Compressor surge, or BOV flutter? (my evo)
Mar 4, 2010, 01:57 PM
#1
Compressor surge, or BOV flutter? (my evo)
ok, I have come across a couple threads in reguard to this, but I think I may not have fully grasped either concept, as I can NOT tell which Im experiencing...
from my understanding "compressor surge" is air being pushed back into the turbo, causing the turbine to slow down, but in the higher rpm range. And BOV is flutter when lifting off? Which leads me to believe I have some surging... not quite sure.
For a while now, Ive noticed that I can NO longer do pulls from 2000 (in 3rd), or 2500 (in 4th) w/ out making that pstpssttpssssttppspsspssprttt fluttering sound. (used to do all my 3rd gear pulls from 2000! It does this till just about peak boost (3500) and is fkn annoying! Obviously there power being lost in the low end... This also occasionally, will cause knock.
Now I tried a pull this morning @ 3000 (3rd) and it did the same thing! pssstpsst WTF? Seems like the rpm point I have to start my pulls is getting higher, and higher... I didnt log the pull, but obviously can hear/feel it...
I originally thought it had somethin to do w/ v.7 and gear dependent control, but it still does it on the stock rom, just slightly less...
Stock IX BOV, crushed a bit w/ the stock IX turbo (ported)
Any ideas to solve this issue would be much appreciated, as always!
from my understanding "compressor surge" is air being pushed back into the turbo, causing the turbine to slow down, but in the higher rpm range. And BOV is flutter when lifting off? Which leads me to believe I have some surging... not quite sure.
For a while now, Ive noticed that I can NO longer do pulls from 2000 (in 3rd), or 2500 (in 4th) w/ out making that pstpssttpssssttppspsspssprttt fluttering sound. (used to do all my 3rd gear pulls from 2000! It does this till just about peak boost (3500) and is fkn annoying! Obviously there power being lost in the low end... This also occasionally, will cause knock.
Now I tried a pull this morning @ 3000 (3rd) and it did the same thing! pssstpsst WTF? Seems like the rpm point I have to start my pulls is getting higher, and higher... I didnt log the pull, but obviously can hear/feel it...
I originally thought it had somethin to do w/ v.7 and gear dependent control, but it still does it on the stock rom, just slightly less...
Stock IX BOV, crushed a bit w/ the stock IX turbo (ported)
Any ideas to solve this issue would be much appreciated, as always!
Last edited by nonschlont; Mar 4, 2010 at 02:36 PM.
Mar 4, 2010, 03:49 PM
#2
bump for any insight...
Could this be a leaky BOV, causing surge? I have always noticed that I need a slight bit more duty cycle than most (that Ive seen posted) to achieve "x" boost levels... Possibly getting worse?
W/ the stock map, I was using 70 -71% to achieve 24psi @ 3500, and w/ v.7 and the MAF IAT compensation set to + 2/5, Im using 67.5% to acieve 24 psi. w/ a GM 3-Port
I just went to the car and checked the vac lines, and all seems fine, no holes... (that I could see) All piping seems fine as well.
@ this point, Im just guessing possibilities, from what I have read...
From my limited understanding, this is "compressor surge", but what is the cause?
Also note that when I was on the dyno last (in Jan.) the tuner said, "yep thats surge" but did nothing to help me, as if its cool...
Dont ask who, its irrelevant, I just wanna get to the bottom of this!
Could this be a leaky BOV, causing surge? I have always noticed that I need a slight bit more duty cycle than most (that Ive seen posted) to achieve "x" boost levels... Possibly getting worse?
W/ the stock map, I was using 70 -71% to achieve 24psi @ 3500, and w/ v.7 and the MAF IAT compensation set to + 2/5, Im using 67.5% to acieve 24 psi. w/ a GM 3-Port
I just went to the car and checked the vac lines, and all seems fine, no holes... (that I could see) All piping seems fine as well.
@ this point, Im just guessing possibilities, from what I have read...
From my limited understanding, this is "compressor surge", but what is the cause?
Also note that when I was on the dyno last (in Jan.) the tuner said, "yep thats surge" but did nothing to help me, as if its cool...
