Gcg Wheel Measuements?

[benl1981]

I have measured the comp housing on my 2nd GCG. It measures 54mm I.D. This means that it must be about a 52mm OD wheel. My other GCG must be around 54mm OD wheel (The one I am having surging issues with)

Anyone measured the comp wheel housing inner diameter.

Ans how about the exhaust housing. It seems to be bored out to around 57mm..on the 2nd GCG - the 1st one must be about 54mm

I.e.

1) Surging - Approx 54mm Comp wheel (About 56mm bore size) , 54mm exhaust wheel

2) Unknown - Approx 52mm Comp wheel (About 54mm bore size), 57mm exhaust wheel

Thanks

[sh@un]

have you rung GCG and quoted the serial numbers to see what they say about 'em?

the sizing seems odd between the two- like one is for a rotor, and maybe the other for a large twin setup

[benl1981]

they are bot the XTRGTST S1

For R33..

Believe me I have been on to them

[R31Nismoid]

Why dont you just send the turbo to them?

Could be that someone killed the turbo and had to get it repaired or anything.

[sh@un]

get 'em to rebuild turbo 1 with the exhaust side from turbo 2- should cure the surging

[benl1981]

Im going to take both turbos to them and discuss. I have already been in contact with them..

I just wanted some dimensions from here if possible

The compressor wheel on 1 is too big - I will be reusing the one of the 2ndturbo. But the 2nd turbo has a chipped exhaust wheel and more play..

too many crap turbos here!

[Cubes]

So which one was having the surging issues? The Rb20 turbine housing one?

[benl1981]

No the other one. It has 21U on the exh housing. It has the larger comp wheel and smaller exh wheel...

[benl1981]

Ok the first 2 pics are TURBO 1 - the Surging one

The other3 pics are the unknown but later GCG

Edited July 25, 2007 by benl1981

[MANWHORE]

Im going to take both turbos to them and discuss. I have already been in contact with them..

I just wanted some dimensions from here if possible

The compressor wheel on 1 is too big - I will be reusing the one of the 2ndturbo. But the 2nd turbo has a chipped exhaust wheel and more play..

too many crap turbos here!

I've found that in the past, gcg haven't been very helpful in regards to discussing turbo tech. It may be that they are being protective of the wheels that they use etc.

Really knowledgeable bloke to speak to on here would be Dale FZ1. He knows his turbos.

Edited July 25, 2007 by MANWHORE

[BHDave]

Just an interesting note.

My old s2 highflow looked to have the same comp as turbo 1 and the same exhaust side as turbo 2. BUT i remember my s2 highflow had a little groove cut into the inside of the snout right where the inducer tips sit (similar to stock). it was about 10mm wide and 1mm deep from memory (anti surge mod?). I'll see if i can dig out my old for sale thread photos and confirm.

[LTHL34]

Hey guys i know this is a bit off topic but how can i get in contact with gcg? what is there number? thanks

[sh@un]

call directory asistance

gcg is in condell park nsw

[Dale FZ1]

Nothing is ever as simple as it seems.

You'd have to consider the size and specs of each impeller, and the size of the housings they are fitted to before trying a mix & match approach. Might work, might not. Might find a R34 / VG30 housing will help to keep that surge prone cartridge in a happy zone.

I have PM'd you Ben

cheers

Edited July 25, 2007 by Dale FZ1

[MANWHORE]

Nothing is ever as simple as it seems.

You'd have to consider the size and specs of each impeller, and the size of the housings they are fitted to before trying a mix & match approach. Might work, might not. Might find a R34 / VG30 housing will help to keep that surge prone cartridge in a happy zone.

I have PM'd you Ben

cheers

Dale, my thoughts exactly. My initial thought was to replace the rb25 exhaust housinng with a vg/gtt housing.

This is not an expensive thing to 'try' at all, since most engineering places/machine shops/turbo places with a lathe can machine the snout to whatever spec you want. That is in comparison to the price that gcg charge to repair/renew highflow turbos.

This should shift the power/airflow up a few hundred rpm (the op6 housing is significantly larger - 0.8ar as opposed to 0.6). The engine should be able to ingest the air at that rpm.

It's not really a waste even if it still surges, because it gives you the ability to make more power. I believe that if a turbo is to be upgraded, it shoudl be a worthwhile one

[MANWHORE]

Hey guys i know this is a bit off topic but how can i get in contact with gcg? what is there number? thanks

Just like how you contact any other business. Use google and type in GCG or look up the phone book.

[LTHL34]

Just like how you contact any other business. Use google and type in GCG or look up the phone book.

thanks mate

[benl1981]

Im trying to track down the vg30 housing for around $100..

They are hard to come by.

[MANWHORE]

Just an interesting note.

My old s2 highflow looked to have the same comp as turbo 1 and the same exhaust side as turbo 2. BUT i remember my s2 highflow had a little groove cut into the inside of the snout right where the inducer tips sit (similar to stock). it was about 10mm wide and 1mm deep from memory (anti surge mod?). I'll see if i can dig out my old for sale thread photos and confirm.

Its amazing that they managed to machine an anti reversion groove into the already significiantly machined housing. Where the groove is, there is almost no meat left.

On my slide turbo, you can squeeze the snout on the comp housing and it moves.

[benl1981]

Bhdave - that comp wheel looks almost like a stock one. See how they have machined it out but right near where the impeller is there is less material removed.

Did your turbo with the larger comp wheel surge?

Thanks for the lengthy PM dale. Will respond later. I have verniers so can measure it carefully