The Top Mitsubishi Galant VR-4 Resource

Join the best E39A 1991-1992 Mitsubishi Galant VR-4 community and document your GVR4 journey.

  • Software Upgraded - Reset Your Password to Login
    In order to log in after the forum software change, you need to reset your password. If you don't have access to the email address you used to register your GVR4.org account, you won't be able to reset your password. In that case, follow the instructions here to regain access to the forum.

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

Well-known member
Joined
Feb 23, 2009
Messages
2,166
Location
Toronto, ON, Canada
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?
 

fuel

Well-known member
Joined
Feb 23, 2009
Messages
2,166
Location
Toronto, ON, Canada
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.
 

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.
 

Specter

Well-known member
Joined
Apr 20, 2008
Messages
367
Location
Karachi, Pakistan
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

Well-known member
Joined
Jun 22, 2005
Messages
1,562
Location
b'ham, mi
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.
 

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.
 
Support Vendors who Support the GVR-4 Community
Boosted Fabrication ECM Tuning ExtremePSI Fuel Injector Clinic Jacks Transmissions JNZ Tuning Kiggly Racing Morrison Fabrications RixRacing RockAuto RTM Racing STM Tuned

Recent Forum Posts

Recent Classifieds Listings

Top