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OEM Boost Solenoid/Low Boost Concerns

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gboson
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OEM Boost Solenoid/Low Boost Concerns

Postby gboson » May 20th, 2014, 12:45 am

I'm new to the Subaru as well as boosted arena so please bear with my seemingly naive questions.

Engine: 1998 WRX STI Version V RA 2.0L EJ207 (Completely stock internals)
ECU: 6S
Turbo: Stock VF28
Exhaust: 3'' Turboback 5zigen exhaust.

I currently have an aftermarket MBC (Halman) installed running approximately 10 psi of boost (its a daily driven car).

1. Are there any issues running such low boost? Research suggests that these engines ran 17-18psi stock.
2. Wastegate pressure (if I remember correctly) is circa 7-9psi. I don't quite understand how I can reconnect the OEM Boost Solenoid, I'll appreciate if anyone can supply me with some images of an engine bay and the appropriate connections etc. Effectively then, will adjusting the MBC to run the desired 18psi be equivalent to reconnecting the OEM Boost Solenoid? IMO reconnecting the OEM solenoid seems safer as proper adjustments can be accurately made by the ECU.

I recently installed an AEM Wideband and A/F ratio at idle was averaged to be 14.7±0.2 and 10.0 at WOT. The WOT A/F ratio seems to be quite rich which prompted my question regarding running LOWER than stock boost pressures and its effect on the ability of the ECU to compensate effectively.

Prompt replies and any knowledgeable insight will be hugely appreciated.

Thanks in advance!

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belalegosi
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Re: OEM Boost Solenoid/Low Boost Concerns

Postby belalegosi » May 20th, 2014, 4:10 pm

gboson wrote:I recently installed an AEM Wideband and A/F ratio at idle was averaged to be 14.7±0.2 and 10.0 at WOT. The WOT A/F ratio seems to be quite rich which prompted my question regarding running LOWER than stock boost pressures and its effect on the ability of the ECU to compensate effectively.

Prompt replies and any knowledgeable insight will be hugely appreciated.

Thanks in advance!



That's quite rich under wot.
It can be a number of things: Dirty MAF, bad tune, boost leaks.
Do you have anyway to datalog the ecu?

Running low boost would not be a problem. If you have a boost leak that is causing you to only run at 10psi then you have a problem. What's happening is that the MAF is measuring the air. If their is a leak somewhere (after the MAF) then the problem arises that the ECU is commanding fuel for MORE air than what is actually in the combustion cycle. Hence rich.

Do simple things first like a boost leak test and clean the maf.
Any mechanic or DIYer with a air compressor can do it easy.

subie_2NR
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Re: OEM Boost Solenoid/Low Boost Concerns

Postby subie_2NR » May 20th, 2014, 4:16 pm

All stock Subaru are that rich, I have the same 10 AFR on WOT as well, that's why lots of owners retune because mileage sucks

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belalegosi
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Re: OEM Boost Solenoid/Low Boost Concerns

Postby belalegosi » May 21st, 2014, 9:38 am

not true.

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gboson
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Re: OEM Boost Solenoid/Low Boost Concerns

Postby gboson » May 21st, 2014, 10:19 am

Yeah I was considering that boost leak as a possiblity. This is the older GC8 so I'll clean the MAP sensor as well. Some also suggested that the car needs a tune.

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belalegosi
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Re: OEM Boost Solenoid/Low Boost Concerns

Postby belalegosi » May 22nd, 2014, 2:01 pm

I don't think turbo subarus came with a MAP sensor. They're all MAFs.

A tune is never a bad idea. Especially with the quality of gas tnt offers.

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