555 EFI

[Greg Hermann]

>Chris Conlon wrote:
>>
>> This sounded like fun so I decided to play with it some, at least on
>> paper. I have a question, though. What's the range of adjustment due
>> to CTS, and what does that adjustment look like? I'm thinking that
>> at "warm" temp or above, there is no adjustment, and below that temp,
>> the pulse width gets multiplied by some value. The colder the temp,
>> the larger the value. What would that max value be, though? 1.1?
>> 1.5? 2.0?  In other words, how much of a % difference does coolant
>> temp make in the pulse width? I'm thinking it's 50-100%, which means
>> I have to put it at a different place in my circuit.
>>
>> >Okay, who's gonna be the first one to say it would be easiear to skip all
>> >the op-amps and use a PIC and some code?  ;)
>>
>> Hah! You beat me to it. This is more fun though. ;)
>>
>> Also a nod to whoever pointed out that this is "just" D-Jetronic, I
>> was thinking exactly that myself. ;)
>>
>> Anyway I'll try to get the circuit drawing into some format that
>> other people might be able to look at.
>>
>>    Chris C.
>Stoich is 14.7:1? Cold enrichment can be as much as something like 8:1
>or 6:1 from what I have been able to find - which is not much.
>
>What pulse width difference are you looking at for MAP?
>I figured about 50Ms for full power (1.5")at 4800 RPM, +/-and about .025
>for idle 15" vacuum- this for a 4 cyl with batch fired X2 setup. Cold
>enrich at idle could be as high as .050.
>
>Interested in seeing your doodling.

I would expect a LOT less cold enrichment with a dry runner manifold
situation than with a wet one tho!

Regards, Greg