Dont ask who, its irrelevant, I just wanna get to the bottom of this!
Mar 4, 2010, 05:04 PM
#3
uh do a boost leak test..... if this is happening in 3rd gear then its likely not compressor surge, i can do a 3rd gear pull at that rpm and im on a fp black.... now if im in 5th gear and try to punch it under 4000rpm it will flutter like you're describing.
do a boost leak test and get that out of the way first and report back. test till about 35psi.
do a boost leak test and get that out of the way first and report back. test till about 35psi.
Mar 4, 2010, 05:36 PM
#4
It sounds more like wastegate flutter than anything, pretty much the same that mine does. I went through and "tuned" my WDC to get rid of it, and it worked for a little while but now the flutter is back with the weather and temp changes. It's getting to be such a PITA that I don't know if I want to try and control my Tial WG on my new setup that's going on in the next few weeks with any kind of ecu controlled boost. 
Mar 4, 2010, 06:52 PM
#5
It sounds more like wastegate flutter than anything, pretty much the same that mine does. I went through and "tuned" my WDC to get rid of it, and it worked for a little while but now the flutter is back with the weather and temp changes. It's getting to be such a PITA that I don't know if I want to try and control my Tial WG on my new setup that's going on in the next few weeks with any kind of ecu controlled boost.
did a 3rd gear pull on the way home, starting ~ 2750, and gave me minor flutter, and pulled like normal...
I dont think its my boost maps, but willing to post em up.
Mar 4, 2010, 07:16 PM
#6
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By setting the WG actuator to "stock" would have to be done with testing the PSI the actuator opens based on your application. I recommend tightening it down as far as it will go since you are running such high boost levels. It will help you to spool better and should help avoid low rpm flutter.
Also....
Do you have a direct line from the intake mani to the BOV? If not, make one. There should be no "T" intersections in the line either. Try to use the largest hose possible to make your BOV very sensitive to intake fluctuations.
The opposite holds true for your boost controller, you want the smallest lines possible. And you want to run a line from the pressure side of the turbo as your boost source for your boost controller. You would be amazed at how many people hook them up wrong.
Since you are running ECU controlled boost....do you have a pill in your boost line?
If doing the above does not solve your problem......
It sounds like you are on the verge of the surge line with the turbo at such a low RPM. Could be that you are running a bit too much timing and/or not enough fuel during spool.
Paul
Also....
Do you have a direct line from the intake mani to the BOV? If not, make one. There should be no "T" intersections in the line either. Try to use the largest hose possible to make your BOV very sensitive to intake fluctuations.
The opposite holds true for your boost controller, you want the smallest lines possible. And you want to run a line from the pressure side of the turbo as your boost source for your boost controller. You would be amazed at how many people hook them up wrong.
Since you are running ECU controlled boost....do you have a pill in your boost line?
If doing the above does not solve your problem......
It sounds like you are on the verge of the surge line with the turbo at such a low RPM. Could be that you are running a bit too much timing and/or not enough fuel during spool.
Paul
Mar 4, 2010, 09:35 PM
#7
By setting the WG actuator to "stock" would have to be done with testing the PSI the actuator opens based on your application. I recommend tightening it down as far as it will go since you are running such high boost levels. It will help you to spool better and should help avoid low rpm flutter.
Also....
Do you have a direct line from the intake mani to the BOV? If not, make one. There should be no "T" intersections in the line either. Try to use the largest hose possible to make your BOV very sensitive to intake fluctuations.
The opposite holds true for your boost controller, you want the smallest lines possible. And you want to run a line from the pressure side of the turbo as your boost source for your boost controller. You would be amazed at how many people hook them up wrong.
Since you are running ECU controlled boost....do you have a pill in your boost line?
If doing the above does not solve your problem......
It sounds like you are on the verge of the surge line with the turbo at such a low RPM. Could be that you are running a bit too much timing and/or not enough fuel during spool.
Paul
Also....
Do you have a direct line from the intake mani to the BOV? If not, make one. There should be no "T" intersections in the line either. Try to use the largest hose possible to make your BOV very sensitive to intake fluctuations.
