boost drop....help
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boost drop....help
I went to the drag strip a while ago and was getting some pretty slow times best so far is 14.40 @ 94 mph. on my last pass of the day i watched my boost and noticed that at around 5k rpm my boost droped to about .5-.6 on the stock gage. Mods to my car are greddy evo catback removed air silencer with hole enlarged in airbox (about 5 times bigger hole for air) , spec stage 2 clutch 9.5 lb flywheel and a ecutek ecu reflash set up for catback exhaust and cold air intake. Just curious if anyone could help me in finding a fix for the boost drop. got ecutek reflash as first mod and put 195 hp to the wheels 205 torque.
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is that .5 - .6 bar?
I cant remember what the stock boost gauge reads out at.
Either way ... yes its normal. boost tapers off
Even if you ran catless with the wastegate shut all the time ... boost will taper off. The turbo is too small and runs out of breath
I cant remember what the stock boost gauge reads out at.
Either way ... yes its normal. boost tapers off
Even if you ran catless with the wastegate shut all the time ... boost will taper off. The turbo is too small and runs out of breath
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Originally posted by theworx
I've heard from other people here and at some shops that installing an uppipe seems to help keep consistent boost through redline.
I've heard from other people here and at some shops that installing an uppipe seems to help keep consistent boost through redline.
at stock trubo
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"Something" is called a boost controller. My EBC keeps boost up, although the ECU tries to fight it. The real cure is a piggy back or replacement ECU.
If the wastegate was always shut, or just not there, boost would never decrease... well at least not until severe detonation shut it down. (Or in our case, its more likely the ECU would dump boost out the BOV first)
jason
If the wastegate was always shut, or just not there, boost would never decrease... well at least not until severe detonation shut it down. (Or in our case, its more likely the ECU would dump boost out the BOV first)
jason
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From: Cincinnati, OH
Car Info: 04 Java Black Sedan
Not to argue but I don't think there is anyway for the ECU to dump boost out the BOV. There is no part of the BOV that is ECU contolled, purely mechanical. I think I am just going to have the ECU reflashed. I have heard good things about it, good power gains, no issues in drivability, better boost response, it really sounds like the way to go. Right now I have a MBC which I tuned to hit a high of about 16(just a hair under), but it still falls to about 13.5 or 14 by 5500rpm or so.
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Originally posted by mmboost
[BIf the wastegate was always shut, or just not there, boost would never decrease... well at least not until severe detonation shut it down. (Or in our case, its more likely the ECU would dump boost out the BOV first)
jason [/B]
[BIf the wastegate was always shut, or just not there, boost would never decrease... well at least not until severe detonation shut it down. (Or in our case, its more likely the ECU would dump boost out the BOV first)
jason [/B]
Not true at all ...
- If you took out your stock turbo ... wielded it shut ... I 100% guarantee you that boost WILL drop. The amount of exhaust the EJ20 spits out as RPM's increase get the TD04-13 out of its efficiency range ... and it does it VERY quickly.
I have about 100 logs that can show you this. No matter what ... the boost WILL fall. I have a lot of experience with the stock turbo. You can exit those efficiency ranges VERY easily. :banana:
- The ECU does not control the BOV
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From: Cincinnati, OH
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Update on boost fall off. I installed a new boost gauge last night. I had originally bought a JC Whitney boost gauge just to get a cheap gauge quick (funny story, I ordered one gauge for $17, they sent me two gauges and a single gauge cup all for the $17). I replaced it last night with an Autometer sport comp gauge, leaving all the vacuum tubing from the other gauge in place and now my boost does not drop off nearly as bad as before. I was losing 3psi by redline, no I don't even lose 1psi. I thought that the gauge could be inaccurate or even leaking, but I never heard the sound of rushing air from the gauge. Just a mystery I guess.
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From: Longing for my ol' white '02 WRX :(
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Originally posted by theworx
Not to argue but I don't think there is anyway for the ECU to dump boost out the BOV. There is no part of the BOV that is ECU contolled, purely mechanical. I think I am just going to have the ECU reflashed. I have heard good things about it, good power gains, no issues in drivability, better boost response, it really sounds like the way to go. Right now I have a MBC which I tuned to hit a high of about 16(just a hair under), but it still falls to about 13.5 or 14 by 5500rpm or so.
Not to argue but I don't think there is anyway for the ECU to dump boost out the BOV. There is no part of the BOV that is ECU contolled, purely mechanical. I think I am just going to have the ECU reflashed. I have heard good things about it, good power gains, no issues in drivability, better boost response, it really sounds like the way to go. Right now I have a MBC which I tuned to hit a high of about 16(just a hair under), but it still falls to about 13.5 or 14 by 5500rpm or so.
At anyrate, I wasn't trying to say that boost will dump out the BOV whenever... it was just an example of how boost can leave the system.
As for your boost still falling, you have an MBC. An EBC that got 1/2 a brain will try to compensate. This is why my boost can maintain.
jason
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Originally posted by theworx
Update on boost fall off. I installed a new boost gauge last night. I had originally bought a JC Whitney boost gauge just to get a cheap gauge quick (funny story, I ordered one gauge for $17, they sent me two gauges and a single gauge cup all for the $17). I replaced it last night with an Autometer sport comp gauge, leaving all the vacuum tubing from the other gauge in place and now my boost does not drop off nearly as bad as before. I was losing 3psi by redline, no I don't even lose 1psi. I thought that the gauge could be inaccurate or even leaking, but I never heard the sound of rushing air from the gauge. Just a mystery I guess.
Update on boost fall off. I installed a new boost gauge last night. I had originally bought a JC Whitney boost gauge just to get a cheap gauge quick (funny story, I ordered one gauge for $17, they sent me two gauges and a single gauge cup all for the $17). I replaced it last night with an Autometer sport comp gauge, leaving all the vacuum tubing from the other gauge in place and now my boost does not drop off nearly as bad as before. I was losing 3psi by redline, no I don't even lose 1psi. I thought that the gauge could be inaccurate or even leaking, but I never heard the sound of rushing air from the gauge. Just a mystery I guess.
Gauges, especially ones that change readings rapidly are good for a roundabout idea... like +/- 10% kind of idea.
jason
jason
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regardless of rather or not the turbo is effecient, if theres no out(ie wastegate) boost will continue to build until it runs out of push from the exhaust. Boost tapering/falling is by design. The stock boost solenoid and ecu will allow the turbo to taper up top. As to where if you are running a boost controller with it's own solenoid, it will hold boost better to redline.
BOV reliefs pressure as it has nothing to do with boost tapering or falling, unless you have a leak of course.
Tommy
www.mpjperformance.com
BOV reliefs pressure as it has nothing to do with boost tapering or falling, unless you have a leak of course.
Tommy
www.mpjperformance.com