What changes will temp have to the engine (in general)?Is there a global type table to make corrections?

 

Oil temp., air temp., coolant temp.?.

 

In the 6E tdf there is a "cool compensation spark vs. load" table. But the original arap bin doesn't compensate until 32 deg C. on the low end and 116 deg. C. on the upper end-so there isn't any diff between 180F. vs 210F. I havn't tried changing anything on that table. As for the fuel- the only table in there is for open loop- "open loop a/f % change vs coolant temp". That one I have had to change quite a bit! Now that it's winter here I found that the original parameters were way too rich for the lower temps. Of course part of that could be living at 7000ft!

 

coolant temp,My understanding is that the higer it is the easyer to detonate.I know basicly but would like to hear others to gain more understanding.But what would be the right way to make changes,add fuel or minus timing or a paticular table?.

 

In that particular case you'd be worring about the end gases in the quench area. Which makes it an issue of combustion chamber design.

In some back to back testing with timing and AFR optimised, I found 0 difference in performance using 160-180-195 thermostats in a SBC using 9:1 and vette AL heads. HOWEVER, I did it with less fuel and timing with the 195.

BUT, in some code, there is some other factors that seem to mysteriously effect things related to CT. Having the actual source code would reveal the whys of that.

One other thing I've done is lied to the ecm, ie tell it the engine is 160 when in the truth was it was at 190. Again this varies by code, and I wouldn't at all recommend doing it, it was strickly a test, done years ago when alot less was known about code.

You always will have better results in fixing things in code rather then hardware, when the problem is in the code.

Besides there is alot of stuff that is tied to CT. Changing all of it is more then just WOT fuel and timing.

 

Funny, I was just talking about t-stats in another post to Formula5.

On my SD car, where the MAT temp does have an affect on the fuel trim, I found it more difficult to tune my car to run "consistently" with a 160* t-sat. Switching to a 180*, I was able to attain even better performance (though my tuning abilities also improved) and much more consistent.

I was a "die-hard" 160* t-stat kinda guy until I got into eprom burning. I personally did not expect my car to perform as well with the 180*, but now, you couldn't pay me to run a 160* just because of the "warmth" aspect.

I haven't tried a 195* since my car was knew and I was just getting into "modding" my car. But the next time I have to change my t-stat, I am might give the 195* a try just to see what happens.

 

Odd what happens when you seriously tune stuff. All that Popular Hot Rodding, Car Crap stuff just gets as laughable as some of the aftermarket chips.

By running the 180/195 vs 160s you also increase the head bolt preload, more thoughly perculate contaminats out of the oil, etc.

There are no down sides to running higher (coolant) temps WHEN CORRECTLY TUNED. TOO many folks though are stuck with the flathead tuning tricks of the 50s.

 

I used a 165 t-stat when I had the LG4 in my bird.I used it for other reasons than the aftermarket industry.My lg4 had about 200,000 miles and 0 oil pressure.I need to get more miles out of it until I got tpi and a 335 stroker(now a 400).To get the oil pressure up would require two things.Lower oil temp and thicker grade.With a 165 t-stat and 50w oil the pressure became stable again .I drove w/ that engine for a year.I think the only reason aftermarket companies stress a 165 is to cover their butts.Hypertech and others cover the all for one calibration detonation with lower temps.It gets cold in Missouri so a 165 t-stat is not good for heating.I think they also promote rapid engine wear.The engine wears at a cooler temp with tighter clearance.Then raise the temp and the tolarance becomes excessive.I was wondering about a way to get the engine to feel the same after warmup.I think I saw a table in tuner cat that could change % change f/a vs coolant temp(or something like that). Is that the right one ?I would like to get into the assembly code.I just need to learn more about how to do it all.Glenn has emailed me with some tips so I guess I'll start there.

 

<sigh>
but no.
It's just cheaper to have the owner use a lower temp thermostat, the them actually having to dial in a fuel cruve.
To 99.9999375463832904938% of the population too rich with too much timing seems fastest with the buttometer.

If you were to set up an ecm bench you would accurately see what temp does to the calibration.

 

Unfortunatly I know jack about an ecm bench

 

Sigh,
It's all mapped out at the DIY-EFI Site, pics and everything. Or at least how I did mine.

 

I did graze over that but could you explain the purpose in general?

 

The purpose of the ECM bench is two fold: 1) If you don't have a "hac", then by similulating (as best as you can) the operation of the ECM based on certain sensor input values, you can see the effect and use the results to develop a hac. 2) Even if you have a "hac", some changes (especially to the source code) are best tested on an ECM bench to ensure the changes operate as you expect and don't do anything adverse.

Bench testing also can speed up testing of changes where certain conditions only occur at a certain load, temperature, TPS%, etc where it is difficult to monitor while driving. Somethings are just too difficult to monitor and track (safely) while you are driving and "bench testing" is the best place to do this.

Many companies use "benchtesting" to monitor "prototypes". In one company I worked at, we were involved in water treatment. The company had invented a special "valving" mechanism to direct the flow of the water through the "membrane" system that was controlled by a microprocessor. Bench testing was the only way for our company to sucessfully monitor the operation of the valve throughout it's operating cycles.