EFI Madness

[CTX-SLPR]

Howdy,

Just a mad question, could you run a V12 off of 2 straight-6 computers? Probably have to have a pair of cam and crank sensors unless you could reprogram the offset for the sensors so they are on the correct locations for the #1.

Just a thought,

[TheSilverBuick]

Re: EFI Madness

I'm guessing it would have to do more with the firing order of the V-12 relative to the L6. Is a cam sensor necessary for anything other than sequential fuel injection? Perhaps a crank trigger and using the sensor placement as a method to trigger #1 cylinder for each bank (like one sensor at the 3 o'clock position and the next 30* off set (360*/12cyl=30*) to make a second #1 cylinder on the opposite bank.... I'm probably in over my head...

[efi-diy]

Re: EFI Madness

If you divided the tach input pulses /2 then and ran batch fire - then yes you can. The ECM doesn't give a rats ass what its hooked to. All it know is the signals feed to it. BMW did this on their V12. Or run megasquirt - it will do 12 cylinders fine.

[CTX-SLPR]

Re: EFI Madness

I like SEFI and MAF systems. I also like factory EFI setups so I am always looking how to leverage them for something else. The problem for my nailhead is that I can't find a thing with the right firing order and will probably have to go MAF megasquirt with no SEFI unless they support that now. This is for something else, I'm not sure what, but I thought I'd ask.

[dieselgeek]

Re: EFI Madness

I like SEFI and MAF systems. I also like factory EFI setups so I am always looking how to leverage them for something else. The problem for my nailhead is that I can't find a thing with the right firing order and will probably have to go MAF megasquirt with no SEFI unless they support that now. This is for something else, I'm not sure what, but I thought I'd ask.

You like MAF and SEFI systems because you've raed about them. But the first time you do an EMS system, you'll like Batch Fire and MAP systems better. Why? Because they'll run an engine equally well, and you can actually tune a standalone using one. There's a reason that 99.999999% of all standalone EFI systems are Batch/MAP and it's because they run just as well, and are tunable. Trust me, once you've done a few, you'll agree with the rest of the tuning world.

Re: V12 using two computers, lots of engines were run that way. Ferrari F40 engine came with a pair of Magnetti-Marelli units each running 4 cylinders. Jag had some v12s that had two computers, each running six cyl.

-scott

[SpiderGearsMan]

Re: EFI Madness

use 3 carbs

[CTX-SLPR]

Re: EFI Madness

I disagree, I think most aftermarket EFI systems are Speed Density because 4 of them were designed pretty much by 1 man John Meaney. The old FelPro system, the FAST DFI systems, and the Big Stuff 3. That leaves the XFI, Haltech, Megasquirt, and the Holley and Edelbrock systems as Speed density and of those the XFI is potentially an expansion of the old FAST system and the Holley and Edelbrock I bet are reboxed versions of something. Megasquirt I know is fresh and new (and does MAF if you want it to as you pointed out) and I don't know anything about the Haltech. I really want a MoTec unit but thats well beyond my budget.

[dieselgeek]

Re: EFI Madness

I disagree, I think most aftermarket EFI systems are Speed Density because 4 of them were designed pretty much by 1 man John Meaney. The old FelPro system, the FAST DFI systems, and the Big Stuff 3. That leaves the XFI, Haltech, Megasquirt, and the Holley and Edelbrock systems as Speed density and of those the XFI is potentially an expansion of the old FAST system and the Holley and Edelbrock I bet are reboxed versions of something. Megasquirt I know is fresh and new (and does MAF if you want it to as you pointed out) and I don't know anything about the Haltech. I really want a MoTec unit but thats well beyond my budget.

I disagree with you, and have installed nearly 200 standalone including all in your list. SEFI and MAF only exist because of emissions laws - not because you can gain any performance with them. Also, I'm not sure you quite understand MAF in the OEM environment. It definitely does not just "measure air and add corresponding fuel" i.e., you can't change V.E. of a given engine by more than a few points anywhere on the load map, and expect a MAF to follow along. I realize lots of people on the internet say it works this way - but it doesn't. I've been having to show this to a couple locals recently, MAFs just plain suck and are an air restriction in the intake. If you're worried about emissions during warmup, then a MAF can be helpful. Otherwise - junk,

-scott

[JustinSuhas]

Re: EFI Madness

oh man, i need an efi for dummies book in the worst way. It just seems like something kinda hard to jump into... and carb's are sooo cheap.

Im not even old, i shouldn't be this efi clueless. Any suggestions where to start an efi knowledge quest?

[dieselgeek]

Re: EFI Madness

oh man, i need an efi for dummies book in the worst way. It just seems like something kinda hard to jump into... and carb's are sooo cheap.

Im not even old, i shouldn't be this efi clueless. Any suggestions where to start an efi knowledge quest?

there are some books at Borders, Barnes & Noble. While they have good info, they always seem to wander off in the direction of the author's comfort, which means you end up reading too much about systems you aren't necessarily going to use. I first learned about EFI out of necessity, I thought the most helpful reading was the Mega Manual, which is the only EMS documentation I ever found that had useful installation, tuning, debugging articles.

Table of contents for the megamanual is here: http://www.megamanual.com/v22manual/mtabcon.htm

The section on tuning, skip the rest if you're not checking out megasquirt, here: http://www.megamanual.com/v22manual/mtune.htm

[SpiderGearsMan]

Re: EFI Madness

yet most oems run maf

[SpiderGearsMan]

Re: EFI Madness

maybe in 1986 maf sensors were a restriction , now it is just a little probe in the hose , thanks to hitachi for designing a reliable maf , something bosch and delco could not do

[TheSilverBuick]

Re: EFI Madness

yet most oems run maf

As DieselGeek pointed out, they are useful for A/F calculations while the engine is cold and before the O2 sensor is in it's operating temperature range. Start modifying the engine to require more air and they quickly become a bottle neck (near as I can tell) to airflow, the MAP system are much more flexible when air requirements of the engine change.

[SpiderGearsMan]

Re: EFI Madness

biggest problem I see these days are Yahoos oiling the crap out of aftermarket air filters , wrecking the MAF

[HoosierGTA]

Re: EFI Madness

Just a EFI novice ( can figure why generally my TPI wont start ) . This is why I just use paper filters!