Mechanical Fuel Injection

[LwCwb]

Is anyone running Mechanical Fuel Injection on their Cobra?

[Anthony]

There was a guy at run n gun with a cheetah, with a sbc with hilborn mech injection. He said he was still working on tuning it. I'm toying with the idea of running mech fuel injction myself.

[HighPlainsDrifter]

Hi,
A mechanical system like Hillborn is a constant flow system that pumps major fuel all the time and is regulated with a barrel valve.
Bottom line is very hard to run on the street at low rpm and absolutly NO fuel mileage. It's a great system for sprint cars that are wide open all the time.
Good Luck, I wouldn't run it on a street car.
Perry.

[Ron61]

Perry,

Didn't Chevy have a mechanical fuel injection for the 283 in 1957 that you could order on the Corvette or the top line cars?

Ron

[HighPlainsDrifter]

Yes Ron,
The early Vets and hi po 283's could have Rochester fuel injection on it. It's OK for resto chevy's but wouldn't work on a big block. The deal with Kinsler or Hilborn is a racing system that pukes gas and has no power at low RPM's.Can you say 3 MPG on a good day and a bottle of gas to jump out and prime the injectors to start this thing. A racing car or boat would be great.
Although it does look cool.... my friend had a 70 Nova with Hilborn injectors sticking though the hood, could go 40 miles on a fill up.
Perry.

[LwCwb]

So, for the most part it is unusable for street use? If thats the case I guess webbers are the way to go.

[Anthony]

typically, the mech FI systems were used for drag racing, but they were also used for can-am racing. Kinsler will design a constant flow inj system for road racing, with additional bypass circuits for partial throttle operation.

I've been thinking about such a system for a while. I figure you would need a fuel holding tank in the engine compartment, feeding the fuel pump. In addition to the primary bypass, you would need a secondary bypass circuit, and maybe a hi-speed bypass circuit as well. Kinsler makes a dial-a-jet for the primary circuit to easily adjust for different temp/pressure/humidity conditions. You may need a separate fuel pump to prime the circuit for starting.

[Cal Metal]

The Rochester FI used on the Corvette was highly dependent on vacuum to run the system. Although it was considered a "constant flow" system, it was nothing like a Hilborn, which gave great performance in a flat out situation. The Rochester was very street worthy and gave outstanding performance over and above the early 2x4bbl. systems. The earlier units, starting in '57, had some gremlins to work out, but the later units were very good. The last year for FI in the Corvette was 1965. There were 771 units produced that year.

The option ran about $450.00, which was always a big negative and resulted in it not being a popular choice as a RPO item.

[elgecko]

Right now I'm setting up a four barrel system but I was thinking of using a mechanical fuel injection setup that has been updated to EFI. It has the retro look of the 60's with the individual stacks, but the tunibility(sp), mileage and startup capability of todays fuel injection. Maybe in my future plans.
Do a search on the web for port injection EFI conversions.
BUT like you said, you are looking for mechanical injection.
Just a thought,
Dave

[Anthony]

I believe the chevy-vette FI system made more hp by not just probably having better/even fuel distribution, like a weber set-up, but the intake itself had individual runners like a tunnel ram intake, as opposed to the four barrel/ 2 X4 intake, again like a weber set-up.

[Ford of France]

Anthony:

The Rochester system incorporated eight injector nozzles in the intake but did not have individual runner systems like Webers. The air meter sat in the middle of the intake with a butterfly much like that found on most four barrel intakes.

The FI system enhanced the cornering speed of the Corvette, in that the fuel would not slosh from side to side in hard cornerning which was a major problem with the 2X4bbl. system that was an option on the Corvette. The older systems cost as much as the cars did new, these days. The '65 is still the preferred unit.

[Anthony]

I thought that the vette FI system had the individual intake runners that each led up to the common plenum, kind of like a tunnel ram. I'll have to look for a picture from a cross sectional view.

[Anthony]

Here's a cut through of a 1960 FI unit, the first series, and you can see, it looks like a small tunnel ram type intake.

http://www.vetteweb.com/tech/0306vet_rochester_II/

[Ford of France]

Anthony:

That looks like a good site. I will bookmark that one. Remember, though, that the Weber has eight separate throttle plates with an accompnaying runner, whereas the Rochester FI only has one throttle opening, much like a regular carburetor.

[Anthony]

Chevy called their FI system "ramjet" in some of their literature, I guess referring to the pulsed ram effect, tuned runners, like a tunnel ram has.

I couldn't find a cut through diagram of a '63-'65 FI unit, but it is basically the same as the first series unit, with individual runners leading up to the plenum, but now the plenum has a removable top, instead of a sealed cast top.

here are some detailed outside pictures that you can tell it is of the same basic design, like an enclosed tunnel ram.

http://www.cranescorvette.com/f_i_-2.htm

Where as the weber carbs are open to the atmosphere (plenum), the corvette FI system runners are open to the plenum, which is like atmosphere at WOT, basically the same effect.

[parhen4]

Call Hilborn at 949 360 0909 They have EFI kits for COBRAS.

[cobrashoch]

Killer Rons - I don't know much on how they run on street cars but I'm going to learn. There is a couple of mustang guys around these parts that run them on the street and swear by them. This guy that sells them is first rate to deal with I hear. Check out the Terminators.

www.killerrons.com/contact.cfm

[Frank Messina]

Mechanical FI will not make you happy on the street, and only maybe on the track. If FI is what you're after, you might want to check out this Fuel Injection System being produced by Quality Roadsters.
There is a temporary hiccup I'll mention in that PRO-M who supplied Mass Air Meters to just about the entire FI hot rod community was sued out of business by Granatelli and is in the process of being restarted. Supposed to be back up in a couple weeks.
Frank

[o'brien]

Ihave had both mechanical e.f.i. and very happy with current set up. If I knew how to post pictures I would show both systems. Ihave the twm on cobra and hilborn on boat. The only way you would be happy with mechanical on street would be with slow opening throttle linkage, T.W.M. works great on street. T.W.M. mills the manifold to help fit in cobra. They do not get into electronics , I went to B.D.S. T.W.M. looks so good I hate to cover up with air cleaners. I will try to make clear upper and lower with filter between to show off , it looks that good. The throttle bodies can be ordered up to 58mm which is good for us with stroker motors. I went to trouble to drill and tap underside of manifold to hide lines, used stainless steel hardlines. Engine going to sacramento to be rebuilt with new stroker crank ,cam ,tune up on dyno. Engines By Rex. Web site for T.W.M. is http:/www.twminduction.com/v8_kits/ford427pic4.html

[o'brien]

SORRY try TWM Inductions-Home




not to good at this.