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Old 03-21-2011, 12:59 AM   #1
troy591
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Default Surge power under boost *with video*

So I've been having this issue for awhile now. When I'm under boost the engine almost feels like it let's off for a split second then comes right back. I just swapped the turbo today to fix my oil seal leak and it's still doing it. Any thoughts on what it may be. I'll try and take a video as well as get some psi readings.

If this rain let's up I'm going to mess with the waste gate but I still doubt it's that.

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Last edited by troy591; 04-20-2011 at 11:07 PM. Reason: video link
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Old 03-22-2011, 07:03 PM   #2
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Anyone got any ideas?
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Old 03-22-2011, 07:44 PM   #3
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Boost leak from inrercooler... maybe? How often does it bounce? Back to back or just once in a while
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Old 03-22-2011, 07:52 PM   #4
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Seems like whenever its under boost in 3rd-5th gear. probably 2-3 seconds between surges.
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Old 03-22-2011, 08:43 PM   #5
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Could be several things. Knock, boost leaks, tune, bad spark plugs, dirty MAF, O2's going out etc.

Hard to say without seeing any logs. Do you have the ability to log?

Clean your MAF first and see if that fixes it. If not, I'd recommend getting a boost leak test and go from there.

You need to provide more background of your vehicle and mods. Provide as much as you can.
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Old 03-22-2011, 08:51 PM   #6
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Quote:
Originally Posted by SVT_WRX View Post
Could be several things. Knock, boost leaks, tune, bad spark plugs, dirty MAF, O2's going out etc.

Hard to say without seeing any logs. Do you have the ability to log?

Clean your MAF first and see if that fixes it. If not, I'd recommend getting a boost leak test and go from there.

You need to provide more background of your vehicle and mods. Provide as much as you can.
COBB stage 2 base map, catless, headers.

Ill look into a boost leak test, thanks.
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Old 03-23-2011, 11:42 AM   #7
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Ive got the same thing, has come creeping lately, but at a higher RPM (about 6500).. Im going to try cleaning the MAF first off... Dont think the 02s have any real authority that far up the revs, boost leak almost definately not, spark plugs is very likely for YOU, but I know the sound and ways of to big plug gap, and its not my problem.

Ill let you know if whatever I do help!
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Old 03-23-2011, 11:45 AM   #8
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Quote:
Originally Posted by RRR
Ive got the same thing, has come creeping lately, but at a higher RPM (about 6500).. Im going to try cleaning the MAF first off... Dont think the 02s have any real authority that far up the revs, boost leak almost definately not, spark plugs is very likely for YOU, but I know the sound and ways of to big plug gap, and its not my problem.

Ill let you know if whatever I do help!
Thanks man.
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Old 03-23-2011, 04:32 PM   #9
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Quote:
Originally Posted by troy591 View Post
So I've been having this issue for awhile now. When I'm under boost the engine almost feels like it let's off for a split second then comes right back. I just swapped the turbo today to fix my oil seal leak and it's still doing it. Any thoughts on what it may be. I'll try and take a video as well as get some psi readings.

If this rain let's up I'm going to mess with the waste gate but I still doubt it's that.
Does it do it at all RPM range or certain RPMs?
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Old 03-23-2011, 06:39 PM   #10
troy591
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Seems like everytime it happens it's at 3000rpm+. But like last night I went to go show my buddy and it didn't do it... That's what confuses me. But I logged yesterday and I'm dropping a good 2-3psi when it surges then it goes back to the top
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Old 03-24-2011, 12:01 AM   #11
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Do you have catless dp? Most of the time with catless DP the boost will spike and the ecu will try to correct it and drop boost and then it tries raising it because it drops it and repeats.. Does it feel like you loose power or is it just audible? Mine only surges like that in 5th gear around 2500and up RPM but below 4500 RPM because its too much boost for that low RPM.. its normal but should be tuned out.. try to post the video you said but drive safe.
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Old 03-24-2011, 12:08 AM   #12
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mine did the exact same thing with the stock tune, I got a custom tune and its fixed. It would happen if I was in a gear too high , I would floor it, boost would build then randomly pause for a second and then continue to build like normal.
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Old 03-24-2011, 12:10 AM   #13
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Yea, I learned that from a tuner.. he explained it too me pretty good.. Now I'm trying to tune my own car but its harder than it seems without Live tuning lol..but yea I want to see a vid from the OP because I think he might have just that.
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Old 03-24-2011, 12:25 AM   #14
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Quote:
Originally Posted by WRX Boss
Do you have catless dp? Most of the time with catless DP the boost will spike and the ecu will try to correct it and drop boost and then it tries raising it because it drops it and repeats.. Does it feel like you loose power or is it just audible? Mine only surges like that in 5th gear around 2500and up RPM but below 4500 RPM because its too much boost for that low RPM.. its normal but should be tuned out.. try to post the video you said but drive safe.
Yes I'm catless all the way back. That makes sense. And yes it is loss of power, not just audible. It literally feels like I have my foot to the floor then quickly take it off then back on, even tho my foot position never changes (unless ever since I bought the car I got a bad leg twitch only when my car is over 3000 rpm)

I'm just trying to figure out if it's "normal" and I don't have something major wrong causing it. Like it is something I can live with until I go 16g kind of thing when I do get a tune.

