Bigpower

I have a GTiR turbo on my 200 at the moment due to my other T28 giving way.

Been doing a little reading as I'm a touch tired of the lag on it and I've read that you can switch the turbo exhaust case for the one from the S14 T28 as its smaller which is brilliant but... I also read that the S14 T28 compression case is bigger and if put with the GTiR turbo with the GTiR turbo exhast case make a more powerful turbo is this true??

Thanx xx


Oh and no I don't have the budget for a gt28r or rs before anyone says get one :lol:

That's a pretty small turbo for you to be worried about lag.

Realistically changing the compressor housing isn't going to make very much difference - even Garrett say it doesn't make a lot of difference:

Compressor performance is comparatively insensitive to changes in A/R. Larger A/R housings are sometimes used to optimize performance of low boost applications, and smaller A/R are used for high boost applications. However, as this influence of A/R on compressor performance is minor, there are not A/R options available for compressor housings.

Fitting the smaller .64 turbine housing will reduce spool time, but only by a couple of hundred rpm.

I agree with Ben,
IMO the Gti-r tubby isn't that bad. It is a higher spec than the S14 and my first Gti-r ran a standard unit with 360 bearings at 1.3 bar and gave 315bhp.
My current one has a stage 2 unit with larger compressor housing plus a retrimmed wheel and is giving around 330 (AFM/injectors maxing) at the same boost with very little lag. Obviously the S14 has a different head/plenum set up so it may be different on that.
Are you not puttting your big turbo back on then?

Thanks for the input boys xx


As for my biig turbo, yes I am putting it back on!!!! But first I need to have the bearings done so may be a month before its ready ***cries lots*** so gotta have good power till then too

In all honesty though I can't make the most of the GT2876 till my injectors and management arrive so with the current running system even with SAFC tweeks to the fuel I'd still spend most the time using the nitrous to keep the boost up. Not that I'm complaining

BenTaylor wrote:
Fitting the smaller .64 turbine housing will reduce spool time, but only by a couple of hundred rpm.

I'm surprised about this. I would have thought going from .86 to .64 would have made more of a reduction in lag than that. For some reason, I'm pretty sure s14 units had roller bearings as standard too. Perhaps the combination of the .64 turbine housing and roller bearings makes more of a difference on the s14.

None of the UK spec S14's had rollerbearing turbos

BenTaylor wrote:None of the UK spec S14's had rollerbearing turbos

my mistake.... I'm sure there's some other significant difference then :oops:

The S15 turbo was a roller bearing

i thought the common upgrade for the S14 200's was to get a pulsar turbo? mines is a little laggy due to the fromt mount IC, but its not that bad, i still get good bhp and torque 330bhp, 318lbft.

PussyCat wrote:The S15 turbo was a roller bearing

Thanks, that'll be where I got muddled

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So are the s14 and n14 turbos the same trim? Just different turbine housing?