gxl90rx7

iTrader: (1)

how so specifically?

Whizbang

i love threads about therories, especially this stuff. Where is that thread from last week that had graphs and charts showing the pressure waves generated in the charge pipe?

the position of a BOV (pop-off, diverter, whatever) is all so damn debated, hell even the idea of HAVING one at all usually comes up on here.

but as for the above, i was noting the use of "preformance". The position's effect on the preformance of the engine will be negligible.

ikari899

ha yeah. your performance will probably be effected more by the oxygen content of the air then the position of the bov.

hondahater

iTrader: (2)

so if they wanted a quite shift wouldn't they just not use a bov all together? I mean in that video I couldn't hear any strange noises like compressor surge or anything when he shifted.

red rex

this is prob a noob question, i understand now about how not running a BOV is better. but what about aftermarket wastegates?

RacerXtreme7

iTrader: (2)

sigh.............

red rex

i told u it was a noob question haha

RacerXtreme7

iTrader: (2)

Don't take offense, it was two things that caused me to laugh out loud histerically. 1st the whole "i understand now about how not running a BOV is better" is just funny. Don't believe every thing you read, especially if theres only a small group of say less then 10 against the whole world on a subject. Internet folklor (sp?). 2, the actual question you had "but what about aftermarket wastegates?" If you knew how a wastegate worked and what it did you wouldn't ask the question. There is no "this side" or "that side" of the camp on wastegates except maybe about brand names (or there lack of). A wastegates function is to control boost pressure. It diverts exhaust energy away from the turbine. So yes, newb question, but at least your thinking (sorta), just take opinions on internet forums with a grain of salt and keep the actual facts lined up in your head and make your own conclusions with other experiances amongst your own. BTW, good hard evedence such as REAL data loggs and dyno runs are worth gold, not *** dynos or retarded theories that ignore good'ol science.

~Mike...........

Whizbang

hey, my *** is accurate to 98%

peejay

He also wasn't driving on the street, where most of your driving is accelerate a bit, let off, cruise, etc. Even driving an automatic turbocar with no blowoff you hear all sorts of weird noises.

I think, primarily from my experiences, the problem is that under certain cruise conditions, the turbo sees enough exhaust gas pressure to build boost in the pre-throttle ducting, but the throttle position is still so low (like 10-15hp worth) that you're still under manifold vacuum. The end result is that you're working the turbo anyway, and it sounds like you're driving a hairdryer or a dentist's drill or something. With a blowoff valve, the manifold vacuum would be holding the valve open, and the turbo would just be free-spinning instead of being under load, so you wouldn't get the turbine noises.