| STi overboosting problem - Click HERE for Original Thread |
| DowntownFocus |
| Any STi or WRX owners have a problem with overboosting once changing to a Turbo back exhaust system and a boost controler? Have heard this is a very common problem. We are sure we have fixed this but just wondering what others may have done to fix it. |
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| dmak_el |
is it a mbc? does it only happen in part throttle? if so, that's probly coz of the mbc. or did u just trun the boost too high??
or it can be boost creep. |
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| DowntownFocus |
| Never heard of mbc before so can't anwser that. Its no creep its a massive spike in gear 4 and 5 only. Long run hits. Will spike at 22 than fuel cut and then okay agian. Untill next spike. Has nothing to do with boost settings. |
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| SplineZ |
mbc = manual boost controller
James Z |
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| dmak_el |
| it can be just because it's too cold outside, and ur boost controller. u probly will not overboost as much in the summer. |
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| DowntownFocus |
quote:
Originally posted by dmak_el
it can be just because it's too cold outside, and ur boost controller. u probly will not overboost as much in the summer.
It is a manual boost controlor. But it spikes. This only happend in the summer. Car is in storage untill weather is good. |
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| dmak_el |
| oh....then u better ask some people on i-club or something. |
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| v8slayer |
It's called boost creep!
Most DSM's encounter it when they make the intake and exhaust systems more effiecent.
Quite simply if you can make power through turbine RPM's faster than you can bleed off exhaust through your waste gate flapper you get boost creep.
-Your solution is to do a big clip on the turbine wheel to increase flow and reduce turbine back pressure to lower your turbine response. This will give more top end power but will create a little lag.
-Get your flapper valve machined out to allow more exhaust bleeding pre turbine.
-Vent your waste gate to atmosphere to help with waste gate flow.
-Put a larger turbine side on with a larger A/R.
-Put a after market turbo on that is larger and doesn't have a creep problem do to proper sizing.
Any of the above will help if done properly.:) |
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| WookeysRX7 |
| Awww yes boost creep. Rx7's experience it if you do the intake and exhaust. The fix, well its kinda a cheap ass fix but its a fix is a Fuel Cut Defender. Another fix would be porting the wastegate bigger or purchasing a larger wastegate. |
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