Thread: VNT Turbo Info

ha john what do you think would be the best size variable vane turbo for the isuzu. I am thinking of putting a turbo on mine and water to air intercooler.

Originally Posted by Bush65

Rick,
This is a pic of the numbers on mine.

Murray's will probably have the numbers in a similar position on the compressor housing.

The top number 724652-0001 is the one which is listed in my copy of Garrett catalogue.

Thanks John, I have the HS2.8 numbers in a file here too, I think they might even be yours
I was really interested to see which 'version' Alisport used as the exhaust housing/turbine inlet looks like a T25 which would be easier to adapt.

Originally Posted by rick130

Murray, does it still have all the Garrett numbers on the ID tag ?

Any chance of posting them ?

cheers.

Had a look at the tag. The numbers are...........721204-5001S KK13763W

Cheers

Originally Posted by rijidij

Had a look at the tag. The numbers are...........721204-5001S KK13763W

Cheers

Well damn, it's a VW transporter van and it's a GT2556V.
Part Number 721204 - Search Applications in TurboMaster

Originally Posted by lambrover

ha john what do you think would be the best size variable vane turbo for the isuzu. I am thinking of putting a turbo on mine and water to air intercooler.

It all depends upon what performance you want, and how much you are prepared to tune the fuel injection pump.

Unfortunately there is very little readily available information for the turbines and compressors on variable nozzle turbos.

From what I can tell, all VNT Garretts have been developed for small European diesels, and the largest I can find listed in my 2006 catalogue are GT2559V
454227-0001 for Mercedes
714306-0006 for Renault
715230-0005 & -0006 for Saab
717410-0005 & -0007 for Opel
727881-0001 for Mercedes

I would expect any of the Garrett GT22 or 25 VNT turbos to perform better than the stock T25 turbo.

I don't know if any of these use boost pressure to control the vane position. I would expect most, if not all, to use a computer controlled vacuum actuator as that is the normal method with modern engines.

While it is possible to change the vacuum actuator to a boost pressure actuator, it may need some experimentation to get the best spring for the turbo to operate to it's potential.

Borgwarner, Holset and others, also make VNT turbos, but I can find very little on these, except for the large Holset models used on 6 cylinder Cummins.

I was nearly going to use my GT2256V (from a HS2.8) as the high pressure stage in a sequential turbo arrangement. Until I found a Borgwarner R2S system.

Originally Posted by rick130

Thanks John, I have the HS2.8 numbers in a file here too, I think they might even be yours
I was really interested to see which 'version' Alisport used as the exhaust housing/turbine inlet looks like a T25 which would be easier to adapt.

I knew you had them, but my main purpose was help Murray identify what numbers to look for.

Originally Posted by Bush65

I knew you had them, but my main purpose was help Murray identify what numbers to look for.

Thanks John,
So, what is the actual difference between, say, a GT2256V, GT2556V or a GT2559V. Is it as simple as a difference in physical size, or is there more to it.

Cheers, Murray

Originally Posted by rijidij

Thanks John,
So, what is the actual difference between, say, a GT2256V, GT2556V or a GT2559V. Is it as simple as a difference in physical size, or is there more to it.

Cheers, Murray

The first two numbers determine the range that the turbine wheel fits into. I don't know the exact measurement break between GT22 and 25, but over a 53mm turbine wheel and it becomes a GT28.
The last two numbers are the comrpressor wheel size in millimeters. Bigger number, bigger turbo.

These are overall wheel measurements and do not include the wheel trim (difference in circle area from small diameter to big). The wheel trim changes with turbo application. Generally turbos running higher pressure ratios run smaller trim to prevent surge.