6 Speed Gt4

[Leeky]

Hi, i was wondering if anyone has ever tried to change the 5 speed box in the celica for the 6 speed supra box?

I find that my top speed is limited by my gear ratios, i can take it right up into the red in 5th but cant go any further so i think the best option would be to have another gear.

Any opinions?

[dawesy]

as the supra is rear wheel drive and your celica is 4wd i wouldn't think it will fit. sorry :(

[yozef]

Good idea it could work on the normal 2.0 GT FWD with a 2000+ celica gearbox, but surely not on the GT4 (4WD)

[Leeky]

I guess i could use a Subaru Impresa 6 speed 4wd gearbox, or a mitsubishi 6 speed 4wd gearbox.

I cant think of a toyota 4wd 6 speed gearbox, dont think they ever made one.

[Leeky]

or there is a 6 speed gt4 on this site, wonder where they got the box from?

http://www.rallyteamireland.com/team_profile/car.html

may give fensport a ring

[Leeky]

ohhhh the US Toyota Tercel had a 6 speed 4wd gearbox i hear

:D

[Tercel GTS - DirtWeed]

far as I know there was never a 4wd tercel made for usa, nor 6speed

[dawesy]

you could ask quaife to make one for you but the bill may come to £50,000+ :(

[cel_94]

Have you thought about keeping the box but changing the ratios? Probably a cheaper option.

Out of interest,what speed are you doing at the redline?

[Leeky]

on the tip of the redline im roughly doing 160mph, i may change the ratio. The car spins up to 140mph in a shade over 10secs. But come 160mph im going into the red line and im too scared the rev limiter will kick in and the force of the engine halting will cause me to loose control at that speed. :o

Scary **** :(

A sixth gear would be better. The 2003 Toyota Tercel has a 6 speed 4wd gearbox as an option.

But whether i can source one is another question. And the final ratio of the 6th gear may be less than that of my 5th.

Maybe im cursed by toyota not giving the gt4 another gear. :censor:

[Tercel GTS - DirtWeed]

Matrix also has that option, and to my error, older tercels DID come as 4x4

[dosenöffner]

Exactly what I went through. The 6 speeds you'll find on rally cars are for them only and cost big bucks.

I am currently modifying a standard box (drilling extra holes and reworking an oil gallery) to take a US 6 speed kit. The kit was about $2,500 US. I bought it some time ago now but never got a donor box till recently.

I will dig out the infor for you. It is Quaiffe though. Maybe they still have a few lying around. Looking to move the top speed to 180mph but you'll need the horses to back that up. It is really more a rearrangement of the other ratios for quicker acceleration.

Changing your diffs might be a better and cheaper option.

[Leeky]

Gear boxes are the thing i know the least about.

Whats envolved in changing the ratios? I guess i gotta get someone like fensport to do this huh?

I guess the whole engine needs removing to get to the gearbox.

[dosenöffner]

You can drop the gearbox out the bottom without taking out the engine. It's a bit of a pig and takes two really as it's a heavy lump. The differential and gearbox are the same unit on the front. Differential ratios can be changed by doing the crown and pinion. Gearbox changes like adding an extra gear are not so straight forward. I'm doing it myself but if I was paying someone to do it lets just say it would be cheaper to buy a Porsche or Ferrari to get the extra speed. ;)

[Leeky]

So is it expensive to get someone to simply adjust the 5th gear ratio to give me an extra 20mph for example?

[dosenöffner]

Just doing the 5th ratio would be in most budgets but there are two things to be considered.

How often are you actually aboce 150mph for any length of time?

How much are you prepared to lose when you change from 4th to 5th when using it as an everyday driver?

I suspect just doing 5th is a bit of a half job and would leave you frustrated.

[Leeky]

Unless i leave the box as is and try to remove the rev limiter. Im thinking of upgrading internals anyway so they should be about to take the stress of something like 9000-10000 rpm.

Whether the gearbox etc would is another question.