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Discussion Starter #1
- can anyone provide me more technical details on the boost functionality on the WRX STI? ive tried searching online, but cant seem to get a comprehensive answer...

- what is the maximum boost/peak boost value?

- does it have a boost cutout when it overshoots? how does the cutout work, ie., fuel cut, etc.?

- what is the worst thing that can happen in an overboost? dooes it really wreck the engine in a single overboost? how really bad is an overboost?

- some acquantainces i know tell me that i need a boost gauge to tell me when the car overboost. however, if the car has a "boost cutout" functionality, why do you still need this (as if the gauge can do anything)?

- how do you prevent overboost? some of my friends tell me that when i need to floor the gas, i should do it in the lower gears (2,3) rather than in the higher ones. this way, i would less likely encounter an overboost. is this correct?

i apologize for the newbie questions... many things to learn!!!

thanks, and much regards...
 

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Re: Newbie Inquiry -- Boost Control/Boost Cutout/Overboost/Etc on a 3G WRX STI

ok i can only say this about my australian spec wrx in singapore.

Note. I drive a WRX not a STI

[hr]

Max boost stock is 0.6

CEL when over boost is 1.1Bar

Overboost to a point of engine damage on a stock Turbo (TD04) is next to impossible. The Stock turbo is unable to go past 1.5Bar and even then its only for a 100-200 RPM range before it drops right back to about 1.0-1.1

The gauge can help you read your boost after u remove the boost cut function from the ECU

A boost controller will help control the boost, and hence reduce boost spike and overboost.

[hr]

Its safe to say on a stock ECU, Stock turbo and stock exhaust, you'll never go past the CEL line of 1.1, or even 0.7 bar.

However, do note removing the cat or changing the exhaust may cause more boost spike (past 0.6). Though its still not a problem.
 

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Discussion Starter #3
Re: Newbie Inquiry -- Boost Control/Boost Cutout/Overboost/Etc on a 3G WRX STI

ok i can only say this about my australian spec wrx in singapore.

Note. I drive a WRX not a STI

[hr]

Max boost stock is 0.6

CEL when over boost is 1.1Bar

Overboost to a point of engine damage on a stock Turbo (TD04) is next to impossible. The Stock turbo is unable to go past 1.5Bar and even then its only for a 100-200 RPM range before it drops right back to about 1.0-1.1

The gauge can help you read your boost after u remove the boost cut function from the ECU

A boost controller will help control the boost, and hence reduce boost spike and overboost.

[hr]

Its safe to say on a stock ECU, Stock turbo and stock exhaust, you'll never go past the CEL line of 1.1, or even 0.7 bar.

However, do note removing the cat or changing the exhaust may cause more boost spike (past 0.6). Though its still not a problem.
thanks pehon... hey, btw, any chance of the global mods coming down to JPN?
 

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On an STi normal boost is approx 1 bar approx 15psi
The cel pops when spikes above 1.5 bar approx 18psi
When overboosting, the ECu forces the car to go into Limp mode with the mechanical boost limit wastegate spring which is about 9psi.
The twin-screw of the JDM STi can boost enough to cause damage but unlikely if your car is stock.
Minor boost spikes are normal and if your car is stock should not affect the engine. (usually goes above target about .7 psi here in the lower gears)
If you are in Japan and the car is stock with that octane the STi can handle close to 22psi under tuned conditions before knocking so you should be okay since ur octane rating is so high.
Stock car, like you said probably does not require a boost gauge. It is more important when modifications are done that alter the boost settings.
Or if you just want to see what boost you are getting (I think its fun to look at).
Preventing overboost? Keep the car stock and it shouldn't. I personally get less boost in the higher gears but yes, generally it is "safer" in the lower gears as the stress on the engine is less due to more easily rotating masses.
 

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Re: Newbie Inquiry -- Boost Control/Boost Cutout/Overboost/Etc on a 3G WRX STI

ok i can only say this about my australian spec wrx in singapore.

Note. I drive a WRX not a STI

[hr]

Max boost stock is 0.6



not sure bout this! logged my wrx stock and got 0.89 .
 

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Re: Newbie Inquiry -- Boost Control/Boost Cutout/Overboost/Etc on a 3G WRX STI

not sure bout this! logged my wrx stock and got 0.89 .
You're right stock boost for WRX is about that
 
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