Correct, some sort of positive displacement pump. Setting that race pump up to trigger off of a Hobbs switch, once manifold pressure gets above, say 3-5psi, may be a big, big help.
what about finding a pump that can be used continuously and just dumping the whole PCV and vac line setup from the VC completely. I'm of course thinking more for my needs when I'm road coursing the car. Do you remember if Darrell had any specific vac numbers about what the engine likes/needs? Was there a threshold above (below?) which additional vaccum didn't make any (significant) difference?
what about finding a pump that can be used continuously and just dumping the whole PCV and vac line setup from the VC completely. I'm of course thinking more for my needs when I'm road coursing the car. Do you remember if Darrell had any specific vac numbers about what the engine likes/needs? Was there a threshold above (below?) which additional vaccum didn't make any (significant) difference?
the belt driven pumps do that and they pull more with added RPM, under high load and RPM I dont think you would ever be able to provide enough VAC , you guys should definatly consult with your engine builder about the piston/ring set up and a vac pump. if the ring/piston set up is not made for it i could see some posible hickups
I only see problems with crankcase pressure in these cars when you have excessive blow by (like from a bad ring or broken ring land). I always run the drivers side vent into the intake. This way under vacuum the pcv evacuates the pressure, and under boost the vacuum from the spooling turbo evacuates the pressure.
that works but most high hp cars dont run an intake tube, remember the vacuum created in the intake tube is from restriction of the filter and tube. kinda like robbing peter to pay paul
that works but most high hp cars dont run an intake tube, remember the vacuum created in the intake tube is from restriction of the filter and tube. kinda like robbing peter to pay paul
I dont know, Have you ever seen the Navy videos where the guy got sucked into the turbine on a jet? Pretty much the same principle.
The exhaust type does not work on a turbocharged vehicle, due to the lack of scavenging pulses, and certainly no venturi effect. The more 'mechanical' methods do work.
Just curious but how do you figure? A LOT of high HP turbo cars run an exhaust setup. It's pretty common.
I have yet to see it successfully work on a turbo car - certainly not a street car. On a N/A car, there are 'scavenging' pulses, basically the time in between exhaust pressure pulses, that pull the vapors out. It is never there on a turbo car. I can see it working by venturi effect at high exhaust flow rates, but that would be a big maybe.
somehow I think an active mechanical setup (pump) will be far more reliable than an exhaust or intake venturi effect. be interesting to see if someone (koff! darrell? aaron?) could get some flow rate #s to acheive specific vacuum ratings from the PCV port(s).
I have yet to see it successfully work on a turbo car - certainly not a street car. On a N/A car, there are 'scavenging' pulses, basically the time in between exhaust pressure pulses, that pull the vapors out. It is never there on a turbo car. I can see it working by venturi effect at high exhaust flow rates, but that would be a big maybe.
All it is meant to do is be a venturi effect. On a turbo car without pulses it has constant exhaust flow and would actually work better at low speed then this same setup on say a carbed BB Chevy. At WOT and lots of exhaust flow it's only going to pull more. If you look at MOST of the fast Supra's and turbo'd LSX's they are all running this setup. I know where your getting at with saying "street" car and that theory of exhaust back pressure from a full exhaust killing the venturi effect is false and has been proven. I set up a similar system on a buddies 7MGTE motored older Supra and it works great. Even after a teardown everything was WAYYY cleaner then stock too!
The exhaust is maybe not the best solution (especially for the environment) but it does work and should not be pushed off for those that understand what it does and how to set it up. I can't think of another solution where you get vacuum to help with crankcase pressure for FREE!
It seems people go back and forth on whether this is a good setup or not. Physics would say it's fine but I just question whether you would have to much vacuum from it? I built a similar setup on my SRT-4 so we shall see how it goes!
Also look at anything built by Parish8 and the Nebraska boys (1100 hp Chevy truck, Nova Wagon with twins on a 6.0 LS1, Turbo 5.3 LS1 Fairmont. The 2 turbo'd quick 16 big block Nova's out here both use an exhaust setup as well.
All it is meant to do is be a venturi effect. On a turbo car without pulses it has constant exhaust flow and would actually work better at low speed then this same setup on say a carbed BB Chevy. At WOT and lots of exhaust flow it's only going to pull more. If you look at MOST of the fast Supra's and turbo'd LSX's they are all running this setup. I know where your getting at with saying "street" car and that theory of exhaust back pressure from a full exhaust killing the venturi effect is false and has been proven. I set up a similar system on a buddies 7MGTE motored older Supra and it works great. Even after a teardown everything was WAYYY cleaner then stock too!
The exhaust is maybe not the best solution (especially for the environment) but it does work and should not be pushed off for those that understand what it does and how to set it up. I can't think of another solution where you get vacuum to help with crankcase pressure for FREE!
It seems people go back and forth on whether this is a good setup or not. Physics would say it's fine but I just question whether you would have to much vacuum from it? I built a similar setup on my SRT-4 so we shall see how it goes!
Also look at anything built by Parish8 and the Nebraska boys (1100 hp Chevy truck, Nova Wagon with twins on a 6.0 LS1, Turbo 5.3 LS1 Fairmont. The 2 turbo'd quick 16 big block Nova's out here both use an exhaust setup as well.
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, you guys should definatly consult with your engine builder about the piston/ring set up and a vac pump. if the ring/piston set up is not made for it i could see some posible hickups
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