HIlborn Mech. fuel injection on a street strip car??

[ecorl]

Yep, been there...done that with my prostreet, blown injected v6, on race gas. I used a small electric pump t'eed into the injector lines to prime it for starting. just hit the button a few seconds and it worked fine. problem with a dial a jet is that you really cant run it inside the cock-pit because you would be running fuel lines inside. I also used a surge tank with a holley blue electric pump keeping it full from the fuel cell in the rear. Yes, part throttle performance stunk, and I was constantly adjusting the BV, butterfly's, and pills. You gotta run them rich because there is no accelerator pump. On a quick tip-in, there is a temporary lean. It would be more forgiving on alcohol. You can make it work with some trial and error but be prepared for constant tweaking, stumbles, pops, and throwing wrenches. I finally wised up and converted to EFI. I put the electronic injectors where the mechanicals were and used megasquirt to tune. I miss the simplicity of MFI. If you are going to drag race and you are concerned with idle and WOT, then MFI isn't that bad.

[dieselgeek]

We tried the Dial-A-Jet on a car at bonneville and it was a horible experiment. The problem is, the "jet" isn't necessarily right at all RPMs or loads. Do you need to be "dialing" all the damn time to keep a decent mixture.

[CTX-SLPR]

If you're willing to run the electrical stuff, a Cold Start Injector off of a K-Jetronic car would fit the bill. Most of them were just controlled with a "thermal time switch" which is like an electric choke but much faster acting. Time switch screws into the coolant passage and is routes power from the starter motor (or relay) to the injector so it fires when you crank and on hot start the hot coolant keep the switch open and doesn't run the injector.

[Saltfever]

A lot of hypothetical ideas and interesting as well. But and electric fuel pump is a positive PRESSURE device and a Hilborn pump is a positive DISPLACEMENT device . . . a very big difference! EFI injectors regulate flow by pulse width and are essentially digital valves that shut-off flow. A mechanical nozzle is not a valve at all but an orifice wide open all the time and has nothing to do with controlling flow. (Tuning is with the pill and nozzles are more or less sized for the HP or fuel and then left alone). The MFI pump controls flow in direct relationship to the engines rpm and flow is perfectly linear up to max torque. As engine efficiency falls off after that various orifices (pills) are incorporated to bypass excess flow back to the tank to get max power at max WOT. .

You have stated you want to stay with MFI and I assume you want to run it now and experiment later. The biggest deal with street driven MFI has always been engine start and partial throttle operation. The first is easy and the second issue is why EFI was invented. The issue with starting is spinning the motor fast enough for the Hilborn to output fuel. Remember a Hilborn pump is not a sucker . . . it’s a pusher. It must be immersed in fuel all the time. The fuel in your tank has to be above the pump inlet. The second issue was 12 volt batters don’t spin the motor fast enough for the pump to start outputting decent flow. Fast forward 30 years and we now have 16 volt batteries. So use a 16 volt battery and one of these:

http://www.aircraftspruce.com/catalog/appages/acsprimer.php

The mechanical primer keeps fuel out of the inside of the car. The plunger goes through the firewall and when you push it you squirt a precise amount of fuel to fire the motor. You only need a small line to a couple of cylinders. That is enough to kick the motor over quickly and the Hilborn pump takes over. This is simple, clean, quick, and SAFE. You quickly learn just how much of the plunger you need to push for just the right amount of prime. Forget an electric fuel pump as a primer. It is difficult to precisely time shut-off, they can easily flood the motor, and can be dangerous in an accident. The mechanical primer is a sure fire easy way for engine start on the street. Surge tanks and float valves were all before 16 volt batteries. Get it running and have fun with it. At some point you will get tired of the rich AFR mid-range partial throttle issue. At that time you can decide if it is worth experimenting your life away or if you want to convert to EFI and be happy. LOL YMMV

[anotheridiot]

Electric fuel pump turned on before you start cranking the starter would be what I would do, no question. Like I said before, most of them have extra pipe taps on the setup where the injectors started, most end up moving them and pointing them right at the intake valve.

Your prime injectors dont even really need to be injectors, just copper tube. Fire a fuel pump and feed them, when it fires the mechanical pump takes over. If you just have one injector, maybe a check valve somehow to not allow the pressure from the manual pump back into the electric circuit would do the same thing.

Anyone wants to send a shitty manifold over, either small or big block, I would be happy to do the R&D.

[William Wilson]

I've been toying with the idea, pure bench racing, that you could use a mechanical setup coupled with an electric fuel pump.

Then using a hidden controller to varry the fuel pressure based on RPM and hidden throttle position and MAP sensors.

I don't think it would be as efficient as regular efi.

But I think you'd get more then 8 MPG and I think no one would be able to tell you'd done it.

[squirrel]

not enough information.

And someone needs to tell these guys they can hold their phone sideways when they are shooting video....

[Pinto289]

Hey guys, im glad I found this thread as I am new to the site. Have any of you tried Instajet? Its some type of fuel controller for mechanical fuel injection and stumbled across some videos on youtube of a guy running it on the street. His car seems to run very well on the street with the use of an electric fuel pump. Im very tempted to buy one for my car but was wondering what you guys thought of it. Please let me know what you think, I will post a link to the videos. Thanks guys.

http://youtu.be/j_aIi_SyJ8A http://youtu.be/TJQNioCEutE http://instajetllc.com/

[racingsnake440]

Interesting, thanks for posting the article.

[tardis454]

No prob, an easy flip..

[STINEY]

Let me try again.....those others lacked in quality somewhat....

How about this?











I swear....I oriented them correctly in photobucket before linking.....#*$& new photobucket crap.

[tardis454]

Neck was gettin sore..

[STINEY]

[Barry Donovan]

Any kind will work, the most important thing is to size the pump. Its just math.
If you're used to a carb all your thinking will be backwards. You take fuel away instead of adding it.

this stuff is interesting.

a way to take fuel away is to pull it back to a restriction, air side...which is not a restriction, but a pull.

it would take away from the classic appearance, I am just babbling.

just rereading that.. the first attempt in history for this was called a choke.
the last of the monojets, as example, had to go over twice as far as the choke, with a similar idea. The larger it can be needs a whole surrounding.

part throttle dumping is backwards to a carb indeed.

I am with dieselgeek.. add some modern wideband to get it done, unplug it, hide it.

I got lost on the last modern gen of carbs without it.. but there was some rocket science beyond a barrel with fuel in it.

[JeffMcKC]

That's why I my first post I talked about a Dial a Jet

http://www.kinsler.com/Cat_32_Pgs/Cat_32_4_09_Pg_85.pdf