Low temp thermostat

[Daniel Ciobota]

Actually, I thought the post was right on target, the original post concerned
itself with the merits and drawbacks of using a low temp thermostat... which he
answered very well and had data to back his claims.  He also answered a couple
of other remarks that were made to the original post, concerning oil temps.  I
remember someone posting that lower water temps shorten bearing life... that's
completely untrue unless there's a direct coupling between oil temps and water
temps, all bearings in a motor are nowhere near water, and the function of the
oil is to _cool_ the bearings as well as reduce friction.  Piston slap _might_
be an issue with forged pistons, but if you run hypereutectic pistons (which
most cars use nowadays), that's a non-issue also.

 If anything, it was the original poster that was not conforming to the list
charter, and certainly this topic is more appropriate than the latest ford ecu
thread!

 All of us who have tried to optimize fuel and spark curves have learned that
cooler water temps allow you to run more aggressive spark advance, thereby
making more power... it's a simple function of cylinder head temperatures,
which dictate which temperature is optimal for combustion without overheating
the mixture.  From the factory, combustion temps are kept higher than optimum
for power and use a conservative spark curve, because this way they can ensure
a more complete burn, at the cost of power.  Remember the old trick for passing
emissions by retarding timing?  Increasing combustion temps achieves the same
effect, up to a point.  Good for the environment, not necessarily good for
power.

 Daniel


CSH-HQ wrote:

> OK so now we're going to drop back ten, and punt, toss in under hood temps,
> and oil temp.
>   Try listing all what ya wanna talk about first time, and we'll start
> there, but now we're off the the list's intention
> By Grumpy
>
> > The point here is just where is the max HP operational range, the
> >testing included changing the chip programming to get the best HP/water
> >temp results.  If you want to run an engine at 220 degrees down 30 HP
> >from running it at 170 deg and forgo the advantages of  an additional 30
> >hp I gain from a thermostat change and chip recalibration its your
> >choice.  I agree the only thing the dyno proved is what water temp
> >produced the best HP for that chip but it was the best HP they could get
> >period and included over 100 dyno runs and at least 25 different chip
> >profiles.  The question I later asked of the engineers (both of whom
> >worked for Lotus on the LT 5 design) who designed and tested the engine
> >was at what temp ranges did the motor give best HP given an OPTIMAL chip
> >program.  They had done extensive dyno testing and saw the best results
> >when everything was OPTIMIZED to run 160-165 deg water temp. (which
> >agreed with what my friend found in his testing) however Emissions
> >testing and certification dictated a hotter water (engine) temp in order
> >to pass the tests (an LT 5 motor water pump will pump 100 gpm @ 6500
> >rpm, Lotus believes in being able to COOL an engine).  I have a friend
> >on the west coat running a 415 ci version of the motor with custom ecm,
> >cams, chip programming, electric water pump and he stages the car with
> >water temps in the 160 degree range for best et (in the low 9s) and sees
> >175 to 180 degrees water temp in the traps.
> >Since we are talking about people who are trying to optimize a
> >particular heat pump it would be of interest to everyone to know at just
> >what temp that pump gets the best HP given optimal conditions. A blanket
> >statement that this temp is 159 or 220 or 190 does an injustice to all.
> >It is obvious to all that you have an experts knowledge of what is going
> >on here but there are three temperatures that are critical to an engine
> >for hp, water, oil and inlet air.  So if an engine can have an under
> >hood water temp range that optimizes these one would set chip
> >programming to take advantage of this range.  It may be that the LT-5
> >motor sees 190 deg oil temp 130 deg inlet temp at 159 deg water temp and
> >this is the best balance that can be attained in a C 4 body style.  I
> >believe that this is a thought process that should be a part of any
> >effort to design a system for a given engine.
> >In summary if you have an LT 5 engine in a C 4 body style and I have an
> >LT 5 engine in a C 4 body style and you insist on a water temp of 190
> >degrees and I use a water temp of 159 degrees I will always have more HP
> >on the ground than you.
> >
> >Tyler Townsley
> >
> >PS Will be off line for a few days got to go close my mothers apartment
> >after putting her in a nursing home.
> >