Lean burn engines

[Ray Drouillard]

----- Original Message -----
From: "Greg Hermann" <bearbvd at mindspring.com>
To: <diy_efi at diy-efi.org>
Sent: Thursday, October 18, 2001 1:18 AM
Subject: Re: Lean burn engines


> At 9:08 PM 10/17/01, Ray Drouillard wrote:
> >Thanks!
> >
> >One nice feature of Pro-Jection is that I can mess with the spark timing
> >electronically (once I get my duraspark pickup to fire the HEI module
that I
> >have fastened to my fender well.
> >
> >I do have open chambers, so I'm out of luck there.  I guess I won't be
able
> >to get it very lean.  Will disabling the EGR help?
> >
> >
> >Ray
>
> If you have good control over the advance, having EGR can actually improve
> mileage!
>
> Greg

That's why I have kept it so far.  I'm just wondering if I can go leaner if
I'm not dumping inert gas into the cylinders.  Either way, I ought to be
able to reduce pumping losses.

I still never found out why engines run hotter when run lean.  I speculate
that the gasoline burns slower, so it's still burning when the exhaust valve
starts to open.  I ought to be able to take care of that (within reason) by
advancing the timing under those conditions.

By the way, I only plan on running lean at cruise throttle and RPM - perhaps
up to 2800 RPM or so.  I plan on running stoich under all other conditions -
except for that area between 70 and 90 degree throttle angle (or somewhere
in that area).  It remains to be seen if I can run closed loop at WOT,
however.


Ray Drouillard


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