DIYEFI.org Forum

OK thanks. I will let you know how it goes.

KA

I know it is an ND CAS, it is cast into the body. I did not know how many engines it was used in though. I admire your enthusiasm for the project, it has to take a lot of your time.

Will the missing top tooth (i.e. 24 and 1) cause any problems with ignition?

You mentioned staged injectors earlier- I am using 4 550 cc mazda low impedance injectors circa 1991 turbo rotary. At the moment I don't see an issue with firing 2 and 2. I am using Jean Belangers peak and hold board, and plan to fire 2 and possibly stage the second 2. Since I am planning 300 HP, and all these injectors should feed is 300 HP, I may fire all 4 and adjust the VE table to make it work.

Thoughts?

No, not using one of the two signals is not a problem. They put them there to double up sync opportunities and increase start up speed. It also aids in verification that nothing went wrong, twice as often. Ignition and injection don't care at all.

Re injectors, you can fire them in a timed fashion, and bring in the second set later on, no code for it right now, but no big deal either IMO. I've got some news for you about the injectors, though, if they're a legit 550cc, then they'll flow more like 365hp, and if they're "550cc @ 85% duty" then it's more like 400hp.

Injectors-

We typically plan the 550s at 300 hp for 4, it keeps the duty cycle down. In the beginning some guys used LT1 GM coils and GM injectors, then Ford injectors, and down the line only to find that after 5 hours at 6000 rpm they burn up. The GM coils cant handle the high duty cycle, and the injectors bail out at a constant 85% or more.

Even race cars don't run continuously at 300 HP without letting off the throttle for hours and hours on end. Every so often there are curves

Mine are the standard brown low impedance Mazda 550s, and rated for max 85% duty cycle. It would be nice to have an extra 75 hp for takeoff though.

I will start with the image that I downloaded, but eventually I will have to compile my own code to make the changes I need to make.

KA

Re the coils burning up, that doesn't surprise me, only because they're GM parts. However, at the same time, I'd guess that the dwell was poorly configured in order to do that. A correctly dwelled coil only gets warm. An over dwelled coil rapidly gets very hot and burns up. Remember the days when if you left the car key on without the engine running you could ruin the coil? :-)

About the injectors, you made my point for me, peak power. You stated a number, "and all these injectors should feed is 300 HP", you didn't state continuous rating. Peak is higher. Peak is useful at take off, too, as you say. What will the injectors flow? More, much more. What will they safely flow continuously? Different question :-)

You should start with the skype call, how about later today?

Fred.

I have to shoot video for our church this morning and early afternoon, should be back by 4:00 our time.

I will check for messages from you here when I get back.

KA

That's 10pm for me, which is fine :-)