Robert-
I think there are a couple of ways to attack this.
You need to reduce aero losses and mechanical losses. If you don't it's
still going to take about 12hp to move the car down the road at 60mph.
The next step is to make that 12hp as efficiently as possible.
For the aero and mechanical losses, I'd try the following:
- 155/80/13 tires pumped up to max pressure. (need 1.6 brakes to do this).
- remove door mirrors and install a big wink mirror on the windshield
header.
- cut holes in rear bumper cover.
- belly pan.
- hard top.
- lowered with front spoiler.
- cover "mouth" in front bumper and duct air to radiator from under spoiler.
- 0w20 synthetic oil and MTL.
- smooth hub caps and fairings on rear wheel openings.
- Make sure brake slider pins are well lubed and all springs are in place.
For the engine - I don't know that just killing fuel to a cylinder is
going to do much. You'll have a wider throttle opening to help reduce
the vac against the throttle plate... but that's about it. The rest of
your frictional and pumping losses are still there. I'd consider this
stuff first:
- hot air induction.
- functioning EGR.
- Tune to 15.5:1 or leaner AFR under cruise.
- hottest thermostat you can find.
- loose PS and AC if you haven't already.
There are a lot of engine/ECU tuning things you could try. If you have
an Innovate LC-1, you could set 1 output at 14.7=lambda, and the other
output much leaner (just rich of misfire), and the rig a switch on the
dash so you could turn on "lean burn" mode (assuming proper Link tuning
to go with this). This would probably be more efficient than killing 1
or 2 cylinders and having those run at stoich.
I think the DOHC valvetrain that's capable of 7800rpm is probably a
little stiff for econo running. My CRX HF has valve springs that look
like they belong inside a Bic pen rather than inside an engine.... Can
you get softer valve springs for the BP? Or, what if you got a second
set of cams and ground half the lobes off - essentially giving you an
8valve engine rather than 16v. That would eliminate about half of your
valvetrain losses right there. It would lower the ability for the
cylinders to fill at higher rpm, too.
If you really wanted, you could get an old 1.3 block and reduce the
displacement that way.
But honestly, if you want a project, you'd probably have more fuel
economy success by purchasing an old CRX shell for $500 and a CRX HF
drivetrain for $500 and building your own econo-buggy. The cheap HF's
are gone from the market, but you can still build one easily. I know
that's not the point of posting on a Miata board... but it is a logical
answer if you are looking for max FE for minimum $$.
-Chuck
--------------------------------------------
Robert McElwee wrote:
I'm not sure I follow - I am definitely not an engineer or physics
major <G>. The engine temp (water temp) is going to be controlled by
the rad fan (Link ECU) and thermostat. The engine speed will remain
the same and the air flow through the mouth will remain the same. I
will be compressing gas (air) but will not be burning fuel to create
"extreme" heat.
In any event, I will take your comments seriously and will keep a
close eye on the temp gauge. Maybe I should try this first on my
lightweight car. It has a ton of extra cooling capacity. Actually,
that isn't a bad idea. If I screw that car up I won't cry as long as I
will if I screw up my DD.
On Fri, May 30, 2008 at 10:38 PM, Tim Secor <[EMAIL PROTECTED]> wrote:
You might try testing it in your driveway. I am guessing you will experience
substantial heating just from the two remaining cylinders having to compress
the gas of four with no reward. Make sure your cooling system is functioning
properly and expect it to be taxed.
_______________________________________________
Miatapower mailing list
[email protected]
http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
_______________________________________________
Miatapower mailing list
[email protected]
http://list.miatapower.net/cgi-bin/mailman/listinfo/miatapower
