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Not to highjack the thread, but how does a van turbo play into all this? I just installed mine, and it doesn't have as much whistle as mt e99 turbo, and when I left off fast after getting into it hard, it makes a zsu-zsu-zsu sound, kinda like the noise a pulling truck makes at the end of a pull. Is this because I have no wastegate? I was told a wicked wheel will do nothing for a van turbo.
That's called off-boost surge. It's not nearly as hard on the turbo's thrust bearings as on-boost surge, but it does put large loads on the compressor blades themselves. That stall or surge is what blow-off valves and compressor bypass valves are for on gas engines (IIRC, someone makes a kit for diesels).
Has nothing to do with the wastegate, even though plenty of uneducated people call it "wastegate chatter". It's caused by the engine's sudden decrease in demand for airflow (or shutting the throttle body in gassers), while the turbo is spooled and outputting more airflow than can go anywhere. The pressure backs up and stalls the airflow in the compressor, and the air escapes out the inducer. Once the pressure reduces, airflow resumes, and if your still off the pedal, does it again and again until the compressor is slowed enough to match the new engine demand. It's really the same concept as the on-boost surge we all encounter with the stock turbo and tunes, the difference being the types of loads induced in the turbo from the lack of exhaust energy.
A real clear answer? the "wicked wheel" design wheel actually flows a bit less air than the factory wheel, that is how it eliminates the surge...
I am not sure you are dead nuts on with that answer. I believe the WW changes the compressor map of the turbo changing the surge point. Dan's explaination hit this on the head stating he can still get surge, but there are too many other things that shouldn't be happening for it to take place. Somebody call me out if I am in error.
Last edited by sflem849; Jan 20, 2010 at 05:19 PM.
Reason: Bad Quote!
Who said a WW wouldn't help a van turbo?? It DEFINITELY *WILL* help! You have bigger injectors, so you'll be able to drive into surge. I was able to with mine before I put the ATS housing on it. Now, if you put a ported compressor housing on, a WW is likely most likely not needed. I'm not surging, and I'm making 35psi with mine (ATS/stock late wheel), but it isn't unheard of. And I can bark mine like the video above if I let off the pedal in a hurry.
Hey Izzy, good to hear ya chime in here- someone on another post I was on said it ain't needed for a van turbo, but although I can't open the youtube link on my stupid work computer, I will say that my turbo does make the same noise when really getting into it as when I let off. So is that surge? And it's not a whole lot while building boost, but enough to where I don't like it. I guess I need to take the WW off my e99 turbo and swap it into my van turbo. Damn- I'm just getting tired of working on this truck after last weeks work I put into it.....
Just watched the video- that's exactly what my rig is doing! I do like the sound. Question is- if I swap in a WW, what will be the result? I'm currently hitting only 28-30psi in 80E, and I was hoping for more than that!
hmm i've never heard my turbo make that noise at all, if i get on it then off in a hurry i just hear a whistle, like spool up, but going from high pitched to low....wish mine barked like that
BTW i have a turbonetics, dunno if that makes any difference, and i have a manual.
I would try calling Clay. I live 10 minutes from Xtreme Diesel Performance and they still said it would be about a month before i could have pick one up. Called Clay, had it in a couple of day.