Mbc PSI

[frankoni]

Ive just installed my mbc (Turbotech)
what would be a safe psi to set it to? I installed the psi boost gauge a few weeks back. When i floored it it spiked to 11psi standard without the mbc then dropped to 10psi, which seems high. What psi are you running???
Cheers
Frank

[Turbo_Steve]

I think you probably need to have a good look around the forum, as this is a question that's only been asked a few thousand times before :) And there is no straightforward answer.

Suffice to say if you go above a certain threshold in the 14-15psi reason, the ECU will cut the fuel, and you'll nearly bang your head on the steeringwheel.

[apeman69]

You should really set these up with some form of knock and AFR monitoring (though how many people actually do this?)
Without these precautions you really don't know how far you can push the car.
I think this is what Steve is getting at with the 'no straightforward answer' comment.
As an example, my car currently safely makes more power at around 13 PSI than any higher setting. I wouldn't get fuel cut if the boost was set higher nor would I get more power but the engine would not like, say, 14 PSI for as long as it will like 13 PSI.

[frankoni]

You should really set these up with some form of knock and AFR monitoring (though how many people actually do this?)
Without these precautions you really don't know how far you can push the car.
I think this is what Steve is getting at with the 'no straightforward answer' comment.
As an example, my car currently safely makes more power at around 13 PSI than any higher setting. I wouldn't get fuel cut if the boost was set higher nor would I get more power but the engine would not like, say, 14 PSI for as long as it will like 13 PSI.

Cheers for the replys.
Can you explain what you mean by 'knock and AFR monitoring'????? What does AFR stand for??

[Ryan]

Cheers for the replys.
Can you explain what you mean by 'knock and AFR monitoring'????? What does AFR stand for??

AFR= Air/Fuel Ratio

http://en.wikipedia.org/wiki/Air-fuel_ratio

Knock: http://en.wikipedia.org/wiki/Engine_knocking

[apeman69]

http://en.wikipedia.org/wiki/Air-fuel_ratio
Don't set the MBC too high or you may do some damage. If you have any running problems then turn it down: stuttering/loss of power/not smooth running. However, it may be too late by then.
On a serious note, if you don't understand what is going to happen when you turn up the boost then you might want to do some research beforehand or have a chat with someone more knowledgable.
As Steve has said, there is a wealth of information on here concerning AFR, knock, MBCs etc so grab a drink and a sarny and start searching.

Regarding your initial query, 10-11 PSI on a standard car is in about the right region if you've got a boost gauge that is reading a touch higher than actual, as I have! Mine is about 1.5 PSI (0.1 BAR) too high compared to the actual manifold pressure. Again, you will not know how accurate your boost gauge is unless you can get a secondary accurate reading from elsewhere. You can, of course, use the gauge's reading at stock boost to determine the amount of change from adjusting the MBC: just don't expect it to be absolutely accurate because it may not be.

[frankoni]

http://en.wikipedia.org/wiki/Air-fuel_ratio
Don't set the MBC too high or you may do some damage. If you have any running problems then turn it down: stuttering/loss of power/not smooth running. However, it may be too late by then.
On a serious note, if you don't understand what is going to happen when you turn up the boost then you might want to do some research beforehand or have a chat with someone more knowledgable.
As Steve has said, there is a wealth of information on here concerning AFR, knock, MBCs etc so grab a drink and a sarny and start searching.

Regarding your initial query, 10-11 PSI on a standard car is in about the right region if you've got a boost gauge that is reading a touch higher than actual, as I have! Mine is about 1.5 PSI (0.1 BAR) too high compared to the actual manifold pressure. Again, you will not know how accurate your boost gauge is unless you can get a secondary accurate reading from elsewhere. You can, of course, use the gauge's reading at stock boost to determine the amount of change from adjusting the MBC: just don't expect it to be absolutely accurate because it may not be.

Cheers for the info, looks a bit involved to me !! I've turned the mbc right down now until i've got a bit more time to do some research.
Frank