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fuel injection ignition

1515 Views 5 Replies 5 Participants Last post by  Mrfixmaster
I have been looking around at aftermarket efi ecu's and it seems to me that the vems genboard v.3 is the cheapest and most powerful ecu, atleast compaired to the accel VII and bigstuff3. anyways, I know I am not ready to get into fuel injection yet(my car has quite a ways to go) but I'm trying to plan out my moves, and I am confused on the ingnition. The fuel injection part(ex. intake, rails, injectors, pump...) I feel I understand.

On one hand I could, or I think I can, run a distributor seperate of the computer to fire the plugs, and have the genboard deal with the fuel system only, bank firing i think. Then I could use a msd bost retard box to control the ignition, if I go turbocharged which I hopefully will some day.

On the other hand I could some how have the genborad control the fuel in sequential firing and spark, This is where my question/s lay. If I did it this way I would have to send the computer a crank position signal and cam position signal. I guess i could use a msd crank trigger, but what about the cam positioning sensor? I guess I am really asking if there is a distributor that has both trigger built in with the output wires ready to hook up? I think crane sells one for only $800?, I've been looking at the vems site and some of that stuff is pretty deep:confused:

Also if I was to have the computer control the spark I would have to use eight individual coils right? and still run a distributor to run the oil pump and or triggers?

Any suggestions on which ignition setup would be great. My ultimate goal is about 500-600 hp turbo sbc (I know I could probibly do that with a carb in a box, but I am very interested in building my own intake/efi setup plus the tuneability of the efi)

any help would be great, I'm trying to learn as much as I can before I start buying anything and wasting $.

sorry about posting twice, i must have enter before i was done:pain:
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Post the website for the vems system, I've never seen it. You will also want to check out and MegaSquirt is a DIY EFI controller, or you can buy it fully assembled. It can be done on a budget.

You can use computer controlled ignition. Those two sites should give an idea as to how. The crank trigger is usually a wheel that bolts to the balancer and has an optic sensor mounted on the timing cover. You can also keep your standard ignition system and just have the computer control fuel delivery.

When you use a multi coil system you only have half as many coils as cylinders. Two pistons are always near the top at the same time no matter what engine configuration (four or more cylinders). The coil fires both cylinders at the same time. The one that fires in the exhaust fires weak because a spark jumps best through "clean" air. It's called a "lost spark" system. All the OEMs use this method.
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The genboard is what TurboS10 uses I believe and he has nothing but praise for it. Maybe you should PM him and see what he thinks.
Wasted spark setups are not really what all the oems are using. Most oems are going to a full COP(coil over plug) setup with one coil per cylinder. This is by far the most powerful ignition system available. Genboard can handle up to 8 ignition coils, so if you have the money and want to set up an old engine with COP, you can do it. If want to save some bucks, wasted spark with COP can be handles by genboard as well and a few guys are doing this already. You can also use the Mallory distributor with trigger built and wire it directly to the genboard. I am using this and it works very well. All the genboard does is see the trigger and then delay the spark output to the coil to adjust the timing advance. It is very cool to be able to tune timing with a key stroke on the computer while the engine is running. Timing is controlled with tables just like fuel.

The most accurate way to control timing is by using a crank trigger. The distributor triggers will work, but they are not nearly as accurate due to chain flex and gear slack.

If you want to do the sequential injection you can do it with one trigger, but the injector phasing will not be possible. Phase specific injector firing is really only helpful for a little gain in fuel efficiency. With the cam(distributor) and crank sensors, you can get dead on timing and perfect injector phasing.

I will also add that the WBO2 on the genboard is just awesome. You can graph timing, fuel, RPM, MAP, IAT, and AFR all in one screan. I actually tuned my turbo engine in three test runs after getting the WBO2 up and running. I did all the tuning with a calculator on the kitchen table basing changes on datalogging.

The vems group is working on getting a manual together to help new people. The developers like the wiki engine, but I personally hate it. After the manual is substantially finished, we will likely put up a simple bulletin board for Q and A. It is almost needed just to tell people where to find things in the wiki. Once you get used to wiki, it is not so bad, but at first it really sucks to navigate. The group is aware of this and is working to a better sollution

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To mis-quote a golfing commercial.."D*MN THOSE GUYS ARE GOOD!!!"
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