To go along with what cdelena said, the SHO was produced under different emissions requirements... not to mention that if you're dirtying your oil significantly more with a richer mixture, you probably have a ring problem!

I've heard of this problem with some older Hondas, but I have not yet seen or heard any data regarding it on the S2000. I have not noticed an increased fouling of the plugs, though, which would tell me the mixture has not changed substantially. Fuel economy hasn't changed for me, either, which tells me the same thing.

 

Part of the reason thermostats have gotten hotter over the years, and the reason that 'dirty oil' is mentioned in relation to a cooler thermostat is that the engine/oil temperature needs to be high enough to burn contaminants out of the oil. Water can (and does) condense in your oil when your car sits, as well as other byproducts of combustion that slip past the rings and into the oil. If the oil gets hot enough, any condensed water will evaporate out of the oil, and even combustion byproducts can be removed by this heat. The reason we don't see 'sludge' in the oil pans of modern cars is mostly due to higher thermostat settings. If the thermostat is low enough temperature, the lifespan of the engine can be significantly reduced. The quesion to me seems to be, how much difference in oil temp is the cooler thermostat making?

 

I won't argue any of these facts regarding running too cool a thermostat, but keep in mind this discussion started regarding the Mugen parts that do not let the engine run cold. In days past there was not ECU's watching for low temps, etc. but this car retains all of that and operates normally. The Mugen units are designed to reduce temps 12F

 

But if you never get to the trip pressure on the stock, you wouldn't on the Spoon. Has anyone popped the rad cap yet? I would guess that it rarely happens. Maybe in SoCal on a hot day on the track.

 

I have expressed my opinion before... I believe the lower temp thermostats are basically useless and may be counter productive. I have temp gauges so I'm fairly familiar with the temp profile for both coolant and oil temperature. If you push the car hard, coolant will be in the 90C + and oil 110C +.

The stock thermostat will be wide open long before that. If you are not pushing the car hard, why bother?

On the other hand a lower temp thermostat may delay engine operating temp at startup basically shortening engine life over repeated startup cycles.

So unless you're a hardcore racer where every picosecond counts, you are basically wasting money or worse.

Now can someone please fault my logic, as I was gullible enough to buy & install a Mugen thermostat TIA.

 

I think we had this conversation in the past. It is obvious that under the hardest conditions the cooling system can only maintain a particular temperature regardless of thermostat.. the engine is under max load, the thermostat is wide open and the fan is going.. makes no difference what kind of thermostat is wide open.

I believe the intent is to maintain a lower temperature under less severe conditions (10C in the case of the Mugen setup) so that there is margin when the engine is put under load. The aftermarket setup will open sooner and close later reducing the average temp over a circuit even if the peak temp is no different than the stock peak. Overall this strategy should result in a lower incidence of timing retard due to coolant temps.

My guess is that comparing plots of coolant temperature with the different thermostats over a period of laps will show the difference you are not seeing in peak readings.

 

What if you were to install just the fan switch? Wouldn't this be of any advantage to have the fan come on sooner to get some additional air flow? My 94 Z28 would get hot at idle or between autocross runs. The lower temp stat did nothing in that car until I put a lower temp fan switch in with manual overr ride so I could run the fan continuously to keep underhood temps down.

 

Chris, the last time I was at the track I paid attention to the water and oil temp gauges. After the first few laps, peak basically equaled average. The needle just sits there without any discernable movement.

 

[QUOTE]Originally posted by Luis
[B]
Chris, the last time I was at the track I paid attention to the water and oil temp gauges.

 

[QUOTE]Originally posted by Luis
[B]

Chris, the last time I was at the track I paid attention to the water and oil temp gauges.