I have had my car boosted for 7 Months and it always held perfect at 9psi(what it was tuned for). In the last few days i have noticed that it will go as high as 11psi and then start to cut out/break up. What could be causing this overboosting? It's a Greddy internally gated 15g. My tuner adjusted the psi threw the wast-gate actuator rod, so i don't have a boost controller.

 

Have you checked your vacum lines for any cracks or breaks?

 

No, i have not. I will do that and see if i can find anything.

 

Vac lines are fine? I just checked them.

 

bump

 

if you have access to a mighty vac hand held, test the diaphram on the internal gate.

 

I have noticed the only time it overboosts is when i am going up hill. So i imagine it has something to do with engine load?

 

You may be getting creep. Also when going up a hill with a higher gear you are putting more load on the engine, but you should not be boosting higher than what you set the wastegate or boost controller set too. I suspect you may be getting some boost creep or there is a pin hole leak on your boost source to wastegate line.

 

temperature get a little colder in our area lately?

 

If I added a manual boost controller would that solve the problem? I am currently just running off wastegate pressure.

 

a boost controller will only let u control boost above whatever the wg is set to, in ur case 9 lbs. So no, that will not help

 

Where can I find a replacement wastegate? Does greddy sell them?

 

Instead of throwing parts at it why don't you figure out what is wrong with it first?

 

Well i replaced the vac line and that did nothing. The only other thing it could be is the wastegate.

 

Same thing I was thinking, lol

 

Cooler denser intake air would make it run leaner but it shouldn't make it over boost.

If you're over boosting it is most likely the wastegate actuator but it could be as simple as the rod needing an adjustment.

If I were you I would take it to whoever tuned it and adjusted the rod to begin with.

What size DP and how full of an exhaust do you have?

Build up of soot or more restriction could be applying more force on the WG Flapper not allowing it to be opened as soon as it should.

Breaking up over 11psi probobly due to no tuned fuel tables for that boost level or ignition cut set at 11psi for safety.

What is the fuel management being used?

Oh also how did you check the vacum lines... did you actually pressure test them or did you just visually inspect? They could be leaking boost under pressure only and have no visual signs of leakage/looseness.

 

I replaced the vac lines and that did nothing. How do i adjust the rod?

 

bring it back to whoever tuned it... you have no way of qualifying if that's the problem. and probobly shouldn't be adjusting it yourself.

 

My tuner adjusted the wg rod and now its fine.

 

Hmm imagine that. You can PayPal me the money you saved by not just buying a new waste gate. Thanks.

 

How much do you want?

 

LOL, naw nothing, but glad to hear you fixed it and didn't just throw parts at it. There is always rhyme and reason for problems.

 

What would cause it to need to be adjusted? I never changed anything on the car and the weather never changed?

 

Metal rod could have strecthed with all the expansion/contraction, the adjuster nuts could have shaken loose the diaphram inside could be weakening with time... lots of things could cause it to need to be adjusted...

Not much on cars is set it and forget it.

 

...and i bet the reason ur car is breaking up when u hit that 11/12 lbs boost mark is because ur using a STOCK MAP sensor, and NO missing link....replace the sensor with an aftermarket one or use a missing link. I'd recommend replacement tho...