Hondata

We do not recommend the use of low temperature thermostats, as this causes tuning problems since the ECU still thinks the engine is still warming up.

For those who think low temperature thermostats stop their engines over-heating - what is the difference between a 160 degree thermostat and 178 degree (stock) thermostat when the coolant is 185 degrees, and both thermostats are fully open?

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Hondata

I agree. I am in the process of putting my built motor in and plan on putting a new stock one in.

I wish there was a way to turn this off in the software. (COld start)

I have been using a Mugen thermostat and I often wondered about this. I have been troubled by the difficulties I've been having getting a consistant tune. Seems everytime I think I'm getting close, the datalog shows the numbers way off again.

My coolant temperature has not been above 170 degrees for weeks now. The ambient temp has been in the 5-10 degree celcius range. I have "flogged" the car repeatedly, loading at 900-1000 millibars for extended periods (20-30 seconds) and the temp never passes 170. The IAT temp generally runs in the 45-65 degree F range during these floggings.

Now I will be installing an OEM thermostat and starting again.

even above 170F there is a significant difference in the AF from the cold-start enrichment. also above 195F it becomes more significant...the radiator fan cycles at 203F so the top temp range is affected, too.

while i agree that running a 170F 'stat vs. a 180F 'stat is pointless, many of the cars brought to me have the lower temp 'stat: this adds significant effort and time to doing a proper tune if the 'stat is to be changed (especially on a hot car driven a distance to our shop).

in the interest of consistant tunes i'd like to see cold start add zero fuel between 170-205F...and a CEL condition when water temp exceeds 210F.

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RaVer Motorsports (559) 733-4711
ravermotorsports@earthlink.net

Yes, fo sho!!!

Doug/Matt,

In an effort to ease my re-tuning, I am looking for a best guess here:

I have changed my thermostat to an OEM. My maps were almost perfect before. I had the ECT enrichment set to 0.92. Could you offer a suggestion as to how much fuel I need to add to the whole fuel map (low cam only, its not Vtec) to make it so the fueling stays the same when the ECT enrichment turns off?

cover 3/4 of your radiator with card board, the side where your AC is or where the fan is not present. That helped me quite a bit in 10 degree weather for tuning at 180.
Use a lambda meter while warming the car up to see if your fuel is too rich and adjust your ECT. ALso if you switched from a ODBII ECU to a ODBI you should change the throttle body with one that has A Cold Idle Valve. Many cars with ODBI ECU's in the junk yard have them. Cold starts are perfect every time now.

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96 GSR / B18C1 Built / AEBS T-Sleeves /~~/
No stickers / no nice rims / 10.4 seconds
other hobbies: PC gaming, Half-Life, Linux Administration, MotocrossKX250, kissing big tities

Honda has superceded ALL thermostat part numbers to one that is 172F. A software fix sounds like the best answer.

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RaVer Motorsports (559) 733-4711
ravermotorsports@earthlink.net

Yes, would it be possible to add in an adjustable value for the temperature at which your thermostat fully opens? This seems like the best solution for people who are tired of throwing money at their car to solve problems.

I agree with a software solution and a value that we can change in the tunning (IE the full open value)

The thermostat is not electrically controlled. It is a wax pellet.

lol, that would be cool though! Actually I did see a kit somewhere, maybe summit I forget. That takes full control over your cooling system / electric pump control and thromostat doesnt use a mechanical tempered spring, it opens it as needed electronically. I think the cost for it was in the ballpark of 650.00..
But it would be cool if hondata could set an electronic thermo to a users setting. that way when you goto the track, before you make your run, have the temp down to like 165 or something, then drive home on 172.

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96 GSR / B18C1 Built / AEBS T-Sleeves /~~/
No stickers / no nice rims / 10.4 seconds
other hobbies: PC gaming, Half-Life, Linux Administration, MotocrossKX250, kissing big tities