I still have that Stant 205 degree thermostat,
but unfortunately it is in a garage
about 1100 miles away right now.



I found the Stant 205 degree F by looking in the Stant part number book in a Napa store back in 1999.

With so many cars running 203 degree F thermostats now (2004+ Hemi 5.7V8)
there are probably more options today.

I think I also have a
Robertshaw/Siebe Model 330
'high performance balanced flow' style thermostat in 205 as well

http://www.flowkooler.com/thermos.php?FKSID=d7449f668762853a549d5cc497b43c1f

and that one almost certainly would fit the older style Mopar water neck.

To make a Model 330 thermostat fit in the Magnum v8 water neck you have to grind the opening larger by at least an eighth of an inch....about a 15 minute job with a Dremel tool with a rag stuffed down in the water neck to catch filings.

Running it hotter will help by vaporizing the fuel better, especially in a carbed engine where the fuel is in the manifold for a short time. Also in theory it would be easier to ignite and therefor you could run it leaner. Not to mention since the metal in the chamber would be hotter it would absorb less heat from the explosion alowing the heat to make more expansion preasure.

The key thing that happens with a higher temperature thermostat is kinda a surprise.

With hotter coolant behind the cylinder wall,
the oil on the wall thins out,
the viscosity goes down,
and there is less friction against the rings.

Running a hotter thermostat
is not much different than running
lower viscosity oil,
except that your main and rod bearings
still get cooler higher viscosity oil.

Not all parts of an engine
need the same lubrication.

At part throttle (not full throttle)
the hotter coolant will heat the intake air.
This is normally undesirable at full throttle when you want maximum horsepower,
but in the case of 'daily driving' part throttle
the heated intake air
makes you use more throttle opening
which raises MAP
and the higher MAP helps push the piston downward on the intake stroke
and allows the engine's other cylinders
to not have to supply horsepower
to draw that cylinder downward against a vacuum.

Complicated, ain't it?

In this way
heated intake air is like
exhaust gas recirculation (EGR)
.....but heated intake air has two disadvantages compared to EGR:

* it makes detonation and pinging more likely and can limit part throttle compression ratio limit

*it takes slightly more horsepower from the other cylinders to compress the hotter mixture on the upstroke of the piston

Notice the newest diesels have gone to 'cooled' EGR? It is better for MPG than either heated intake air or hot EGR.....but it loads the lube oil up with soot

A little interesting up date here.

Tn. gasoline all is putting %10 ethenol in it now and it didn't seem to affect the miledge when they switched so I tried topping off with e-85 the other day and it took about 5 galons to fill up. Driving it like that didn't seem to change the way it drove at all so I got real brave today and filled up an empty tank with straight e-85 before a 100 mile highway run for a controlled test. Previously with 93 ocatne @ 75 mph I got 27 mpg. Today driving 75 mph on e-85 it got 25 mpg on the same stretch of road the previous test was done on.

The e-85 was 80cents a gallon cheaper than 93 at the same station.
25 mpg at 3.00 = 12 cents per mile.
27 mpg at 3.80 = 14.07 cents per mile

I am sure I could run up the compression with the e-85 also and that would help. I bought some mopar thin head gaskets and will probably get .060 milled from the heads when I put them on and have a straight up alcholic engine.

As for how it runs with the straight e-85 the only differance I noticed was a tad softer sound from the exhaust, normaly it is pretty raspy under heavy acceleration.

I'm really suprised you didn't need to do a ton of tuning, as the stoichiometric AFR for E-85 is somewhere near 9:1, vs. 14.7:1 for gasoline....

The way it apears to me is if I wanted max hp then yes I would have to add a buch more fuel and timing, however since I am just leaving everything the same for MPG purposes and simplicity it is fine. I pulled a couple plugs after running most of the tank out and no sighns of metal flakeing or burning or anything abnormal. Some guys told me it would be so lean it would cause detonation even with 100+ octane but it was the oposite, the ocational one or two knocks going up a steep hill were totally gone all together, no knocking whatsoever. It will probably be a couple more tanks of it before I pull the heads for the compression bump and inspection.

I am thinking of jetting up the secondaries a bunch for the e-85 after I do the switch so I can take advantage of the extra fuel and oxygen content. That way I can have my MPG and HP too!

Keep the ports and valves small not sure which part number but there are high swirl heads that would work well also. Use 1.6 rockers on the intake and 1.5s on the exhaust that will allow in more air fuel and keep the velocity on the exhaust side for better scavenging.Get the compression up to 9.5 to one for better torque, stock or RV type cam. Over drive tranny a must. I would toss the thermo junk and go to an aftermarker fuel injection and lighten the car as much as you can. Light weight aerospace brakes and or wilwoods,Light weight wheels narrower than ussual tires also taller than ussual. Cal trac monoleaf springs,or afco mono leafs no caltrac bars.No jack or spare carry less fuel and kick the chubby brother inlaw out.LOL

consider some 'rear wheel spoilers' ?