The opposite holds true for your boost controller, you want the smallest lines possible. And you want to run a line from the pressure side of the turbo as your boost source for your boost controller. You would be amazed at how many people hook them up wrong.
Since you are running ECU controlled boost....do you have a pill in your boost line?
If doing the above does not solve your problem......
It sounds like you are on the verge of the surge line with the turbo at such a low RPM. Could be that you are running a bit too much timing and/or not enough fuel during spool.
Paul
Not sure on the line from the IM to the BOV, but will check it out...
runing the GM 3-Port, so no pill.
Heres my timing map, maybe I am running too much, (dont think so) but hey, maybe... AFR is 12.5 ish tapering to 12.0 ~ 3200, and @ 3500 is 11.7 ish.
and heres my boost tables...
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Mar 4, 2010, 09:51 PM
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I realize you are trying to use MIVEC to increase your spool, but I think you may have over done it just a tad.....
Take about 1/2 to 1 degree of timing out of the MIVEC timing at the 90 load to 120 in the 2000 rpm area.
To improve spool try...to remove a little bit of fuel from where you start to taper richer from 12.5 during spool. You want to hold 12.5 until you hit peak load then taper quickly to mid 11s and hold till redline.
Take about 1/2 to 1 degree of timing out of the MIVEC timing at the 90 load to 120 in the 2000 rpm area.
To improve spool try...to remove a little bit of fuel from where you start to taper richer from 12.5 during spool. You want to hold 12.5 until you hit peak load then taper quickly to mid 11s and hold till redline.
Mar 4, 2010, 10:53 PM
#9
I realize you are trying to use MIVEC to increase your spool, but I think you may have over done it just a tad.....
Take about 1/2 to 1 degree of timing out of the MIVEC timing at the 90 load to 120 in the 2000 rpm area.
To improve spool try...to remove a little bit of fuel from where you start to taper richer from 12.5 during spool. You want to hold 12.5 until you hit peak load then taper quickly to mid 11s and hold till redline.
Take about 1/2 to 1 degree of timing out of the MIVEC timing at the 90 load to 120 in the 2000 rpm area.
To improve spool try...to remove a little bit of fuel from where you start to taper richer from 12.5 during spool. You want to hold 12.5 until you hit peak load then taper quickly to mid 11s and hold till redline.
Im gonna do a pull tomorrow mornin from 2000 and post it up and see if theres anything that stands out...
ppssffftttsfffttssstttt..... lol
Mar 5, 2010, 12:25 PM
#10
FK the ghost in my comp.!!!
well, Im getting to the point of "tapping out" on this v7 rom. ONCE AGAIN, the rom got scewed, somehow, and gears are reading off again! Ive been working on 1 stock rom, and 1 v.7 rom ONLY! And it still somehow got scewed!!! Now its reading the gears fine (meaning its a solid #), just the wrong damn gear!
Im almost positive, Im doing things correctly, as I have been playing w/ v6 when it first came out, v7 when it first came out, and the roms "seem" fine, but a few days later the damn ghost in the comp decides he doesnt want me to be running v7... IDK WTF is going on here, but Im TOTALLY FKN FED UP!!!!
I threw in my stock rom, and gonna run that for a while, so I dont drive myself Nucking Futz.
Now on to the flutter issue! It seems to do it less w/ the stock rom. Did a few pulls w/ v7, and noticed the gears were off, swapped in the stocker, did a pull, and it seems to be doing it slightly less... IDK
All I know is for the last 2 months, I have been trying to figure out the damn gremlin in my comp. and it just wont go away!
And I spent a good amount of time gettin my v7 .xmls to be like the 9653, where you can input the side notes for values for different boost control, sensors, etc...
Im almost positive, Im doing things correctly, as I have been playing w/ v6 when it first came out, v7 when it first came out, and the roms "seem" fine, but a few days later the damn ghost in the comp decides he doesnt want me to be running v7... IDK WTF is going on here, but Im TOTALLY FKN FED UP!!!!
I threw in my stock rom, and gonna run that for a while, so I dont drive myself Nucking Futz.
