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Old 01-10-2008, 12:04 AM   #21
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Definately you ought to give some thought to completely characterizing the AFR's from a 1962 VW bug. And get the timing off a '27 ford of some sort. Maybe record the gear ratios for the rear end in every tow truck made in australia from 1960 to 1977, and sort it by weight.

Then, plug the MS into the car, and drive around. If your wideband says you are rich, take out some fuel. It will take 1/10th the time, and you could argue it's at least a passible representation of your year car with your manifold, your turbo, your injectors, your seat belts.....

Anyway. :-)
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Old 01-10-2008, 11:57 AM   #22
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Actually, I'm using a '75 Beetle. That was the first year for the L-jetronic EFI system which, while analog, worked pretty well.

Seriously though. This bench-testing period is valuable to me. I'm getting a chance to play with all the software settings and learn how they respond without worrying about blowing up the car or otherwise not having it in service for an extended period of time. And I'm a geek- looking at squarewaves on an oscilloscope that cost more than my car falls into my broad definition of fun.

I did make some interesting observations last night. Initially, I'd plugged in Ben's Req Fuel number of 4.2ms, and lag of 1.0ms. He's using essentially the same injectors as I am, and those nmbers came from DIY. No reason to doubt them.

However, when I ran the Req Fuel calculator myself, inputting 1600cc, 440cc/min, and 14.7 AFR, it gave me an output of 6.2ms. What the hell, I say. So I put that number in, and also increased the lag time (which I must admit is a total unknown to me) to 1.2ms, and now I'm seeing output durations that are a whole lot closer to what I expected when using Ben's VE table with EGO turned off.

So that was a valuable (if puzzling) learning experience. I'm going to try running these numbers to start with and see what that gets me.

In all seriousness, it's going to be a little while before this goes on the car. I've got some work-related travel coming up, and my car seems to have developed a rather nasty hestation all of a sudden. That needs to get fixed before the MS goes in. I'm thinking that my fuel pump may be on the way out, so I ordered a new Walbro from lightning Motorsports yesterday. This pisses me off as I'd had a Walbro 190HP sitting on the shelf (I bought it way back before I learned of the EMU when I thought I'd be stuck in AFPR hell but never installed it) and I finally sold it just about a month ago.
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Old 01-10-2008, 06:05 PM   #23
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Haha. Sorry to hear about your fuel pump troubles, as well as your being under the weather.

I do sometimes wish I could go back and get some measurements off the stock ecu, but aside from the idle valve settings there's not much I'd want to know. I imagine I can measure that empirically. The VICS switching RPM maybe I can get from someone who has a 99.

The other thing is that I'm going to be running totally different injectors, I'm already running totally different coils - all the truely important outputs are going to be different. So I just want to get a "how do I tune a MS" understood, then start over on the new equipment.

I want to figure out a solid charge time for the coils.

Oh, *AND*: I had a crappy idle, it was stalling at stops. Regularly. Then I went to the MS and it stopped happening. Go figure. :-)
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