Hi all,

Just a simple question.

I found that the coolant temperature of my S2k is a bit abnormally hot.
It is almost always greater than 95 C (203F)... it only goes down (slowly) to around 85C (185F) at highway when the engine is < 3k rpm. The ambient temperature is around 28C (83F) which is a bit hot.

I've read that if the coolant temperature is greater than 85C (185F), the ECU will start to retard and power down the engine... so in my case, I've never got F20C in full power !!

Can anyone give me any information on their S2k coolant temperature for my reference? Do you think my S2K's coolant temperature is normal?

Any help is appreciated!

Peter

 

Here are some measurements that I took a few months ago. Both cars were side by side. One was completely stock, while the other had a Mugen fan switch, thermostat, and radiator cap. Ambient temperature was probably in the upper 80s that day. The coolant temps did not rise above these temps at extended idle, and when we pulled into a parking lot after a long drive, and immediately measured temps, the fans weren't even on.

 

I don't think your ECU is going to start retarding timing that soon, since the stock thermostat isn't going to allow the coolant temps to go much below 200F. I think intake air temperature is going to play more of a role in timing.

 

Gernby, I just wanted to say thanks for putting that info together. I have been debating this mod for a while and after reading that, I am ordering tomorrow. Excelent work!!!

Jeff

 

Thanks Gernby. Your info is really helpful. That shows the effect of the T-stat + switch + rad cap. I did have a Mugen rad cap, and T-stat on order.

However, can I ask you how you measure the temperature? It seems that you should be measuring the surface temperature of those components. I assume it will be a bit lower than the real coolant temperature sense by coolant temperature gauge or in my case the reading from ECU directly.

BTW, the stock T-stat opens at 190F (88C) and the fan on 194F (90C). So that it's safe to assume the NORMAL operating temperature will be 190-194F, which in case my reading of > 203F (even at idle) all the way is actually too high.

FYI, I get the stock T-stock and fan switch data from Spoon's page
http://www.spoonsports.co.jp/e/products/pr...ducts_s025.html

The power down temperature is not an official news. I read it from a famous Japanese S2k web site (http://toshi.cside.ne.jp/). http://toshi.cside.ne.jp/qa8.html

Peter

 

It is true that your coolant temperature reading is going to be different from mine, since the sensor is in a completely different place. I measured these temps using an IR surface thermometer (Raytek). I still don't think you are loosing power from it.

My cooler temps are not just because of the thermostat, switch, and cap. I also have the Hondata intake manifold gasket (insulator / spacer), and I use LESS antifreeze in my coolant mixture (20%). I also added Redline Water Wetter, and went with 1 step colder spark plugs. I believe that I have COMPLETELY eliminated my power loss due to hot weather. It seems to run just as strong at 100F as it does at 70F.

 

[QUOTE]Originally posted by gernby
[B]It is true that your coolant temperature reading is going to be different from mine, since the sensor is in a completely different place.

 

Do you ever get a 4th bar on the temperature guage? It could be that your temps are completely normal for a stock car, since there is such a small difference between your measurements and mine. When you consider absolute temperature, we are really only talking about maybe 1% difference, which could easily be attributed in the measurement (sensor location and / or calibration). Keep in mind that my measurements were not taken DURING a drive.

 

During normal driving using the OBDII coolant temp sensor (the only one the ECU cares about) the numerous S2K's I've tested will see 180-185 F coolant temps. Ambient conditions are around 70-80F with 50% humidity. When sitting at idle in traffic, the temps will rise in the 190-195 F range. Short duration WOT events don't change temp much, but extended high throttle/low speed running can bring coolant temps up into the 190's and even low 200s. At higher speeds cooling tends to be more effective.

All dyno tests I make are between 185-195F and the results are pretty consistent. However as temps climb above 195 power does start dropping noticeably.

UL

 

[QUOTE]Originally posted by gernby
[B]Do you ever get a 4th bar on the temperature guage?