between the DoS and NM wich one do u say its batter?

 

It's so weird that Jan tuned it to make it sound like that. Typically that flutter comes from all hard pipes and a short metal intake (called a dose pipe). Its air being pushed back towards the turbo, causing reverberations. It sounds so much better than a loud blow-off.

 

between the DoS and NM wich one do u say its batter?

 

Is your bypass not working? Light Compresser surge makes you lose spool(turbo loses momentum due to backtracking air) during the release of throttle (shifts). Lots of different types of compressor surge out there, some can lead to turbos going kaplut.


Sounds good though but seems like your bypass isnt opening

 

I've always heard the flutter was a BAD thing..

 

Not true at all. People have been running dose pipes and completely closed bypasses without any problems at all. Even in highly tuned cars pushing 20+ lbs of boost. 3 years after driving, they check the turbo, everything is still fully balanced without any shaft play.

 

Oh ya its a problem. It causes premature turbo wear.

 

Once again, that is a huge misconception. On newer small turbos (like ours) there isn't really much of a problem. My friend has been running his tuned jetta for 6 years on a closed system as a DD, and he is still on the same turbo, no power loss, no change in sound (the jetta 1.8Ts use the same turbo as ours).

 

The damage that most people think will happen, happens the following way: *Too big of a turbo for the engine. Half throttle. STUTTER, BUCK.*

I've been reading into running no BPV for a while now, it's been done A LOT, especially by Subie guys and Skyline guys. And look at some of those WRC cars

 

So why aren't you doing it if there is nothing wrong with it?

 

I asked Jan about that sound when he tuned my car back in April. He says that is a map directly from the MINI Challenge car.

 

That flutter was put their on purpose due to the map "borrowed" from the MINI Challenge car. Its there to allow the turbo to spool up quicker for the next shift. It is not harming the car or the turbo. It is done electronically. Nothing is blocked. All of Jan's JCW tunes have that flutter.

 

Its really a toss up. I think the NM intake looks better and is easier to install. The DoS intake sounds better, seems to provide some more power and is less expensive.

 

Thanks for asking!

I'm still trying to figure out how to do it. I've never even looked at our BPV.

 

The turbo flutter that you have is the same flutter that people claim is dangerous for the turbo. It's just not the case. It's the BPV not opening as much as stock. That is what causes the "flutter". The same thing can be done by replacing the stock spring on some BPVs with a heavier one.

I'll probably get myself a Forge BPV with a heavy spring.

 

the "flutter" is the turbo being slowed by air being forced back up the tract, how can that help spool?

I have a jan tune and dont have flutter.

Imagine a a pin wheel spinning one way and you blow against it.

I am not taking away from your claim just that that def doesnt add up.

I was an ex wrx'er and my s2k was boosted as well. I have worked on quite a few setups(not claiming savant-ism) and have only seen a closed system on a car running of a straight map sensor fuel map and over 30psi of boost(blow off wouldnt stay shut at those pressure levels).

 

Hell instead of doing this why not just get a 2 step and an anti lag kit and call it good. Well nvm the antilag would tear up your turbo but it would be freaking sweet while doing it.

 

excited for the WRC

 

Just a lil.

 

You do not have the flutter becuase you do not have a JCW. It's JCW specific. And if it was destructive to the car then why would it be a standard feature of the stock tune on the Challenge car?

 

Take it easy this is a conversation not an attack. The jcw and s are the same other than the charger and pistons, and little peripherals contrary to what was thought before. im trying to figure out the benefit of compressor surge... which to date has none, sounds great yes, but if its compressor surge its slowing the charger down I read somewhere that the jcw BPV flutters which might make it sound like surge while it isnt but i havent been able to verify it.

 

my 07 had MAJOR flutter when it had the unichip installed along with an open element filter. I haven't heard it in my jcw while running 23lbs boost but I also have the stock intake which may mask the noise. Perhaps with an open intake I'd be hearing it. I enjoyed the flutter until I started reading about compressor surge. After that I tried to minimize the amount of time it happened instead of trying to make it last longer.

So is the flutter just a harmless noise from the BPV or is it compressor surge? That would be the million dollar question I wish we had a technical answer for.

 

On shift the turbine spins freely. The air being forced back into the system is there for the next gear, hence spool is quicker.

This is a huge debate, especially in the subie community. No BPV or BPV. Personally, I take the side of the WRC guys and the track guys

 

The BPV can't make that "shu shu shu" noise. It's the turbo making the noise.

 

i could see if the boost in the tract is still boost having a benefit, but the purpose of the valve is to spin more freely.


Like the pin wheel scenario i said before.

Now if the air after the compressor that is backing up is still **pressurized** it would be instant boost to flow when the throttle opens.

Longevity...

All compressor surge is not good to an extent, a comparrison can not be made with the WRC/ Race Car vs the street car.

Race cars and WRC cars get rebuilds and are for a purpose... reliability is not an issue unless its an endurance race platform.

From fia website

"There shall be no minimum or maximum special stage distance. However, there shall be a maximum of 80 kilometres between service halts. The special stage distance of a World Rally Championship event has been broadened to between 300 kilometres and 500 kilometres (formerly 340-400 kilometres). These stages may be on mixed surfaces on either a complete Day or within a Day."

also same source

"In the case of engine failure between scrutineering and the first time control it is permitted to replace the engine. In this case the engine must be re-sealed. Only one spare engine per rally and per Manufacturer or WRC Team is allowed."

point being that they can replace and engine and rebuild them constantly

In WRC they average 80km before a "service stop" is had...


now i want compressor surge, kinda makes sense if its for a short span of time, if its not hard shifts you lose that boost with the surge.


physics wise it makes sense...