St185 Gt4 Compared To Mr2 Turbo

[EarL]

My best mate has a 1990 GT4 ST185 A (that's waht it says on the side), and he's wondering why it can't keep with my MR2 turbo. Both have similar mods (pipe, induction etc), but my tubby leaves his GT4 for dead!

Driving the two back to back is amazing! The tubby pulls like a rhino, but the GT4 wouldn't pull the skin off a rice pudding.

Watching the boost guage in the GT4, it comes on boost, but you don't feel any pull.

He's changed the plugs, wires, dizzy etc, but it's made hardly any difference.

Any ideas? :(

[Jamies Celica]

The 4 has transmision loss due to the 4wd and is a lot heavier than an mr2.

[Leeky]

On tarmac the MR2 whips the st185, get the cars on mud or gravel though and its a diffrent story. Both cars are designed for totally diffrent things.

[Bibbs]

The GT4 will toast ya when traction is less .. corners, wet roads etc ..

But the MR2 is lighter, has less transmition loss and is RWD .. it'll "feel" quicker ..

[EarL]

Thanks for the reply's guys, but I think it's more than just weight, feel or surface. I think it's a mechanical problem 'coz the damn thing just doesn't feel like it's coming "on boost", but the guage says it is!

Any more suggestions? :(

[djdna2000]

any error codes, e.g. 51 (knock sensor)?

Checked all hoses etc? a common fault is for the hose from the turbo - ic to crack. Check all vac/boost hoses, leaks are common.

Funny whining noises from the turbo/white smoke may indicate the turbo on it's way out?

[quodus]

doesnt the tubby have more bhp than the gt4 anyway? i thought it was something like 250bhp for mr2 turbo and gt4 was 205 ish bhp. Not to mention the weight of the car. I hear that the gt4's acceleration is better once its running rather than from a stand still.

[djdna2000]

doesnt the tubby have more bhp than the gt4 anyway? i thought it was something like 250bhp for mr2 turbo and gt4 was 205 ish bhp. Not to mention the weight of the car. I hear that the gt4's acceleration is better once its running rather than from a stand still.

In any given year the GT4 and MR2T had the samne engine, with the same nominal power output. However the GT4 has more drivetrain loss.

[Jamies Celica]

doesnt the tubby have more bhp than the gt4 anyway? i thought it was something like 250bhp for mr2 turbo and gt4 was 205 ish bhp. Not to mention the weight of the car. I hear that the gt4's acceleration is better once its running rather than from a stand still.

Nope its the other way round, the GT4 has slightly more power than the MR2 but because the GT4 is four wheel drive there is something like a 25% transmission loss of power.

[quodus]

How can you counter the transmission loss? heavy duty clutch and gearbox ?

[daktari]

Very expensively. You`d need to reduce friction, drag etc of the component parts. i.e. Gearbox internals, CV joints, Propshaft joints, rear diferential. Plus you`ve got to reduce the mass of the moving parts.(Takes a lot of power to get everything moving) But doing this may also reduce their strength as well.

The only practical alternative is to produce more power from the engine to compensate.

I think you need to make sure that what you`ve already got is working ok. Might be worth your while getting it booked in for a session on a rolling road. :D

[quodus]

can anyone confirm the actual % lost I cant imagine it be as high as 25% cos that means 50bhp just goes missing???? - that is a lot

ps - I just read something in the mr2 section saying that the mr2 turbo produces 225bhp + so the gt4 doesnt have more power!!!

[daktari]

25% Sounds a lot doesn`t it? However there are a lot of variables to take into account as well. For instance any given car will produce more power on a cool damp day than a hot sunny one. (Thank god for english summers !!!) And things like tyre wear and pressures will have an effect too. And mileage. Engine wear etc etc.

So your never going to get a 100% true figure.

You might find a web site somewhere with information from dyno tests that would give you a rough idea. Best way to tell is by the seat of your pants. If it feels right it probably is and if you spend enough money, you might get it feeling right. :D

[daktari]

Have a look at this link Clicky Here It gives you a bit of detail about the 3S-GTE engine and whats possible. :D

[Fizz]

can anyone confirm the actual % lost I cant imagine it be as high as 25% cos that means 50bhp just goes missing???? - that is a lot

ps - I just read something in the mr2 section saying that the mr2 turbo produces 225bhp + so the gt4 doesnt have more power!!!

indeedy... the MR2 produces more bhp than the GT4..

The ST185 (5th gen GT4) will push out about 200bhp...

The Revision 1 and 2 MR2 Turbo pushes out about 230bhp and the later revisions push out around 250ish bhp...

[Jamies Celica]

Sorry ment that the ST205 pushes out 251 bhp for a jap import and 236 bhp for a U.K spec.

[daktari]

Yep. I agree with fizz Thats what i`ve read. Which makes the MR2 that much quicker. Especially as it only loses about 20% through the transmision. And it weighs in a good bit less.

BUT we`re losing the thread here a bit. Your mates GT-4 should still have very noticable acceleration, get him to have it looked at. :)

PS Not wishing to be provocative at all. (Yeah right) but....... How much can you push an MR2 Turbo in the wet??????

Serious question. I`ve never driven a turbo one. But i would think it`s a bit lairy.

:D

[Fizz]

Yep. I agree with fizz Thats what i`ve read. Which makes the MR2 that much quicker. Especially as it only loses about 20% through the transmision. And it weighs in a good bit less.

BUT we`re losing the thread here a bit. Your mates GT-4 should still have very noticable acceleration, get him to have it looked at. :)

PS Not wishing to be provocative at all. (Yeah right) but....... How much can you push an MR2 Turbo in the wet??????

Serious question. I`ve never driven a turbo one. But i would think it`s a bit lairy.

:D

yup... the Rev 3 like my mota... should be able to hit 60 in 5.2 sec... B)

And you cant push a tubby for !Removed! in the damp!... let alone the wet!!!!

I've had a few scares.. and even in a straight line in slightly damp conditions ive overtaken someone fishtailing!...

[daktari]

:D Outstanding. Want one. :D :D :D :D

[Leeky]

Still the ST205 pushes out more than any of the MR2's, big jump between the st185 and the st205

[Fizz]

Still the ST205 pushes out more than any of the MR2's, big jump between the st185 and the st205

still aint as fast in a straight line though... :P

[Fizz]

ooopsss...

Double post.. please can this be deleted...

Edited July 16, 2004 by Fizz

[quodus]

I here you have to clean the drivers seat everytime you drive an mr2 turbo in the wet!!! :D

Plus the i also hear the mr2 turbo and N/A were design a little bit too high making it less stable around corners than the mk1

Going back to the original thread - try timing it 0-60 if it hits around 7.5 secs then thats more or less right. Also try flooring it whilst on the move against the tubby . The gt4 picks up alot better when on the move. If it really doesnt seem to pull then get it checked.

[Fizz]

I here you have to clean the drivers seat everytime you drive an mr2 turbo in the wet!!! :D

Plus the i also hear the mr2 turbo and N/A were design a little bit too high making it less stable around corners than the mk1

lmao... too tru mate.. when it rains.. i have to dry the seats off fist as well as my T-bar leaks!...

The Rev 3 MR2 is a lot better setup and more stable than the earlier revisions...

[GTForbes]

not sure if you's know this but since it's not been mentioned i'll do it

not sure about the MR2 but the GT4 runs lower boost in first and second gears, ment to aid traction from a standing start, could be what your speaking about, as for transmission losses, one of my mates had a pulsar, 300bhp at he fly wheel 200 at the wheels 100 bhp loss!