car won't boost past 18 psi (not 16 psi like the other guy)

I am targeting 21 psi of boost on my 91 GVR4 before I start tuning. Today I installed FIC 650 injectors and tried to crack the boost up by turning the boost controller a few turns. The previous owner had the boost set at 16 psi and it sure pulled hard then.

To my dismay, I cannot get boost to reach higher than 20 psi at any point and it falls to 18.

This is even when I open the boost controller up all the way.

Any idea what could be going on?

Here are the performance mods if this helps:

Ported Big 16G Turbo, ETS FMIC & Piping, Counterfeit XBC MBC, Custom 2.5" tubular SS O2 housing with 40mm TiAL gate, Buschur 2.5" mandrel bent SS exhaust turbo back, CATCO cat, Socketed EPROM ECU with Ostrich and ROM emulator, Stutterbox and Check Engine shift light, Warlboro 190 lph pump, Fuel Pump Rewire, FIC 650 injectors, Innovate LC-1 Wideband O2 with guage

 

[fuel]

how about if you pull the line off the wastegate actuator entirely and blank it off? That will tell you if it's the turbo running out of boost or your boost controller at fault. I don't think people generally tend to get much more than 20psi out of a TD05H anyhow?

I'm guessing the diameter of your IC piping is about 2.5"? How about your throttlebody, is it stock or has it been enlarged?

 

[Dan D]

I don't see anything about a BOV. My stocker leaked at 18 psi

 

[fuel]

Ah yes I missed that bit - I assume with the ETS piping came an aftermarket BOV of some kind, but even aftermarket BOVs leak too.

 

[SouthCaliVR4]

Partial clog at the cat? try dropping it & see if that helps. If your blow off valve is uncrushed, try that next.

 

Thanks for all the help. I went driving and plugged off both sides of the boost controller and removed the boost controller and when I did, boost fell to only about 12 psi.

The BOV is stock per the previous owner. Time to crush it?

I'll just take this slowly since I don't have alot of money to play with. /ubbthreads/images/graemlins/grin.gif

 

Also the TB is stock. I'll try dropping the cat if I can get it off without too much hassle and back on etc.

 

[fuel]

if you're running a stock BOV then it will very much be the BOV which is preventing more boost.

 

Wow, is there a way to stop it from operating temporarily to verify?

 

[Specter]

This how i checked my bov, I disconnected the reciculating hose from my bov, blocked the other hole in the intake pipe, asked my friend to push the rpm to a higher level, and i saw the bov open before my friend even let off the accelerator, try it, might sort things out for you.

 

[beaner]

Quoting blkchr91:
Thanks for all the help. I went driving and plugged off both sides of the boost controller and removed the boost controller and when I did, boost fell to only about 12 psi.

The BOV is stock per the previous owner. Time to crush it?

I'll just take this slowly since I don't have alot of money to play with. /ubbthreads/images/graemlins/grin.gif


Have no line going to the actuator. I feel like you have a line with no boost controller before it connected to the actuator, resulting in 12psi.

Stock bov should be fine to like 18psi. You can 'crush' it just a little in a vice to make it hold more psi.

 

Try pressurizing the IC pipe with the BOV attached(home depot boost leak tester) to 20psi and see if it's holding. If no, time to crush or upgrade. Do not over crush.

 

Thanks all, I read that you can use a hand vacuum pump to test it all out. I guess I will try that and see how it goes.

/ubbthreads/images/graemlins/dunno.gif

 

Man, stock BOV begins to open at 12hg and is fully open by 14hg....just checked it out with a vacuum pump!

 

Crushed to 21 hg. I can now achieve target boost and beyond. Thanks for your support.

 

[SouthCaliVR4]

/ubbthreads/images/graemlins/applause.gifAwesome good to hear you got her figured.

 

Thanks man.

 

Good job /ubbthreads/images/graemlins/grin.gif

 

Thank you and couldn't have done it without your patience and support. /ubbthreads/images/graemlins/applause.gif /ubbthreads/images/graemlins/wink.gif

 

Any time bro. Hope everything else is smooth sailing from now on for you. I don't mind helping when I can understand the poster.