profec b on, still boosting too much

[nazthug]

ok, put it on nicely and all is well, doesnt spike to 18psi anymore, but still cant get it down below what i want

I ran a vacuum line from the COMPRESSOR nipple to the IN on the greddy solenoid, and from OUT on the greddy solenoid, straight to the wastegate, each vacuum line is about 12" long, not much length, nice and straight, and its hard, its actually rubber fuel line, its much harder then vacuum line.

turned it to lowest, and slowest balance, and still goes to 15psi, and falls off to 12


Now thats nice, that what i want but i want my low boost setting to be lower for first gear to control wheel spin

I figured getting rid of the stock BCS and getting boost refrence from the compressor instead of after the intercooler would give me the LOWEST possible boost

How do i bring my low boost down below 10psi??

Should i put the bcs back on and incorporate it? Isnt having the signal go from the compresor to the greddy box and to the wastegate the way to get the lowest possible boost????

Because it should start working when the compresor is putting out X amount of boost, even though that boost is gonna be 3-4psi lower at the intake manifold after it looses boost through the intercooler

Any help???? i want to get 1st gear to hook up under Wot and then hit the high boost in the rest of the gears

 

[FearceDSM]

If you read the paperwork that comes with the Profec b, I am pretty sure that it notes that you can only set the low boost level at stock. If not that, then it recommends that you do not set boost below stock levels. I have the same setup and my BCS has been eliminated. I believe the wastegate actuator is made to open up at stock boost levels.
Also, it does not matter how much you retard the balance on the wastegate, the problem is that the turbo is unable to sustain boost in the upper rpm ranges. If anything, I try to set the balance so that it will react faster to help with boost creep.

 

[nazthug]

i understand

so the wastegate stock is set to around 10psi

does ading a downnpipe, intake, exhuast, uip actually make it boost that much more, regardless of what you do?

And hooking it up to the comppressor wheel for boost refrence, should give it the least possible boost because youre going before the IC, and the boost gauge is after the interccooler boost drop. Most people are taping their boost controllers into the bov and stuff, so they must be seeing way over 15psi for their lowest boost....cause the IC has like a 4psi drop.

IF the wastegate is set to 11psi, and you are refrencing it from the compressor, that 11psi should be like 7psi at hte manifold because of the boost pressure drop from the ic no?

Im putting on a t28 and there has to be a way to go lower than 15psi, thats rediculous

what is the wastegate set at with the FP big t28?

I want lower boost for first gear to get traction, and then hit high boost(profec b)

plus i also want to keep it a bit lower until i finish out the fuel upgrade

 

[nazthug]

Originally posted by FearceDSM
If you read the paperwork that comes with the Profec b, I am pretty sure that it notes that you can only set the low boost level at stock. If not that, then it recommends that you do not set boost below stock levels. I have the same setup and my BCS has been eliminated. I believe the wastegate actuator is made to open up at stock boost levels.
Also, it does not matter how much you retard the balance on the wastegate, the problem is that the turbo is unable to sustain boost in the upper rpm ranges. If anything, I try to set the balance so that it will react faster to help with boost creep.

thats the thing, the stock is NOT 15psi

is there any adjustments on the wastegate arm?

I still dont understand how stuff like downpipes, exhuasts, intakes change boost, if your boost controller is tapped into the compressor, it only sees the boost the compressor is making, so it should cut it at stock, no matter what you run


unless it just cant dump enough through the o2 housing to keep boost down

will my new evo o2 housing help this? The ports are way larger in it then the stock o2 housing...

i hope so, with my t28 coming, i really would like to bring boost down to around 11-12psi

 

[FearceDSM]

I am pretty sure that 2g stock boost can be as high as 14 pounds. It varies for the simple fact that not all cars are the same. Some lower than others but they fall within an acceptable range that the factory deems within their standards. The wastegate actuator will only let you go as low as stock. What the boost controller does is alter the pressure signal that the wastegate actuator recieves so that it thinks that it has not reached its set limit and thus keeps the wastegate shut for more boost. The low boost that you are trying to achieve is below the stock levels. In order to lower the boost below stock levels you will have to get a wastegate actuator that is set lower than the stock unit. If you shut the boost controller off it is almost the same, if not the same, as running the stock bcs. That is the lowest you can go.