TURBO HELP. I CANT HIT BOOST!
Turbo Mini Forums

Recently rebuild metro turbo 20 thou over. Std cam and 8.5:1 compression, Only mods made are a small intercooler from a mazda rx7 and t2 turbo was fully rebuilt and hi-flowed

On the dyno mixture leans out and turbo is only making 2.5psi at the inlet manifold

Most power it has made is 53 bhp at the wheels
Have measured fuel pressure through the whole system and is working fine and malpassi valve is also working.

Have put plenty of pre tension on actuator but does not increase boost levels As yet,

I have not modified needles using BDD and BDG
Have slightly modified plenum chamber to take intercooler piping
but keep restrictor ring intact.

Have found a 2 psi boost reduction across intercooler but thought this may be fairly normal.

really want to make some serious power some time soon!

any idea's help thanks :)

Get the mixture sorted then go from there. Avonbar sell some higher boost needles as a starting point. Is fuel pressure rising with boost?

ok tah, yes fuel pressure is rising with boost. :)

Is the fuel bowl getting pressure? Have you fitted the correct plenum-carb gasket?

yes. I have even plumbed pressure from the plenum into the fuel bowl.

Sounds to me like the wastegate is open all the time. Are you sure the pre-load is set up correctly?

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yep 100% set up even had it all checked over.

is it actually running pulling properly upto high revs imo if it was fuel or even spark it would hit a wall as the boost started to build, i would edge my bets it not boosting soo look at wasegate, turbo, blocked down pipe, seriousl restricted inlet?... even the rubber poppet in the plenum?
dont know what else to say

Yes i moved to the darkside

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it seems the seals in the carb has air coming out the dash pot.

so going to replace that could that be a the problem>?

is this meant to happen?

It would have to be leaking massively to wipe out all the boost.

I think you need to answer the question about how is it running. Does it rev properly through the gears? do you have a print out from the rolling road?

http://www.twin-turbo.co.uk
http://www.hillclimbandsprint.co.uk/default.asp

A man without a project is like a like a woman without a shopping list.

thanks for the reply's guys.

it runs through the gears fine. no problems what so ever.

when it hits boost it just leans out massive & only can get 2.5boost.

it leans out dangerously!

we are going to replace all seals & RRoad it again tomorrow.

Is this the classic wrong gasket between plenum and carb?

Sounds like the float bowl isn't pressurising to me.

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