safety pressure switch

[Mike_R5GTT]

hi my manual boost controller wont adjust my boost no higher than abot 0.8 bar and thats my acuator pressure do i have to disconnect the safety pressure switch

[RICHIE]

if its a manual boost controller were does the safety pressure switch come into play.

come to think of it are you sure a boost controller is a good idea;)

[Mike_R5GTT]

well wen i wind the controler out it still boosts the same just fort that might stop it boosting up higher than that i wanna go to 17psi but wont adjust any more than a bar

[RICHIE]

well wen i wind the controler out it still boosts the same just fort that might stop it boosting up higher than that i wanna go to 17psi but wont adjust any more than a bar

why dont you just set it via the actuator to run the 17psi then pressuming the actuator is capable of holding 17 psi. what id vacume tubing you using

[Mike_R5GTT]

its 5mm

[RICHIE]

its 5mm

can you run 17 psi without the bleed valve

[Tiny Tim]

Lose the controller, set the boost level via the actuator and fuel the carb accordingly.

[Mike_R5GTT]

so ill adjust the acuator then and get rid of the controller, when i brought the turbo they said it can run 20 psi so i recon i can get 17 on the acuator

[Tiny Tim]

That's probably what the turbo can handle, not what it should run day in-day out.

Is your carb standard?

[Mike_R5GTT]

groupe a carb and what happened was i had it rolling roaded monday and the fueling was wrong so we sorted that and drilled the main jet but we couldnt get it to boost any more that 0.8 bar and he reconded it seams like it was blocked did wanna rev up that quick,seam real slow

[Tiny Tim]

You took the main jet out to drill it and cleaned it after?

[Mart]

Probably increasing the main jet didn't help matters (read probably miserably over-fuelling throughout the rev range now).

Perhaps you've got a boost leak, hence the engine not wanting to rev/rev slowly, and which would also explain why you're struggling to obtain any more boost.

As a side note, you might find the turbo a touch more responsive if you use smaller diameter actuator pipe.

[Mike_R5GTT]

ok well the carb was running reali weak on boost but the vac pipe on the enrichment valve was off so thats ok now just the boost side the bloke who r and r it said it seams like the disc on the wastgate has possible got a chip out of it causing it to not hold higher boost

[RICHIE]

someone pop round and have a look before he has to order a r11102 :mart:

[Mike_R5GTT]

lol:crap:

[Mart]

ok well the carb was running reali weak on boost but the vac pipe on the enrichment valve was off so thats ok now just the boost side the bloke who r and r it said it seams like the disc on the wastgate has possible got a chip out of it causing it to not hold higher boost

Ok, but increasing the main jet size is a bodge way (no offence meant) of increasing on-boost fuelling. It's not the way to go.

It's possible the wastegate could be damaged, but apart from cracks around the wastegate port, which could cause spool-up prob's, I'd say it's pretty rare (and bloody unlucky) to see a damaged/chipped wastegate flap.

You could whip the turbo elbow off to prove if that is the case, but I'm guessing you'll find the wastegate flap is intact...

If possible, plumb in a boost gauge on the turbo outlet, and compare that to manifold boost pressure. There shouldn't be no more than 5psi (give or take a couple of psi) difference between the 2 gauges. If there is, suspect a leak in the boost circuit (hoses, intercooler, dump valve (if one fitted), perc-fan connection, carb elbow o-ring, carb elbow itself, inlet manifold nrv's, etc).

If there aren't any leaks, it could just be that the actuator has seen better days & is struggling to hold the wastegate shut when on boost.