Date: Sun, 18 May 2008 19:12:21 -0700
Reply-To: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Sender: Vanagon Mailing List <vanagon@gerry.vanagon.com>
From: Scott Daniel - Shazam <scottdaniel@TURBOVANS.COM>
Subject: Re: Belly Pans for speed or MPG
In-Reply-To: <008201c8b8e5$9566e830$0101a8c0@gpa207joel>
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VERY GOOD work unca Joel !
Nice work, and it looks like you went to pains to make it accurate too.
( oddly, the formatting sucked until I clicked on 'reply' ..........only
then did it become rows with the rpm's on the left that I could dechiher
easily . )
and......55.6 mph gave best mileage.
Also............HOTTER IS BETTER.........the warmer you can get
it..........the better. If you could run it at 195 on the t-stat, good.
Summer is better, hot summer.
There is something to be gained in rolling resistance dept , tire type, and
tire pressure.
Especially in the reasonable speed ranges like 55 mph.
I wonder if any has any thoughts or calculations on this :
we now have in Oregon, ONLY.....it's all we can get here........
10 % ethanol gasoline.
That should yield worse mpg's slightly, right ?
Good work again unca Joel.
More............
Just think what you might be able to get tinkering with more exotic spark
plugs, or even multiple-discharge ignition say !
I have long said - it's two fires in the combustion chamber.
One is the spark plug, it has to be right to cause the other fire to happen
- the fast burning of the fuel-air mixture.
If the fist one is weak, it won't make the second one strong.
As you increase the strength of the spark.........
And a lot has been done here too ...........there are ignition systems that
fire multiple times.......there are all kinds of exotic spark plugs, there
are super strong ignitions systems ..........the more you burn every last
droplet of fuel in there.......the better.
And..........the combustion chamber shape and technology of a waterboxer
engine combustion chamber - just pathetic to what is more modern.
No swirl for example..........there is a LOT that goes into combustion
chamber shape on modern engines, intake manifolds that induce swirl ( VW tdi
turbo direct injection does this ) and so on.
But.....just from the ignition dept only............there could be at least
1 mpg, possibly more.
There is one trick though.........the only way the waterboxer ECU knows the
engine is turning, is that it sees a signal from the distributor. Whatever
retrofit high performance ignition system that would be fitted would have to
account for this, or some other way to provide that signal.
The waterboxer fuel injection system is desperately crude compared to other
systems - just the 90s era Subaru is so superior ......twice as strong in
the systems, and twice as accurate.
Btw........a 2.2 Subaru vanagon.........if it was a 20 mpg vanagon before,
it can be up to a 23 mpg vanagon with a Subaru engine. They are much more
efficient.
Sorry to rag, but the waterboxer engine is very old tech. Early
80's.......that is now 28 years, which i9s eons in modern car development. .
There is just no way around two valves per cylinder and push rods, for
example, or dorky shaped crude intake manifold runners. A Waterboxer engine
sitting next to a DOHC 2.5 subaru engine ......the wbxr looks like a lawn
mower engine, sorry.
Even 24 mpg is attainable in 2WD in a 2.2 subaruvanagon.
At 55 mph, even 24.5 with the right driver and tires, I bet.
And I think 'real ' gas helps too, not the ethanol junk we have now.
There is less energy in ethanol.
There really is not anything better , and our vans were designed for
it.....than real petroleum-sourced gasoline.
Members should be relieved to know I have to get back on this Porsche 914-6
( FS btw ) and I'll try to stay off for a while !
Scott
> IMHO.
you are correct, ol' Kaolin-breath. :)
remember that little computer-thingie on the dashboard of the blue 88
bus?
when i did the testing of mpg vs mph with it, the calculated
reference speed of 55.6mph (at steady 3400 rpm) gave out an averaged
mpg of 22.3.
notice that 3400 rpm is just a tad above the max-torque rpm for the
2.1 waterboxer engine. so you've got a little margin of torque to get
you up small hills (molehills) on the highway. problem is, if it's a
bigger hill, you're either going to have to shift down into 3rd or lug
the beast over the hill in 4th, which drops the mpg dramatically.
anyway, for funnsies sake (assuming full tank for the range part) ...
3200 rpm = 52.3mph = 21.9 mpg = 2.4 gallons/hour = 348.4 miles/tank
3400 rpm = 55.6mph = 22.3 mpg = 2.5 gallons/hour = 354.3 miles/tank
3600 rpm = 58.9mph = 20.8 mpg = 2.8 gallons/hour = 331.0 miles/tank
3800 rpm = 62.1mph = 19.2 mpg = 3.2 gallons/hour = 305.8 miles/tank
4000 rpm = 65.4mph = 19.8 mpg = 3.3 gallons/hour = 311.5 miles/tank
4200 rpm = 68.7mph = 18.8 mpg = 3.7 gallons/hour = 301.6 miles/tank
kinda interesting that 4000 rpm actually calculated out (averaging the
4-5 runs i did with each rpm) to better range and mpg than 3800 rpm.
go figure. all bad tests? dodging too many trafficers on the road?
all these tests were done in the summer, with a 1988 vanagon gl
4-speed transmission, on interstate highway that was very flat for
about ten miles,using a Zemco ZT-4 digital trip computer.
have fun. :)
unca joel
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