sequential injection

[hoshy]

I fancy bodging together a sequential system for my m40. Any ideas what I can use for the cam position? Something simple and/or cheap.

[320Touring]

a midgit with really good eyes???

honestly tho-i take it you're talking about a sensor of some sort?

could you not bastardise an m42 cam sensor?

[hoshy]

does the m42 have a cam sensor? cool it I can make it fit.

Doubt I'm gonna see much by the way of improvements in econmey or performance but it's a cool little project and then I have the satisfaction of know it's more efficient

[320Touring]

does the m42 have a cam sensor? cool it I can make it fit.

Doubt I'm gonna see much by the way of improvements in econmey or performance but it's a cool little project and then I have the satisfaction of know it's more efficient

well once you perfect it-maybe you can develop a 6pot version

here's hoping it goes ok?

ps what exactly does it do?

[hoshy]

non-sequential injection fires banks of injectors, I have 2banks of 2. so every time one injector fires for the intake cycle the other injector fires into another cylinder. I guess behind the valves where the fuel deatomises so when it finally gets to burn it won't burn as clean. I'm sure that somebody can give a far more complete description but that's the rough idea. Sequential on the other hand just fires one injector as required.

I spose a 6pot version would be just as easy.

[320Touring]

non-sequential injection fires banks of injectors, I have 2banks of 2. so every time one injector fires for the intake cycle the other injector fires into another cylinder. I guess behind the valves where the fuel deatomises so when it finally gets to burn it won't burn as clean. I'm sure that somebody can give a far more complete description but that's the rough idea. Sequential on the other hand just fires one injector as required.

I spose a 6pot version would be just as easy.

ahh, right cool!thanks!

had basic thoughts going that way-and would make a helluva difference knowing u aint pishing extra fuel down bores and making the engine run cleaner

[hoshy]

yeah that's what I'm thinking. I just don't like the idea of it not being efficient. And unless I'm completely missing something it should be damned easy.

Just fit a sensor, run individual ground wires to the injectors and have it make the redundant injector go open circuit whilst the other one is fireing. That way all the fueling run form the orginal ecu trigger, only difference is the unused injector really is unused. At least I hope it's that simple

[320Touring]

yeah that's what I'm thinking. I just don't like the idea of it not being efficient. And unless I'm completely missing something it should be damned easy.

Just fit a sensor, run individual ground wires to the injectors and have it make the redundant injector go open circuit whilst the other one is fireing. That way all the fueling run form the orginal ecu trigger, only difference is the unused injector really is unused. At least I hope it's that simple

wont be a problem with pressure build up in the injector thats closed? given that the FPR would be maintaining the presure but the injector aint opening?

[320Touring]

an arguement against (using a bmw engine )

http://yarchive.net/car/fuel_injection.html

[hoshy]

yeah that's what I'm thinking. I just don't like the idea of it not being efficient. And unless I'm completely missing something it should be damned easy.

Just fit a sensor, run individual ground wires to the injectors and have it make the redundant injector go open circuit whilst the other one is fireing. That way all the fueling run form the orginal ecu trigger, only difference is the unused injector really is unused. At least I hope it's that simple

wont be a problem with pressure build up in the injector thats closed? given that the FPR would be maintaining the presure but the injector aint opening?

Don't think so cos fpr keep the pressure on all the injectors. you even have pressure there when the car is off that's why if you get a leaky injector you'll have starting problems.

[320Touring]

yeah that's what I'm thinking. I just don't like the idea of it not being efficient. And unless I'm completely missing something it should be damned easy.

Just fit a sensor, run individual ground wires to the injectors and have it make the redundant injector go open circuit whilst the other one is fireing. That way all the fueling run form the orginal ecu trigger, only difference is the unused injector really is unused. At least I hope it's that simple

wont be a problem with pressure build up in the injector thats closed? given that the FPR would be maintaining the presure but the injector aint opening?

Don't think so cos fpr keep the pressure on all the injectors. you even have pressure there when the car is off that's why if you get a leaky injector you'll have starting problems.

ahh, good point! what do you think of that article?

[hoshy]

an arguement against (using a bmw engine )

http://yarchive.net/car/fuel_injection.html

not really an argument against it. just says there's prolly not much point... which I already realise. but as I said it's the peace of mind and the satisfaction of playing and learning. And that doesn't mean the *won't* be any benefits... I could always strike lucky and end up get much better atomisation due to the fuel not standing behind the valves for those few milliseconds

edit: damn interesting read. I love it when sombody who knows what they're on about gives a little discourse on the futility of an excercise. It's the voice of experience that will never be listened to by the likes of me who will bash on and do it anyway in true youthful arrogance ... still a good read and food for though though

[Turbo-Brown]

Aah, now the fuel on the back of the inlet valve helps cool it and also the heat atomises the fuel (this is with the batch fired system)

Also, don't forget that with fully sequential, you need injectors with twice the flow capacity as all the fuel is injected in one hit, whereas with batch firing, it goes in in two halves.

