MSefi.com read only forum (Jan.15,2018)

thinking about doing a megasquirt on a 4.3 vortec that is currently running on a carburetor mixer setup that runs very inefficiently. I don't know enough about propane, but where would I find an injector that I can control with megasquirt? multiport or even throttle body injection. I will be using an ms2 unit

There are some "gaseous" injectors here: http://www.rceng.com/Peak-Hold-Fuel-Injectors-C5.aspx
Look at p/n: PQ2-3200 (I don't know if these are even close to the size you need, only that they are gaseous injectors).

ah. gaseous injector, never used that term. however, that seems to be the only one I can come up with. Could they be called anything else?

I truly don't know. I use RC fuel injectors and saw those on the list.

I know this isnt a propane forum, but I figured I'd post a little more details about the project.

it was a toyota truck with a 22r that has a 4.3 vortec out of what im told is a chevy s10.
it has a really bad intake system setup for this propane. -bought it this way, and friend thinks the 4.3 was originally carb'd.
it has a vacuum dist with no lines hooked up to it. it lacks power and economy (no timing marks or anything to even go with)
we can get an electronic distributor from a newer vortec

im hoping maybe we can leave it carb'd but get some timing control and o2 feedback on there and see whats going on. I dont know anything about propane

You can determine TDC on an engine by removing the spark plug and doing a little "checking". This will give you a timing mark you can use for MS to control your advance. This would allow you to use your current dizzy by simply locking the mechanical advance and leaving the vacuum unplugged.

If it's from an S10, it was originally injected. Chevy used a TBI unit or MPFI depending on the year and which model. All the S10 4.3s were injected. The S10 carbs disappeared before they started using the 4.3

good to know thanks. doesnt appear to have multiport and the stock intake is long gone, so I wasnt sure. must be throttle body injected?

FyreDaug wrote:must be throttle body injected?

If it wasn't, maybe it should be now....

I was just answering another post, and remembered that the 4.3 V6 I worked on a few years ago had a MPFI, but it was weird. It had a single injector underneath the intake manifold, with distribution tubes to each cylinder. This system has an intake manifold that looks like a TBI manifold so it can easily be mistaken for one, especially if the TB was replaced with a carb. If this is what you have, you can pick up a TB that will bolt right up, having a TPS already built in, (I don't remember if it had an IAC or not). Does your engine run on gasoline and propane, or just propane? Wondering if you still have the original TB in place and someone just added the propane "hat" to it?

well we bought it this way. it runs and drives but gets poor economy. and lacks power. and yes. strictly propane

the dist is just in a fixed position with no electronics and no vacuum lines connected to the nipples open on the dist. so as far as I can tell, it was "set" to a point where it wont ping on full load, but has no sort of change anywhere in between for load or rpm.

as for the mixer, man, dont get me started on how bad it is. all that is on the motor is the lower intake that bolts to the heads. on top of that is a few ghetto-ly created pieces (not even securely attached!! I can rock the top of this "manifold" around, theres air leaks galore I bet) and the mixer itself breathes through a smaller tube than the stock vortec intake would be. like theres a maximum of a 2" opening on this tube they used.

we have found a good running stock 4.3 vortec with 90% of the stuff on there. it has a complete intake system which I want to swap over to this thing and bung an injector in by the tb, and just do a single electronically controlled nozzle/injector. originally the idea was just to put the ms on it with some o2s and see just how messed up it was, but then we got digging into it, and I want this whole intake system replaced.

the current dist has a coil built into it, which im not a fan of (due to lack of experience with said device) but there is a dist on this other motor. I have not personally looked at this other motor as its a friends project im helping him set up, and I dont think COPs are necessary on something like this. if anything - with mods - we want to get up to the stock 4.3 horsepower with propane. so we got about 30% worth of improvement to make (not including all the inconsistencies with the current setup, it probably doesnt even have half the power a stock vortec does)

but anyways, enough rambling. what I want to do is swap over the stock intake to this motor, put a ms on it, use an electronic dist so I can get a VR pickup and play around with it. ive been reading alot on propane but I still cant figure out how to calculate max hp rating of an injector when all it says is
Flow Rate - LPG:
2.0 grams/second @ 18.5 PSI

