I am wondering why on stock turbo cars (and maybe some after-market ones, idk) while in neutral if you rev the engine it will make boost and the BOV will sound. Why is this not possible on my Hahn ecotec turbo? I know the engine needs a load to make boost right? Well how do these other cars get their bov to sound while in neutral? Just a curious question thats been bugging me for awhile. Thanks.
try posting this in the boost fourm....or preformance....sorry i couldnt answer your question/.
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I guess it all depends on what the BOV is designed to release at.
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Madjack wrote:Like I said before, building an engine like ours (2.2 or 2200) is a painstaking chore , since there is so few custom made parts. It's frustrating to me too, but that's what I like about doing this engine, it's the challenge.
put the clutch in try that works on some doesnt on others worth a try
Another thought came to mind....this is just speculation mind you. A BOV was designed to release the pressure when the throttle body plate snaps closed during a shift so you wont break it. Maybe when you rev in neutral due to the nature of the blow off valve when it snaps shut its just not as much pressure as when you driving.........maybe.
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Madjack wrote:Like I said before, building an engine like ours (2.2 or 2200) is a painstaking chore , since there is so few custom made parts. It's frustrating to me too, but that's what I like about doing this engine, it's the challenge.
Jbody2nr wrote:Another thought came to mind....this is just speculation mind you. A BOV was designed to release the pressure when the throttle body plate snaps closed during a shift so you wont break it. Maybe when you rev in neutral due to the nature of the blow off valve when it snaps shut its just not as much pressure as when you driving.........maybe.
I can understand your theory but still has nothing to do with what gear you're in, your still revving the motor, you're just not putting any of the power to the wheels.
Aaron, depending on what car you are revving, you will either hear the blow off valve or not. Some vehicles have it setup to be atmospheric (which is when you can hear it sound) or not have it atmospheric. Also remember, not every turbo car has the same setup, some have big turbos, some have small turbos, it all depends...that can also deal with how loud a BOV is in some cases but in most parts, a BOV sounds the way it sounds because that's how it's designed.
If you want yours to be louder, change your BOV.
If you want to hear what different ones sound like, go to
www.blowoffvalves.com.
www.kronosperformance.com / 732-742-8837
well, take this as an example. with the engine under load, you've got alot of fuel and air going in, and therefore you've got alot of exhaust to create some boost and blow off when you let off the gas. now try driving in a low gear, without stepping on the gas. you will see high rpms, but no boost. why? almost no fuel going through, therefore nothing to spool the turbo.
if you want to hear your blow off valve when revving, you need to create boost. revving up high and easy wont do it. put the pedal to the floor, and snap off right as youre about to redline. you should definitely hear your BOV. if youre really desperate for it, just floor it in neutral. every time you bounce off the rev limiter, you'll blow off.
if you want it to be a lot more fun and noticable, buy the turboxs RFL blow off valve. I have it, and love it. all installation takes is putting it in place of the hahn bov, and connecting the hose. dont put any of the washers in it. then, pretty much everyone in the vicinity will know your car is turbo. ive heard many a girl on the street scream from the sudden poosh.
rob (the one with the vette) wrote:well, take this as an example. with the engine under load, you've got alot of fuel and air going in, and therefore you've got alot of exhaust to create some boost and blow off when you let off the gas. now try driving in a low gear, without stepping on the gas. you will see high rpms, but no boost. why? almost no fuel going through, therefore nothing to spool the turbo.
Thats exactly what I was trying to say I just couldnt put it into words. Thanks
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Madjack wrote:Like I said before, building an engine like ours (2.2 or 2200) is a painstaking chore , since there is so few custom made parts. It's frustrating to me too, but that's what I like about doing this engine, it's the challenge.
Thanks for the explanation guys.
Rob, so the RFL is a direct replacement for the hahn? I don't have to weld any adapters or any of that crap? Thanks.
yep.. you just slip that little silicon tubey thing over the inlet on the rfl, and clamp it on with the little clampy things hahn gave us. it attaches exactly the same way. youll cream your pants when you hear it blowing off.
the bov is not to keep your throttle plate from breaking a blow off valve is a device used to release excess pressure in the intake system between the compressor wheel and
the throttle plates, to prevent compressor surge which can damage the compressor
wheel and or housing
