I've put a MK4 manifold on my car (along with a Q45 throttle body) and would like to retain some sort of semblance to the stock PCV system. At the current time, I'm not using any catch cans or anything fancy like that.
My problem is that the q45 throttle body is obviously not set up to handle PCV like the 7m-GTE TB. (I.E. there is no port with orifice).
My current solution is to make use of the 1/8 BSPT port on the intake manifold and install a PCV valve (from a DSM, which happens to be the only PCV valve I could find with a similar thread pattern). This is a sprung PCV valve which seems to act as a check valve over a certain pressure (likely a few psi).
I understand that the orifice (which, for the record, is approximately 2mm in diameter) in the 7m-gte TB acts as it should, restricting flow in both directions. I did a quick and dirty blow test (yeah, thats right) to compare the flow of the pcv port on the GTE TB with the flow of the PCV valve and they seem relatively similar, so I think I'm in the clear here.
My question is, will this system suffice? I know I'm eliminating the pcv system from seeing boost at elevated manifold pressures (>~5 psi), but I'm thinking (nothing to back this up of course) that the pressure drop caused by the turbo should be able to handle the task of evacuating the crankcase vapors under these conditions just fine.
I considered using the large vac port off the intake manifold (8mm ID IIRC) and plumbing in a check valve, but this would likely result in a higher-than-desired idle.
Anybody have a good reason I shouldn't do this?
Adam
My problem is that the q45 throttle body is obviously not set up to handle PCV like the 7m-GTE TB. (I.E. there is no port with orifice).
My current solution is to make use of the 1/8 BSPT port on the intake manifold and install a PCV valve (from a DSM, which happens to be the only PCV valve I could find with a similar thread pattern). This is a sprung PCV valve which seems to act as a check valve over a certain pressure (likely a few psi).
I understand that the orifice (which, for the record, is approximately 2mm in diameter) in the 7m-gte TB acts as it should, restricting flow in both directions. I did a quick and dirty blow test (yeah, thats right) to compare the flow of the pcv port on the GTE TB with the flow of the PCV valve and they seem relatively similar, so I think I'm in the clear here.
My question is, will this system suffice? I know I'm eliminating the pcv system from seeing boost at elevated manifold pressures (>~5 psi), but I'm thinking (nothing to back this up of course) that the pressure drop caused by the turbo should be able to handle the task of evacuating the crankcase vapors under these conditions just fine.
I considered using the large vac port off the intake manifold (8mm ID IIRC) and plumbing in a check valve, but this would likely result in a higher-than-desired idle.
Anybody have a good reason I shouldn't do this?
Adam