2009 Ford Escape, 2009 Mercury Mariner See Aero Boost

DEARBORN, Mich., May 14, 2008 – Cheating the wind with aerodynamic improvements helps the 2009 Ford Escape and Mercury Mariner become more fuel efficient.

Already among America’s most fuel-efficient and environmentally friendly SUVs, the Escape and Mariner receive aerodynamic refinements on top of powertrain upgrades that contribute to an overall estimated 1 mpg improvement in fuel economy for the four- and six-cylinder models.

“Aerodynamic refinements are the most cost-effective ways to reduce fuel consumption,” says Van Stewart, Escape/Mariner aerodynamicist. “Without significantly altering the design of the vehicle, we can find ways to optimize the flow of air to reduce drag and improve fuel efficiency.”

For the 2009 Escape and Mariner, engineers redesigned the front bumper spoiler and added rear tire spoilers for better airflow management.

The front spoiler was extended further over the wheels to diminish drag and was lowered by 40 mm to redirect air flow. The rear tire spoilers help reduce the aerodynamic drag of the rear wheels and tires.

“Thanks to the aerodynamic refinements made to the Escape and Mariner, they are now fully optimized given the current design of the vehicles,” said Stewart.

This is no small feat, because the Escape and Mariner already were aerodynamically efficient designs.

Stewart and his team of aerodynamics engineers tested all aspects of the vehicle to find areas of potential improvements for incremental fuel economy. From underbody shields to door sealing and new mirror designs, the Ford team spent hours in the wind tunnel and with sophisticated computer modeling to analyze airflow patterns and measure drag data.

I guess this really explains the E-85 thing and blows out all the myths about the mpg and A/F ratios. Notice it is from the EPA itself and not some fly by night con artist dude.

http://www.epa.gov/otaq/presentations/sae-2002-01-2743.pdf

Here is a little something neat to read from 360veiw on another thread.


(here's an attempt to figure out gear ratio for highway cruise in a scientific way, based on piston speed and intake manifold vacuum. comments welcome)
------------
Now lets discuss gearing and fuel economy.

In city driving gearing doesn't matter nearly as much as not having a
'heavy foot' or hauling a lot of weight in the bed of the truck.

A vehicle that is either overgeared or undergeared will lose MPG at highway
cruise.

An engine is numerically overgeared if it is not cruising at about
60-75% open throttle.

An engine is undergeared and "too weak for the job"
if it has to operate with its pistons going faster than an average of about
1200 feet per minute when at 75% throttle.

Note that you could reduce engine weakness by turbocharging
as well as the much more common thought to just make the engine larger in
cubic inches. This is the reason nearly all diesels have become turbocharged
in the last 20 years.

How do you calculate this average piston speed?

Multiply the stroke of the engine in inches by two (because the piston goes
both up and down on one rpm) and then divide by 12 to convert inches to
feet. Multiply this by the rpm.

So where does 1200 feet per minute end up for various engines?
Here some examples:

For the 3.58 stroke of 3.7, 5.7, 5.9 Dodge engines:
2011 rpm = 1200 ft/min /( 2 x 3.58 inches/12 inches per ft)

For the 3.405 stroke of the Dodge 4.7V8
2114 rpm = 1200/(2x3.405/12)

For the 3.00 stroke of the Ford 5.0L V8
2400 rpm = 1200/(2x3.00/12)

For the 4.72 stroke of the Cummins Inline 6 diesel
1525 rpm = 1200/(2x4.72/12)

Is it possible for an engine to be made to get its best fuel economy at a
piston speed above the typical 1200 feet per minute?
Yes.
Very thin piston rings, using less than the normal 3 rings,
slippery coatings on piston skirts, extremely hard but slick coatings
on bore walls like "NikoSil" and keeping the bore walls very hot
so that the oil there will be thin and less viscous can all allow the
'best economy' piston speed to be raised but even 'state of the art'
giant marine diesel where nearly every trick is used seldom exceed
1500 feet per minute.

Honda has announced that over the next 5 year period that the major
part of their engine research $ will be spent on ways to reduce internal
engine friction, and this is from a company that NASCAR engine builders
already admit has the best rod and crankshaft bearing material for sale.

Which is more important: having the rpms near this 1200 foot per minute
speed for the pistons, or having the throttle in the 65-75% open range?
Answer: it is more important to be in the 70% throttle range and you should
slow down the rpms to get there. There is not much change in efficiency
when piston speed drops from 1200 down to 800 ft/minute but there is a big
change in efficiency when the throttle goes from 70% open to 40% open.

Why?

Imagine that you have a disassembled engine in front of you. Put a loose
piston in a bore and pull it down against the friction of the rings. It won't
be very hard.

Now imagine that same piston in the bore has the top of the
bore sealed off and has a vacuum sucked of 12 inches of Mercury.
12 inches of vacuum is about 6 psi of negative pressure. If the piston is
4.00 inches in diameter it has an area of about 12.5 square inches
(remember pi R squared but most cherry pies are round?)
6 pounds per square inch times 12.5 square inches = 75 pounds would be
required to pull the piston down - you probably couldn't do it with the grip
of just a couple fingers! An engine running with a high vacuum in the intake
manifold has to do just this, and for eight cylinders!

