Gt4 Models/engines Help Please

[mal_k100]

Hi All,

trying to find specifications of the engines on the GT4 with pop up headlights. I think this is a ST185 but there seems to be a later ST185 H.

I think the engine is the same as the MR2 turbo and in late 1992 they upgraded the engine. I have seen a 1993 GT4 with pop ups and I need to know whether these are the uprated engines which, according to the MR2 site, can give more power for minimal changes.

Not interested in the rally specs - just ordinary UK/Japan models.

Pointers to a website that has the details would be fine.

Also - am I down the right lines folks ? Do I need to worry or can the ST185 be tuned with minmal changes to give 250+ brake ?

Thanks for any/all help

[quodus]

The car you want is the st185 gt4 i think there is a 1993 model but only in the earlier part of that year as the st205 took over production.

As for uprated engines, yes, a later engine in the series is always better but there probably hardly any differences. I think the japanese imports have more bhp than the uk cars- as for 250bhp i'm not sure, tho i know is possible

[Leeky]

250bhp is very very easy to acheive, in the Revision 3 engines 1994+ they were 255bhp stock. The Revision 2 engines (up to 93) had approx 205bhp stock. That extra 45bhp is going to be very easy to get. Firstly an induction kit, exhaust and decat then turn up the boost. Your probably end up close to 270bhp though.

[mal_k100]

I think that is what I was afraid of - the revision 3 engines seem to be in the new model with the non - pop up headlights and seem to be more expensive.

I was hoping to find and older model with the newer engine -i.s. a series 2 engine but in a pop-uip headlight model. I saw a 185 H engine and wondered whether this was an interim before the series 3 came out ?

Thx Leeky - at least you give me hope that I can get a 1991 or thereabouts and still tune it up. The MR2 engines seem to be able to give a hell of a lot more if I get a K Reg (1993) and there seems to be an overlap hear in that in 1993, pop-up headlights were still around. I'd be happy to ask a vendor for the engine number from the log book so as to look it up if I knew where to go !!!!

[Leeky]

Im pretty damn sure they never put the Revision 3 engine in the Gen 5 celica (pop up lights) so its going to be revision 2 only im afraid. But this doesnt matter much as the main diffrence between revision 2 and three was the turbos.

The revision 2 has CT26's and the Revision 3 has CT20b's. If you get a revision 2 you could just upgrade the turbo. Get a nice HKS system for 400+bhp :D

[djdna2000]

There are 2 different ST185 engines, the standard (with air-to-air intercooler) and the one fitted to the Carlos Sainz/RC version which had a water-to-air intercooler. The CS/RC unit was not fitted to the SW20 MR2, it produced around 230 bhp so around 20 more than standard. There were other minor differences in the throttle body, head and turbo IIRC as well as different ECU fuel and ignition maps.

I have seen the designation ST185H before, the engine is no different but I think poss may refer to the narrow body version

I would be very wary of tuning the standard earlier model too much without being careful, they are prone to blowing headgaskets. The CS/RC unit is better but tbh it's all a question of good modification combinations. An uprated turbo, boost controller, exhaust, filter, and for example water injection or an uprated front mount intercooler will easily see you past 250 bhp with reasonable safety. You would be best off investing in an aftermarket ECU but expense can be prohibitive.

Get on www.gt4oc.com where there is a wealth of information and advice specific to the GT4.

[GT-Four NZ]

I have a 1990 JDM and mine is a standard as ST185 the only "H" that I have seen is on the manufacturing plate of a friends RC (ST185H). THe 1992 on I think was a widebody edition, just look at the rear guards as a wide body stands out like dogs balls. We have 1993 pop up lights in NZ but yeah just check the i/c setup. Apparently the CT20B is a smaller unit than the older CT26??

[Leeky]

I have a 1990 JDM and mine is a standard as ST185 the only "H" that I have seen is on the manufacturing plate of a friends RC (ST185H). THe 1992 on I think was a widebody edition, just look at the rear guards as a wide body stands out like dogs balls. We have 1993 pop up lights in NZ but yeah just check the i/c setup. Apparently the CT20B is a smaller unit than the older CT26??

Yeah the ct20b is smaller than the ct26, but i think the reason they used a smaller turbo was so it would spin up faster to full boost and on top of that this 'b' revision was strengthened to handle more boost than the ct26 even though it is smaller.

Apparently the original ct20 was a diesel turbo

[djdna2000]

Actually, the CT20b is very similar to the CT26, but has a larger compressor, this shifts the efficiency range higher up the pressure band so the CT20b is happy at 13 psi stock rather than the 7 or so of the CT26. The old CT20 turbo was really no relation to the CT20b, it was found on the 3T-GTE and 4T-GTE engines in the mid-80s, they produced around 150 bhp IIRC.

the CT20b has a smaller shaft than the CT26, perhaps this is where the confusion arises. The smaller shaft helps reduce lag (along with the ceramic exhaust turbine also on the CT20b).

[Calisto]

Can some one fill me in on my girl with all this jarrgon me is lost.

[mal_k100]

Thanks for all the information guys - I am still looking but my son has a 1990 Supra that he may not be able to keep on the road due to hih petrol costs. I've asked for first refusal. It is the older model around 225 bhp but it is red, has stunning 5-spoke split alloys and I may end up with that instead. Knowing himn he'll make a good profit on it anyway !

Still looking into the GT4 looks like the older model. Have a great gut who looks after my cars and he would probably fit the 20b for me and maybe even find a cheap one in the trade.

Thanks again !

[Spartan]

As far as I know from a tuning stand point (with the exception of the ST205 3S-GTE) the SW20 (MR2) and the ST185 engines are near identical in engine out-put. The differences you see between them is mainly due to ECU tweaking and higher jap octane levels.

I read an excellant tuning guide for a MR2 3S-GTE, i'll go have a looksies for it. From the guide it said 235 WHP (thats right Wheel horse power!) is easily obtainable for under £1k. The site also goes into dispelling the myth of the CT26 producing nothing but hot air at higher boost levels. I'll post in couple of links you might not have found.

Oh if the Supra is the MA70 (pop up lights) they are great cars, and one for my next ride (after a ST185 CS! :)). I've heard those engines can take 500BHP without many internal upgrades (bar a steel head gasket). Which would be my first mod when going for power in any turbo'd Toyota!

[Spartan]

Those sites I was talking about:

http://www.mrcontrols.com/primers/power.htm

http://www.alltrac.net/

[KiwiMR2]

The site also goes into dispelling the myth of the CT26 producing nothing but hot air at higher boost levels

Myth.......they certianly don't produce power at higher boost levels ;) The Hybrid versions only make 288whp when the CT20B has been known to make 319whp see http://www.turboforum.net/dyno/ for details. The closest modified CT26 (Actually a complete recast of the housing to mate it to a GT35R compressor) was 304HP

Cheers

KwiiMR2