anyone turbocharged their TBI? what are you using for a TBI hat?

[stackz]

with the tbi unit having two hold downs for the aircleaner coming up out of it, what are you using for a TBI hat if you boosted your setup?

did you just make it custom? I was thinking of welding the factory air cleaner together and just using it maybe.

I see this one as part of what looks like an old procharger kit.

M198643753.jpg

I did have the instructions from the old vortech truck kit on how to modify the TBI for blow through but cant seem to find them right this second. I remember it being that we had to drill two holes and put a TBI spacer in between with a port for a 2 or 3 bar map sensor IIRC.

I've got a 4.3, 5.0, 5.7, and 7.4 TBI unit and have both sets of 7.4 regular injectors as well (not the goofy ones that needed the higher fuel pressure to run higher).

I have also been dabbling with the idea of doing draw through as well. I have two 79 buick 3.8 turbos with the carbon seals and the 4bbl intake that bolts to it which I can get a tbi adapter plate for.

Just not sure which route I want to go at this point.

[In-Tech]

Hiya,
If the injectors are seeing boost, you will need to boost compensate the fuel pressure regulator.

[stackz]

didnt think about that. so something like a boost-a-pump would probably work.

[In-Tech]

Hello,
A "boost-a-pump" increases the flow, the pressure has to rise at least 1:1 vs. Meaning if base pressure is 12, at 10 lbs boost the fuel pressure needs to be 22 to maintain the flow. Any boost will push push back on the injector, reducing flow...hence the need for boost compensating regulator. If hooked to a vacuum/boost port, the pressure will reduce when in vacuum and VE table will have to be adjusted. Otherwise you can use a one way check valve just for boost, it will need a small "leak" so it doesn't work in vacuum.

[stackz]

so a fmu so a rising rate fmu then

[In-Tech]

If iirc a fmu is about 1.25:1
Your real struggle will be to find large enough injectors for the TBI. There was a time I had to use BBC 75's @ 12lb injectors and then use a 3:1 regulator. Figure out your hp requirement and then adjust accordingly.