[Mk2] [Turbo] turbo surge/flutter

[black gts]

hi people
at the minute i have a bailey recirculating dumping to atmos , and iv been told that baileys arnt the best it does not surge or flutter
so i tried a few different bovs on......
im getting the above mentioned noises when i put a greddy /arc/ bov on my rev3
i also went and got a proper toyota bov and that surges/flutters
the bailey has air coming out of it all the time until engine comes on boost.
the others dont .
no cat .
mongoose.
1.2 bar boost.
st205cc fiat pre rad.
also better mention that i have a straight intake pipe(air filter to turbo)
these noises have my head done in now, never mind the damage that can be done.
thank you
ps i have apfc to go on so would like this sorted before mapping.

[RobCrezz]

A small bit of flutter doesnt hurt, but normally you only have to tighten or loosen the spring to adjust how it dumps.

[Marf]

1. Throw the bailey BOV in the bin, as you have found it allows unfiltered air in until boost forces the valve closed.

2. if you have a stock toyota BOV that is allowing surge/flutter, either its hooked up wrong or its busted. The stock toyota BOV is probably the most responsive valve I've ever seen, it should not flutter in either vent to atmos or recirc modes.

[black gts]

the bailey dose not suck , it blows mate until boost then closes .
iv had the springs in every position possible.

[Marf]

the bailey dose not suck , it blows mate until boost then closes .

Well not sure how thats possible given the inlet tract is under vacuum until the turbo makes positive pressure.

[black gts]

could it be with no cat,straight pipe from air filter to the turbo and no breathers going back in , that the turbo has no restrictions on it so spinning free?
maybe thats why its making them noises as it not usally spinning that freely?

[Dundee]

Are you sure it's turbo flutter you are hearing not just the air going back through the air filter? I have this with my apexi filter. It baffled me to start with, I tried a few bovs with no change untill someone that pointed out.

[Aimson]

Just had to remove my bailey dump valve it was a piece of it leaked and nopt only did i loose power it made the car run rich also, best just to keep it stock or use a HKS BOV as they are more reliable I have heard.

[black gts]

Are you sure it's turbo flutter you are hearing not just the air going back through the air filter? I have this with my apexi filter. It baffled me to start with, I tried a few bovs with no change until someone that pointed out.

i have no pipes going back into turbo inlet pipe
thank you any way mate
is there any one in the north east i could come to you and try my bovs on your 2 or yours on mine
cheers people

[Jimbob]

I've got two Greddy RS in series, I don't get any flutter when coming off throtlle, unless I do it on purpose. i.e. load it up and really gently ease off.

[black gts]

sorry its been a while

Well not sure how thats possible given the inlet tract is under vacuum until the turbo makes positive pressure[/quote]


the butterfly is closed , turbo is still spinning which is producing a draft. there is vacuum on the other side of the tb until the throttle is opened.

right , the greddy rs bov was off high pressure car and someone had put 2 springs in it , removed 1 of them and a the jobs a goodone

[Jim Galbally]

guys, all of you that have replied with regards to the flutter noise seem to have things muddled up.

in really simple terms what happens is:

the noise is known as SURGE. this is where there is more air coming into the turbo than it can deal with and so the incoming air will stall the blades slightly. this occurs normally when 1) you come off the throttle with no dumpvalve and so the air has nowhere to go 2) the turbo has been incorrectly specced and is providing more ar than the engine can consume.

when this happens you hear this as a fluttering noise, this is what youre thinking of when youre saying "air coming back out the airfilter"

the reason the guy is hearing it here is that the dump valve is not operating correctly either its broken or set up wrong.

due to the fact the rev1 and 2 use an air mass based management system (ie have an air flow meter) it is strongly reccomended you use a recirc DV, as any air that is allowed to escape has ben metered by the AFR and so the ECU fuels for this volme of air!

[jimGTS]

There are plenty of cars running no bovs, let alone just a slight 'flutter'

making a fuss over nothing.


Long as WITH a dump valve it's dumping on full boost you'll be fine. You at least know it's doing it's job. Part throttle, part boost I would expect it to flutter(sound wise).
If it's dumping at every opportunity it's set up way to soft spring wise and I'd bet your be leaking some boost.
IMO perfect setup with a bov is full blow off at full boost and full revs.
Least you know spring is tight enough to not leak any boost.

with no bov, I ran that for a good 6 months, and I'd imagine it ran no bov in japan for god knows how long. Never done any harm.
Am now running a HUGE greddy type r. Set pretty tight.
Sounds awsome to

[Tubby]

Just out of interest,for you guys that are running hks ssqv,how far have you got the thread running out of the back of the bov??

[Jim Galbally]

jimGTS, dont forget that as standard MR2s run ceramic turbos!

i wouldnt want to run a tuned one of those with no bov!

[jimGTS]

I didn't say anything about running a stock turbo with no bov at all.
I know about the ceramic aspect, I've had a couple of stock turbos.

[Mike]

Can you adjust the stock BOV?