How Do I Lower My Boost?

[Liger Zero]

Well, pretty much everything is stock on my car except the front mount intercooler setup, the walbro 190, and the Thermal R&D Exhaust from what I know of. I just bought a REAL boost gauge and hooked it up to see just how much psi im pushing before I keep hitting fuel cut. I found out that I hit 15 psi before it cuts and I cant figure out why its boosting that high... I have all the vacuum lines hooked up according to the factory diagram I found on here. Now I think my ISC is acting up so I oredered a new "black" one and plan on replacing that, the only other problem I have is that the adjustment bolt on my Greddy BOV is completely removed because it was stripped and I put in a small rubber stopper to prevent the vacuum leak. Any ideas as to why im overboosting? Or is there a way I can turn it down? I do not have a mbc or anything like that either... Thanks!

 

[gats0101]

Well if you want to turn the boost down on a stock setup, you can always run the pressure source straight to the wastegate.

 

[jrohner]

Unplug the boost solenoid and it will stay shut, which 'should' lower boost.

Is the boost that high as soon as it hits, or is it creeping up with higher rpms?

You need to get rid of fuel cut with EPROM tuning so you can boost higher. Get it up to 20 psi and you'll wonder how you could stand 15 psi. Just getting rid of fuel cut and leaning out the rich factory maps should allow you to be fine at 15-16+ psi on the stock injectors.

 

[erald01]

Boost creep problem always relates to either the wastegate or the bc. To rule out your bc conect the vacum line straight from wg to the j-pipe, then go from there.

 

[TurboATM]

you can always get a mbc and go with that...

 

[NOSLO2PT0]

Boost creep problem always relates to either the wastegate or the bc.

Boost creep doesn't have anything to do with the boost controller at all. It's an inadequate wastegate size for an exhaust system that is flowing a bit too well, plain and simple.

 

[JusMX141]

You shouldn't be hitting fuel cut with a 14B at 15psi and a FMIC. I think you have a boost leak somewhere.

Regardless, running a vacuum line straight from the j-pipe's boost source to the wastegate actuator will run wastegate pressure only, which is around 8-10psi. If you're still creeping, you either have a hole in your actuator diaphragm or your exhaust is too big and flows too freely to run low boost on such a small turbo.

Yes, there is such thing as "too big" in terms of exhaust size.

 

[knochgoon24]

Yes, there is such thing as "too big" in terms of exhaust size.

My 3" exhaust makes me have 15psi on wastegate pressure.

 

[TurboATM]

on my 14b and sidemount, iwas hitting fuel cut and spiking to like 20-22...

...and having it connected to the wastegate was still spiking to about 17 and hitting

 

[Liger Zero]

Thanks guys for all of the ideas! Im not sure what it could be but I did happen to notice that my wastegate has been crushed, so I dont know how that will affect anything? Is there something that could mess things up with how my throttle position sensor is set? My friend pointed that out to me that its adjusted all the way to one side and he claims that it should be somewhere closer to the middle...

 

[Liger Zero]

Nothing?