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Same cylinder head temps after 170 thermostat install???

BMR Tech

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My CHTs went down about 10-12 degrees after installing the Reiche 170 stat
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I got mine 170 thermostat installed about 2 weeks ago. My CHT are on average 15-20 degrees cooler.

My highest CHT on stock during some long idles was found 215-220. Now in the same situation, I average 196. I have not seen 200 since I got mine installed.
 
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ero 5.0

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damn, alright thanks guys, sounds like theres definitely an issue. Thanks again for the replies.
 

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ero 5.0

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Its a Reische 170 thermostat.
 

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The only way to get a benefit from a lower temp thermostat is to also adjust when the fans come on (eg. earlier).

By not changing those settings and allowing the fans to come on at the same temperature as before then you aren't doing anything. The thermostat isn't the one actually keeping the coolant at a certain temp, it's the fans in conjuction with the radiator. What you are doing by using a lower temp thermostat is allowing the coolant from the engine to go into the radiator earlier, and by turning the fans on earlier then you maintain that temperature. If you install a lower temp thermostat but don't turn on the fans until later then nothing is happening and the coolant will still be the same temperature as before.
 

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The only way to get a benefit from a lower temp thermostat is to also adjust when the fans come on (eg. earlier).

By not changing those settings and allowing the fans to come on at the same temperature as before then you aren't doing anything. The thermostat isn't the one actually keeping the coolant at a certain temp, it's the fans in conjuction with the radiator. What you are doing by using a lower temp thermostat is allowing the coolant from the engine to go into the radiator earlier, and by turning the fans on earlier then you maintain that temperature. If you install a lower temp thermostat but don't turn on the fans until later then nothing is happening and the coolant will still be the same temperature as before.
this is correct at very low MPH and idle but if you are going, say, over 30 the fans in many cases are not even turning....the car will benefit from the lower temp stat.
 

markmurfie

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Even when you are not moving the tstat opening sooner will allow circulation sooner and cht will not climb as fast.
It will eventually climb to the fan temperature which is where the Benefit of fans coming on at lower temperatures come in. I think even the stock tstat could benefit from the fans coming on sooner. It's just not fuel efficient to run at lower temperatures and having the fans on more creating alternator load.
 

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this is correct at very low MPH and idle but if you are going, say, over 30 the fans in many cases are not even turning....the car will benefit from the lower temp stat.
True, but that is only the case if you start the car and get up to speed over 30mph before the engine has a chance to reach full temp. However if you then slow back down to near idle and let the temps climb back up to over 200* (due to the fans not being on earlier or getting airflow from movement) then you're right back where you started of OEM type engine temps that you won't get down to 170* unless you shut off the car and let it cool on it's own.

So to truly get the full benefits of a lower temp thermostat all the time, you also need to adjust the fan settings. You can't rely purely on airflow from movement.
 

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markmurfie

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True, but that is only the case if you start the car and get up to speed over 30mph before the engine has a chance to reach full temp. However if you then slow back down to near idle and let the temps climb back up to over 200* (due to the fans not being on earlier or getting airflow from movement) then you're right back where you started of OEM type engine temps that you won't get down to 170* unless you shut off the car and let it cool on it's own.

So to truly get the full benefits of a lower temp thermostat all the time, you also need to adjust the fan settings. You can't rely purely on airflow from movement.
As soon as you start moving again air flowing over the radiator will cool cht back down to the new tstat temperature. You just won't be taking advantage of the lower temperature tstat at a stop or low speed. The factory fan settings don't take full advantage of the factory tstat at a stop or low speeds. Lund tunes do. That's why people complain about how much the fans come on.
 

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True, but that is only the case if you start the car and get up to speed over 30mph before the engine has a chance to reach full temp. However if you then slow back down to near idle and let the temps climb back up to over 200* (due to the fans not being on earlier or getting airflow from movement) then you're right back where you started of OEM type engine temps that you won't get down to 170* unless you shut off the car and let it cool on it's own.

So to truly get the full benefits of a lower temp thermostat all the time, you also need to adjust the fan settings. You can't rely purely on airflow from movement.
let me put it this way. I have a low temp stat in my C7 and my GT and both cars went from 215-220 to 175 in the C7 and 185 in the GT full time all the time except for sitting at idle for at least 2 minutes in which case they can creep up and the fans kick on the hold them at 195ish, which is where I have them set. Otherwise, the fans are literally never on.

I understand speaking in theory, but have you used a low temp thermostat in reality? They don't work like one might think, like you described.
 
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ero 5.0

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Ya mine literally didnt make any difference. Mine is 205-210 when cruising at 75 at 2k rpm on the freeway.
 

markmurfie

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Ya mine literally didnt make any difference. Mine is 205-210 when cruising at 75 at 2k rpm on the freeway.
Where did you get it from? Before you installed it did you make sure it said 170* on it and it wasn't just a stock replacement?
 
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ero 5.0

ero 5.0

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ya, im sure it was a 170, got it from lethalperformance.
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