iLLuMiNaTi

Hey,
My friend's telling me that BOV "suck" compared to DV. Are they really that much better? I mean, I can't imagine that blowing the air pressure into the intake will make THAT much of a difference... and also, the sound of a BOV owns that of a DV!

thx in advance
Axel

Boosted2k2

iTrader: (3)

a good amount of BOV's can be turned into DV's. Some of them are necessary on some cars like GTi's, TDI's, and 1.8T's. (VW in general). DSM's have them. They are necessary so the air that has been metered by the MAF (Mass Air Flow), is accounted for by the ECU for what enters the engine. Also, DV's help spool up time because more air enters the intake. But yeah, BOV sound own's DV's.

iLLuMiNaTi

So will there be a lot more power gain? or a significant gain??

Boosted2k2

iTrader: (3)

I don't think you see any power gain... not from an aftermarket turbo'd car. Just a slightly (notice I said slightly) faster spool up.

PdchasinR6

on my 1G DSM i would notice approximately a 200-300rpm faster spool with the bov recirculating compared to having it dumped into the atmosphere. for me it was easier for tunings sake to have it hooked up for racing but in my honda it would seem pointless to have it recirculating since its not dependent on that metered air near as much as a DSM or VW is.

C2i0v0i1C

iTrader: (2)

explain what is DV

my04wrx

dump valves are better than atmospheric blow off valves because of the air recirculation. also, with an atmospheric bov you can run pretty rich during shifts.

Boosted2k2

iTrader: (3)

Doesn't apply to a Honda. Air circulation obviously applies to any car... but still doesn't make power... just makes it available a little quicker. But running rich between shifts is only for cars with an MAF type sensor. Where the air volume is monitored before the intake manifold. The Honda has an MAP, with pressure monitored in the manifold. Whatever is in the manifold obviously controls the injectors. With the MAF, whatever is in the piping controls the injectors... and if it doesn't make it to the manifold because it is blow off, then you'll run rich because the Air:Fuel was "predetermined".

And no, I'm not saying you are wrong. For your car, WRX, you're right on point. I'm just stating what applies to our cars, and others with a MAP.

MatrixShark

Sitting here thinking about this:

It seems as though a DV would also lower intake charge temp. Logically speaking, this air has already been compressed, heated, and then cooled by the intercooler. It then expands as it is vented back into the intake, cooling it further. I don't know, but it may actually be cooler than ambient (outside) air temp. This would then lower the average charge temp and increase power while lowering the posibility of detonation.

I have no idea if this is what really takes place, it just seems like it would IMO.

Boosted2k2

iTrader: (3)

Not really... it'll just go back through the compressor and and be heated up again to the same amount. That air is also hotter than the ambient air temperature. Unless you have a air-water intercooler filled with ice.