Not sure how you'd rig a batch firing ECU to trigger sequentially either.

Finally, with the smaller injectors that batch firing allows, you get finer control over the fueling which has potential to lead to better economy etc.

[hoshy]

Cool.

I was waiting for you, brianmoore ant or the like to comment. I hadn't figured out the two loads of fuel bit yet.... That may be as how stopper. Hmmm..... requires further discussion with daddy me thinks.

I guess I'd either have to flow twice the amount or open them twice as long. neither of which were part of my orginal simple plan. damn it.

[Ant]

Batch fire is not as old skool as you might think, sure its evolved from Bosch CIS and shares many similarities to that setup, but its a good workable system with very few pitfalls, indeed its still the most commonplace system out there.

I wonder how tight the camshaft sensor would allow control anyways? the sensor resoloution cant be that high due to the physical size of the cam pulley, older mercedes use a similar setup to what you're proposing, it works but I fear wont give you what you're looking for dude

Alex , as always has brought up some excellent points. good call dude !

[hoshy]

cheers man. looks like I'll have to back burner it for a while but I'm gonna keep on collecting info and thinking about the posibilities... no doubt some other fantastic idea will jump out at me before long

I'm sure if it's on a BMW, even an m40 that it's a good, well tested system but I really like the idea of sequential... it's on of those things that "just seems the right way to do it"

[hoshy]

Ant, Alex

Would doubling the opening times each cycle work or would it *have* to be a case of having higher flow with the same duty cycle?

I guess the problem with having longer cycles would be when you get high up in the rev range... would there be enough time to inject the required amount of fuel... hmm I guess that leads me to all those flow rate equation things I see on the net. hmm.

[Turbo-Brown]

Yeah,it's at higher engine speeds that you'd need the extra flow capacity.

Now if you could do something like the Honda NSX has: It runs sequential at low engine speeds switching to batch at high speeds, effectively doubling the amount of injectable fuel.

At the other end of the scale, the 205 GTi largely ignores the position of the engine and just triggers all four injectors at the same time. Still manages just over 68bhp/litre, which is about the same as the M20 2.5, which incidentally also doesn't pay too much attention to crank position.

Now, if you could get sequential ignition using 4 coils, you might be onto something as the longer charge time each coil would have should lead to a more powerful spark meaning you could run a bigger spark gap and even higher compression

[Martinaston]

If you really want to go for it, What about fitting a second set of injectors that only come into play over a certain speed.

If you have sequential injection you would probably run into even/smooth running problems as the injectors age and clog, This is a problem i have now with the current system. And redex doesn't do what it says on the tin

[hoshy]

If you really want to go for it, What about fitting a second set of injectors that only come into play over a certain speed.

If you have sequential injection you would probably run into even/smooth running problems as the injectors age and clog, This is a problem i have now with the current system. And redex doesn't do what it says on the tin

This whole idea came about cos I popped out my injectors to run them through the Lucas ASNU injector cleaner. I'm sure there's a dealer round London way somewhere.

It was when they were out that I noticed it was batched injection... I'd not even thought about it before then.

[hoshy]

Yeah,it's at higher engine speeds that you'd need the extra flow capacity.

Now if you could do something like the Honda NSX has: It runs sequential at low engine speeds switching to batch at high speeds, effectively doubling the amount of injectable fuel.

At the other end of the scale, the 205 GTi largely ignores the position of the engine and just triggers all four injectors at the same time. Still manages just over 68bhp/litre, which is about the same as the M20 2.5, which incidentally also doesn't pay too much attention to crank position.

Now, if you could get sequential ignition using 4 coils, you might be onto something as the longer charge time each coil would have should lead to a more powerful spark meaning you could run a bigger spark gap and even higher compression

When I first mentioned the idea we talked about using the twin coil packs form the m42 as part of the deal to run bigger plug gap so we could get the extra benefit of leaning off the mixture... but I think pissing about with flow rates and stuff is a bit out of my league atm...

[Martinaston]

Yeah found one that cleans them for Ԛ£15 each so i'm still in two minds as to weather they'll tell me there knakerd anyway and would be better off just getting a new set.

[hoshy]

it's a tough one considering how easy it would be to get some 2nd hand injectors I guess.

[Martinaston]

I've already got 9 spare

[hoshy]

I've already got 9 spare

so what are you waitng for man! it ain't hard to swap the little bad boys over! Took me a couple hours and I've got two left hands* when it comes to spanners


*er. actually two right hands cos I'm left handed if you see what I mean.