I have been looking for tech explanation about going to a lower temperature thermostat. I went to corvette, fbody forums and for sure here. I couldn't find a clear answer about the pros and cons of running colder.
I read that a low temp thermostat will harm the engine performance since the stock ecu will try to warm up the engine, but I read that running colder improve the performance since the ecu can advance the ignition timing making more power.
I'm confused

I guess that a lower temp thermostat 160 instead of the stock +- 180 will help in my case since I have a Ralliart ECU that advance the ignition timing and turns on the engine fan earlier.

What Do you guys think?

What are the benefits of advance the ignition timing?

 

I want to know too

 

Found this:

Advancing the ignition timing is an inexpensive (free) modification that can make a noticeable difference in throttle response and through the entire powerband with the largest gains in the midrange, around 5500 rpm. Fuel economy is also improved if your driving habits remain the same with the additional power. Adjusting the timing can produce gains of up to 5 hp at the wheels on a GA16 for instance. The amount of gain, you can expect depends on where the timing is currently set now. If it is too low you will feel a larger SOTP difference. Timing advance helps produce more power by igniting the sparks sooner, providing more time for the fuel/air mixture to burn completely, increasing cylinder pressure, thus providing more power. Remember that our engines are sensitive to timing advance and can gain quite a bit of power by adjusting the timing over other, more performance oriented engines, like some Honda engines. So here's the procedure as described by FSM with some comments. Good luck!!! - Edgar S.

What Do you guys think?

 

Good find. I think that a lower operating temp. would lower the viscosity of the oil in the lubrication system and perhaps not properly protecting oiled parts. Does anyone know if that is true?

 

Found this:
HKS KANSAI ECU
http://www.kansaiss.co.jp/
KCM010　Kansai スペックメインコンピューター
価格￥102,900（本体価格￥98,000）
通信販売をご希望の方は、こちらをクリックしてください。
エアクリーナー ＨＫＳ　スーパーパワーフロー
サクション Kansai　フルパイピングＫＩＴ
ブローオフバルブ Kansai　ＳＴＤブローオフバルブ
マフラー Kansai　ストリートマフラー
Kansai　チタンマフラー
フロントパイプ Kansai　ステンレスフロントパイプ
触媒 純正
プラグ ＨＫＳ　Ｓ４５Ｇ
フューエルポンプ 純正
サーモスタット ラリーアート製（７１℃）

To english: ( recommended parts) Notice that they recommend a low temp thermostat made by Ralliart!!!

HKS superpower flow suction Kansai full piping KIT blow off valve Kansai STD blow off valve muffler Kansai street muffler Kansai titanium muffler front pipe Kansai stainless steel front pipe catalyst genuine plug HKS S45G fuel pump genuine thermostat rally art make (71 ℃)


Why? ? ?

 

We have an oil cooler which isn't thermostatically controlled. Oil viscosity, while obviously affected by coolant temperature is also affected by ambient temperature. Driving on a 0 degree day would probably have more effect on oil temps than going to a 160 degree thermostat.

Edit: Someone on here has to have an oil temp gauge who can report what they look like summer v.s. winter.

 

There is a thermostate that is part of the oil filter housing that only lets oil flow to the oil cooler after it reaches normal operating temp.

Keith

 

I would like to know the fine details on this as well...al recomends a colder theromstat and larger radiator on every evo...

 

My temps are 10-15C higher now in the summer than they were in the winter under normal driving conditions. It is also much harder to get my temps below 75-80C during my cooldown period after driving than it was in the winter. I used to cool it down to <70C in only a few minutes, but not now...

 

I would love to add a small fan to the oil cooler. Since it gets no air flow at all when the car is sitting still it doesn't cool down very well at all after a hard run unless you have winter weather conditions.

Keith

 

Some observations:

1) Car is a JDM Evo 8 MR
2) Stock ECU
3) ARC water thermostat

Local conditions are 30-35 degC in the day, between 23-28 degC in the night.

Typical coolant temps are 80-90 degC, depending on traffic. Highway cruising is typically around 80 degC. After installation of the water temp thermostat, it went down to 50 degC. Result? Uneven idling due to excess fueling, poor fuel economy, surging on WOT etc, everything that's indicative of a fueling problem. I'm surprised a CEL was not thrown since the water temp should be fluctuating wildly between cold and fully warm.

I'm unsure if the stock ECU cuts boost if the coolant temp is too low, since the car had an EBC. I wouldn't be surprised if it did though.

Replaced the thermostat with the stock one, and all the problems went away.

re: article on spark advance, that's true if you consider it in isolation. But tuning a car is more than just the spark advance alone.

 

Wow, 50degC is too low. I never heard about ARC W. thermostat.
Do you think that with a 71degC thermostat you would be fine?

 

Tomei makes this for the stock oil cooler:

http://www.z1auto.com/prodmore.asp?m...ne&prodid=1169

I have it and it lowered the oil temps 10-20 degC according to the stock oil temp gauge. I just drove the other day in almost 100 degF humid weather and the oil temps never went over 65 degC while idling in traffic and averages 55-60 degC while driving. Oil temps were any where from 70-90 degC before installing it. Its a little known item in the Evo community and a must have imo.

-Russell K

 

Ahh! I looked at the service manual to make sure there wasn't a thermostat for the oil cooler, and didn't see that.

 

Car wasn't mine, but the point is that this car is used for the occasional trackday (roadcourse) and it doesn't have any issues with overheating even in tropical weather.