Chevy big and small block engines

[Bill Allen]

	Hi again,
	If you have been monitoring all the traffic today, there has
been a lot of discussion about dual injectors, variable fuel pressure
and all that. Yes, dual injectors will work (the control algorithm is a
little different) and I will probably be using that approach on my
motorcycle (11,200 RPM on gas). As for handling methanol, you should be
OK too. Most automotive injectors seem to be pretty rugged and meth is
pretty easy on things compared to Nitro or even gasoline. 

	Also, the throttle position-only algorithm is something I've
been working on too. For racing it should work just fine (pretty much
all a Hilborn/Enderle system is), and a lot easier to tune than a
mechanical system. The basic idea of the system I am working is a
mechanical pump (belt-driven off the crank), a mechanically adjustable
pressure regulator (Holley makes one for the Ford EFI system), timed
injection and the above mentioned throttle-position control. One of the
ideas I had that would make the thing a whole lot nicer than a
mechanical system is an absolute (barometric) pressure sensor. This
would alleviate the need to re-tune for varying density-altitude (a
constant problem at Bonneville and El Mirage Dry Lake where I race the
bike).

	All for now,
	Bill

	-----Original Message-----
	From:	Grant Gatenby [SMTP:grantg at iname.com]
	Sent:	Friday, June 19, 1998 2:15 PM
	To:	'diy_efi at efi332.eng.ohio-state.edu'
	Subject:	RE: Chevy big and small block engines

	-----Original Message-----
	From:	Bill Allen [SMTP:BAllen at Vetronix.com]
	Sent:	Saturday, June 20, 1998 3:57 AM
	To:	'diy_efi at efi332.eng.ohio-state.edu'
	Subject:	RE: Chevy big and small block engines

	You will probably have problems with a one-throttle body per
cylinder arrangement. MAP and/or mass airflow sensing is almost
impossible due to pulsations at low and mid-range. You are much better
off with a single throttle body on a plenum with one injector per
cylinder. The plenum will average out the pulsations over all the
cylinders.
	Yes...I had thought about the MAF or MAP on single throttle
bodies and saw 
	it as being a problem too....but had a couple of ideas there,
one was to 
	take a small tube from each port to provide MAP vacuum and
connect them to 
	a central canister and the other was to fairly much use TPS or
most likely 
	a combination of both
	As for methanol, that is a can of worms with EFI. Although there
are injectors out there that will flow enough (remember that you are
going from 12-15:1  AFR down to 5-6:1), they are going to be very
difficult to find. I have been looking around for a source, possibly the
Indy guys, but so far no luck. If anyone knows where to find such items,
I'd be very interested too.

	The solution I was thinking of was using 2 petrol injectors per
cylinder to 
	acheive the required flow, although not ideal for spray patterns
so long as 
	the injectors will handle methanol should work

	Grant__