Now on to the flutter issue! It seems to do it less w/ the stock rom. Did a few pulls w/ v7, and noticed the gears were off, swapped in the stocker, did a pull, and it seems to be doing it slightly less... IDK
All I know is for the last 2 months, I have been trying to figure out the damn gremlin in my comp. and it just wont go away!
And I spent a good amount of time gettin my v7 .xmls to be like the 9653, where you can input the side notes for values for different boost control, sensors, etc...
Last edited by nonschlont; Mar 5, 2010 at 12:29 PM.
Mar 5, 2010, 10:52 PM
#11
well, to add to my frustration, today I blew of an IC pipe logging on the stock rom... 
Atleast it was the upper. 
the fluttering seems to have lessened (from 2500), but still does it right after tip in, for a sec... Only got 2 pulls in before I had to limp it home...
luckily I dont log too far from the crib.
So I noticed that my .xml got scewed as well, cleaned up a new .xml file for my rom, disconnected the battery, turned the key a couple times, reconnected the battery, loaded up my stock rom, and noticed that there were more changes to the rom, than maps I had adjusted, so there was some **** goin on there....
Note: If I delete the "versions" file that pops up in the ecuflash folder, it automatically scews my .xml (even the stock .xml)... It did NOT do this (pop up w/ a versions file) before the demon in my comp. woke up! Its as if theres still a damn folder somewhere thats working against my folder...
Edit: Just noticed that if I edit the the maps to change to developer or advanced, it scews the .xmls!
idle seemed a bit more stable, although, it wasnt too bad to begin w/. I'll do some logging/tuning in the morning, and see how she feels... Hopefully this rom will stay uncorrupted for more than a few days... And my piping stays plumbed in!
Looks like Im basically stuck w/ a stock rom, till I can get my hands on another laptop...
FKN B.S.!
Atleast it was the upper. the fluttering seems to have lessened (from 2500), but still does it right after tip in, for a sec... Only got 2 pulls in before I had to limp it home...
luckily I dont log too far from the crib. So I noticed that my .xml got scewed as well, cleaned up a new .xml file for my rom, disconnected the battery, turned the key a couple times, reconnected the battery, loaded up my stock rom, and noticed that there were more changes to the rom, than maps I had adjusted, so there was some **** goin on there....
Note: If I delete the "versions" file that pops up in the ecuflash folder, it automatically scews my .xml (even the stock .xml)... It did NOT do this (pop up w/ a versions file) before the demon in my comp. woke up! Its as if theres still a damn folder somewhere thats working against my folder...
Edit: Just noticed that if I edit the the maps to change to developer or advanced, it scews the .xmls!
idle seemed a bit more stable, although, it wasnt too bad to begin w/. I'll do some logging/tuning in the morning, and see how she feels... Hopefully this rom will stay uncorrupted for more than a few days... And my piping stays plumbed in!
Looks like Im basically stuck w/ a stock rom, till I can get my hands on another laptop...
FKN B.S.!
Last edited by nonschlont; Mar 5, 2010 at 11:13 PM.
Mar 6, 2010, 04:29 AM
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Since I have gone to ecu controlled boost I have been experiencing the same flutter that you are. For me it happens during the same 2-3k rpm in 3rd or 4th. I am achieving more boost than with my forge mbc. My feeling is that I need to crank the WGA down a bit. I was never happy with the dip after peak boost that the forge was giving me. Some say the Hallman was better. Basically they both are a ball and spring...so I can't see that they would be drastically different.
If I were you I would experiment with the WGDC 100% under this load. I found that moving it down from 200 helped. It almost seemed that something was conflicting with that setting creating the WG to open/close very fast. There is a thread on this somewhere. Tephra alluded to this problem.
This stuff is a challenge isn't it?
If I were you I would experiment with the WGDC 100% under this load. I found that moving it down from 200 helped. It almost seemed that something was conflicting with that setting creating the WG to open/close very fast. There is a thread on this somewhere. Tephra alluded to this problem.
This stuff is a challenge isn't it?
Last edited by chmodlf; Mar 6, 2010 at 04:35 AM.
