Turbo CRVTEC - how much power can gearbox handle?

[trancier]

My 98 Civic has a turbo B16A and is currently undergoing a B20B bottom end conversion. The workshop estimates that the standard gearbox can handle a max of 220hp at the front wheels. This is the only thing preventing us from getting more power, as we expect the car could put out around 250hp at the wheels.

Does anyone know from experience how much the gearbox in this car can handle?

PS The model is VTiR here in Australia, which I think is called Si or SiR in the US.

[Oz]

to another Aussie. Come on over to the Asia/Pacific section sometime - they're just about all Aussies.

Your question - I'm assuming you have a VTi-R 6th gen with a turbo. If all you want is a gearbox to get your power to the ground, use the VTi-R box out of an Integra with an aftermarket LSD or alternatively, the driveline out of an ITR. You have to ask yourself why you want this amount of power though - the only reall application is for drag racing. Street driveable (TRACTION) power is about 220 in a VTi-R Civic. If you go through with it and one of the two mentioned boxes breaks, it's time to step up to dog engagement gears. Hope this has helped,

Oz

PS-There's a lot of local knowledge on the Aussie only board www.performanceforums.com

[edman24]

for that kind of a setup i think your best bet for a tranny would be the integra LS tranny. dont know what model that is in autralia but its the non-vtec 3rd gen integra tranny. it has wider gear ratios to maintain boost and like most honda trannies can handle a lot of power. with an upgraded clutch and flywheel you should be able to put down 400hp and not worry about the tranny breaking. seen it done many times before so dont think you really need to worry about it.

[trancier]

Thanks for the feedback guys

Oz >> I check out performanceforums quite a bit but it seems there aren't many turbo/crvtec hondas in australia (at least compared to the US). You're right about there being a limit to the amount of power this daily driven car makes, but it's hard to deliberately turn the boost down when you know it can easily make more power. 200fwkw in a civic would be so cool

edman24 >> I'll look into the integra tranmission when this box breaks - the only downside I can see with a non-VTEC tranny is that it probably won't have factory LSD, which would be a useful upgrade. The ITR tranmission might be the way to go.

[edman24]

yah i think youre right about the lsd. but if i could suggest a vtec tranny it would be the gs-r. im almost positive that the gs-r still has lower ratios then the type r and thats what you want.

[Oz]

Originally posted by edman24
yah i think youre right about the lsd. but if i could suggest a vtec tranny it would be the gs-r. im almost positive that the gs-r still has lower ratios then the type r and thats what you want.

Sorry to burst your bubble Edman, but the ITR has a 6 speed with VERY close ratios as opposed to the 'GSR' VTi-Rs 5 speed, no LSD and higher spaced ratios.

[edman24]

yah i know the ratios are close on the ITR tranny. thats what i was saying. the type r has higher gear ratios . higher means the gear ratio is quick and short and will go through the gears quicker. hence closer. the gsr has "taller" gear ratios which means it holds each gear longer. i think we were tryin to say the same thing but in different words. and about the LSD the gsr tranny can come with an lsd if asked for. so what bubble you bursting?

[Oz]

:right:
There was never an LSD option in Australia.

[trancier]

Originally posted by Oz
:right:
There was never an LSD option in Australia.

That sucks huh...

but then how much difference would it really make in launching? my car has zero torque steer (at 140fwkw), so I'd be guessing that an LSD would only really matter when cornering hard. Is this right?

[shepworldwide]

b18b tranny alll the way if this is your daily driver

[edman24]

well then thats a different story if there is no lsd option in australia. i wouldnt have known that. im in america obviously. but you could get one shipped there so its not that big of a deal

[thetoymaker]

hey,
I crushed my thrust bearing on my input shaft during the first 1000 miles on mine, I am have to switch to a GSR gearbox to handle the power.
This was even before I put in the turbo, the damn ls tranny gave me some issues.
perhaps it was a manufacturing defect, but the guys up at the shop say that a gsr tranny can handle the power.

oh, I'm running CRVTEC, so it applies.