ok, thats what I read lol... my bad... I mustve disregarded that last bit about cam sensor signal.


Cheers for the info

Don't feel bad. I wasn't trying to shoot you down, I was just giving everyone all the info.

EB-EL 4L all use Bank fire (2 banks of 3). AU 4L onwards uses Sequential.

So yes, it would be an issue for AU4L and EB V8 onwards. But then again.. how much of a wank is SEFI? I'm going to be using it on my waggin, cos I can. But its not a huge deal... just like injector timing. There are MASSIVE threads for all ECU's which support adjustable injector timing, and no one seems to be able to agree if there are performance advantages to be had.

Nahh I think the debates of performance gains from SEFI are long over, SEFI is more for the fuel economy, emissions and higher state of tune you can get at low rpm or cruise conditions, so it might take some of the gruff out of it at idle compared to bank injection.

If you read ion the MS site somewhere, or even if you do the calculations yourself, you'll find that sequential and banked are exactally the same above about 2800RPM full throttle, 12.5:1 AFR.

The thing about sequential is that it injects the fuel into the cylinder when the intake valve is open.

If you've got 270 degrees duration on the intake valve, you've got 16 miliseconds to inject the fuel within the 270 degrees valve duration @ 2800 prm

Go any fater than that and all of a sudden you need to open the injector BEFORE the intake valve opens. When you're producing max power and your injectors are at 80% duty cycle, (i'e open 80% of the time) obviously there is fuel being injected when the vavle is closed.

Work it out! If you've got 270 degrees duration every 2 revs, the intake valve is open 37.5% of the time, but the injector is open 80% of the time.

So, like it states on the MS site, sequential will give you a slightly smoother idle, lower emissions and a bit better fuel economy.

Now, consider this! A banked injection system giving you an AFR of 16.5:1 (max economy) is going to give you far, far, far better economy than a sequential system running at 14.7:1 like the Falcon does.

So any economy gains you get from running sequential @ 14.7:1 AFR over banked @ 14.7:1 AFR are going to be overshadowed when you use MS and run your engine @ 16.5:1 AFR even though it's banked injection.

I guess i was thinking about the architechture of the wiring system - how much would need to be changed to "covert" a SEFI loom to a bank-fire MPEFI, and what other little "intricacies" you'd come across in doing so??

And if SEFI is a factor only below 2800rpm, it sounds like it contributes a fair bit to driveability.... (i.e. i didnt see anything above 3 grand coming into work this morning)... prolly not an issue for stocko/forced induction engines but surely there's good driveability gains to be had on a radical n/a tune?

BTW.... is running an engine at 16.5:1 AF a good idea? Even under cruising? Never experimented myself but ive read that running an engine lean over prolonged period tends to shorten its life....

An engine run too lean will burn out it valves. It has bought many an airplane over the years. In the planes the pilot has full control over the mixture and we use the exhaust gas temperature as an indicater of mixture.

You lean it out to peak EGT then richen it up a little to stop the vavle burn out. If an angine is designed to run at 14.7 then leave it there. If you do the maths and workout the cost saving of running 16.5 versus installation cost, engine wear etc. then I think you would give up on it.

If you are tuning for max performance then thats a different story.

It would be a no brainer. Just connect your X opposing injectors to one injector driver, and the other X opposing on the other.

Going from Bank or Batch to SEFI is a little harder, as you'd have to install individual wiring to each injector.

Agree. Running an engine too lean will burn out valves.

If you run an engine @ 16.5:1 AFR @ full throttle then you will burn out valves. However, when you're cruising along the freeway with the engine producing 10-20% of max power, the amount of heat that is required to burn out valves simply isn't being created because the engine power is so low.

Running an aircraft engine @ 16.5:1 AFR in a 75% cruise is very, very different to cruising along the freeway in a 20% cruise with 16.5:1 AFR. Running 16.5:1 instead of 14.7:1 will get you a lot further on a tank of gas. Some people who have used MS have reported up to 25% more mileage out of a tank when they tuned their engine for 16.5:1 instead of 14.7:1. Most of the car companies are now incorporating wideband oxy sensors into their higher spec cars and running them @ 16.5:1 in cruise.

Also, have you ever heard the term "lean burn engine" These are the Jap engines that are incredibly efficient and the reason they get such good economy is because they run @ 16.5:1 in the cruise.

So while you're right, you're actually speaking in the wrong context. And there are a lot of d***head out there who don't know how to lean a plane out correctly(Yes I do know what I''m talking about cause I'm a pilot too)

There's actually a lot about engines that isn't covered with standard aviation theory. I was tought for instance, that carbies used in cars did not posess any sort of accel enrichment devices. Now that was COMPLETELY wrong!

To make the best of it, you should wire up your injectors so that, starting from no 1 cyl, the first three cylinders that fire are bank 1, and the last 3 that fire are bank 2.

There are also people that believe that the pressure drop in the port when the intake valve opent is dramatic enough to re-atomise any fuel sitting in the port and as such, it makes very little difference when the fuel is injected.