Why are my CHTs rising like this?

[Dragster]

Hey everyone! After my latest install, I've noticed that my cylinder head temps vary more than they did before. I added Comp stage 1 cams (have a GT350 manifold) and a Mishimoto radiator, and the car was remote tuned by Alex at Lund. Previously, my car had the same setup but had stage 3 cams and the stock radiator, and my CHTs would rise to 190 or so and basically just sit there. Now, they will vary from the 180s up to low 200s. This mostly happens when the car is stopped or in traffic. My initial thought is that the fans aren't coming on, but is there anything else that could be causing this? I need to monitor the coolant temp, but I assume that it's getting warm enough for the fans to come on. If the CHTs are in the low 200s, the coolant has to be warm enough for the fans to come on, correct?

Thanks in advance for the help!

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[BmacIL]

Low 200s is fine. When you see 220+ in traffic, that's not necessarily an imminent issue but a sign of problems.

 

[Dragster]

Low 200s is fine. When you see 220+ in traffic, that's not necessarily an imminent issue but a sign of problems.

Yeah, it's not the temperature that I'm concerned about, but rather why it's rising so much more than it did before. I really don't ever remember watching it rise before, and I've noticed it several times so far in the couple of times that I've driven the car.

 

[BmacIL]

It's the radiator difference. The varying temperature is fan off to fan on. It'll let it climb to the low 200s and then kick on. Likely the radiator is more efficient so the same fan output will cool more.

 

[Ace21]

BmacIL is absolutely correct, you changed to a more efficient radiator, however, you are still using the stock fans and thermostat. That fluctuation is the new radiators ability to shed heat during airflow conditions via fans pulling air through it. If you want something more stable then you will need to change the thermostat to one that opens a bit earlier, or ask Alex to change the Fans deactivation temp limit to be higher.

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