It definitely does it in like 4-5th gear when im kind of lugging it. But I was surprised to have it happen in second and third as well. I will try and get a video or something to help solve the problem. Once it stops raining I'm going to reflash again to stage 2 and play a little with the wastegate and see if that helps at all.
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Old 03-24-2011, 12:38 AM   #15
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Yea, OTS shelf maps are not really meant to unlock the best of your vehicle, more of a starting ground for a more custom tune.. I wanna say its that because you say you drop couple pounds then goes up.. does your boost gauge jump around like crazy when it does it?
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Old 03-24-2011, 01:13 AM   #16
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troy591 Whats up man I think I met you at the SCV meet last Friday. I had the Blue WRX on White WORK wheels. I have had the same problem with my car too. I build up to 15 psi then goes down to 11-13 psi then back up to 15 psi. Im catless. From what I heard it just needs to be tuned. So you are not alone with this problem. I think it is the ECU trying to correct it self like WRX Boss said. Cause I tried cleaning out the Stock EBC and didnt change, switched the Stock EBC and didnt change. Disconnected the stock EBC and held Wastegate pressure just fine. So its the ECU correcting itself.
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Old 03-24-2011, 01:27 AM   #17
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Quote:
Originally Posted by teamsti
troy591 Whats up man I think I met you at the SCV meet last Friday. I had the Blue WRX on White WORK wheels. I have had the same problem with my car too. I build up to 15 psi then goes down to 11-13 psi then back up to 15 psi. Im catless. From what I heard it just needs to be tuned. So you are not alone with this problem. I think it is the ECU trying to correct it self like WRX Boss said. Cause I tried cleaning out the Stock EBC and didnt change, switched the Stock EBC and didnt change. Disconnected the stock EBC and held Wastegate pressure just fine. So its the ECU correcting itself.
What's up man! Nice meeting u the other night hopefully you can make it out to more of our meets and come out to dinner or chill with us after!!!

I'm just relived to hear it doesn't sound major and it's almost a normal thing. I'll just try and try my driving style to try to deal with it until I go bigger and get a tune.

I'll still try and get a video out to show u guys. Also I'm just using the live boost gauge on my AP and it doesn't jump around a lot really. It's more of a smooth dip it power but again that's while driving so it's hard to tell.
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Old 03-24-2011, 01:33 AM   #18
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It was nice meeting you too man! It was cool hanging out with new Subaru peeps . I wanted to go to the photo shot last night but I thought it was a SCV thing haha.

Yeah I just adjusted my driving style now. I stay under 5 PSI the most I hit now is like 10 PSI. Just cause I dont want to tweak with things. But I think once we get tuned we should be fine with our problems. Let me know what you do if anything helps it and ill do the same.
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Old 03-24-2011, 09:44 AM   #19
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Wow, I am glad I came across this thread. I'm having the exact same problem, but only notice it when im at 85+ in 5th gear with the pedal floored. I'm not saying it doesn't happen otherwise, but I've only had the car 5 days and that is when I notice it.

No mods that I'm aware of. I just cleaned the MAF and changed air and fuel filters, but no luck.

I don't have a boost gauge, but it definitely feels like the boost is cutting in and out.

Hopefully we can get this issue solved!
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Old 03-24-2011, 09:57 AM   #20
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OP. I've had a similar boost problem. Although your's may be caused by something else. When I would go WOT my boost would spike above what it was meant to go, the ecu would correct itself (overcorrect) and the pressure would drop, then go and spike again, then drop. This would continue and never really settled on a pressure. If that is what you have, I can tell you how to tune it out. From Cobb, you can download a free beta version of their tuner, and do some things yourself.
If that senario is not what you're experiencing, then you may have a leak somewhere. I don't think it's your wastegate. I've fiddled with mine before, and it does almost nothing to change the loss and gain in pressure.
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Old 03-24-2011, 10:06 AM   #21
troy591
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Quote:
Originally Posted by ionthecrawfack
OP. I've had a similar boost problem. Although your's may be caused by something else. When I would go WOT my boost would spike above what it was meant to go, the ecu would correct itself (overcorrect) and the pressure would drop, then go and spike again, then drop. This would continue and never really settled on a pressure. If that is what you have, I can tell you how to tune it out. From Cobb, you can download a free beta version of their tuner, and do some things yourself.
If that senario is not what you're experiencing, then you may have a leak somewhere. I don't think it's your wastegate. I've fiddled with mine before, and it does almost nothing to change the loss and gain in pressure.
Was yours everytime u were in boost? Or there were times it was totally fine?
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Old 03-29-2011, 09:29 AM   #22
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So I talked to the previous owner, and he says that I have a bad Boost Control Solenoid. I don't mind replacing it if that is the case, but I'm wondering if I should buy another manual one or upgrade to an electronic BCS that requires a tune after installing?? If I have no other mods is the electronic BCS worth it? I do plan on mods in the future.
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Old 04-07-2011, 01:57 PM   #23
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Quote:
Originally Posted by troy591 View Post
Was yours everytime u were in boost? Or there were times it was totally fine?
the overboosting only happened above about 90% throttle. it had to be pretty heavy load. but under 13 or so psi, it ran just fine. i'm still getting a little wiggle at wot in 5th gear, so i try to not use it.
sorry for getting back so late. did you figure out the problem?
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Old 04-07-2011, 01:59 PM   #24
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Nope. Mine does it right when I get under boost at like 1/4 through wot....
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Old 04-07-2011, 01:59 PM   #25
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Quote:
Originally Posted by maw230 View Post
So I talked to the previous owner, and he says that I have a bad Boost Control Solenoid. I don't mind replacing it if that is the case, but I'm wondering if I should buy another manual one or upgrade to an electronic BCS that requires a tune after installing?? If I have no other mods is the electronic BCS worth it? I do plan on mods in the future.
don't know if you've done it yet, but what kind of boost control device did you have on the car that went bad? i would look to replace it with the exact same if you're not looking to tune/retune just for that
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