Re: Compressor Surge
 

I wanted to eliminate the possibility of the bov system killing my turbos and so far it has worked great for me.

Re: Compressor Surge
 

I'm going to bump this thread up again because i know i have this issue with the galant now...i hope I'm not hijacking this thread. I will post videos of it soon. It's weird because I have the greddy type-s bov and I've adjusted the spring to it's softest and it's still doing surging while on a stand still and it feels like it is dangerously surging after a uphill cruise.

Re: Compressor Surge
 

First things first, I really doubt that is compressor surge, especially at a stand still, that is basically impossible. Are you just talking about BOV flutter? What is it actually doing?

Re: Compressor Surge
 

here we go! i got a video up....ugh...i feel bad for driving it around this way. anyways, just a heads up that this is a MAF from the 95-96 Summit Wagon/Vans. it is just temprorary because I'm cleaning the HKS filter from the original one.

EDIT: you can hear it after 13 seconds.

http://www.youtube.com/watch?v=LcQ4h5gB_iI

Re: Compressor Surge
 

Holy noise, batman! That didn't seem like very much, and you can't build much boost just free revving it.

Re: Compressor Surge
 

lol..yeah...i dont have a great camera. but i tried my best to get/obtain the noise. you can hear the wooosh woosh noise after 13 seconds...

Re: Compressor Surge
 

I heard it before 13 seconds too. :D

Re: Compressor Surge
 

^^lol...yeah i guess. but is this the 'infamous' pressurized air going into the turbo instead of going to the bov?!!

Re: Compressor Surge
 

Sounds more like flutter to me. Like others have said, would be hard to get surge at idle.

Re: Compressor Surge
 

Especially using a turbo small enough to use the stock intake.

Re: Compressor Surge
 

I found a pretty good video on Youtube of what compressor surge is.


http://www.youtube.com/watch?v=<object width="425" height="344"><param name="movie" value="http://www.youtube.com/v/nCj6Spwl1CU&hl=en&fs=1"></param><param name="allowFullScreen" value="true"></param><param name="allowscriptaccess" value="always"></param><embed src="http://www.youtube.com/v/nCj6Spwl1CU&hl=en&fs=1" type="application/x-shockwave-flash" allowscriptaccess="always" allowfullscreen="true" width="425" height="344"></embed></object>&hd=1

Re: Compressor Surge
 

Yours is just BOV flutter, it happens after you let off the gas, so it can't be compressor surge. BOV flutter is normal and should happen when there isn't a ton of air to blow off.

Re: Compressor Surge
 

maybe u should stop modding dsm's, doesnt seem to be ur forte

Re: Compressor Surge
 

hey rocket, how bout you shut up! hes asking for help, not a flaming!

Re: Compressor Surge
 

the 1g blowoff valve is amazing! sounds like your oil feed line is messed up.

Re: Compressor Surge
 

So just for the record, the fluttering noise in this video is not compressor surge?



http://www.youtube.com/watch?v=LZUbo_mNDZM&hd=1


Reason I ask is because my 14b setup was making that exact same noise as the one in this video (I have a crushed to maximum 1g bov) and I wanted to make sure that the noise I was hearing was not surge.

Re: Compressor Surge
 

That half sounds like what my starion was doing before I switched the vac line set up on my bov. I know my sound was alot more turkey gobble like and was a result of my bov not cracking open. Now with my two line vac setup on my bov its just solid woosh. (HKS Racing BOV)

Re: Compressor Surge
 

Real compressor surge happens during spoolup/high boost, not when you let off of the gas. The surge noise in that video is caused by the BOV not letting all the air out in 1 smooth blow. Too tight of a BOV opening and closing over and over might not be the best thing for the turbo, if the air is actually backing up that far, but it isn't real compressor surge and the kind that ported/anit-surge compressor covers are for. People call this noise BOV surge/flutter or "internet surge" because most people on the internet don't know what real compressor surge actually is.

Compressor surge happens when the turbo is flowing A LOT of air and the motor can't actually ingest all that air. A turbo makes boost inside the compressor housing, it isn't like a roots blower/positive displacement blower that works by stacking air in the intake manifold. When air starts stacking up on a turbo car and gets stacked all the way back to the compressor housing, then surge happens. The stacked air starts stopping the spinning compressor wheel or trys to turn it backwards. When you try to stop a compressor wheel going 80,000RPMs, bad things happen.

Compressor surge is common on 2.0l motors with the 61mm turbos. The 2.0l spools the turbo to high boost levels too fast and makes more air than the motor can take in. You can try to get rid of surge by going to a larger exhaust housing/wheel, to make the turbo spool up slower. You can get bigger cams, bigger intake manifold, port the head, to try to be able to take in more air. You can goto a bigger displacement motor that can take in more air each stroke.

A ported shroud/anti-surge cover has passage ways for the backing up air to come back out the front of compressor housing and into your intake pipe to try to avoid reverse flow pressure waves from causing surge.

Basically you can't have your cake and eat it too. If you spool a big turbo too fast you get surge.

Re: Compressor Surge
 

So what your saying is, that the people running the 14b's are having bov problems that causes the bov to either not open all the way or not at all, and the air is then stacking on your throttle plate and backing up into the turbo causing a "surge like" symptom, but is really not related to the turbo at all, instead is related to their bov/bpv. Makes sense. Stop crushing your bov on a 14b turbo you cant even really push that much pressure with a 14b to need that.

Re: Compressor Surge
 

Goatblower: Thank you for the proper definition of compressor surge, how about a proper definition for the symptoms I am describing? does BOV surge work? anyone?

This happens, so we have to have established terminology.

And in case anyone is wondering, when the BOV flutters, it does shorten the life of the turbo, I have several examples myself :(