Low Temperature Thermostats – Yay or Nay?

Lately, I’ve been looking into getting a new thermostat. “Why?”, you may ask. Because, currently, my car doesn’t have one.

Several months ago, my SR20DET suffered a blown headgasket caused by overheating, which was caused by a worn-out stock thermostat that stuck closed. Since then, I’ve run the super special N.T. (no thermostat) mod style. You know what they say, “less points of failure are better,” right? Well, yes there are some pros to running “stat-less,” but there are also some cons.

The good thing is that you don’t have to worry about your thermostat failing because you simply don’t have one anymore. Some people report having lower water temps without a thermostat as well. (There are also people who report the opposite.)

The bad things are:
1. It’s harder to set ignition timing because the engine cools to below operatnig temperature while you’re working in the engine bay. So, to set ignition timing, you’ve got to race around the block a few times to get temps up and then quickly do all your work before the engine cools off.

2. The engine takes forever to warm up, which can be bad supposedly.

So, as you can see, there are some tradeoffs. In my experience, doing what I do with my car, I may need a thermostat. This situation may apply to you, or it may not… but here goes:

I like to do drift events, and typically, you’ll do one or two laps around a drift course, and then you’ll get to the back of the line until it’s your turn again. Depending on the weater, sometimes when I finish a run and get back in line, the engine will cool off before it’s my turn again. And so, when it’s time for me to make my next run, the engine is too cold, and ignition timing is not proper, and the car is running rich. Sometimes, you get this hot-cold-hot-cold battle throughout the day, and it’s probably bad for the engine.

So, what are the options? Some say to go stock, some say low-temp thermostat, and there’s also “high-flow” thermostats.

Comparing stock to low-temp, the main obvious difference is that the low-temp thermostat starts opening at a lower temperature compared to the stock varient. Now, the thing that’s important to know is that the thermostat is somewhat like a window. There’s a range – it can be slightly open, more open, and wide open. A low-temp thermostat will spend more of its time wide open compared to a stock one. At least, that’s the theory. Currently, the popular low-temp thermostats for SR20DET’s are made by Nismo, SARD, and Billion. There are also less-expensive versions by companies like ISIS and Mishimoto, but I haven’t heard of the quality of these. I think most people who go low-temp tend to not chance it, so they go with one of the first 3 brands I listed.

Then, there’s a company I just discovered called Tridon, which has the same temperature range as the stock thermostat but also has a larger valve to allow more water flow. But I feel a bit iffy about these, since I read a few posts online about people having their Tridon thermostats get stuck in little time.

So, which one do you think is better? Stock, Low-Temp, or Large Valve thermostats? As for me, I’ll probably run stat-less a bit longer until I can get my hands on a Nismo.

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