Author Topic: Turbo Compressor "Surge" (Read 10616 times)

Smokey Eddy · « **Reply #15 on:** March 05, 2009, 08:13:27 pm »

thanks for all the discussion Fellas! I'll be sure to "ease" off the throttle from now on =)

Rabbit TD · « **Reply #16 on:** March 05, 2009, 10:10:38 pm »

Quote from: "zukgod1"

Quote from: "truckinwagen"
how much boost were you running?

Just a coulpe lbs :twisted: :twisted: :twisted:

Well ok maybe a tad more than that but as dillenger1 pointed out throttle plate or no if that suka is pushing 20 psi and you let off the fuel its still pushing 20 psi for a sec. That air has to go somewhere and back past the compressor is the sound you hear. Not good for the turbo either way

I still don't quite understand why the pressure would back up into the turbo tough because the pressure is a straight shot into the combustion chamber through the intake valves which are still working and the exhaust valves also just no fuel being injected. I am new to turbos though but I just don't understand that part.

Smokey Eddy · « **Reply #17 on:** March 05, 2009, 10:20:04 pm »

the impeller no longer has that force (energy) coming from the compressor side of the turbo and just milliseconds ago it DID have LOTS of energy pushing 20psi of boost (or what ever it is) towards the valves. So, when that force goes away. It's the path of least resistance in comparisson to closed intake valves (or say even just 1 intake valve being open?).

So, it equalizes and escapes.

jtanguay · « **Reply #18 on:** March 05, 2009, 10:33:29 pm »

i myself wouldn't be too concerned unless running more than 20 psi. things that i would do to minimize this, is just completely letting off the throttle after the hard acceleration, unless in an emergency braking situation. leaving the engine in gear will also help reduce the stress because the engine will be consuming more air.

running 30 psi might pose some issues though... then you might want a BOV.

MRDART · « **Reply #19 on:** March 06, 2009, 06:21:22 am »

I know what compressor surge/stall sounds like in a turbine engine it sounds like a series of loud bangs.
Radialcompressors as whe have in our turbo´s is not so prone to do this, but when running high boost you might get the problem when letting off the throttle however I think it is only for maybe a 100/second or so until the pressure has decreased.
Best regards / Tommy

truckinwagen · « **Reply #20 on:** March 06, 2009, 08:10:55 am »

Quote from: "libbybapa"

I'm not at all convinced that the sound described has anything at all to do with residual pressure in the intake, in fact I don't believe it has anything to do with the intake side of the turbo at all. The pressure on both sides of the turbo will drop at virtually the same time due to the unthrottled nature of the engine and the fact that the engine is ingesting the same amount of air as before. I am convinced that the noise described is simply the effect of the turbo basically being on overrun. When the pressure on both sides of the turbo dissipates faster than the turbo slows down, the fins are then pushing the air in the turbo rather than the other way around and the noise results. This is especially apparent with an exhaust that has no back pressure. Add even a small amount of restriction and the noise goes away.

Andrew

those were my thoughts exactly!

Smokey Eddy · « **Reply #21 on:** March 06, 2009, 07:52:52 pm »

Ahhhhhhhhhhh!!!

YES!

Because it only happens with BIG wide open exhaust! with my ressonator and muffler it didn't do it at all. (it also didn't make any boost though :evil: )

truckinwagen · « **Reply #22 on:** March 08, 2009, 12:24:34 pm »

with a restrictive exhaust it is still happening, you just cant hear it.

I wouldn't worry about it, I know I dont

Smokey Eddy · « **Reply #23 on:** March 08, 2009, 09:27:32 pm »

Quote from: "truckinwagen"

I know I dont

Lolz! :lol:

Rabbit TD · « **Reply #24 on:** March 08, 2009, 11:34:01 pm »

Quote from: "Smokey Eddy"

the impeller no longer has that force (energy) coming from the compressor side of the turbo and just milliseconds ago it DID have LOTS of energy pushing 20psi of boost (or what ever it is) towards the valves. So, when that force goes away. It's the path of least resistance in comparisson to closed intake valves (or say even just 1 intake valve being open?).

So, it equalizes and escapes.

Thanks for the answer, that does make sense and I can see that happening now.

Smokey Eddy · « **Reply #25 on:** March 09, 2009, 12:11:51 am »

on another note im almost done changing all my HUD lights to 48k millicandela red LED's i found on Ebay. Did that over the weekend

Here is the thread for the OP but im changing it so you can do the job with just a rotary tool (dremel) and some LED's, glue, wire, solding iron, and a couple resistors.

IE. you don't have to get that special plastic machined or laser cut.
http://forums.vwvortex.com/zerothread?id=4206297

You can follow the OP's post there but instead of ordering your own pieces you can just paint the backing black. Anyways, my post will be up shortly. Hopefully after tomorrow in the DIY (monday, march 10th. Wed at the latest, i need to put that dash back together! I also finally got a fuse box for my GP's Vince style. Yay! Exciting.)

foxracer1 · « **Reply #26 on:** March 09, 2009, 03:06:16 pm »

Quote from: "spencebm"

where are you Tom when we need you

Sorry was at the autorama all weekend and haven't been on here. I agree with andrew its the exhaust side making the noise. Its the turbo changing speed quickly. Surge normaly happens at low rpm under high load.

http://www.youtube.com/watch?v=mHmdO350xcY&feature=PlayList&p=ECAD9EEDD2186EA0&index=0&playnext=1

Smokey Eddy · « **Reply #27 on:** March 09, 2009, 07:17:17 pm »

That dog barking sound is NOT what im trying to describe... I'll look for the post... I can't believe he hasn't posted his video yet. He's a really turbo/exhaust noise savy guy...

http://www.youtube.com/watch?v=JP67FLK-xBM

0:22-0:24

THERE IT IS!!!!!!!!!!!

foxracer1 · « **Reply #28 on:** March 09, 2009, 08:32:23 pm »

@ 0.30 or this. To me that is an awesome sound but not bad.

http://www.youtube.com/watch?v=Vzm-j4k9tNI&feature=related

Smokey Eddy · « **Reply #29 on:** March 09, 2009, 10:53:57 pm »

yeah, 0.32 too.

So that sound isn't ... harm being done to the turbo? phew. It was deafening inside the car.