Garrett Variable Geometry Turbos (vnt Or Vgt)

[waz]

Has anyone tried the Garrett GT37V or GT40V Variable geometry turbos.

I have a R33 GTST and have been considering using one of these turbos. I have spotted these on ebay for US$600 and think they may ideal for the RB25DET.

I completed a project in 2004 using a GT15V on a 600cc CBR600 motor and found the turbo to offer almost no lag. Because of the laggless nature of these turbos I think they would be ideal for a 300+rwkW everyday driver.

The above turbos are from Ford F series Powerstroke diesels and of cause petrol engines operate with higher exhaust than diesels. However from my CBR600 experiment we found that because the VNT turbo can act like a large turbo backpressure is kept down so are EGT's. Reliability of the VNT was not found to be an issue.

I have read up a bit on a late 90's Ford 2.2L fitted with a GT25V and the only unreliability problems stemmed from carbon (soot) clogging th guide vanes. I am considering water injection as a method of stopping this as well as intercooling as people report this having a cleaning effect on engine internals.

Any light shed on this idea would be great as any knowledge shared could save me a lot of money and heartache if it is doomed.

[DAN00H]

the guys on the UK GTR forums have discussed this topic at great length - go have a look.