running no BOV

[o_man_ra23]

Hmm... looking at all this (and the other linked thread), I will start running my 3S-GTE RA23 without a BOV. If it becomes a noise issue (compressor flutter), then I will acquire and install a plumback BOV to shut the bugger up. The less noise this thing makes, the more Falcadores and other common 'performance' cars I can surprise

[YLD-16L]

then I will acquire and install a plumback BOV to shut the bugger up.

Plumb back doesn't always = silent or quiet.

[brett_celicacoupe]

i got a better idea. put a one way valve before the turbo, no noise and no boost drop through gear changes

sure its a restriction but imagine the benefits

[Merudo]

turbos are so 1991 anyway, as if you'd want a turbo car

[abently]

No BOV vs BOV is really all about Turbo response time in between shifts.

It's different from set-up to set-up though so you really have to datalog your own setup to see which way you need to head.

[o_man_ra23]

Plumb back doesn't always = silent or quiet.

Hasnt this discussion, and others, shown that when setup correctly they reduce noise?? As also stated, its usually undersizing them that causes excessive airflow noise. So having a large diameter plumback pipe would reduce airspeed, and thus reduce noise... or so the theory would say eh??

[Norbie]

Plumb back doesn't always = silent or quiet.

Indeed, my 2JZ sounded quite hektik with the stock plumb-back BOV and a pod filter. You're always going to get whooshing noises unless you're using a factory-style filter box with expansion chambers etc to shut everything up.

[rke_011]

i wish my car fluttered like a turkey... but i spose the bov will just have to do..

what causes the flutter?
should a stock 3t have a flutter?? hahah

i love the turkeys!!

[Norbie]

Flutter = compressor surge.

[Mr DOHC]

WRONG

its the wastegate

[The Real Roadrunner]

Interesting Linden as the back to back testing (Haltec data log) i did on my old turbo 18RG running a big TO4B front cover, showed no BOV provided better response with no BOV. Was bugger all in it though and the BOV whoosh was quieter than the surge so still ran the BOV.

Seems to be very much effected by the type of BOV and the setup of the car as to how much effect on response it has?

On the 3s it would drop off boost for about 2.5secs between the 2nd-3rd shift (w58 + 4.11 diff) and it was a prick to drive hard as it came on so aggressively that it would then cook the tyres (great while drifting, shit while racing) but after the BOV went on it wouldnt drop off as much and was easier to drive the car hard.

i suppose most of it would depend on the type of valve used and where its positioned but the drift car i sponsored last year did the same thing (sr20 with hks gtrs) as mine till we fitted a bov 5"from the TB then it wouldnt drop off as much between changes, it was airflow sensed so that may be part of it.

once your 800-1000rpm past the boost threshold most cars will respond quickly enough, but if your playing with the throttle close to the threshold or your gearing isnt spot on it can help substantially.

i like the trust bovs cause there quiet and most of the time you cant here them cause there so big and dont have alot of machined edges, GFB bovs i cant stand because there so noisy you feel like your at autosalon every time you back off the throttle. its mainly due to there small size and every part of them is machined with a hard edge that [cuts] the air as it passes.

cheers
linden

oh btw on hotwire AFMs try to run the bov return facing into the inlet of the turbo as it can make them alot nicer to drive as they dont cough as much between changes.
if theyre MAP then you dont really have to worry at all.

[Mr DOHC]

[The Real Roadrunner]

WRONG

its the wastegate

um hate to tell you but NORBIE is very much CORRECT.

[Mr DOHC]

[YLD-16L]

WRONG

its the wastegate

Ah no.

Norbie is quite right, it's compressor surge and it's common knowledge.

Waste gates don't "flutter".

Simple test to prove it to yourself if you need to.

Find car with adjustable BOV, ascertain it has normal function and releases the common psshhhhhh sound. Then remove the spring from the BOV, replace with spacer so it can not function as a gate to release pressure, you will now have the sik "flutter". Or just remove the BOV and blank its mounting point and you'll have flutter.

Edit: Well I now see you've back pedalled on your statement and made out you were joking Sad thing is a lot of people do think what you wrote so I'm going to leave my statement above un-edited.