I've read some scary things here that are telling me I'm running out of injector capability. Since the addition of a WB O2 my tune has come along quickly and I've found that I keep bumping my fuel pressure up in 2 psi increments to keep the WOT injector DC% down. Right now I'm at 33 psi at WOT and my injector DC is 93%.

If I keep bumping the FP when should I be concerned about the injectors going static due to pressure lock?

I'm starting to think that a 4bbl Accel throttle body may be a necessity now. I could run 4 90# port injectors...

I have heard of 90# injectors run at 70+ PSI. I have personally ran a set at 43.5 psi on an injector flowbench. They sprayed fine and did not lock up.

If you're making the HP to go along with all that fuel then you may have the most powerfull TBI vehicle we've seen yet. Post up the details of your build when it all starts coming together.

Teh biggest concern would likely be the diaphram in teh regulator blowing out. Id be willing to bet that the actual mass of the pintle is the main thing the coils have to overcome.

Teh biggest concern would likely be the diaphram in teh regulator blowing out. Id be willing to bet that the actual mass of the pintle is the main thing the coils have to overcome.

Could also run dual 2bbl TBI units.

RBob.

Can't run 2 TBI unit's we are both running a Weiand 142, which only alots for 1 carb mounting.

Ah, didn't know that. I take it the top cover is part of the housing and not removable. Thanks.

As to the original question, I've run the TBI unit at 60 psi with no leaks. This was for a short 5 - 10 second period of time. Just to see if a gasket would let go.

RBob.

I don't think I have to worry about the TBI regulator diaphram



The OEM regulator has been cut off and the passage plugged with a 1/8" pipe plug (JB welded in place).

Another pic...sorry a little blurry...


I do indeed need to raise the fuel pressure. I have consistant datalogs showing 92-93% DC @ 4400 rpm @ 33 psi.

Thanks to RBobs EBL raising the fuel pressure is easy. I just raise it 2 psi and do a VE learn going to work and going home. Done!

What the......

drool...I like your unit

I am now inspired and won't sleep at night until i've mimiced it. What FPR are you using, and I assume its under the hood.

I'm using the Aeromotive 13301 FPR with the high pressure spring. My Impala was originally a CC QJet car so I used -6AN adapters with a compression fitting on one end to convert my fuel lines. I took the fuel sending unit out and cut the restricter orifice out of what used to be the evap canister line. I used that hard line for my return.

You can see the regulator mounted to the brake booster. The feed line runs across and the return line runs down.

I've run mine in the mid 30's to low 40's for a couple of years

External regulator also.

The external regulator is definatly the way to go. FWIW, the small FWD/late model TBI injectors are rated for up to 100 PSI, so they can take some pressure.

Im surprised it requires any other change then just the BPC. Are you maxing them out real bad?

When I went to 30 PSI from 16 I had to change the injector constant and that was it...

The tune is extremly lean in places. So I bump the pressure, adjsut the BPC and go for a drive. I get a little braver going into those places where I knew it was lean before.

I've been fighting some issues with my fuel system. It all came together when RBob got a clear view of my TBI and regulator setup. The fuel supply line went to the regulator, and another feed line went from the reg to the TBI. So I had 1 feed line going to the TB. It was suggested that air and fuel vapor would get trapped in the injector housing and the only way out is thru the injectors.

When I got close to 1/4 tank I would hear a banging in the front of the car. My return to the tank shoots straight down. I assume the jet of return fuel was cavitating and the pickup was pulling air. The hammering noise I heard was the big air bubble hitting the reg diaphram. This bang was always associated with a slight lean spike on the WB.

I'm waiting for some -6AN hose ends to show up. I'm going to re-do my fuel supply. I'm using RBob's suggestion and installing a block-off plate where the OEM TBI reg was.