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Highest boost pressure on daily driver (18g)

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Old 09 April 2006, 09:16 PM
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p_ilis
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Default Highest boost pressure on daily driver (18g)

Hi,

What would you say would be the recommended highest boost to run for a daily driver? The tune will be pretty conservative (regarding fuel and ign.).

The followings mods are done:
800 cc injectors
Walbro 255 fp.
Fuel rail
Large TMIC
3 inch exhaust (+uppipe and downpipe)
Intake

The car is a 2004 STi.

Thanks!
/Peter
Old 09 April 2006, 11:53 PM
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Brun
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Haven't a clue but are you sure you need 800 cc injectors? I'm guessing you're looking for high 300's power wise?
Old 10 April 2006, 12:31 AM
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WRX_Rich
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might be worth asking your mapper what he thinks of 800's as i ve heard they are a bugger on idle
Old 10 April 2006, 07:05 AM
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p_ilis
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Havn't heard anything about the problems with the 800 injectors but I'll guess that's too late anyway (they are allready in the car)..

I'll be using 99 octane fuel. My tuner thought it would be ok to run about 23-25 psi of boost. Is this too high?

My driving-style is pretty normal I think. Everyday to work and back in pretty slow haste. Maybe one or two track-days and some weekend "spiritued driving".

/Peter
Old 10 April 2006, 06:17 PM
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Brun
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Who is your tuner? Is he experienced with Imprezas?
25 psi is 1.7 bar which seems too much to me Willing to be told otherwise though!
Old 10 April 2006, 08:29 PM
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p_ilis
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The tuner is the biggest Impreza-tuner in Sweden. They are called JRM. I don't know the maximum boost yet but in I'll know and tell in about a week.
Old 11 April 2006, 10:59 PM
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Andy.F
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Originally Posted by p_ilis
The tune will be pretty conservative
Not at 25 psi its not !
You would be better running around 1.5bar midrange - 1.4 top end and optimising the timing and fueling, especially if you are doing trackdays on a TMIC.

Andy
Old 17 April 2006, 04:31 PM
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theotherphil
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Originally Posted by p_ilis
My tuner thought it would be ok to run about 23-25 psi of boost.

/Peter
That's what worries me...I'd like to know that my tuner knew that it'd be ok to run that boost, not guess! I'll stick with Andy thanks
Old 17 April 2006, 07:14 PM
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Bob Rawle
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On that car I wouldn't run quite up to Andy's suggested levels, 1.4 mid range and 1.3 bar max at the redline (if the turbo will hold up to that). Your tuner needs to pay lots of attention to his choice of afr.

800's are fine given he knows how to set up for them, is he fitting aftermarket managment or remapping the OEM ecu ? Is he trying to do this using the std VF35 turbo ? If so at his suggested boost levels it will produce a lot of very hot air and not much else.

edited to add you are using an 18G so turbo comments not so relevent but his values still ott even for that I suggest.

best regards

bob
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