TBI injector placement question

[droopie]

Hi,

I have been researching MS for a couple of years. I have an 85 Mustang with a warmed up 302 in it. I already have a holley 4bbl throttle body and was thinking about a cloverleaf efi intake, but it's too tall. I saw something in Hot Rod or some such newstand magazine a while back on a blown LS motor. They put 4 injectors in a carb spacer under the throttle body for a TBI setup.

Would there be any issues doing that on a normally aspirated setup? I have about 9.2:1 compression, a TFS Stage 2 cam, aluminum 2.02/1.60 heads, and a Weiand stealth dual plane. I have a 750 dbl pumper on it now...and it flat out screams. But the afr and idle change day to day with the weather. I get about 14 in of vacuum.

So I was thinking I could just take a carb spacer and weld four bungs in it for 4 60 or 80lb injectors and just put that under my holley throttle body. Basically EZ-EFI a lot cheaper and more tunable.

Does anyone have any pros or cons to this setup?

[Matt Cramer]

Our experience has been that injectors installed between the throttle blades and the plenum give absolutely horrible fuel distribution. You'd either need to put the injectors above the throttle blades, targeted at the blades so the fuel shears off them and vaporizes, or point them down the runners. Blowers can get away with injector plates like that because the air/fuel mixture is agitated by the supercharger lobes.

For a NA motor, you could drill your Stealth for injectors, or pick up something like a used GT40 intake manifold. There's a lot of guys pulling these off wrecked Explorers and selling them cheap.

[droopie]

Thanks Matt. That's what I was wondering. I am looking for the simpler, straighter path to efi. My 85 is setup for a carb, so I'd have to add changing throttle linkage and cruise linkage to the list if I went with traditional 5.0 efi setups. Plus I like the carb/aircleaner look versus the 5.0 log look.

I know the quickest and easiest path to efi would be a GM TBI. But I am wondering how much HP can it really support. All of the 4bbl tbi setups have 4 60-80# injectors. Even the 454 TBI only have 2 80's.

My car is making about 315 to the rear wheels.

I guess I could sell the cloverleaf I have that is too tall even with a cowl hood and the holley 4bbl throttle body and look for a holley 4bbl tbi.

[Matt Cramer]

Got a TBI 454 powered Suburban myself, and I don't think it puts anywhere near 315 hp to the wheels. You could probably get a 454 TBI to support that much power if you bumped up the fuel pressure - some of the GM TBI crowd has managed to pull that off before.