Open vs Closed bypass...whats the difference?
Open vs Closed bypass...whats the difference? I was looking at the Procharger bypass from EPP. Right now I have a new int he box Vortech race bypass that I would have to fab an adapter plate for if I want to use it....so I was going to pick up a PC bypass that will bolt right to the EPP FMIC tubing.
My question is...whats the difference between the open and closed versions? I'm a n00b, go easy.
My question is...whats the difference between the open and closed versions? I'm a n00b, go easy.
These are not terms commonly used for bypass valves but I believe an 'open' one would refer to a bypass that dumped into the open air, as opposed to a 'closed' one that dumps back into the system. If you use a MAF and a bypass, you must use a 'closed' one that dump back prior to the MAF, otherewise your air metering will be off.
Jim
Jim
How so? All the set ups I've seen have the bypass place before the maf. Since it is before the maf how would that cause any issues at all with metered air?
It depends where everything is placed. If its metered than dumped to atmosphere with a maf than ya, thats a no no. With SD it doesn't matter regards obviously which most people should be doing anyways.
With a maf you can dump it to atmosphere but it must be before the maf see's it and not after. If thats the case than you need to recir it back before the maf.
With a maf you can dump it to atmosphere but it must be before the maf see's it and not after. If thats the case than you need to recir it back before the maf.
It depends where everything is placed. If its metered than dumped to atmosphere with a maf than ya, thats a no no. With SD it doesn't matter regards obviously which most people should be doing anyways.
With a maf you can dump it to atmosphere but it must be before the maf see's it and not after. If thats the case than you need to recir it back before the maf.
With a maf you can dump it to atmosphere but it must be before the maf see's it and not after. If thats the case than you need to recir it back before the maf.
My old setup was draw through so the maf was on the intake side of the blower and the car would not even run if you had a big leak between the blower and tb. I now have a blow through setup and I run the Procharger race bypass and vent to atmosphere. Just put the bypass between the head unit and the intercooler. I hope you like loud cuz to say its loud is an understatement!
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I am not too familiar with the s/c setups as I have always been a turbo guy which in most cases calls for custom work. As s/c kits are more or less bolt on unless you are going extreme and also need custom/fab work than ya the s/c kits would be made to either recir it or blow it off to the atmosphere I'd assume. It would obvioiusly have to be before the maf than. Again not too sure about the s/c setups but thats the general idea behind the recir/bypass whether its a turbo or s/c. As long as its not blown to atmosphere after the maf than its ok, again, unless its tuned SD. Which I reccommend
Just curious 
8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
Posts: 4,092
Likes: 2
From: Savannah, GA
No matter what kind of BPV you have ('open' or 'closed') it needs to be BEFORE the MAF. The MAF meters the amount of air coming into the intake manifold and uses that measurement to adjust the fuel accordingly. If you place the BPV after the MAF you will actually have less air than what the computer thinks you have, and it will be adding too much fuel for the amount of air you actually have.
???
All you need to do to prevent the blower from surging is to vent the pressure side back to the inlet side. If the MAF is before the blower, and the bypass return is after the MAF, you'll be golden.
This may not be a common F-bod setup, but you see it out there frequently on other cars.
Jim
This may not be a common F-bod setup, but you see it out there frequently on other cars.
Jim
All you need to do to prevent the blower from surging is to vent the pressure side back to the inlet side. If the MAF is before the blower, and the bypass return is after the MAF, you'll be golden.
This may not be a common F-bod setup, but you see it out there frequently on other cars.
Jim
This may not be a common F-bod setup, but you see it out there frequently on other cars.
Jim
All you need to do to prevent the blower from surging is to vent the pressure side back to the inlet side. If the MAF is before the blower, and the bypass return is after the MAF, you'll be golden.
This may not be a common F-bod setup, but you see it out there frequently on other cars.
Jim
This may not be a common F-bod setup, but you see it out there frequently on other cars.
Jim
With a maf like explained, the ecu would think there is more air going in than there actually is so you will be rich and the maps off.
8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
Posts: 4,092
Likes: 2
From: Savannah, GA
All you need to do to prevent the blower from surging is to vent the pressure side back to the inlet side. If the MAF is before the blower, and the bypass return is after the MAF, you'll be golden.
This may not be a common F-bod setup, but you see it out there frequently on other cars.
Jim
This may not be a common F-bod setup, but you see it out there frequently on other cars.
Jim
The MAF is very simple. It measures the amount of air to adjust how much fuel to supply. If more air goes thru the MAF than actually goes into the engine, your tune will be out of whak. 