Doofnoil

blow me off baby

Turbo-Dan

it also depends on your plumbing, if you have really long pipes routing across the entire front end of the car and through an intercooler you probably wont get any pressure.
but if you have one short pipe with no intercooler going straight to the throttle body you are sure to get better pressure and have less pressure drop. in turn this will make the pressure build up much easier under no load.
with longer pipes and biggar intercoolers, you need to really work the turbo to get pressure under no load.

JD

very true. Good point turbo-dan.

Spenser

I know you can hear a SRT-4s BOV very easily, all you have to do is rev it up to say 1500 and let off, PSSHHH/.

digihippie

just my 2 cents... i have a t3 from saab 9000 for now and if i rev to about 6k and hold about 1-1.5 secod then depress accelerator then i will hear PSHHH. =)

megatronmax

My inlaw's STI having very short piping and a relatively small turbo for a 2.5 liter engine, will open up the HKS BOV in neutral if revved over 4k. In comparison, my civic with a FMIC, large T3/T4 and and a 1.8 liter won't produce boost if not under load.

Doofnoil

it takes TIME to produce boost or a bov sound...example:

you quickly rev the engine in neutral and the bov does not sound; this is because the turbine in the turbo has to be sped up or accelerated via constant and increasing amounts of exhaust gas. This in turn spins the compressor which needs a certain amount of shaft speed to produce boost(duh). It also takes a few moments for the intercooler and charge piping to be filled with pressurized air once the compressor is rotating fast enough...

therefore, with the short amount of time that you stab the gas pedal, the amount of exhaust produced by the engine isn't enough to spin the turbine/compressor up to speed AND fill the charge pipes with compressed air... Other cars with larger engine/smaller turbo combinations DO produce enough exhaust to "spool" the turbo up with a quick rev. Get it?

So you (or your friend) need to figure out at what rpm the turbo starts making boost under load. Let's say it's 3k rpms. So in neutral, you want to HOLD the rpms at 3k for a couple seconds(count one mississippi, two missi...) then quickly stab the gas to about 5k rpms and completely let of the gas. Since the turbo was spooled up to begin with(via 3k rpms of exhaust flow) then when you stab the gas it will be able to spool faster and produce the sound you want...

there.. that's all there is to it... now let this topic die please.

Spenser

hahaha, not true buddy, even at idle you turbo is spinning right? so on some cars, with the right bov, you can get it go off by tapping the gas. I've seen this before.

Doofnoil

stfu