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the series 4 rx7 compressor wheelis 51 mm the series 5 one is 54 or 55 mm and they are steel I ahve driven an r32 with this turbo set up with a t4 front wheel worht some though.

btw still ahvent fittted that turbo waiting for the ceffy to come back. also detonation could be because of a lack of fuel have you upgraded injecotrs and afm?

cheers

meggala

when will it have full boost on the RB20, and is it responsive? thanks meggala

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sprint32, a smaller comp wheel, would reduce the chance of surge and also lower potential power. I went for the TO4 Vtrim as it is the biggest and highest flowing that will fit in the standard comp cover. Increasing the waste gate flow will always reduce back pressure, the trick then with the turbine housing is to not have it to small and inturn boostin to early and causing surge. The rotating mass with the ceramic turbine is very small and has extremely quick spool up. Hence why so much air has been allowed to bypass.

Guest Jordy32

BOOSTED- sounds like you ahve a winer with that turbo,

after reading that after you grooved the comp cover that the surge was not present at all.

making me belive that you would be able to reduce the vg30 rear hsg from 53mm to something like 47mm & have better boost response & still not surge.

i know this question has been asked before but do you think that a std rd20 turbo could have that same mod carried out???, ofcause you need that turbo with the thick shaft.

the sr20 Turbo has a t25 flange. The Vg30 is has a t3. I am not sure about the bearing housing. The same theory could be used with a larger compressor and enlarging the waste gate and or increasing turbine clearance to increase flow and reduce spoolup to get past the compressor surge zone. The sr does not have a ceramic turbine so increasing the turbine outlet would quicky reduce spoolup hence not providing as large gains from reduced back pressure....which in turn would limit compressor size. So in other words It may not be worth the hassle with only small gains viable with acceptable lag. Only one way to find out =)

I'm just curious thats all and i didnt fully understand the exact procedure thats all. Cause i just bought a vg30 bb turbo recently so i could do these mods on it, and i was advised by garrett not to pull the turbo apart cause i might brake the exhaust turbine etc etc..

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