They sound silly however you play them. Might as well replace the pssshhhhhttt with riiiiicccceeeeerrrrrrrrfooooooooolllllll everytime they lift the throttle one iota.
I was proving that ALL turbo car's have diiferent sounding BOV's. The XRT does not have a HKS BOV, it doesnt have a nissan skyline bov, it has an XRT Bov.
I'd say it is pretty realistic. I mean, if you let off the gas, the throttle closes and the pressure rises, making the BOV push a spring, and open. BUT, when you mash the throttle again, the throttle opens. The pressure then can go through the throttle plate, and the BOV closes. SO, a real BOV will stop letting out air when you press on the throttle again.
EDIT: I found out the difference between a BOV and a wastegate. The wastegate opens when there is too much exaust pressure, which lets it limit the boost pressure (The exaust goes to the atmosphere instead of the turbo). A BOV is after the turbo, but before the engine. If the throttle is closed, the turbo is still spinning, and is stressed (this depends on the boost level) which could screw up the turbocharger. Instead of the turbo getting screwed up, the BOV opens, venting the compressed air into the atmosphere. A BOV is unnessasary. The wastegate is pretty much needed.
a blow off valves 'psssshh' sound, its the sexiest noice that car can do!
but u probably ment turbocharged, not supercharged? or if u did mean supercharger, do they have blow-offs in those too?
A blow-off valve is the silliest noise that a car can do. Why waste all that compressed air by making a pointless and power reducing noise? Why not get a silent recirculating dump valve, make less noise (and therefore look less like a complete idiot who likes 'phat carz') and actually go faster too.
This does not apply so much on a race circuit where you want to keep the turbo spinning as fast as possible, are using high engine revs and WOT most of the time, so boost build up is very rapid. Much like WRC cars. Which is why they make that silly noise, and makes the cars sound like malfunctioning toys.
I was going to ask if a BOV actually did anything performance-wise, besides sounding like Herbie sneezing, but good ol' TC answered my question already I don't understand why you'd put something on your expensive hot car that actually robbed it of performance. Call me an old fogey if you like, but the only things going in or on any car of mine are to make them more fun to drive and I'll leave the cosmetics to the fashion victims
The default sound does not annoy me at all, I kinda like that. Some cars sound like a can of Pepsi opening and others like the disembowellment of a musabi-filled Sumo Wrestler suffering from acute explosive diarrhea.
These things are always going to appeal to racers on a personal level. It's ok to like one way or the other, whatever floats your boat. Perssssshonally I prefer a lesssssh perssssshishhtent appraoachhhh. But maybe thatshhhhh jussshhhhht me?
as for the psssssssssst noise, im sure all noises in LFS will imrpove when the sounds engine becomes the next focus of the devs attention. meanwhile i think you just have to settle for 3rd party replacement sounds clips.
Man, come on Tristan - usually you're one of the most sensible guys around here hehe. Beauty is in the ear of the beholder my friend, there's nothing concrete about something so subjective. As you can tell I'm for BOVs, I like them.... although I like milder ones, not personally a fan of obnoxious squeeling sounds, I don't feel that someone 3 blocks away MUST know I am releasing some boost. But to each their own. How come you called it a "power reducing noise"? If the turbo stays spooled that's a good thing in my books, I'm assuming recirculating mechanisms accomplish the same task?
edit: grammar
edit2: spelling (seemingly not awake yet)
Recirculating BOVs/bypass valves don't dump the air to atmosphere but back to the system, if there's a marginal difference in engine power output and response between them and atmospheric BOVs/blow off valves it's right there. For a short period of time after opening the throttle the recirculating version has more air flowing into the engine = more power. Other reasons for using recirculating type of BOV is that they are less noisy and don't mess up airflow metering (mixture).
Besides, a bypass valve can be audible as well if you want, just remove any unnecessary intake scoops and resonators etc. But the sound doesn't bring any performance gain
The "power reducing noise" I refer to is the pssssssssssshhtt. It's the sound of power being thrown away for no reason, as explained above (thanks Huru-aito). As a purist (yes, I am) I can't understand why anyone would ever in their wildest dreams want to make their car make a silly noise at the expense of dynamic ability (i.e. all noise and less go).
For messing about at car shows and events, I'm all for noisy things. Their whole point is to entertain a crowd or provide good entertainment. But for road or track use, I don't see the point. Maybe it's short sighted of me to think like this, but this is how I think, and I like thinking like it.
So what you guys are saying is that the recirculating system is maintaining some mainfold pressure - which I assumed to begin with. However is the net effect of the lack of pressure drop enough to offset having to spool the turbocharger up again? I would think the impeller would still be experiencing some load keeping the manifold pressurised and would therefore cause more lag when you get back on the throttle... however I am no expert.... And I definitely agree with the philosophy stated regarding "show" (notice quotes) and no go... hehe I've always considered myself a purist as well, but maybe igorance has left me unpure on this topic LOL. I still like a little "PSsshh" so to speak however if it truthfully does actually decrease performance (I assumed it had no net effect really) then I'm facing some serious ambivalence in the near future....
Well, the normal dump valve gets rid of all the excess manifold pressure. But there is still pressure there (up to whatever the valve is rated at) slowing the turbine. With the recirculating valve, the manifold pressure is not allowed to go above the same value, but the excess air isn't 'lost'. When you get back on the throttle, the boost can be built up much more quickly from this reserve. The normal dump valve means the turbine has to do all the work of building boost itself. If that makes sense.
Of course, if anyone can prove me wrong (not by saying 'dump valves rock innit' please) then feel free, cos I like to be corrected on things if I am wrong
If you are running 'insane' boost level, then you probably don't won't to let boost get back into system, turbo might get damaged as it may get overrevved. Overrevving may happen also when you have too small wastegate or too small exhaust side of turbo, this makes also heat to become a problem.
I could not care less from street respect or things like that however and there is relative quiet BOVs available too, no need to get one that has silly trumpet or whistle, some even installed duck hunting whistle(word?) to BOV and put video to net, all teenagers were going crazy, me me me I wan't one, ok I may bit bit old alredy
So in my opinion we could have also car's with not so insane boost levels and without BOV too.
With the recirc system ... Honestly I'm not dense (at least I don't think so ) the volume of compressed air must go somewhere, and putting it into some other piping is not going to release as much intake manifold pressure as rapidly (the key to maintaining impeller RPM right? wrong?) as venting to the atpmosphere should. Therefore the turbocharger should have LESS work to do with an atmospheric valve installed.... And also I may be wrong and I too enjoy some construcive reproof and edification. And I am obsessed with cars / physics and turbochargers so I really should know all this already
note: no time to check for typos please excuse any
