I have searched for a long time on this forum, and many others for a proper answer to this. Guess what? many different answers I havent really got the money to buy a $400 procharger race bypass valve, so want a cheap alternative. Ive seen cars using cheap Ebay ones, but they are closed on idle? the procharger one, is OPEN on idle, then snaps shut when on the throttle. Do any others out there do the same thing?

 

It is called a bypass valve.. There are many companies that sell them. It depends on how you want to protect your investment.


If you buy a $30 valve, you have the bottom of a line product. If you spend a few hundred, you will get quality equipment. Remember that most new automotive stuff that is on Ebay is from companies that mass produce their stuff and they can make money selling it on the internet. If they weren't making money on them, they wouldn't be selling them, especially so cheap.. Here is the one that I use, it is called a Mondo Racing Valve. Hopefully this helps

http://www.vortechsuperchargers.com/product.php?p=23

 

u can use some of the ebay rfl valves , as these are piston type valves.

u would need to replace the springs in them with a much lighter spring , the lighter spring will allow them to open up at idle and cruise when the engine is under vacum , once u start building boost the presure ontop of the valve will close it

and actually if u select the right spring as the engine aproaches 0 vacum the valve will close itself .

theres nothing to break in these valves as they arenothing more then a brass valve inside an aluminum housing with a spring.

depending on the headunit u run u would need to use 1-2 of the rfl's for enough flow capability but even if u need 2 ur talking 60 bucks or so for the pair + a few bucks in springs form mc master carr or local hardware store

 

The procharger one snaps shut by spring pressure it's held open by vacuum. You can use any bov and adjust the spring pressure so that it's open at idle and closes when the vac. drops below spring pressure. Adjustable allows you to tailor this closing point.

 

heres one of these valves taken apart

 

Here are my valves, both adjustable

 

dead on except i would think u have to use a piston type like i posted above, i dont think u could adjust the diaprgham type bov enough to make it work.

not to mention they tend to leak under high boost when u take the preload of them

 

The Procharger bov is a throttle blade type thingie and even closed it leaks a lot of air indeed, that's why I don't use them.

Mine are piston types. I especially like the blue one, it's made by AMWorks in Finland. The other one is an Active Autowerke (BMW stuff LOL) but it fits my intercooler flange

 

ive heard of ppl using ebay wastegates with very light springs as bypass valves on supercharged apps , on paper it seems like it would work just as good if not better then the bov

iirc they use a light spring and plumb the top port to vacum/boost so that the vacum holds the valve open, and boost presure helps keep it shut

u can get a 40-50mm wg for around 65 bucks but springs are 8-12 bucks each but with a 50mm valve they would support a bunch more flow then the rfl style bov i posted


i have 2 of those rfl's on my tt iroc , and a single one on my v6 car and they work great

 

That's what I have mine set like. Light spring so it's open @ idle, if I throttle it however it closes a lot faster than the procharger thing and snaps open when I let off because it's not onlu dependant on a vacuum signal but also the pressure in the plumbing before the throttle blades adds to the differential pressure that needs to be overcome spring pressure. This is something the blade type procharger thing does not do.

 

This is the best information ive read on the subject, and believe me, ive spent hours looking! So something like this http://www.ebay.co.uk/itm/Universal-...item2ec5aedd16
Would work? providing I install the correct springs?

 

You're in the UK? I have an old Procharger bypass vale if you're interested. It's not the new spiffy black one but the older bare aluminum one. I'm in NL

 

I do have an original procharger one that would have come with the setup, if thats what u have? Im assuming ill need a much larger 50mm to allow that much air to vent?

 

That is a beautiful setup.. Did you do your own work?

 

Thanks yes, I built everything myself. Main concern was packing it under the stock hood and not cutting up the car. Even the intercooler is mounted off stock bolts/ bolt hole locations. I hate drilling extra holes if I can avoid it.

 

Yes. It works fine on a 355 D1SC and 383 P1SC setup we have here. Vents plenty to eliminate surge

 

Ive got a 406ci motor, far from stock! With a D1sc unit.

 

I like the fact that you left the battery up front. I relocated mine to the spare tire area and put my MSD box and intercooler piping there.