Got a few older Hilborn/Crower intakes collecting dust and would like to convert them to EFI. Trying to avoid welding in the injector bungs as the heat causes distortion, which will likely require the intakes to be remachined in order to straighten them out. However- I'm wondering why you can't machine an intermediate adapter to hold the injectors and bolt in place underneath the ram tubes. I'm sure this will work ok at part and full throttle. My concern is that, at idle with the throttle blades closed, the injectors will be positioned above the blades (instead of below them like most setups) so it might not idle so well. On the other hand, tbi's & carbs work that way, and the two Crower mechanical intakes I have also work that way (but I DO realize these weren't meant for cars who's main purpose was idling!). Still, the more I think about it, the more I think it will probably work.
Will it work? Yeah, it probably will. But you'll have some idle and low rpm performance issues. I think it would be fine for a race car. But a street car will have some real annoying derivability issues. When the fuel hits the nearly closed blades, it will puddle a drip off. Have the bungs welded in below the throttle plates. have a pro do it so there's no distortion. It will cost you, but worth it. Take a look at how Kinsler does it.
I think you might be right but I'm still wondering if anyone has done this. . .
I think it would be fine for a race car.
That what I thought at first but it doesn't do that with tbi (maybe because tbi works with less pressure?). I don't know that it will actually hit. It might depend on how far above the blades the injector tip is. And it sprays so little at idle that I think the atomized fuel might just find it's way around the blades (vaccuum) and work ok. Sure the spraying fuel is under a lot of pressure but it's also atomized and there is a fair amount of vaccuum at idle. Maybe the tip of the injector will have to be some minimum distance above the blades to allow for a smooth flow around them.
Talked to a couple of pros about this. Depends where you want them welded and how thick the metal is there.
It will cost you, but worth it.
I have. And talked to them on the phone. They do it a few different ways: One, with Lucas metering (not EFI but makes no diff in this case), bungs welded into the ram tubes and sprays fuel down onto the throttle blades. Another (most common for Kinsler) is below the blades BUT spraying from the outside at the opposite side of the intake runner wall instead of toward the valve. According to the theory above, the fuel would then splash off the opposite wall and drip into the cylinder. But I'm not sure it really does. Yet another (actually own one of these) is a 3 piece magnesium intake from a chevy SB (well actually "Pontiac" but in name only) turbo gtp car. The throttle blades are way high (maybe 10 inches high) in the runners with the injectors just below them on the inside of each runner- so there is still probably a good 9 inches of wet flow before the fuel makes it into the head...(quite a contrast with the direct port injection used on some sprint cars) I called kinsler a few weeks ago and asked if this adapter method would work and they said they had done it using a Hilborn setup on a hemi and it worked great. But admittedly that was a race car.
I guess there's no way to know without actually trying it. . .
MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here.
All logos and trade names are the property of their respective owners.