[DML] Re: PRV Performance - Set me straight please

["endotex23" <endotex23@xxxxxxxxx>]

--- In dmcnews@xxxxxxxxxxxxxxx, "Rick" <rdevaux@xxxx> wrote:
> 
> Is there a way to modify the warm up regulator so that it acts like
a rising rate pressure regulator?

Sure. You can also change the CPR's limits by changing the position of
the plug. You can even make it externally adjustable if you want. But
as I mentioned, mixture control using CP isn't very elegant nor does
it work as well as doing it via the FV. After all, Bosch chose to do
it that way and they know something about lambda control: they
invented the O2S. And as Mr Kuchan pointed out, the stock K Jet has
more than enough headroom for normal driving. In fact it has enough
dynamic range through the lambda alone for mild boost without
resorting to diddling control pressure.

David T point out that messing with this stuff won't get you much more
fuel (he said 10% as I recall) and suggested you go with a better
system. I'm in complete agreement with him because the K Jet is lame
past a certain point and not all that capable for mods to begin with. 
It is does however provide a pretty decent job of maintaining a lambda
of 1 during most conditions assuming you don't get too crazy and 
assuming the basic mixture is set within it's operating range.

Having said that it's important to remember it's not how much fuel you
deliver per say, it's what that fuel does to the mixture. Plus A/F
ratio is affected by other things than fuel metering. Remember, there
is the  "A" part of the A/F equation and I remind you there are 6
"engines" in your car, not one. Without a balanced induction system
there is a way to cheat and get equal mixture across all cylinders for
best performance: you need to alter each injector after measuring EGT
at each cylinder. This isn't theory, it's done all the time in other
applications and I had an instrument that did just that on my car. The
problem is it's not easy to do with Bosch injectors but if you're on a
mission for the smoothest running engine you'll ever see it can be
done.

I've spend many hours doing A/F anaylsis on Deloreans while repairing
them and researching it's K Jet for mods. I can tell you the exact
effects of mixture changes on anything from removing the dipstick to
WOT manipulation of the FV to using the manual enrichment inputs, both
the WOT one and the normally unused input that Volvo later used to
ditch the crappy accel vacuum enrichment of the 066 CPR. Why you'd
want to add that is beyond me. What form of cold accel enrichment does
the car have now?

In the Delo's case you can run the K Jet in excess of 10% CO (the
limits of most NDIR analyzers) at almost any point. That's way richer
than you'd need for most most cases and I'm talking about only the
lambda, with control pressure maxed out. Diddle it or primary pressure
and you can get more. You're going to eventually run into the limits
on other things (the fuel distributor for example) but for the mods
you're talking about using the lambda either in open or closed loop
(shifted rich or left at stoich) will deliver plenty of fuel.

Continous mechanical injection systems are old technolgy and well
understood. Reliable too, they're used on 99% of the world's
certificated piston powered aircraft. Heck, even turbine engines use
them. They suck at doing certain things though, one of which is tight
mixture control.

I don't know (exactly) what DMCH does to it's engine but it's not
rocket science. As Mr Bill points out the B28 in foreign trim is not
rated at 130 HP and you'd be nuts to think any 3 liter engine is
inherently stuck at that by design. I'm assuming it's much of what
you're suggesting: increasing volumetric efficiency (while remaining
normally aspirated) and tuning to match it. Nor do I know what Martin
does but he's a pretty sharp bloke so I believe him when he says it
works. As I said, rocket science it's not. You just have to have lots
of patience and the test gear to tune after making changes. A dyno
helps but you can get away without using  one. 

I know one thing though: neither of them stood a chance of getting any
of my money for it. Martin is OK but Mr Esprey had the balls to whine
back when I posted anonomously, then he goes ahead and posts under a
fictious name solely for personal financial gain. Maximum hypocrisy,
minimum ethics. Then he doesn't even bother to apologize for biting
the hand of the people who feed him, many whom go on to feel he did
nothing wrong. Lol, D owners are a powerfully queer lot...but that's a
topic for another time.

Greg (or Gary, Sonny, Donny...I've been called much worse).








To address comments privately to the moderating team, please address:
moderators@xxxxxxxxxxx

For more info on the list, tech articles, cars for sale see www.dmcnews.com

To search the archives or view files, log in at http://groups.yahoo.com/group/dmcnews 
Yahoo! Groups Links

<*> To visit your group on the web, go to:
    http://groups.yahoo.com/group/dmcnews/

<*> To unsubscribe from this group, send an email to:
    dmcnews-unsubscribe@xxxxxxxxxxxxxxx

<*> Your use of Yahoo! Groups is subject to:
    http://docs.yahoo.com/info/terms/