Ok first off...WHAT causes surging exactly?

cuz i think its my BOV. I have a HKS SSQ and lately i been playin wit the adjustment knob cuz i thought it wasnt letting me boost high enough/or feel taht strong pull so now im decided on a TiAl BOV(any1 have 1 for sale PM). why is it surging no matter how loose or tight the adjustment knob is. i'm pretty sure the bov isnt damaged or anything but i dont think it wants to cooperate with my car. I practically figured out why my car is "bogging" or not "kicking" when i shift (ACT clutch setup). Its cuz when i shift, the turbo doesnt continue to spool, or doesnt spool fast enough inbetween shifts to give me that "kick" im supposed to get when i shift gears. Its usually at higher rpms, at low rpms u could feel that light kick when im shifting around 2500-3000rpms. at higher rpms, it kicks nothing. Feels like an automatic.

 

Ok.. I doubt your SSQV is preventing you from boosting high enough.. the SSQV is made in such a way that it won't leak under boost (unless you damaged its internal diaphragm)

I think your problem is a boost leak somewhere though..

Compressor surge is when the BOV cannot release enough pressure and the excess pressure "Stalls" The turbo.. Its generally felt as a shuddering and heard as air blowing out of the intake (Sometimes a whistle) but you don't always feel it. It can damage the turbo over time though.. Compressor surge will cause your boost to drop though and could hurt your ability to shift while producing boost, but at higher RPM and higher loads, its not as pronounced..

 

Stop playing with the adjustment screw!

https://www.evolutionm.net/forums/sh...ad.php?t=88637

read #4 !!!

 

This is not generally the problem when someone speaks of surge. Turbo surge or stall occurs under heavy load conditions where boost pressures are high. The main cause is generally an imbalance of pressures between the turbine side and the compressor side of the turbo. When the forces on the turbine are no longer strong enough to drive the compressor side of the turbo adequately, stall occurs

 

Well my definition of surge is when the turbo is more efficient then theou engine can handle. Is my case the problem was my cams. The turbo was producing all this boost but the cams could not flow the air causing terrible surging problems at WOT and only in 3rd through 5th gradually getting worse in every gear. Soon as i went from a 260 duration to a 280 duration it cleared the problem right up. Also when i had the 260's in if i would set the boost to anything higher then 22psi is when i would get the surge problem. If i left it below 22psi the car would be fine. Anyway this doesnt really sound like your problem. I would say a boost leak like malibu said but then you would see a drop on your boost gauge and last i talked to you everything was fine in that department. I would say that it is possible the ecu pulling timing but im not sure why it would be doing that since you dont seem to not have any major mods i guess it is possible "bad gas?" Also what boost gauge do you have? Are you sure it is accurate? Is it possible that you are boosting more then you think and thats why the ecu could be pulling timing becouse of knock?

Just my 0.02
Chris

 

hey chris...anyways, hmm well doubt its boost gauge cuz i tried BOTH my gauges, the Blitz BLM 60mm (bars) and the apexi EL series 60mm (bars). The Apexi was a BIT more steadier, but the needle was still shaky during high boost. Well my MBC is coming in 2 days, and i already ahve 1 of the restrictor pils out (near the actuator) and with MBC, i hear we're supposed to take BOTH pills out correct? I guess i can just wait until that shows up. But its so odd cuz the car will hit full boost, but it wont feel like it did. it feels like its boosting 14psi or somethin. When it would usually start spooling and it kicks in, the car hauls *** pulls u back in ur seat, now i feel like 50% of it and i guess the reason my car isnt "kicking" even with my ACT clutch is because its not a drivetrain issue, its my turbo not giving me enough power to let the car KICK inbetween shifts. i'm pretty sure thats it. Well even IF i was boosting too high (today i hit 1.6bars which is 23.4psi) with no MBC and on stock boost controller with 1 pill removed, would that be relating to my surging? thats odd tho cuz when i rev it in idle, i just rev it to 4k and let off an di hear fluttering air noises coming out of the air filter. thx for ur help guys

 

Well thats not good to be hearing that. It sounds like your BOV isnt working and like Malibu said its backing the pressure back into the turbo. Check all your vacuum lines and make sure they are all in the right place and are nice and tight with no tears or rips. Also you are going to have to put your BOV back to the way it was as far as that screw you played with. Read the directions and they probably can get you close to stock at least. Good Luck

Chris

 

mine was a diff prob.. my turbo is to small so i get part throttle flutter. after 3 diff bov i finally figured this out.. i have no resttriction on my int or exh.. when im part throttle and let off partilly the bov will open slightly but the turbo would keep the rpms it was at not slowing down.. as soon as i got on it the bov would close and then the turbo would slow down real quick and then spool up again real fast.. so if i got on and off the throttle quick i would get surge... and the factory wastegate is to small, so that isnt helping either... just a thought for you.. thought it was my bov's.. well the gt35r kit will solve my probs soon.. btw if it is turbo flutter it will destroy your turbo very quick.. i drove about 6000 mi with this prob and im starting see the seals leak already...

 

eeeek. thats scary thought, but why would this happen to me? maybe tears in lines like 2k4 said? im running stock turbo. no internals, just the ACT clutch is the only heavy mod i did. everything else is BPU's (int,exh,bov,catless) theres nothing wrong with my bov, but i dont think its doing the job that its supposed to. i dont hear any leaks at high RPMs from what i know. im thinking of just going with the TiAl bov. Do u think new BOV might solve this issue?

 

nope i stillhasnt solved it for me..
https://www.evolutionm.net/forums/sh...&page=28&pp=20
scroll to my post.. is that the prob your having.. too much for me to type again..

 

ok update: i got rid of total of 4 vac lines by installing an MBC and setting it at 1.3bars (20psi). MBC set off a CEL light for some reason, is that normal? the stock BC still has the sensor plugged, but the 2 ports are capped off. Anyways, i reset the ECU cuz the CEL light, andthen started it up, boom surging again, and it stopped before the MBC. But its weird, with the same setup except MBC, it would surge, then a while later, it went away, i put on MBC without reseting ECu and its fine, then i reset ECU then flutter and its about to stall out. could this be a recirc or intake issue? I dont really see dafarmers post relating to me saying his turbo's too big when im running stock turbo? I have an intake and i think that might be the cause? i have no freakin clue cuz my BOV sEEMS like its blowing off correctly. what ELse could it be. i was pretty sure it was BOV, but i guess its not. this is confusing tha crap outta me. I mean boost has nowhere to go after throttle plates closed except BOV, if it doeesnt go to bov it'll backspool and cause that flutter wouldnt it? so thats why im guessing its BOV. Thx

 

Sounds like you are venting to the atmoshere. That could also set off a check engine light. A boost controller won't. Plumb it back in and Ill bet it is perfect (If you are venting out currently).

 

it sounds like your in the same boat i am... if your venting to atmosphere that is your prob.. if you arent good luck i havent figured it out yet...watch the busher thread im on to see if it gets answered..there is a link on my last post