James93A

Hey guys,
I'm new to the forum and to owning a rotary.
Recently I purchase an FC3S and the entire setup is not very stealth at all.

Currently it has a supersonic turbosmart BOV and it is in the top right hand corner of the bay between the intercooler and the intake manifold. It flutters/doses VERY loudly and it attracts a lot of attention.

It's running a pod filter and a hi-flowed turbo. So basically my question is, if I have the blow off valve moved to after the intake manifold next to the intercooler (to hide it) will it make the flutter quieter and will I keep the same performance that I had before?? It's currently tuned to 300HP with a 3" exhaust as well if that makes any difference

Appreciate any advice,
Thanks
- James

3rdgensleeper

iTrader: (10)

Hey bud, first off welcome to the group. I will just give you a very high level reply and if you need more info please feel free to message me. Moving the BOV will not change the sound, you would need to swap BOVs completely, I would recommend a large Tial valve, it doesn't have the annoying ricer BOV sound.

James93A

Thank you for the welcome. For some reason it won't let me send PM's.

I was more worried about the position change. Will moving the blow off valve to next to the intercooler after the manifold instead of before the manifold affect anything?

Thanks again

3rdgensleeper

iTrader: (10)

That's a long debated topic, there are two sides of the fence on this, short answer no it will be fine either side and location.

The debate is usually is it better closer to the turbo it the TB, I side with the TB as I have a background in fluid dynamics and air moves like water.

3rdgensleeper

iTrader: (10)

Turbo or* the TB lol sorry stupid typo

James93A

Ahh ok haha, yeah I want to side it inbetween the turbo and intercooler.

Is there also a way of removing the flutter noise or greatly lessering it?
I know it's blow back from snapping the throttle shut but I don't want it as loud as it is, and blow off valves dumping atmospherically are illegal here in sydney.

3rdgensleeper

iTrader: (10)

so that noise I assume you hear mostly on light throttle and the BOV isn't really making much noise?

The shuttering noise you hear is air passing back into the compressor housing due to the BOV not opening at light pressures. At least this is what happens most the time. Only way to lessen it is to lighten the spring pressure on the BOV.... Downside is it will make the BOV sound at lighter throttle....

James93A

So basically, it is impossible to eliminate both. You have to have one or the other?

3rdgensleeper

iTrader: (10)

There are ways, for example you can re route the BOV exhaust back into your turbo inlet / intake , this will help muffle the sound.

So it's illegal to have any modification to the turbo system down there?

James93A

ahh okay, I will try it, do you have any links to a setup like this? I'm not sure how i'd go about making a line for the BOV vent to the inlet manifold.

Well for starters the police down under don't like turbo noises lol. They see it as "hooning". There a lot of "anti hooning" laws. If you are caught street racing, doing burnouts, reckless driving, "dangerous" acceleration, etc, you can have you can lose your license on the spot or have you car impounded from anywhere inbetween a couple of months to permanent impoundment.

So cops don't particularly like flutter but it isn't illegal. BOV atmospheric dumping however IS illegal, they claim that it dumps C02 into the atmosphere even though it wouldn't if it were before the inlet manifold.

All modifications are legal when they pass an engineers test and receive an engineers certificate.

Without them, cops can deem it unroadworthy and you have to fix it within 3 days or your car loses it's registration.

Monkman33

iTrader: (28)

What engineer claimed that a charge air relief valve releases anything but clean charge air?

Sounds like he needs to go back to school...

3rdgensleeper

iTrader: (10)

I agree^ the air coming out of the charge relief is merely compressed clean air that has been pulled through the filter.....

Now the only way I can see some logic to the stupidity is that the "blow by" created from turbo charged cars, this blow by is usually created when the combustion chamber leaks into the oil pan and then the oil pan vents via pvc valve or crankcase vent is routed to the vac source in front of the turbo. Then the charged air would be "contaminated". However I know for one I do not route my oil pan vent this way it goes to a catch can, and stays separate from my intake system all together.

James93A

Yeah indeed,
It's not the engineers who claim this, it's police that will issue you with a defect notice for having a BOV.

It's illegal for the noise, and also because they say it dumps polution. I'm pretty sure engineers can pass any modification as long as it has been done properly and will be safe to operate. Whether or not the police will like them is a different story...
They just want to cull down the hoons, there doesn't have to be a valid reason for them to issue you with a defect notice. Usually comes down to how you drive and how you act when you get pulled over.