does anyone have any ideas or comments on the location of the bov valve on a gen 3 rx7 i.e by the compressor discharge pipe or after the intercooler

 

after the intercooler

 

Best place. You want to maintain the original direction of air flow which is towards the throttle body.

 

Why do most OEM (and all OEM rotary) turbo applications place the BOV BEFORE the intercooler, just after the turbo, if "after the intercooler" is the best placement?

Stock is certainly not always best, but I tend to side with well-backed factory engineers on this one...though in reality, it is one of those things that makes so little difference it's not worth arguing about.

 

One reason may be that they vent the BOV back into the inlet and the associated plumbing is considerably less(well on MAF cars anyways).

 

OEM does not mean best or correct, it means cheapest that still works.
Owning a Mazda, you should know this by now, but then I read your statment

"well-backed factory engineers "

and I see that you still have some childlike misconseptions.

 

Another reason for not placing it before the I/C.
The pressure below the valve would always be higher that what the top side or the vacum side would see because there is always a pressure drop through the I/C. The higher the boost the worst the problem gets to the point where the valve opens and release boost.

 

I appreciate you repeating that for me...

How is it "cheaper" to place the BOV on one side of the IC versus the other, when you're designing from scratch anyway?

Name one smaller aftermarket company that has the financial backing and manufacturing structure that an actual auto manufacturer has.

What, you think that a small group of guys working out of a 4000 square foot shop are going to come along and figure out something that factory based designers couldn't? Sure, the aftermarket does things that the factory cannot, but if you gave factory designers the same goals to meet, allowing them use of their much larger budget, work space, equipment, and knowledge base, there is no doubt they'd turn out a setup superior to what your average joe can do in his basement.

yeah...okay.

 

Which explains why the BOV I have currently mounted on the intake side piping leaks boost like a mother...

 

If you sit back and examine the placment options for the blow valve you will see that the argument for which side of the IC it should be on is like.......arguing over the internet especially on a street car.

The most advantagious placement of the valve is before IC, but again on car that sees any kind of street driving, the argument is really point less.

Ryan

 

thanks guys the consensus seems to place the bov after the intercooler .this setup is on a race car and isn't driven on the street so it seems logical to put it in the place that will be best for the engine and performance we will try it in this location and see what happens

 

[QUOTE=crispeed]Another reason for not placing it before the I/C.
The pressure below the valve would always be higher that what the top side or the vacum side would see because there is always a pressure drop through the I/C. The higher the boost the worst the problem gets to the point where the valve opens and release boost.[/QUOT

This can occur in any position. That is why the better BOVs come with spring shims.


With the BOV before the IC, reverse flow is possible.

 

If the throttle body side has lower pressure due to the IC and the control line is still in the same place, how in the hell does this cause more leakage than being on the turbo side.

Unfortunately Crispeed's statement does not make sense.

 

Mazda uses an open/ no loop BOV where it dumps to atmosphere.

If a car has a closed loop BOV, it dumps back into the turbo enlet to help keep the turbo spooled.

So when we talk Mazda, do not bring in crap that does not apply to our cars.

 

I like the idea of plumbing after the IC and re-circulating after the intake filter...its already filtered and cooler than before the IC.

The idea of dumping already cool air seems pointless, being on the turbo side, could this prevent surge better?

 

i have 2
i put on each side
enough of this argueing :P