Any consesus on thermostats?

The only thing I can think of is that heat cycling is bad for aluminum heads and gaskets on iron blocks, and that a thermostat might help smooth out those cycles. I think we're going to add a radiator and leave in a cool thermostat and see what happens. The crazy thermostat design int he Fiat would require some replumbing to bypass anyway.

We used to run a SBC (late model dirt track car) and tried running it w/o a t-stat, but the water was leaving the radiator to fast to be cooled, so we had to put it back.

Personally I'd get a low 170-180F t-stat and leave it in.  FWIW, we ran our E30 (with 180F t-stat) the entire time at CMP and the water temp stayed at 210F.  We also wired the cooling fan to run constantly for extra insurance on caution laps, pit stops, etc.

We drilled a series of small holes in ours so that it allowed SOME flow if it ended up sticking closed.  We also did a lot of ducting work to bring as much air in through the radiator as possible.

One thing we also did was gut out the heater box from under the dash.  We have 2 coolant lines in the whole car... one to and one from the radiator

Guys -- the 40-year trick set-up has always been to remove the thermostat from the outer restrictor ring.  Cut the thermostat valve from the outer ring and replace just the ring in the housing.  That way, you slow the water flow down to promote heat transfer in the radiator but you also avoid any possibility of the thermostat jamming and causing a catastrophic failure.  Age old solution to an age old problem.

John

e or i? Our little naturally aspirated E28 eta ran at a steady 170 with the thermostat, no fan unless stationary for more than 5 minutes. It was 160 without the thermostat but sometimes ran way too cool so we put it back in. Now with 9 psi of boost it runs at 190 and only running the fan when still. We did find that using a pressure pump and bleeding the cooling system multiple times at multiple points made a big difference and brings leaks to your attention well BEFORE you get on the track.

For anyone, I'd recommend running with the thermostat in to keep temps steady. Cold or erratic temps are equally bad and the thermostat is there to maintain a steady temp. Pull the thermostat, heat it up in a pot of water with a temp gauge and make sure it opens fully at the right temp. If it doesn't replace it, maybe with one that opens 10 or 20 degrees lower than stock.

I am curious to see what will happen at Buttonwillow with both driver and engine cooling. OATs will be between 100-110. I suspect much overheating. Whatever budget Jay gives us will probably go to additional engine cooling. That and a cool suit set up for the drivers.

John is exactly right.  A thermostat is an unnecessary risk to run in racing.  If that $3 part gets stuck closed, you're done for.  However, taking it out will result in poor cooling as well.

Water is excellent at heat transfer, far better than coolant, but it needs to be in contact with the hot surface in question long enough to wick that heat away.  As John mentioned, removing the center of a thermostat creates, in effect, a restrictor plate.  Water flow is slowed in the circuit and yet it can never be 0. 

For those who are obsessed about details, the size of the restrictor plate can be changed to optimize the heat transfer abilities of the water.  Generally speaking though, a cored out thermostat is just about perfect.

At CMP in April, we ran the stock radiator and a cored out t-stat.  The radiator had an electric fan on it with a switch on the dash.  The only times we needed to turn the fan on was if the car was sitting still.  We had great cooling (180deg) with no fan at track speeds.  Granted we have a tiny engine, but the radiator was the size of a magazine.

In every form of racing, it is good to get your engine up to operating temp before you race it.  The temperature will reach a maximum level with or without a t-stat in place.  Say you have a 195 in your engine, once it gets over that temp, you are in effect running just a restricted water flow continously through your radiator.  The only downfall to "gutting" the t-stat is the length of time it takes for the engine to heat up (which in racing apps is not a bad thing).  Thermostats generally do not fail but for these semi race situations as seen in Lemons, gutting the t-stat is the way to go hands down.  In every engine used for race applications, at least that I have come into contact with, I have never seen a t-stat in any of them.  The only reason I would run a t-stat in this case would be if I planned on needing to run the heater and I didn't want to be cold, you know for the proposed frozen tundra Lemons Winter 2010.

HEI is more reliable than points, IMO... At least when it comes to SBC's

And if the coil bites the dust it's a 3 minute swap, if that.

I had 2 brand new thermostats fail on 2 different cars in the span of 2 months earlier this year. On both of them the bridges failed and they got stuck closed. Had never seen failures like that before, but suddenly Murphy came calling.

Normally I boil them under pressure to see when they open, and have found about  15-20% don't work correctly.

On the flip side, especially for cars running carburetors, the temp effects the air/fuel tuning so I don't like mine to run below 180. Steady and warm seems better and more consistent than wide temp swings.

Unfortunately I run an English car in Lemons, so none of this really even matters; It going to overheat and die soon in glorious fashion no matter what we do. That should be fun.

a failed thermostat is what ended Huey Newis' weekend in Reno. spend the 6 bucks, get a new one. do it.

Well I'm 28. That oughta make you feel better.

The thermostat question depends a little bit on the car--some newer cars with computer-controlled fuel injection can go into fits if the temp isn't within a certain range. At Lemons, we've seen some weird issues on cars that are running non-stock radiator locations where the water doesn't circulate properly through the cooling system--sometimes, keeping the thermostat in promoted the proper flow. Also, we've seen teams monkey with their thermostats for hours, when a crappy radiator was really at the root of the problem.

But, generally speaking, running sans thermostat is a good, simple approach. Certainly wouldn't hurt to try it out.