BOV question?
 

All you guys that have blow off valves on your Fc t2, how does your sound?? I have turbo xs and it only makes that swoosh sound, but i heard some of them whistle and swoosh at the same time. Any of you have one of those? I don't know if it's The HKS one or BLITZ. I don't want to get the one that sounds as my turbo xs.

I've got the HKS and I have the "whistle"... Sounds great :)

Which HKS one is that? Is it Super Sequential or which one?

Yes, it's the super sequential....

I've got some pics where you can "kinda" see it...

http://www.rx7t2.com/hksevc

I got a GReddy Type-S and it does a whistle/whoosh at low boost, but totally whooshes at WOT shifts.

The whistling one is probably an HKS Sequential...



-Ted

its not the blitz bov. i have the blitz and its a "whoosh" sound. i prefer it to a whistle type sound though.

does the HKS sound like the one on Tokyo Xtreme Racer? Kind of like a bird, or the ghosts from Super Mario Bros.

The TXR blow off valve doesn't sound very good :P but yeah it's sort of like the HKS SS, a wistle. If you let off the gas gently it will draw out the wistle, it sounds pretty cool. (I have it on my car) It also starts with a pshhh sound, so you get a "pshhh-eeeeeew!" sound

Someone dropped this link on EFNet #rx7...

URL server is pretty slow in upload, so be patient.

http://alltrac.net/tuning/blowoffvalve.html


-Ted

i got the blitz whooshuuuu....
i like the hks sequential one also, but my roomate's 180sx has it already,

i have the old blitz, i think it's call the super sound bov or some stupid name like that, anyone know how the new blitz bov sounds?

The one I heard was different, alot of people in Japan have it. Pretty sure its a BOV, it sounds whenever they let off the gas. Its sooo frickin hard to describe. Kind of like water dripping really fast and a whistling. That sounds really weird but someone must know what I am talking about. I'll try to find a video with it.

Here it is, go to davescholz.com and to Multimedia, then click drifting and download - fdchokudorispeed.mpg
Thanks to velocity.isfaster.com for the Slide Squad link!
Someone please recognize that sound. You hear it right as it goes by twice, and its not squealing tires.

alot of WRC cars have them if that helps

could it b the diff in the wrc??

im just guessin...

I installed the HKS SSQ blow off valve in my younger bro's WRX and it sounds sweeeeett! I guess my point is, the whisltling/swooshing sound is the HKS.. K, just wanted to let you know eventhough it's probably too late now... :cool:

I heard the HKS one from RETed's link but its wasn't the one. That one is a whistle, someone please tell me which BOV that is in the video!

how hard is to install that SSQ HKS bov? I mean i installed my turbo xs without welding or anything, can i do that with HKS if i buy just universal without the kit. It's cheaper.

That flutter like sound? Almost like a pigeon or turkey call? It's probably the HKS racing blow-off valve, not the super sequential.

Yeah a fluttering sound, like some bird call. Thats the best way to describe it yet.

Hello everyone.

First post in this forum, so please be patient with me. :)

Normally, I'm content with just looking for the information I want and leaving, but in response to the ""Turkey call", et al sound and what it is:

It is not a blowoff, but the absence of one. It is what we (being everyone I know) call "Back-pedal". Any boosted (read: turbo) car can do it simply by removing the BOV completely.

The sound is created when the intake line pressure has nowhere to go (because there is no BOV) and has to "back-pedal" against the turbine. The result is the sound in question. Most japanese run w/out a BOV because they're expensive as shit over here and aren't good for much but trying to impress your friends.

Hope this helps.

Sorry! One more thing...

Having a stock airbox will muffle the sound, as will having the flow meter infront of the turbine.

The answer (if you absolutely must back-pedal) is to a couple of things:

- if you have a good engine/fuel management system blow through the flow meter (wicked back-pedal from an open-faced turbine)

- the HKS Vein Pressure Converter (VPC) will eliminate the need for the flow meter (but for the price, you could afford your own stand-alone engine management system -- I did)

- get rid of the stock plastic crap from the front of the turbine on and just run a pipe with the flow meter... WARNING: I did this for a couple months, but blew the flow meter's guts out at 1.1 kilo of boost.


Good luck...

Yep, thats what I thought too....I mean, this sound is nothing like a BOV, or a big wastegate or the turbine slowing down or anything. It sounds much more like the engine is suddenly cutoff from the oxygen supply, and is "starving" for air. But not having a BOV at all ? Wouldnt this be too much for anything less of a race-prepped engine ?
I have heard this sound only on WRCs...

