308 Practicality Modifications

Per the manual again, the radiator temp switch is supposed to turn the fans on at 195, and turn them off at 167--and I'm sure it does, but the coolant temp indicated on the gauge is measured at the engine, where temps are higher. Typically, the fans don't come on until 210 or 220 indicated. Obviously, the coolant temp we care about is the higher one of the two--especially if it's in the engine itself. For my money, (and the hundreds of hours I'd spend rebuilding my engine) 220 F where the expensive aluminum lives, is too close to critical material temps.

Based on actual observation, I can truthfully report that turning my fans on manually when I'm slowing down for traffic or a parking lot, or exiting the track, translates to steady temps 10 to 20 degrees lower than where the would otherwise stabilize. You may not believe it, but that is what I'm seeing.

 

On a race track, at speed, overheating engine coolant should never be a problem--because of the massive quantities of air being ingested. If it is, you're about to be black-flagged for leaking coolant all over the course. (Caveat: it is possible to get your coolant temp high if you are riding another cars tail long enough and thus trying to cool your engine with his hot exhaust, but I only do HPDE, so I don't bump draft people lap-after-lap.) Anyhow, Oil temps are what you should concern yourself with on sustained high-RPM running. Until, of course, it's time to slow down and get into the paddock. That's when all the lovely and completely acceptable heat in the oil starts soaking into the coolant, which is 1.) not circulating as quickly, and b.) not getting as much airflow.

And no, I would say catastrophic overheating is something to worry about with every car you give a damn about, especially one that is old, and expensive to fix. In my misspent youth I overheated and destroyed multiple car and motorcycle engines--and cluelessly tore them apart to try to rebuild them. The damage was always shocking to me.

 

I have no reason to doubt what you're saying. 20+ years ago I removed the fan temp switch and use the engine coolant temp to trigger the fans, i set the fans on 5C above the t'stat set point and off at the t'stat , so on at 75, off at 70 in my case as I run a 160F (70C) t'stat, and it works quite well. I did it because it easier to just let my new ECU handle it and it saved me adding another bung to the chevy radiator I run, it never really occurred to me it would be running cooler as a result.

 

Hi Tommy,
Meant to comment on this earlier to prevent confusion. The lowered coil over setup is not harsh at all. In fact, the way I have it set since it is adjustable on multi settings is very supple. I also have the carbon impregnated bushings which I can attest do not squeak one bit. The problem comes when you hit a deep road patch that is below road level with force and somewhere on the bottom scrapes. The car just needs to be higher an inch or so for the street. Hope this clarifies.