I think I'd try contacting the injector manufacturer and ask them what size you will need, although, I think you'll need more than one to get the flow you want.

well as it turns out, the motor that is in the truck must have originally been carb'd because the heads are different. so I convinced buddy to spend some money and we will be rebuilding the newer efi motor and propane injecting it. might be a little complicated, but no big deal

I might be able to shed a little light on your mystery engine. IF your engine truly came out of a s-10 truck or blazer, it had a Rochester model 220 twin bore throttle body with (2) 43 lb/hr injectors. Chevy's RPO (Regular Production Option) for this engine was "Z".The intake would have been cast aluminum, single plane. If by chance it came from a 1987 Astro van, it would have had a cast iron dual plane manifold with a Quadrajet carb sitting on top. I believe that was the only year/application that used it. Somewhere between 1990 and 1994 Chevy switched to the infamous CPI (Central Port Injection) system that Devastator was alluding to. This engine had a RPO designation of "W". I believe it is the same time that a ballance shaft was also added to help damp out engine vibration. It had one fuel injector mounted inside the plenum of the intake (which was cast aluminum, comprised of a top and bottom half) and used a "distributor" to send the fuel down plastic fuel lines to poppet valves positioned roughly where standard port injectors would be located. The throttle body is cast integrally to the upper half of the manifold and the inlet faces forward and slightly to the passenger side. You'd be hard pressed to find a fan of that injection system. In at least one year (1995) the blue bowtie used a composite plastic intake that retained the CPI system, but had a more centrally located throttle body that, although I haven't measured it, looks suspisiously like the same one they are using on the '04 Denali with the 6.0 liter. A distinguishing feature of that year was a "flat top" distributor that had the plug wires exit horizontally from the cap. At some point Chevy got religion and finally went to a full-blown port injection system, I believe but am not positive, that it was around 1999--that's getting newer than the project engines I've been working with.

I believe all these engines used a distributor with no vaccuum or centrifigual advance mechanism, and with an externally mounted coil (not the coil-in-cap HEI distributor)

The manifolds for the TBI "Z motor" and CPI "W motor" ARE interchangeable, the center four manifold mounting holes enter the head at a slightly different angle on the two engines, but work fine by elongating the corrosponding holes in the manifold slightly.

Hope this helps you or someone else figure out what they're working with.

tonkatoy wrote:Somewhere between 1990 and 1994 Chevy switched to the infamous CPI (Central Port Injection) system that Devastator was alluding to.

Thank you for the clarification. Yes, this is the system I was referring to.

tonkatoy wrote:I believe all these engines used a distributor with no vaccuum or centrifigual advance mechanism, and with an externally mounted coil (not the coil-in-cap HEI distributor)

This would be an easy dizzy to use with MS2.

ok wow, lots of thoughts went through with this. and now the new motor is half apart, I might aswell shed some light as to what we are doing too. thanks for the informative post, ill get to my observations in a sec....

we are building it with high compression pistons, bored block. rebuilt heads, coltcams mild cam (possibly rockers? havent looked into it, just saw buddy had the heads actually off) and rebuilt bottom end. I suppose I will go post this on a chev forum, but does anyone know how much power these motors can take? tonkatoy sounds like he knows alot about them. being that its propane, our horsepower expectations-ish are 90-100% that of stock rated gas power. with the high comp and the timing control aswell as a nice mild exhaust system+cam I think we can get close to rated horsepower, maybe im too optimistic....

