MFilippello

iTrader: (2)

Anybody running some sort of oil pressure regulator to limit the oil pressure going to their turbo. I have a gt40r and from what I've seen they are very tempermental about oil pressure. They are already internally restricted but I remember reading somewere that Garret specs them out around 65psi incoming oil pressure to be happy. Having more oil pressure could require a smaller restrictor but wouldn't a better approach be to keep the oil pressure at a constant psi by using an inline regulator. Anybody have any info on something like this?

Mike

MFilippello

iTrader: (2)

OK, nobody has done this. I know a while back, rotarypower and setzep were working on this. The specs on the gt40r and the 35r for that matter are 30 psi min at peak torque and 10 psi min at idle. We all know that the 7 makes way more oil pressure than this. Who has actually measured the oil pressure in the feed line. One person did and it pegged his 100 psi guage. If this is the case, and the turbo was designed with piston engine oil pressures in mind, which it most likely was, then I would think that 65 psi would be at its upper limits. The internal restrictor was most likely sized to compensate for this pressure range. Hell we make 20-30 psi at idle. More than 100 psi at 2000 rpm and up.

The poor solution in my book is to put a smaller restrictor. This seems to be more of a backward approach. What I was thinking was to put a pressure regulator inline and set it to around 55 psi. This would stay constant and keep the turbo operating at max efficiency. This is well above the 30 psi min spec and more inline with a piston engine operating range.

I just do not know where to start looking for the proper device. It also seems likely that the regulator would jhave to have a bypass/return loop similar to our fuel pressure setup. In this scenario. the oil feed would "T" before the regulator. One line would go to the turbo, the other to the inlet of the regulator. The outlet would then have to tie back into the oil system. Where would be a good place to have the return tie into. Possibly the oil filter pedastal.

Any input would be greatly appreciated.

Mike

rotarypower101

iTrader: (1)

Hey Mike I actually went as far as to put a pressure transducer inline and log the oil pressure to the turbo at different loads, and IIRC I was running right around 50-60 Psig with a –4 line.

I was going to run a inline needle valve to decrease pressure and have a finitely adjustable orifice to put the pressure in a spec range that the turbo liked.

I had all the parts sitting ready to be installed, but then I decided to see if I could assist the oil pan evacuation (as setzep had mentioned, thanks for the great advise buddy! ) by running the stock line to the oil filler neck and that really took care of all the problems that I was seeing.

I did end up with a very odd sound eventually from the vacuum of the manifold I later found out, and so I installed the PCV valve back inline and have never had a problem since.

Personally I don’t think if you wanted to bring the pressure down that you would need something as fancy as a bleedoff regulator, just putting the proper sized restriction inline should work as the pressure the turbo needs is not nearly as important to the operation as the precise pressure a fuel injector needs to keep consistent AFRs I would think.

HTH