Engineers refer to this as one of the two parts of "Pumping Losses". The
other part of Pumping Losses is due to pushing the exhaust out the tailpipe.
Most engine owners easily imagine that exhaust loss, accept it, and spend
a lot of time and money on mufflers, headers, Y pipes etc. These same
engine owners would do well to remember the "Pumping Loss" on the intake side
and try to keep it low during highway cruise conditions.

{Note to engineers: Yea, I know, 'negative pressure' does not really exist and
what actually happened is 14.7 psi of air pressure is pushing the underside
of the piston and there was just less pressure on the top of the piston to
create a delta P - but the general public thinks in 'vacuum' terms.
And it is not just the general public - talk to the biologists who think
-100 psi or more of 'negative' pressure pulls water up capillaries to tree
tops}

Setting Gear Ratios to suit the Customer's Expectations

Most auto manufacturers intentionally overgear their vehicles because they
know from experience that customers will bitterly complain about a vehicle
that downshifts to climb a hill.

Engineers know that to give their customers the best possible highway MPG
the transmission would downshift on EVERY hill, but the sales department
reminds them that that every employee at the automaker (including engineers)
will lose their jobs if customers {even ignorant ones} get mad
and buy someone else's vehicle that meets their expectation.

So vehicles are overgeared to 'feel strong' during the 20% of the time they
are climbing hills in Overdrive, even if it means this hurts MPG a bit during
the 80% of the time the vehicle is on level roads or going downhill.

An engine is numerically undergeared if it is trying to cruise in the
'Power Enrichment' zone above about 80% throtttle opening where the
PCM computer greatly enriches the air to fuel ratio from 14.7 to 11.
On most vehicles with automatic transmissions it is not possible to cruise
in OD on level highways in the power enrichment zone because the
transmission will downshift to a lower gear long before the accelerator
is pressed that far.

For the same reason anyone who presses the accelerator down all the way near
the floor whether they are driving in the city, highway, climbing a hill, or
pulling a trailer is going to get about 25% worse MPG than someone who
presses right up to about 70% throttle but never goes over it.

This is why the old advice to install a vacuum gauge
can certainly help MPG if the driver watches it out of the corner of his eye.

When the vacuum gauge reads about 1 to 6 inches of mercury
you are in the fuel guzzling 'Power Enrichment' zone that you want to avoid
except when you want the highest horsepower and accept the higher fuel usage.

When the vacuum gauge is showing about 7 to 9 inches of mercury vacuum
your engine is converting fuel into horsepower at its most efficient level.

Each engine goes into Power Enrichment at a slightly different MAP sensor
level, but if you listen closely to the engine sound you can hear it happen
as the engine gets a bit smoother with the very rich mixture.





I guess acording to that an OD should really help me, I cruise at 75mph with 19 inches vacume.

Thanks for the info.

I need my computer fixed so I can save this thread...this stuff is too great!

Interesting read, but where did the magic piston speed of 1200 come from, and on what basis?

And would not a wide open throttle show the least pumping loss on a efi system that would be immune from a power enrichment zone if tuned correctly? Of course there would be no reserve power, but maybe a progressive throttle body or something would handle that. So the main advantage on throttle body percentage opening is simply pumping losses? I thought on a carb it was better fuel air mixing and velocity becuase of a partially open throttle, etc. EFI changes all that since fuel is under high pressure and sprayed

I would like to know where the ideal piston speed figures come from.

As for pumping losses you can slow down the engine to reduce pumping losses.

When you going to come and get your Stromberg 2bbl?

Just dropped that shiney '65 model BBD that I massaged on to the slant. Fired right up

In my real-quick-read here of this topic ...one quick point someone raised before that was not discussed and thought of more seriously.....

That is water-injection.

Using W I ... you can go way leaner in the A/F ratio, put more timing in the motor and use more compression ratio. ..... BUTTTTT ...don't EVER run it out-of-water !

I had a long-ago project(truck/camper/trailer combo) that I did using an old Spearco system that helped a BUNCH but I did not flog-it-out as much as I would have liked to. But now ... I have a vintage Dodge motorhome that I DO want to "flog" this out on now ... as the price of gas is alot diff than back in those days.

More later ... if anyone is interested.

the 1200 feet per minute piston speed
come strictly from experiments
... no theory to it, just many many dyno tests of brake specific fuel consumption (BSFC)

this book has a good graph showing fuel economy by piston speed and manifold pressure
near page 378:

http://www.amazon.com/gp/offer-listing/0262700271/ref=lp_g_2

or

http://www.amazon.com/gp/product/0262700271/ref=olp_product_details?ie=UTF8&me=&seller=

repeating for emphasis
you can create engines that get maximum fuel economy above 1200 fpm,
but only if you use
special bore coatings (ceramics),
special rings (very thin & hard),
etc

or "chop the Gordian Knot instead"
and do away with
rings altogether

http://www.newscientist.com/article.ns?id=dn8658

1200 is the critical speed of the assembly. as things go faster the change in momentum will end up taking more energy than it can produce.