hypertech performance settings

[chcknugget]

Just wondering why Hypertech advises putting in a 160 stat when doing their "performance upgrades". Will it make engine run hotter, or does the performance come from a colder engine?

[kzuby]

I purchased the programmer from summit and it came with a free 160 thermo. I noticed it keeps the engine much cooler, at least 20-30 degrees lower on mine. I've always noticed that the engine ran stronger at the lower temps until it got to the full temp with the old 180 thermo. I am very pleased with the results. I'm no mechanic, so as far as any downsides (wintertime,ect.) I would be interested to find out also.

[bobbylr]

Originally Posted by chcknugget

Just wondering why Hypertech advises putting in a 160 stat when doing their "performance upgrades". Will it make engine run hotter, or does the performance come from a colder engine?

i have the hypertech in my 88 s10 4x4 and love it.it makes my motor run colder producing more power.your heater wont get as hot in the winter time but it is worth it.produces more rpms also.

[wolfox]

Normal operating temperature for these engines is about 180 degrees. The 160 degree thermostat fools the on-board computer into thinking that the engine is still cold, so it dumps more fuel on each intake cycle. The slightly richer mixture is supposed to elevate engine temps, and quickly warm the catalyst up to operating temperatures, then the computer "weens" the fuel flow back to normal and there is a subtle drop in noticed performance.

Basically, you are tricking the engine computer into thinking the block's stone cold. All you are doing is burning more gas. Though, quenching the catalyst over a prolonged time like this may (PLEASE NOTE: I said *may*) have adverse effects on it. I would advise against tampering with the termostat in these trucks. At worse, putting in a 180-190 degree stat will allow *proper* engine operating temperature and shave up to 20 degrees off of the operating temps of your transmission - adding much safety margin for towing and prolonging components plus the fluid bath it sits in.

The 160 degree stat's gimmicky. Though the driveline computer tweaking is not. Skip the thermostat IMO and tweak to your heart's content on the Summit/Hypertech power tuner.

[chcknugget]

Originally Posted by wolfox

Normal operating temperature for these engines is about 180 degrees. The 160 degree thermostat fools the on-board computer into thinking that the engine is still cold, so it dumps more fuel on each intake cycle. The slightly richer mixture is supposed to elevate engine temps, and quickly warm the catalyst up to operating temperatures, then the computer "weens" the fuel flow back to normal and there is a subtle drop in noticed performance.

Basically, you are tricking the engine computer into thinking the block's stone cold. All you are doing is burning more gas. Though, quenching the catalyst over a prolonged time like this may (PLEASE NOTE: I said *may*) have adverse effects on it. I would advise against tampering with the termostat in these trucks. At worse, putting in a 180-190 degree stat will allow *proper* engine operating temperature and shave up to 20 degrees off of the operating temps of your transmission - adding much safety margin for towing and prolonging components plus the fluid bath it sits in.

The 160 degree stat's gimmicky. Though the driveline computer tweaking is not. Skip the thermostat IMO and tweak to your heart's content on the Summit/Hypertech power tuner.

I don't see how the thermostat "fools the computer into thinking the engine's still cold," when the engine is actually cooler. There's no fooling the computer on that one. The thermostat just regulates the coolant flow through the block at its specified temperature.

If the computer dumps more gas because the engine temperature's lower than so be it, but that has to do with sensors and programming, not the thermostat.

[blazee]

Okay here we go:

The thermostat doesn't fool the computer, the thermostat lowers the engine operating temperature.

When an engine starts up, it runs in "open loop". While in open loop the computer uses default settings to operate the engine. After the engine warms up to a set temperature, it switches to closed loop. While in closed loop the computer actively controls all aspects of the engine to provide optimal performance.

If you use a lower temp thermostat in conjunction with a programmer there is no problem because the programmer will set the PCM to go into closed loop at a lower temp. The engine will operate more efficiently at lower temps, because it will have a denser air/fuel mixture. (molecules contract when cool and expand when heated) With the denser mix, the engine gets more energy per volume in the cylinder.

You should never use a lower thermostat without reprogrammimg the PCM, because the computer will never go into closed loop. This will make your fuel economy and performance suffer.

[wolfox]

Thanks Blazee for the life-line. Pretty much what I had in the back of my head to say, but had trouble leveraging it out. Damn, I am still dizzy from being hit in the head with a tranny pan it would seem. :P It also did not help that I managed to swallow some fluid too... boy was I sick for the last 2 days. Anyway - I'll shut up now. Really. Honest. Watch me do it. In fact...*ERK* (Passes out from Dex-III embolism in the brain)

[blazee]

Originally Posted by wolfox

Thanks Blazee for the life-line. Pretty much what I had in the back of my head to say, but had trouble leveraging it out. Damn, I am still dizzy from being hit in the head with a tranny pan it would seem. :P It also did not help that I managed to swallow some fluid too... boy was I sick for the last 2 days. Anyway - I'll shut up now. Really. Honest. Watch me do it. In fact...*ERK* (Passes out from Dex-III embolism in the brain)

I really enjoyed reading about your tranny experience. Now I know that I am not the only one who has had problems like that.

[TonyMazz]

Blazee isn't there additional issues with the low temperature and oil varnish etc. My blazer had a bad thermostat, and typically ran around 154-F. Gas mileage went way down i.e. probably the open loop....think the threshold is 158-F right...

Anyway I put in my 195-F thermo, blzr runs smoother, gas mileage went right back up to 21 mpg and things are fine.

But am wondering what the other effects are with a stat of 160 etc....

Can we really get more horsepower..or is it just more fuel ?

[blazee]

The 160 thermostat used with a programmer will boost horsepower and performance, fuel economy will remain basically the same, you may get a slight increase, but the program is designed to be used with 93 octane so any increase will be eaten up with the extra per gallon fuel cost.

I researched these issues quite a bit when I put I JET performance module in my Impala SS, ultimately I decided against the 160 thermostat for several reasons.

The lower temperature thermostats can actually double engine wear:

1. Today's engines operate at high temperatures to fight combustion by-products and pollution. Lowering the temp below 175-180 won't accomplish this.

2. Engine oils are designed to work over a specific temperature range with optimum performance starting at temperatures that require the coolant to be the very same 175ish range.

3.Your engine forms moisture inside when it cools and condensates on the walls of the inside. This moisture then is washed down into the oil when started and then awaits vaporization by internal temperatures rising enough to bring the moisture to the appropriate corrected vapor point (boiling). If enough moisture is left behind it combines with combustion byproducts to form acids that become dissolved in the oil itself. The oil becomes more acidic as the age of the oil progresses and picks on certain parts eventually. Also moisture will corrode other surfaces. So, it's important to get these engines to a satisfying operating temperature as soon as possible. Usually oil pooling temps are about 30 to 40 degrees higher than the coolant temps. This is a generalised statement and can vary with load and engine design but you can see why you want your oil over 212 degrees to boil out the moiture immediately!