratios of the Vtec and the Si trannies, but how much difference is there when it comes to driveability? The Si shift point is at 6500....can it be driven up to 7500 like the Vtec?
Thanks, Kango

brendon2k · 08-08-2003, 05:23 PM

Your question doesn't really make sence. The shift point is 6500 and the rev limiter is set to 6800 because the engine cannot rev higher wiht out damage. A H23 tranny can rev just as high as a H22 tranny. The only real problem with using a H23 tranny with a H22 is that its hard to stay in vtec for the 1-2 shift.

Kango · 08-08-2003, 08:01 PM

Sorry about the post, I was being distracted while I was typing it. I was wondering if the Si tranny would work okay with the vtec motor. I've heard about the difficulty staying in vtec even WITH the actual vtec tranny. Hmmm, perhaps if I were to build the head up a bit i.e., cams, valve springs, valves, it would allow me to rev higher obviously, and perhaps stay in vtec. Would that be an option, or is my best bet just to go with the H22 tranny? Thanks again, Kango

[SUB[EX] · 08-08-2003, 10:19 PM

get the vtec tranny. I have the Si and i really want the Vtec now. The vtec just feels more natural. And unless your chipped and can rev past 8k then the 1-2 vtec is very hard.

irishpilot · 08-08-2003, 10:47 PM

with the VTEC engine and si gearing do you have a higher top speed???

I have a wild dream to make a project Lude that goes 170MPH or higher on the salt flats

I understand a custom tranny is whats needed for something like this but I'm assuming that with the si tranny you can stay in gear longer and with the longer gears a top speed should raise also?

[SUB[EX] · 08-09-2003, 12:43 AM

well, technically i think it should have a higher speed.

But a better choice for top speed would be the F22 tranny because it has really really long gears. Top speed FWD car huh.

Kango · 08-09-2003, 09:50 AM

http://www.hondata.com/pressreleaseprogress204.html

Yep, top speed FWD car.

BTW, thx for the info Sub....I think I'll listen to your advice, rather than use the Si tranny now, and regret it later.

preluda92 · 08-11-2003, 03:38 AM

The only difference it 1st and a tiny bit of difference in fifth. That is all same final drive, and 2,3,4. If you take it to 7500 with the VTEC engine in a Si tranny you can shift and still be in VTEC. I'd only spend the money on the VTEC tranny if your Si one is going bad. Which it probably will do.

Forbidden · 08-11-2003, 04:34 AM

Actually first and final drive are the only gears that have the same ratio. 2nd and up are all a bit different. With a 5th gen tranny you would be able to stay in VTEC more easily on the 1-2 shift though since the 1st gear is a bit less aggressive than on the 4th gen VTEC and Si. If you really want to know the exact speed, rev drop and stuff I suggest you do a search for the gear ratios and go to www.autocrossing.com and put the numbers in there and see for yourself.

4bidden · 08-11-2003, 10:51 AM

Why do people talk like all that matters is staying in VTEC on the shift? Sure, you could get a VAFC and set VTEC down to like 4600 and stay in VTEC on the 1-2 shift with a Si tranny, but youre still going to be slower because the guy next to you with the VTEC tranny that is at 5100-5150 or so after his shift, making more power. RPM in the next gear is the important part here, VTEC is not, that can be adjusted so you dont fall out.

Satan_SRV · 08-11-2003, 11:00 AM

H23 tranny on an H22a...

Shifting at 7800 every time
gear rpms top speed
1st- ------- 39mph
2nd- 4380 70mph
3rd - 5544 98mph
4th - 6110 126mph
5th - 6125 160mph

VTEC tranny

Shifting at 7800 every time
gear rpms top speed
1st- ------- 39mph
2nd- 4644 67mph
3rd- 5360 96mph
4th- 6001 121mph
5th- 6125 149mph

these are mathematical numbers, fact is you can stay in VTEC with a VTEC tranny, but we're talking about 300rpms you hit by hitting the gas at the right time.

Anyways 4bidden is right you may think the 2-3mph in each gear is no big deal but it is. That means faster acceleration as you are higher up in the rev range in most gears as well.

Kango · 08-11-2003, 02:27 PM

More useful info. Thanks again, guys.

95VTEX · 08-11-2003, 03:49 PM

Ok Ok I need a new tranny as well. I have a H22 w/H22 tranny now and was wondering if I should go for a H23?

So trying to understand what has all been said in this post. Is is a better idea just to stick with another H22 tranny. Or am I better off with a H23?

Kango · 08-11-2003, 07:00 PM

Stick with the H22 tranny. That's why they geared it a little steeper....more "vtec friendly" by the sounds of it.