Garrett Gt3540r - Modified ?

[discopotato03]

Yes very interested . By 66mm comp wheel do you mean the Garrett/Turbonetic T66 compressor ?

If so it could prove laggy ie 52 trim ~ 90mm compressor . There is alternatives with compressors for the GT35 cartridge .

Thanks but not too keen on the GT3040R because the total turbine/housing flow ~ 27lbs with largest 1.06 a/r turbine housing . The tip speeds are very different between the comp 82mm and the turbine 60mm for any given rotating group rpm . I want to be able to use the GT35 turbine in a large a/r housing and get the response by reducing the load imposed by the compressor , I'm working on the theory that with little work to do the large and low restriction turbine should zip up to speed quickly . I can live with limited airflow potential (if you consider ~ 55lbs limited) and am not likely to need any more than 1 bar max .

Am still not sure whether to use a large trim GT37 compressor or a small trim GT40 . I had been under the impression that the Garrett plain bearing GT4082 which uses the 50T 82mm GT40 compressor was using a .58 TO4E cover but I think its a GT40 or TO4S cover . Arguably the GT30R's GT37 compressor end can move the air but will the GT35 turbine in the big housing spin it fast enough ?

Cheers A .

Edited March 18, 2006 by discopotato03

[DoughBoy]

No, the comp wheel off a T04Z. ~66/84mm

[BezerkR32]

No, the comp wheel off a T04Z. ~66/84mm

I think its great that you know what you want, but I think you may be overthinking this a little. This application is for a street car is it not?

[Cubes]

We run Gt 30/40 on a couple of customer cars, very streetable and make 285kw at the tyres. would be ample.

Have you had this turbo on a RB30DET?

A friend had a GT3040 on his RB30DET only to be dissapointed with the lack of top end (not peak power but acceleration feel) due to the restrictive hotside. Basically it made a heap of mid range power then power goes flat across the top, big arsed diesel feel.

I believe I have an old dyno sheet from an early rb30det conversion, it has an rb25det -> rb30det back to back done with the same turbo. I'll try and dig it up as that too illustrates the flat top end.

[discopotato03]

Still researching this one . Been looking at the GT40 turbine based turbos to see if I can move the exhaust flow up and the compressor flow down a little so that pressure is not too high on either side but the volume flow is high . Still waiting for some info from OS about the GT4088R on 3L 4 valve engines . Garrett appears to have played about with turbine trims and comp styles/housing AR with the BB GT40R so it may work well in a lowish boost application as it is . I would still prefer it with the 82 rather than 88mm compressor but the cost to change it may be out of the question .

One thing I have learnt is that generally increasing a compressors cover AR generally widens the islands of the map , so being big is probably no great disadvantage provided the lower gas speed is not an issue .

Cheers A .