MegaSquirt & propane systems

Propane, Butane, LPG, GPL, C3H8, C4H10
Frank
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MegaSquirt & propane systems

Post by Frank »

With the relative scarcity of custom components for non-fuel injection propane systems, it seems to me that modern electronic controls can give us better control over fuel mixtures and timing.

The one system that comes to mind for this is MegaSquirt. There is more information about it at the other MegaSquirt site. There is also a MegaSquirt Forum. While the Dual Curve and Impco feedback controllers can control the fuel mixture to stoichiometric under most conditions if a feedback gas valve is used, they do not have the capability of running lean fuel mixtures for best fuel economy nor do they have any timing control capability.

While the original MegaSquirt (MS) controller could only control fuel injectors, the MegaSquirt II add-in daughter card provides for timing control. Once Bowling & Grippo develop this system further, they will release the UltraMegaSquirt controller with even more features.

Since the current propane feedback system controllers rely on a solenoid to regulate converter supply pressure and the MS system controls fuel injector solenoids, I think it wouldn't be a big stretch for MS to control the converter solenoid. Ideally, it would great to use a MSII or UMS system to optimize timing as well. Unless you have a small block Chevy, timing recurve kits are generally not readily available.

Having done a quick through the MS forum, I came across a propane injected Mazda RX7. Interestingly, that system does not come close to meeting any installation codes.

Do you have any experience with MS propane systems or do you know of anyone who does?

franz
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fuel management

Post by franz »

I have looked at the Megasquirt systems and like what the controller does, for fuel injection. I am have used the DualCurve vacuum controller for Impco and OHG systems for many years and they are effective, but we still are dumping fuel in one location, relying on an archaic means of air-fuel distribution, plus the time delay lag feature inherent to this system.

Active fuel injection management solves that problem by the capability of individual cylinder monitoring, faster response time etc. The biggest problem is not the controller, there are quite a few real good ones out there (FAST, Motec, Electromotive, TwEECer, Holley, Crane, Edelbrock, etc), the problem is injectors. We cannot use a gasoline injector, they will not hold the pressures and do not like to operate in dry mode.

Also, for what its worth, the Ford does offer user tunable timing advance, just look through the small square window in the distributor plate and you can bend the two tabs holding the springs to change the rate of advance. This obviously doesnt work with totally electronic distributors.

Franz

alehander
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Post by alehander »

Using an MS to control the converter solenoid with carburetion and w/ or w/o spark control seems moot. You're still stuck with the carb & manifold and all their inherent flaws, as Franz states. MS is really designed for full-on EFI, gasoline or LPG.

LPG injectors are the real problem. The ones available with the full-authority EFI propane kits are big $$$. I think I've asked Franz about adapting a CIS-style injection system as well, doesn't work for some reason. I'd still like to try plumbing 100-psi regulated liquid propane into a CIS distributor to see what happens.

What about using 4-8 IAC valves to regulate fuel supply? These are stepper-motor or solenoid-based and don't respond as fast as injectors but flow dry gas just fine and are appropriately sized?

P.S. That Mazda is a death trap.
Lenin zhil, Lenin zhiv, Lenin budet zhit'

Frank
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Post by Frank »

I wasn't all that concerned about propane injectors because I know that propane vapor injectors are commercially available. From what I have been able to gather so far, if anyone were interested in building their own propane injection system, they would be more likely to use a MegaSquirt system rather than the others mentioned above.

Having done a search of this forum, I see that Dylan86GL10 is already running propane with MS. I was hoping he might post some information about his car.

For people with older carbureted engines, I thought that the MS system would be an economical alternative to the Dual Curve PN 5952 or the Impco PN ADP because it has the added capability of timing control and lean mixtures. While injection is obviously superior to carburetion, a simple propane carburetor could work just fine for commuter applications.

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IAC

Post by franz »

ALGAS used an IAC motor for their system, but it didnt react fast enough to avoid terrible sags in performance.

The only way to plumb 100 psig liquid injection is to chill the propane to around 60 degrees F, always. You will have to deal with the return fuel line and the heat it absorbs too. Most liquid systems I see are around 175 to 250 psig, depending on ambient heat and idle time, plus how close the injectors are sized for the engine. The more fuel that is bypassed, the hotter the return line temp.