Ace says:
"But not having a BOV at all ? Wouldnt this be too much for anything less of a race-prepped engine ? "

No way! It's being done by many, many cars every day. Hell, when I first started on my FC, I blew through the flow meter, running an open face turbine with no blow off on a stock motor.

I stuck it on the rollers and pulled 263ps on stock boost. It (the back-pedal) sounded nice, but nothing near what a ported 13B with a nice T04E sounds like!

The larger the turbine, the deeper the sound is. My buddy with the stock IHI bearing turbine on his WRX back-pedals so fast it sounds like a video game. Then again, a full-tune GT-R with a T-51R is awesome to listen to...

Trust me: anyone can run without a blow off. However, I wouldn't recommend it -- it's not healthy for the turbine at high boost. The cars you see racing and doing it on TV can do it because they don't have to pay for their turbines (sponsorship has its perks).

We call it "compressor surge". :)



-Ted

LOL, and we aviation types also call it "compressor stall". :D

http://www.arinc.com/fsemc/99report/sf-uals.pdf

Good to see aftermarket BOV’s being exposed as the marketing hype they are! At low boost levels there is no performance/reliability loss from not using one, the only reason manufacturers fit them is to eliminate the noise of compressor surge.
That’s not to say I don’t like the sound of a BOV (I prefer a subtler sound though, not a ricey “look at me” sound), I just can’t understand paying so much for no real gain

Thats what I meant. The feedback from the closed plates onto the turbo may make a pretty sound, but it hurts the turbo plenty...;) On WRCs the turbos are always made out of titanium (also the Makinnen Lancer and the Extreme Impreza have titanium turbines), so they can withstand this abuse, but stock turbos on TII or FDs ? I dont think this is a good idea.....

Man I am glad RotaryMiata knew, I was expecting to buy some expensive Japanese imported BOV, but all I have to do is take mine off. I prefer the sound of the "back-pedal" over the whistle or psssh! over a BOV.

I hope you like and can afford rebuilding your turbo every few months! :D



-Ted

yeah thats going to suck

But seriously is it THAT bad for your turbocharger (or should I say mine)?

Take to a reputable turbo rebuild shop...



-Ted

I might put my old stock turbo back on and try this out just to see...

Don't run boost without a BOV! Compressor surge is a bad thing for people that can't afford to buy now turbos all of the time. That "cool" sound you hear is your turbines being blown backwards, in my friend's case, they were blown off his 3K turbo. Buy a $200 BOV!

Yes, compressor surge is bad folks, mmmkay? Also there is a performance benefit... if you don't blow off the pressure and you stall the turbine, it has to spool again when you get into the next gear, because it's not spinning as hard. BTW, another valid reason to replace the stock BOV is that they often leak at increased boost levels. Or even at normal levels once they start to get old.

the dolphin sound from tokyo extreme racer is an aftermarket wastegate.

I have the stock one and it sounds like NOTHING.. it's so friggin' quiet.. stupid "average joe" drivers like cars quiet..

ROFLMAO

:)

i think this does the fluttering noise,
http://www.takakaira.com/php/template.php3?id=702&cat=2

There is nothing to be gained by removing a BOV. Its there for a reason. As mentioned numerous times before, it eliminates compressor surge, also known as "boost spike". Not only does it keep your turbo from lagging as much, it also prevents more "back pressure" in the turbo, increasing turbo longevity. And it has that kick ass sound, too. Keep it on.

WRC cars have a system, I don't know what the name is, misfiring system or something, that puts fuel into the exhaust right by the turbine to spin the turbine up as the driver shifts. It beats the hell out of the turbo though. :)

Well, guys I guess I'm in the minority here. My car gives me that flutter sound and I have a Greddy BOV on!!! Could the spring be too tight? What does tightening or loosening the spring do to the BOV? How do I know if I got it set properly?

Thanks,

-M

I've got a Greddy type-s and it goes "tckssssssseeeewwww" (sort of) and it is LAF, if I rev the engine from under the hood it almost hurts my ears, you can turn it down so it's a little quieter

Fluttering sounds from BOV usually means its NOT adjusted properly. What your hearing is the BOV piston oscilating up and down relieving boost pressure. This oscilation also is SURGE (pressure waves bouncing back and forth in your intake track from throttle plate to compressor wheel). NOT GOOD, adjust it!!!!! Also, alot of the noises people hear in racing videos and TV (World Rally etc.) are sequentual (sp?) trannys and gear whine from straight cut gears. A lot of times when gas is let off the back lash in the straight cut gears makes a what could be a BOV sound but isn't. Just for the record, I like whistle BOV.

~Mike.......