Hilborn Mechanical Fuel Injection

[David H.]

Hey guys, my friend and I were talking about alternate fuel systems for our engine and my friend mentioned the Hilborn mechanical fuel injection system mainly used in the midget series. I'm wondering if any of you have considered using their system and your opinion on mechanical fuel injection. Thanks.

[David H.]

Hey guys, my friend and I were talking about alternate fuel systems for our engine and my friend mentioned the Hilborn mechanical fuel injection system mainly used in the midget series. I'm wondering if any of you have considered using their system and your opinion on mechanical fuel injection. Thanks.

[B Lewis @ PE Engine Management]

Hi David,

Let me start by saying congrats on throwing your hat into the FSAE ring. Get ready for allot of sleepless nights .

I have experience using mechanical injection on a sprint car (think big midget) over several race seasons. The mechanical system has its limitations including the following:

- Because of the mechanical nature of the system, it is difficult to tune for all engine conditions. Things like changing air temp, engine temp and barometer are just a few of the conditions that the mechanical system cannot compensate for. The biggest advantage electronic fuel injection has over mechanical is the ability to fine tune for all operating conditions.

- Most of the current motorcycle engines are already designed for electronic fuel injection. Typically, when you buy an engine you will get things like injectors, sensors, pressure regulator, fuel pumps, etc. This makes it a pretty easy swap to use a stand-alone engine management system. I would venture to say that you would have to invest more time and money in getting a mechanical system to work than you would to get an electronic system up and running.

- Using a mechanical injection system doesn't allow any way to control the ignition. This means that you would either have to "trick" the stock ECU into performing this function or purchase/design another stand-alone controller to do this. Either way you will spend more time/energy and get less flexibility than just using a stand-alone electronic engine controller.

- Another advantage of using electronic fuel injection is the availability to use additional features such as data logging, no-lift shifting, custom inputs and outputs, rev-limits, launch control, etc.

I have used both kinds of systems and for tune-ability, mechanical fuel injection falls way short.

[Jarrod]

i have experienced mechanical injection on sprintcars as well, and they only like to operate in one mode, wide open. You spend a lot of time at small throttle openings in FSAE, and if it doesn't have excellent response you will have a lot of trouble. i don't know how well it would work with the upstream restrictor either. It may be because of the methanol fuel, but some engines can be very sensitive to weather conditions, some guys will constantly change the fuel settings between heats as the night cools off.

[Big D]

I don't know much about the system, other than it looks cool on a Buick Nailhead, but it makes me think about simplification of things.
Especially if your team is made up of all Mechanical guys, limiting your electrical system to starter and brake light might be cool. Go totally retro with the technology. Run a magneto, crank driven fan, Hilborn, no telemetry, nothing. Sure, it won't perform as well, but if you get along as well with electricity as I do, you might be better off that way.
While you're at it, run straight axles, and front engine. Wow, now we're off topic

[GTmule]

A Carb would be approxamately 59834572039458723049587234095828973476123413468208 times easier to deal with (not to mention cheaper).

[MoTeC]

Mechanical injection, also known as piss and dribble, man what a night mare. I am sure the saftey officials at the event would be happy for you to use the old squirt bottle down the throttle body to start the thing.....oh that's right no one else can touch the car when changing drivers in the endurance.

Sorry guys, in "simplifying" a system you are just going down the same path of having to learn the tricks for a less adaptable system. I am a mechanical engineer who used to hate electronics but now I kind of have to know a bit. If you surround your self with people who are interested in helping (electronics wise) you can't go wrong.

Guys/Gals, you are products of the internet world, you can find out how everything works with a few key strokes.

[Big D]

That's a fairly predictable reply for a guy with the name MoTeC.

I'm not saying it would be better, just that it got me thiniking of a car that's not an electrical nightmare. A huge portion of endurance DNFs are electrical, so why not get rid of that? If you don't have any electrical engineers on your team, you should get some, but in the meantime, don't screw yourself with a bunch of stuff you don't get. Also remember that we are designing for a non-professional autocrosser. Maybe that person's 50, and doesn't want to touch a computer with a 10ft pole....

Don't get me wrong, I am glad my team has electrical guys, but they can just go at it, and as long as they can show me it works, and dumb it down so I sort of understand, that's all I ask for. Mechanical injection is again, probably something you won't fully understand, but it's cooler than a whole stack of ECU's. Carbs would be a reasonable comprimise if you are trying to avoid electrical hassle.

[GTmule]

Youre missing the point, mechanical injection is bout 500 times more fiddly and crappy than all but the worst doddled together EFI systems.

He's form Motec, fine, but I'm not, if you wana simplify, get a carb, NOT a mechanical injection setup (unless you enjoy grinding cams and stuff). And paying vintage prices for vintage parts look REALLY bad on the cost report.

[Dave M]

Have you guys even touched a mechanical fuel injection setup? I agree that they are not a good choice for a FSAE car. EFI is better for FSAE, but Mech fuel injection isnt that picky. yes, you can screw it up easily if you dont konw what your doing. Changes for air density in mech injection are easy. There is a quick connect that houses a pill that regulates the flow. very simple change. Again, they arent the best for FSAE cars, but they work damn well on a sprint car or midget (where we aren't allowed EFI). Mech Injection can also handle more lateral G's than a carb, as mech injection doesnt have any float bowls. I'm just defending them because I know how to use em.