Anybody have any idea/opinions on how a GTX2860R would perform on an st205 with pretty much everything standard exept full 3" exhaust and and downpipe (oh, and forged pistons not that that makes any difference at this point in time). Spool up time? power @1.2bar?
How would it compair to a ct20b? (or ct20.. don't want to start that argument... )

Almost got hold of a GT3071R (glad I didn't) but found that the lag would not be any better (probably worse) than a CT20b? Did I read that wrong?

Basically, in the future, i'm NEVER going to go above 400bhp,
eventually, I'll go front mount (and aftermarket ecu if i have to) but 360-380 with minimal lag is what I'd like. Is there a better GTX series turbo that might do the job?

I'm still new to specing turbos so go easy (no big words please lol)

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St205 WRC - Running sweet.

I presume this is the new improved disco potato. We need a Guinea pig

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If at first you don't suck seed, try drier grain.

Ok, who's willing to nurture the guinea pig?

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St205 WRC - Running sweet.

Define nurture:-
1) Pay for it, fit and map
2) Laugh to the point of incontinence when it all goes wahoonie shaped

I'm all over 2 like a rash

I meant option 3, Guide me in the right direction...

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St205 WRC - Running sweet.

But option 1 sounds amazing!

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St205 WRC - Running sweet.

I think I'm reading it right...Going by the Compressor map,
you would have to run this at 2 Bar to achieve your 400Hp. That's almost into choke. Charge temps would be high. Especially if you have gone for a 0.63 AR housing. (not sure if anything larger is available on this frame) This would not be my first choice if 400 was a serious consideration. As far as spool. I would say this would match the the CT on a conservative map. Maybe bring it in 100-200 Revs on a lean, all out jobby. Difficult to say as there is other things that can affect this. I think this turbo would be good in a 350hp application. But I would not want to track a 0.63 turbo without massive cooling. Road should be fine. My opinion. Probably bollocks....

On a slightly more serious note

There will be quite a bit to sort out. Possibly the opportunity to solve your MOT query at the same time
Naturally there's the question of budget but IMO you shouldn't really be looking at stuff like this if budget concerns are serious as it will get a bit spendy

In essence there's a few hurdles to overcome
1) Fit turbo to manifold - you need a T25 manifold adapter

2) Connect turbo to exhaust - new downpipe required as the 5 bolt Garrett flange is nothing like the stock one - also the manifold adapter will reposition the turbo

3) Connect turbo to intercooler. For a stock top mount it might be trivial. It might not be. Depends on how the compressor snail lines up compared to the original. The extra space created by a manifold adapter might well be your friend here.
For a front mount it doesn't really make any difference

4) Hook up oil and water fittings. This will be a bit trial and terror. I'm not aware of any off the shelf stuff so it will likely require a bit of head scratching and thumbing of the think auto catalogue

In reality for most people without ninja fab skills you need external help with this. Hopefully someone with a kit.
I would be looking to someone like Tim @ TBDevelopments as this type of thing is right up his flagpole
If you get really lucky you might even be able to get a downpipe with sports cat thus curing the emissions worry - I can't remember if it was Tim or Ray (yellowchinaman) who offered these

Oh, offs
Should have checked first. Tim has a kit available. Would be my path.

Edit. As already posted by Davy (I'm really on a roll today NOT)

Needs a bit of studying of compressor maps to see if its a good match. The old one was reasonable but the Russian doll map has lost its head which might make the setup less desirable now

Totally agree with the above post and it kind of makes the compressor maps moot.
The effort to fit one will be massive compared to gains. Unless you have a failing turbo. Id spend the cash on an ECU and a remap at this early stage.
330hp is achievable on a standard turbo with a good map. With improved spool too. ECU would get my vote. But if you really want a new turbo just state you requirements and i'm sure between a few of us we can point you toward the ideal mate

Well; 360 to 380 is my goal but you've scared me all the extra work that needs to be done lol

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St205 WRC - Running sweet.

It would be an undertaking that's for sure.
Bear in mind you wouldn't achieve the 360-380 on a standard ECU.
You standard ecu would allow you 1.17-1.2 Bar of boost. would not yield much more than a standard turbo with supporting mods. you would have to drive it to 1.5- 1.6 bar with a remap to get you targets.

It's perhaps not as much work as you might think though

To achieve numbers in that region you will most likely already be thinking of a forged build so the engine will be out of the car anyway. In that situation jigging up downpipes and general monkeying about is quite a bit easier

Anything over 330-340 (my personal figure, yours may vary) is already a pretty major undertaking as you're talking engine build, fuel system upgrades and ECU replacement as a minimum and hopefully chassis upgrades to take advantage

Not quite sure why you're glad you didn't go for a GT3071R? Nowadays you can get a GT3071 with a billet wheel compressor which spools from much lower down the rev range. Allegedly the equivalent GT35 series turbos are even an option for road use!

Agree with the comments above on the work you should do to the engine if you want to run mid to high 300's reliably. By the time you cost it all up you will be staring down the barrel of £8-10k for a forged engine build, intercooling, ECU and mapping plus a fuel system upgrade. You might be able to trim some of the cost if you do a lot of the non-precision work yourself.

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Don
GT4DC Chairman
1994 Toyota Celica GT-Four ST205WRC JDM 269bhp @ 0.9bar
1994 Toyota Celica GT-Four Special GT 590bhp @ 1.8bar
1989 Van Diemen RF88/89 Formula Ford 1600
2008 Nissan Patrol GU 3.0L ZD30DDTi 154bhp

Think it was the gt3071r Tim, tbdevelopments (Garrett retailer) recommended me for my goals of high 300 low 400s. He had one recently make 450bhp @1.5 bar as I recall.