Franz

sleepybu
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Post by sleepybu »

i'd like to do a ms injection system... one day :wink:

schwoch1
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Post by schwoch1 »

I have thought of the same thing, and in my opinion, there is no reason that the megasquirt cannot control a LPG vapor injector instead of a gas EFI injector, a solenoid is a solenoid. As long as you can get the propane injector to open and close fast enough to control the fuel mixture, there should be no problem. I do have to agree that the LPG mixer is sort of, for lack of better wording, outdated. Don't get me wrong, carburetors are good and do their job, but nowadays, about the only thing that come with them are lawnmowers and weedeaters :) With today's technology, there has to be an alternative. I have been doing some research for my next project, a 1975 Chevrolet Vega with a LS1 5.7 V8, and I would really like to use propane for the "different" factor ( I used to purposely search out full size GM cars with the Oldsmobile diesel V8's if that tells you all anything about me), but really don't want to use a standard mixer. I am hoping that I can come up with some sort of vapor injection setup using an aftermarket EFI system. I kinda looked into the liquid propane injection, but there are too many complications and too many new paths that have to be blazed to make it practical.
I do have a megasquirt controller that I am going to use on something, why not this, I just need to come up with the vapor injectors, which seem to be that hard part. Seems like the people who know and have answers don't talk because then you will know what they do and then they won't be the only person to know it all (no one on this list, just some propane people in general in my area).
Anyways,enough rambling, I am going to start doing some research, if anyone has some advice or suggestions, or just wants to know if I made any progress, drop me a line!!!

Mike Schwochert
1967 GMC 2500, 351 V6, soon to have 430 Buick with propane

schwoch1
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Post by schwoch1 »

And I do have to say that the Mazda on that website looks like an accident waiting for a place to happen. The 5 gallon propane cylinder cut into the floor put's his installation over the top on my "hack-o-meter" :)
Mike Schwochert
1967 GMC 2500, 351 V6, soon to have 430 Buick with propane

franz
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Mazda

Post by franz »

I agree, the tank installation is pretty scary. I did a closeup look at the fuel system and the propane is used as a supplemental fuel only. It looks like at boost the propane comes on to supplement the gasoline. The way the tank is configured, it will not feed a high performance application, it will freeze over quickly.

Franz

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Mazda

Post by franz »

I agree, the tank installation is pretty scary. I did a closeup look at the fuel system and the propane is used as a supplemental fuel only. It looks like at boost the propane comes on to supplement the gasoline. The way the tank is configured, it will not feed a high performance application, it will freeze over quickly.

Franz

Dylan86GL10
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Post by Dylan86GL10 »

Sorry for an unclear posts - I'm currently building a dual fuel (petrol injection / lpg carb) with MSnS'e. Its not done, I still need some LPG parts. I would like gas injection if I can source the parts cheap enough. But I am more familiar with megasquirt and can add some to this discussion:

Megasquirt n Spark Extra (MSnS'e) is a modified MSI (same cpu and board, firmware flash and code changes, minimal wiring differences).

MSnS'e can:
Control gaseous injectors
Control spark
Use dual tables for dual fuel on the fly

I believe MSnS'e can be modified to:
Control feedback loop to carb. It has a couple outputs that could be used. Boost control for instance, uses a PWM solenoid to control the wastegate actuator. I don't see why some minor code changes couldn't change it to adjust PWM to a carb solenoid based upon O2 readings instead of MAP readings like its currently setup. Alternatively, in a single fuel carb setup, feedback could be controlled on one of the inejctor drivers via the O2 feedback. I've met the guys that write to code and think that this would be feasible.

I look forward to this discussion progressing.

Dylan

Dylan86GL10
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Post by Dylan86GL10 »

Further -

Best price seen on gaseous injectors?

Group buy to import from Europe?

Frank
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Post by Frank »

I'm in the process of sourcing propane vapor injectors for my e-commerce site. When I have more information, I'll let you know.

sleepybu
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Post by sleepybu »

schwoch1 wrote:Seems like the people who know and have answers don't talk because then you will know what they do and then they won't be the only person to know it all (no one on this list, just some propane people in general in my area).

Mike Schwochert
dido :?

gravespropane
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Post by gravespropane »

I am in the process of getting an off highway/high performance efi system together. It will be able to run gasoline injectors or gaseous injectors, (peak and hold). I plan on using it to convert carbed engines. It doesn't control the ignition though, I was planning on using MSD digital stuff. I was going to try the VEMs system or the MS system but I am working with a company from Europe and plan on using their computer. It is much easier to tune.

More later when I get some more info.

John

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