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Weird boost, 12 psi in 1st?? JDM STi 2003

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Old 24 August 2008 | 04:18 PM
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Default Weird boost, 12 psi in 1st?? JDM STi 2003

Hi guys,
What boost should this car be running standard? (JDM Twinscroll STi 2003 EJ207)
Car seems to be boosting a little strange. Just got a boost gague linked up to it and the results seem a little strange to me...

From a launch and through the gears:
1st 12 psi
2nd 15 psi
3rd 15 psi
4th 15 psi

But if i just put my foot down in one gear without changing

1st 12 psi
2nd 18 psi
3rd 4th 5th and 6th 20 psi....

Can really feel the difference when its only boosting to 15psi...

Any one know any reasons for this? Car is completly stock.

Thinking of getting a powerstation stage 3 or just get the exhaust and filter (Fit them myself) and get Bob to Ecutek it, would this fix the boost problems??

Ive got a greedy profec b spec 2 from my Honda which im thinking about putting it in so where ever i put my foot down should hit 20psi?? I think

Cheers guys!
Steve
Old 24 August 2008 | 04:32 PM
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It's probably down to loading and the way the boost is being controlled.
Old 24 August 2008 | 04:35 PM
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Sounds normal to me. The reason the boost won't be as high when gunning it from a standstill will be due to being further up the rev range after each change. If you floor it from 30mph in 4th or 5th, you'll see the higher boost figures. A remap and a few choice mods won't do any harm!
Old 24 August 2008 | 04:46 PM
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You dont get full boost in first gear, hence why its lower.

Tony
Old 24 August 2008 | 06:36 PM
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ahh i got you!! yeah of corse, the boost drops off towards redline anyway.. ahh

How about using the greedy untill i can afford the tuning? or just wait for it? ecutek, exhaust and filter!
Old 24 August 2008 | 07:11 PM
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Well ecutek is your best way forward but your still never going to get full boost in first gear unless you want to keep repairing your gearbox that is (thus the reason it doesnt boost fully in first gear )
The only other suggestion is dont play around with the boost too much on these, the ecu is very good but you dont want to get det on one of these engines, its very expensive to replace them

Tony
Old 24 August 2008 | 07:42 PM
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Ok mate, thanks for the advice.. ill wait for the Ecutek then really cant afford a rebuild!

What do you guys think of the powerstation stage 3 (No cats) package? im tempted for that over Bob Rawle as it is just drive in and drive out.. from what i understand Bob is arguably one of the best tuners but then ill need to get the exhaust changed before i drive down to him.. descissions, descissions lol..

From emailing Bob he said i should be looking at about 360-370 with about 350 torque and powerstation claim about 350hp with simular torque on their website... (With Tesco 99 or Vpower)

Looking to get it done most prob the begining of October.

Cheers
Steve
Old 24 August 2008 | 07:55 PM
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Yes 360bhp is about what you get from these cars, 380lbs of torque is not unheard of also
You can go either for the full decat or a sports cat (Milltek do the full exhaust, not the cheapest but you will know your car will pass its next MOT and you dont lose any power over a decat ) its just a little more expensive, oh and it has to be for the JDM car and not the UK one, there is a bit of a difference in downpipes due to the engine (sumps are different due to the engine being twin scroll).

Tony
Old 24 August 2008 | 08:13 PM
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Originally Posted by TonyBurns
Well ecutek is your best way forward but your still never going to get full boost in first gear unless you want to keep repairing your gearbox that is (thus the reason it doesnt boost fully in first gear )
What has a 6sp gearbox got to do with not achieving full boost in 1st as regards to having to repair it if full boost could be achieved?
Old 24 August 2008 | 08:30 PM
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Because if you have full boost in first gear it puts too much strain on the gearbox, hence why it has lower boost

Tony
Old 24 August 2008 | 09:12 PM
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Who told you that rubbish?!?

You can not normally achieve full boost in 1st, as you do not have the load on the engine like you do in other gears.
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