im not sure what motor is in this truck right now, I did a little research myself and what you just posted tonkatoy, is the best info ive found so far. however.... the dist in the car does infact have a built in dist, WITH vac cans. we checked the timing, its set to a static 35 or so degrees by the looks of things. im not sure how the damn thing ran. but it has some nice shiny VORTEC valve covers on it.... the intake manifold wont bolt up, perhaps they will LINE up, but the bolt holes are either in a different angle or just wrong all together. the way the manifold looks makes me think it HAD to be carb'd. its just pretty much a flat manifold across the heads

the new motor, wow, looks like a piece of art in comparison. Im digging the manifold design on this, it has this central injection system, looks like a great place to put some nitrous nozzles direct port-like (I think I have him convinced) this dist does require an external coil, and has two connectors on it. one two wire, one three. havent looked into it yet, but its definitely the dist we need (as opposed to the carb one)

only thing im looking into is a good propane regulator, so its not liquid propane (high pressure in-tank) but still below [something like 18psi?] and in vapor form. Ive found a few gaseous injectors but haven't figured out how many I need.

FyreDawg--
If you want to know exactly what engine you have, I suggest this link: http://www.marineandstreetmotorsport.co ... page_id=13

It's a website for a speed shop down under. I found it invaluable to determine what the heck year engine I was rebuilding for the MegaSquirt project. (It'd been given to me almost a decade earlier!) As for how much power the engine can reliably make, the weak point will be the crankshaft. If you've had the oil pan off and looked at the bottom end, you will understand what I'm talking about. In order to get an "even fire" 90 degree V-6 it is necessary to use a "split" rod journal. The journal for each set of rods needs to be offset a certain number of degrees to each side of an even 60 degrees of crankshaft angle. That means that there isn't a continuous diameter between adjacent cheeks, there is a small section between the rod pair that is football shaped. That's what makes the crank weaker than a typical V-8 crank (the rod bearings also must be slightly narrower also which reduces bearing surface).

Stock horsepower numbers for the 4.3 were 160 hp for the throttle body "vin Z" engines and 200 hp for the C.P.I. "vin W" engines. The power increase was due more to a change in cam grinds than the injection setup. For the record, the calculations show that I should expect about 260 hp for my project running about 7 psi of boost. The crank should hold up to that because they used the same crank in the turbocharged Syclones and Typhoons, they only changed cam grinds and pistons in those engines.

Buick and Olds had some "odd-fire" 90 degree V-6 engines that retained the common rod journal that V-8s used, but power strokes (and ignition events) were at 50 degrees, then 70 degrees then 50 degrees, ect. of crankshaft revolution. That would be a strong crank, but more difficult to set up timing control in MegaSquirt.

As far as you diggin' on the CPI intake manifold, like I said, almost nobody cared for that system. It was a half-step between TBI and Multiport. The injector assembly is quite expensive and there isn't really any way to upgrade the flowrate, and the system required a "pulsator" (I've seen it described as an accumulator) that if it fails will not cause the engine to stop running, but will in most cases prevent it from starting. Hate is strong enough for the setup that a retrofit to true port injectors was developed. On the positive side, it was constructed to create long intake runners, which is good for low end torque, but there was a butterfly valve which was actuated by the ECM that opened above a certain rpm that would in effect shorten the runner length to help the engine breathe better at the upper rpm scale. Also, I'd shy away from the nitrous on this engine because the peak cylinder pressures it causes is hard on bottom ends and like I said the crank is the weak link in this engine.

The distributor on the new engine is typical of those that were used on the 4.3 and other fuel injected Chevys of that era. They were designed to have the spark advance controlled by the ECU so it will work nicely with MegaSquirt--sit down and a couple times and it'll wire up like a snap.

You're on your own with the propane questions--all I know about that is off-roaders consider it "poor man's fuel injection" because it can't flood out in off camber situations and that you can go a lot longer between oil changes because it burns so much cleaner.

Good luck on your project!

good link thanks for the read, waiting for parts is the hardest part