MSefi.com read only forum (Jan.15,2018)

Hey everyone.

I'm turbocharging my 90 Sambar KS4 pickup and have a question about the TBI assembly I chose (from a scrap yard).
I pulled the TBI assy. off a 91 Chevy Sprint 1.0L TBI. According to my research, the injector is there should be rated at 59.15 lbs/h @ 43.5 psi... which should provide more than enough fuel for what I'm doing.

Here's the thing; the engine in the Sambar is mounted on it's side. For me to have the TBI unit sitting "face-up" (like how it sat in the Sprint) I would have to make an adapter with a 90 degree bend in it before it gets to the intake manifold. Not only would this eat up space, but the fuel and charged air won't like all the bends.

Can it be mounted on it's side and still function properly?

Also, I have a vacuum operated fuel pressure regulator specifically for turbo applications. I read on the DIYAutoTune site that GM TBI units have a built in fuel pressure regulator, is this true? Should I install the vacuum operated one just to be sure?

Any help/knowledge is greatly appreciated.

WELDER,

Yes, you can run the GM TBI's on their sides - I have done this with 2 TBI units on my Honda 4 cylinder. A very small amount of fuel will 'spit back' from the throttle blades, but this will be captured by the air cleaner and reintroduced into the air. There are absolutely no issues otherwise.

The GM TBI have a built in regulator, and these work fine. I have never felt the need to use another regulator with them. In fact Holley copied the GM design on their TBI injection units.

Lance.

Thanks Lance.

Do I need to run a vacuum line from the TBI unit to the intake, or does it have an internal meter?

WELDER,

That's one of the nice things about the GM TBI - the regulator passages (vacuum and fuel) are internal, so you don't need add do any lines, etc..

The other nice thing is the built-in stepper motor IAC that makes warm-up idle easy.

Lance.

Lance, you have all the answers.

Haha, thanks yet again.