quick boost pattern question... tried searching
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Joined: Feb 2006
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From: Canada
quick boost pattern question... tried searching
Hey guys... here is a low down of my car and my question.
First... engine was totally rebuilt... street port.. new apex seals.. the works... down pipe, silicon hoses, solnoids etc etc....great job.. www.mpsys.ca
Heres my question... I installed a boost gauge... now when driving the car... my boost is as follows
10-8-9ish???? sometimes i hit above 10... sometimes it goes like 11-8-8.5-9?
could this be a bad gauge? slightly inaccurate readings??? also is the below statment true? Is it true that from 6000rpm onwards both turbos boost at 8psi?
Road test with boost gauge
Drive to third gear with normal acceleration
Accelerate from 35 MPH at WOT until passing 4,500 RPM
A slight and smooth increase in power should be felt at approximately 4,500 RPM. This will be about 65 MPH.
RPM PSI
3,000 10
4,500 8 as secondary turbo comes on
4,500 + 10 recovers almost immediately
6,000 + 8 and holds to redline
First... engine was totally rebuilt... street port.. new apex seals.. the works... down pipe, silicon hoses, solnoids etc etc....great job.. www.mpsys.ca
Heres my question... I installed a boost gauge... now when driving the car... my boost is as follows
10-8-9ish???? sometimes i hit above 10... sometimes it goes like 11-8-8.5-9?
could this be a bad gauge? slightly inaccurate readings??? also is the below statment true? Is it true that from 6000rpm onwards both turbos boost at 8psi?
Road test with boost gauge
Drive to third gear with normal acceleration
Accelerate from 35 MPH at WOT until passing 4,500 RPM
A slight and smooth increase in power should be felt at approximately 4,500 RPM. This will be about 65 MPH.
RPM PSI
3,000 10
4,500 8 as secondary turbo comes on
4,500 + 10 recovers almost immediately
6,000 + 8 and holds to redline
At high rpms the stock setup will sometimes see the boost lower a little (from 10 to 9 or 8) psi because of exhaust restriction. This is usually blamed on a cat that's beginning to fail, either the precat or main cat. If the car flows well it will hold 10psi all the way to 8k.
Your pattern sounds pretty normal - many folks don't get an exact 10-8-10. Are you using stock boost control solenoids and pills? Do you have a PFC that you can use to tweak those a little bit?
Dave
Your pattern sounds pretty normal - many folks don't get an exact 10-8-10. Are you using stock boost control solenoids and pills? Do you have a PFC that you can use to tweak those a little bit?
Dave
Originally Posted by dgeesaman
At high rpms the stock setup will sometimes see the boost lower a little (from 10 to 9 or 8) psi because of exhaust restriction. This is usually blamed on a cat that's beginning to fail, either the precat or main cat. If the car flows well it will hold 10psi all the way to 8k.
Your pattern sounds pretty normal - many folks don't get an exact 10-8-10. Are you using stock boost control solenoids and pills? Do you have a PFC that you can use to tweak those a little bit?
Dave
Your pattern sounds pretty normal - many folks don't get an exact 10-8-10. Are you using stock boost control solenoids and pills? Do you have a PFC that you can use to tweak those a little bit?
Dave
From personal experience I'd have to agree with Dave... Once I eliminated the main cat I saw a steady hold at 14 psi, my boost doesn't fall past 6000 rpm anymore... When I had the cat I had the same 10-8-10 with a decrease in boost at high rpm
Thread Starter
Full Member
Joined: Feb 2006
Posts: 88
Likes: 0
From: Canada
my mechanic just told me that i have a small exhaust leak... will this cause me not to get full boost??? its gotten a little worse... sometimes i'll go from 10-8 and then it stays at 8??
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