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[Mk1gti] on "euro" injection.....
I may be shoting blanks here, but as far as i know, o2-based fuel
mixture control on cis-e is for idle only. once that idle switch on the
throttle body is open, all of that goes out the window. They system relies
on the design of the airflow venturi+fuel distributor to get 'close' to
correct a/f ratio all the way up. The one thing this system didnt take into
account was fuel line pressure drop. Well, it does, just to a point. It was
tuned to compensate in a linear fashion, where the pressure drop is actually
exponential. Bosch had to compromise there, pick a good line for overall
drivability (not wot). The real problem with cis at wot is fuel starvation
due to the design of cis, not due to the o2 sensor setup. This is overcome
with our 'power modules', which cheat by boosting control pressure
(therefore fuel pressure at the distributor), so for the same fuel plate
position you get more fuel (overcoing that exponential rise in pressure drop
in the lines/injectors).
The only other cases i know of where cis alters control pressure
regulator current is for idle coast-down fuel cutoff and for some extra fuel
enrichment (based on rate of change of accelerator position) on
cis-motronic.
Just my 2c
Al
Allyn Malventano, ETC(SS), USN
87 Rieger GTO Scirocco 16v (daily driver, 170k, rocco #6)
86 Kamei Twin 16V Turbo Scirocco GTX (shell donor ready to rock, still
planning)
87 Jetta 8v Wolfsburg 2dr (daily driver, 260k, 0 rattles, original clutch,
driveshafts, wheels :)
----- Original Message -----
From: "McGarvey, Peter" <pmcgarvey@fcg.com>
To: <mk1gti@yahoogroups.com>; "''scirocco list' '"
<scirocco-L@scirocco.org>; <vwautox@yahoogroups.com>
Sent: Tuesday, January 08, 2002 4:42 PM
Subject: RE: [Mk1gti] on "euro" injection.....
> I'll take a stab here, I would say your assumption that 'more fuel' =
'more
> power' could be argued. From what I know: the o2 sensor keeps the A/F
ratio
> at stoich for the greatest amount of power, economy and emissions at
normal
> conditions, except for WOT. The O2 has less sensitivity at WOT, so the
full
> throttle enrichment runs a fuel map to predict how much fuel it will need.
> I think the only way to adjust WOT fueling is to use an EGT gauge.
>
> Your euro fuel injection, probably has worse overall economy/emissions and
> probably power b/c of the lack of an o2 sensor. I'm not sure *exactly*
what
> the thicker lip of the fuel dist 'cone' does, but it may have something to
> do with how much or at what speed, air flows through it, since that's
where
> the metering plate actually tells CIS how much fuel to provide to the
> injectors. But, I would think I thinner lip would provide more air (and
> fuel) due to its larger opening - but then again, a small opening would
> actually increase velocity, right? As far as which is more important,
> velocity or volume of air at WOT, I'm not sure - I would say velocity -
> which would follow the thicker lip theory.
>
> So I think the only difference in the end is how either system handles WOT
> conditions. I think for the street, I would stick with the lambda system,
> b/c I can't see any real worthwhile gain in hp b/t the two, over stuff
like
> emissions and mileage for a street car. For a race car, I don't know, I
> know some racers pull the o2 sensor, and tune the car with an EGT and run
it
> that way - possibly the only way to know exactly what's going on inside
the
> car - since economy/emissions are not an issue.
> Of course the other way, would be to put both on a dyno.
>
> As far as shimming the control press. reg., the book 'Bosch Fuel
Injection'
> by Robert Bently publishing has some good info on CIS tuning, and may have
> something about this, but I don't remember it that well. I could check and
> find it if you're interested in getting the book for that reason - either
> way it's a good book for learning about Bosch FI.
>
> PJ
>
> -----Original Message-----
> From: Andrew Stauffer
> To: 'mk1gti@yahoogroups.com'; 'scirocco list'; 'vwautox@yahoogroups.com'
> Sent: 1/8/2002 2:58 PM
> Subject: [Mk1gti] on "euro" injection.....
>
> Okay gang, it's winter time, garage projects are well underway, there
> isn't
> much seat time, a good time to do some bench racing and
> engineering................
>
> The topic is CIS"euro injection". I'm going to ramble on a bit about
> the
> subject, please correct or adjust my thinking as necessary.
> At any rate, this has puzzled me for some time and I'd love to hear some
> thoughts. AutoXers, I know this is a little OT, but please bear with
> me,
> there isn't alot of traffic these days.......
>
> Euro Injection- It's a thick lipped 80mm CIS flow cone/fuel dist/control
> pressure(or warm up reg) regulator. I'm under the impression that it
> will
> add some power over conventional CIS and CIS lambda. This is the way
> the
> eBay add reads, the way that RPI sells it, and the way that the end
> users
> seem to feel about it from conversations that I've had. In a nutshell,
> it
> drops the O2 sensor/frequency valve from the fueling equation, runs
> richer,
> and therefore provides more power. Accurate so far?
>
> But-and here's where I get confused- If I want my CIS lamda fueled 2.0
> 8v
> motor to get a richer mixture, I can dial it in with the 3mm mixture
> control
> adjustment in the airbox/fuel dist. So I'm left to wonder, if I
> unplugged
> the O2 sensor and dialed in more richness, were is the benefit to Euro
> injection over this? I know from experimenting/experience that
> unplugging
> the sensor will result in higher emissions and lower mpg, as I'm told
> the
> Euro inj will. I don't see where the euro inj is any diff than cis
> lambda
> with the O2 sensor unplugged. Anyone got any ideas on that? Doing
> this
> for CIS lambda will make the full throttle enrichment non functional,
> which
> is not a good thing in my experience. Dan Bubb can back me on this. Is
> the
> Euro inj air cone shaped such that this full throttle enrichment is not
> necessary, it's already "in there" and accounted for?
>
>
> Going beyond this simple a/f mixture adjustment , I've heard folks say
> that
> you could also reshim the control pressure reg. in the fuel dist
> itself(not
> the block mounted cpr or warm up reg), and arrive at a richer(via higher
> system pressure) mixture. What's this offer that dialing in a richer
> mixture as above via the 3mm does not? I assume you'd have to uplug
> the O2 sensor for this trick to be of any benefit, but again, I must be
> missing something. I have never tried this, no first hand experience.
> But
> again, richer is richer, there must be a reason that this doesn't equate
> to
> "euro" standards as well. Still with me?
>
> The crux of the issue: If I want rich, I can get rich with the stock
> stuff.
> So if there is truly any benefit to euro injection, it doesn't soley lie
> in
> it's ability to run rich. What makes this stuff special? It comes
> highly
> recommended from some, I'm thinking it's supposed performance benefits
> wouldn't be that hard to emulate with any ole CIS fuel dist.
>
> Whaddya think?
>
>
> Andrew Stauffer
> Cannondale Purchasing
> www.cannondale.com
> andrew.stauffer@cannondale.com
> ph. 814 623 4516
> fax 814 623 8917
>
>
>
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