max safe coolant temp?

**texevora** · May 19, 2019, 05:34 PM

With the weather starting to warm up here in Texas, it was about 85 degrees and sunny today. While running the car today on track, I experienced a few brief coolant temp alarms when it hit 215 degrees. Although everything was fine and the temps came down by just backing off for a half lap or so, it does concern me that i'm hitting the temp alarm with ambient temp in the mid-80s, as it often hits 110+ in Texas in July/August.

To you track junkies out there with SRAs, a few questions:

1) Is 215 degree coolant temp in mid-80s F ambient air normal?
2) What is max safe coolant temp on the SRA?
3) If I need additional cooling, is there an easy way to accomplish that?

Not sure if this matters, but my SRA was delivered from the factory with water and water wetter. I flushed and replaced with Honda pre-mixed coolant as we had a few sub-freezing days and I didn't want to risk a cracked block from frozen coolant.

**sector: 4** · May 19, 2019, 10:22 PM

Coolant isn't as effective as straight water at cooling. You want to use water on the track. Preferably distilled.

**argonaut** · May 20, 2019, 04:58 AM

I don't think 215 is an issue. I routinely see 225 on track in warm weather. In Corvette world (I tracked a C5 before the SRA) hitting 250 was not unheard of.

**texevora** · May 20, 2019, 08:34 AM

@argonaut, are you not getting a hi temp warning on your Dash2 dash when it hits 215?

**cvjoint** · May 20, 2019, 09:47 AM

Dash 2 is pre-programmed to show hi temp at 215* or so. What you are seeing given the ambient is normal on a K24Z7 if ran hard. I was getting up to 220* on clean laps when I had the K24z7 and close to 230* when trying to pass some car (and blocking some of the airflow).

You can program the Dash 2 to move the warning to 230*, that's what I did. I believe a K24Z7 will run forever even if you regularly see 220*.

Extra cooling can be had via horizontal radiator (hot country radiator) which I have asked TMI for but it's on backorder. I suppose the more of us order one the more likely they'll make them. The other option is sidepods from TMI from the 3S. One sidepod is an additional radiator.

Fun fact, the K24Z7 runs hot. The 4 into 1 head is notorious from pulling heat from the exhaust, it was designed like that on purpose for emissions. I have a 4 port head on the K24Z7 bottom now and the coolant stays pinned below 200* while making 59whp more. The SRA cooling system is quite good, it's the head that sucks. Another reason why I don't care much for the Atom 4. The K20C in that one is also 4 into 1. Worse design for motorsport ever.

**argonaut** · May 21, 2019, 05:12 AM

Originally Posted by texevora

@argonaut, are you not getting a hi temp warning on your Dash2 dash when it hits 215?

I replaced the Dash2 with AiM MXS and I have it programmed to warn of high water temp when it hits 230.

**cvjoint** · May 21, 2019, 03:49 PM

A few notes about the Corvette references. The C7 Z06 has a 262* limit before limp mode protection kicks in, but it's also a 20psi system, ours is a 15psi system. I ran the Z06 engine to that limit many times and nearly always above 220*. Engine lasted less than 25 HPDE hours. To me that experience suggests that materials do fatigue noticeably if you run that hot all the time.

**texevora** · May 23, 2019, 03:25 AM

What is the easiest way to test whether or not the radiator fan is working?

Under what specific conditions does the radiator fan turn on?

**argonaut** · May 23, 2019, 05:22 AM

I can let the car idle and eventually the fan will turn on and stay on until temp drops back down. Can't remember the exact temps when it turns on and off though. The coolant fan and the oil cooler fan are on the same relay - they should both come on and off at same time (at least thats how mine was wired). I didn't like that so I put the oil cooler on a separate relay with separate temp sensor. Also installed a different sandwich plate with built in thermostat so it doesn't send oil thru the cooler at cold temps. I tried putting a thermostat into the coolant system also but that didn't work out - it would never open. I gave up and now, in cool temps, I just tape up the front end opening so that I can get water temp to proper range (I was having big problems last fall getting temps high enough during cool weather)

**cvjoint** · May 23, 2019, 09:53 AM

Originally Posted by argonaut

I can let the car idle and eventually the fan will turn on and stay on until temp drops back down. Can't remember the exact temps when it turns on and off though. The coolant fan and the oil cooler fan are on the same relay - they should both come on and off at same time (at least thats how mine was wired). I didn't like that so I put the oil cooler on a separate relay with separate temp sensor. Also installed a different sandwich plate with built in thermostat so it doesn't send oil thru the cooler at cold temps. I tried putting a thermostat into the coolant system also but that didn't work out - it would never open. I gave up and now, in cool temps, I just tape up the front end opening so that I can get water temp to proper range (I was having big problems last fall getting temps high enough during cool weather)

Which sandwich plate with built in thermostat did you use for the oil cooler? This sounds genius.

I believe the solution for the coolant is to run an electric water pump. I plan to do that at the end of the season. Just as you mentioned, I tried to plug in a thermostat but it would never open. Tape works decently well in the dry. But in the wet last time I simply could not get the engine hot enough no matter how much tape I used. Tape takes time, it's also hard to stick on when it's pouring rain.