MoTeC Global Forum

Hi
I have a 347ci small block ford that I'd like to run via throttle body injection using the Holley Terminator X Stealth throttle body. It has four independently addressable injectors and a TPS. I also have a manifold pressure sensor. Does anyone have an M1 package that would be a good starting point, including accommodating throttle body injectors rather than sequential injectors?

Thanks,
Kurt

Hi Kurt,

What trigger system is there on the engine?

With only 4 injectors, I think that the best way of configuring this system would be as a 4 Cylinder 2 stroke engine (assuming that the ignition is controlled by a distributor) to get the most pulses out of the injectors for as consistent a fuel flow as is possible with that setup.

Thanks for your reply. I have an MSD 7A ignition unit that will provide a REF signal and an MSD 2358 distributor that has a SYNC signal. I had previously run the system on sequential fuel injection but couldn't get it to run super well. I think this was mostly due to the particular manifold I had to run given the very low clearance between the engine and car hood (this is a '67 Sunbeam Tiger).

I have been wondering if I can have multiple M1 injector leads fire a single injector. So either I could pair up a couple leads to one of the four injector or even have each lead fire all four injectors each time. Obviously, you'd have to make sure the duty cycle of the injector wasn't exceeded at top end.

Kurt

kurtd wrote: I have an MSD 7A ignition unit that will provide a REF signal and an MSD 2358 distributor that has a SYNC signal. Kurt

Kurt, are you sure you can get a ref output from any of the 7A family? I'd have thought you need something like a digital 7 plus to have a usable ref output?

Sorry, it’s a Digital 6A. It’s been in the car a while so I’d forgotten. It presently drives the rpm input to my C125 display, so I presume it’ll work as the REF signal for my M130.

Can I wire multiple injectors to a single injector channel on the M130? (wired in parallel, I assume)? As I said, the throttle body has four injectors total. I figured I could either fire them all at once each time one of the eight injector channels fires or wire two cylinders that are opposite in the firing order to a single injector. Obviously I’d have to make sure the duty cycle of the injectors doesn’t get exceeded at full revs.

With the setup Stephen proposed, setup as 4 cylinder 2 stroke, it gives you 8 injector firings per complete engine cycle rather than 4. I'd advise checking that the digital 6 can actually do what you want regarding the ref signal.

Thanks for the reply. With respect to not being able to provide a ref signal from the MSD Digital 6 box, can a distributor that puts out an engine speed signal as well as a synch pulse be used with the M1? I was thinking of something like the Holley Dual Sync Distributor that puts out a ref signal per cylinder fire and a single pulse per engine cycle.

Kurt

I just read the specifications...... A trigger wheel on the front or back of the crank and use the Holley distributor as a sync input will work. You could run the whole engine off the Holley distributor, both ref and sync, but you'd need to bear in mind the timing would be inherently less accurate than a trigger on the crank, which may not be a problem if you aren't planning on getting really sporty with the tuneup.

Thanks for past help on this. I have ditched the MSD Digital 6A in favor of a Motec CDI-1 (running with my Motec M1). Ref and Sync come from a MSD dual sync distributor, and it seems to have a healthy signal from each, and the car starts and runs at the right timing. The documentation that came with the CDI-1 doesn't have any recommended settings for the M1 ignition section. Are these available anywhere?

Kurt