I have a 98 Convertible A4 and am looking into purchasing a HyperTech Programmer and a new Thermostat. The PowerStat comes in a 160 degree and 180 degree version. Which will yield the best performance?

 

Up where you're at I'ld go 180.

Bob
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The opening temp of your thermostat has Nothing to do with the power output of your engine. Once the thermostat has opened at 160, 180, or whatever, it's the operating temperature that will have a slight effect on power output. If as "performance" implies you are asking the engine to deliver a lot more power than a slow cruse down the highway.

This means the engine will be creating enough heat that the coolant will be at least 190, even on a cool day. The operating temperature of the coolant, while the car is "performing", will depend upon the amount of heat the radiator can remove, which depends upon the temperature of the outside air, the size of your radiator , and the temperature at which the fans come on or how fast the car is moving through the air. In a stock C5 the fans come on at about 220, and the heat removal capacity of the radiator is not adequate to keep the temperature below 190 during "performance " driving.

So, it really doesn't matter if you have a 160, 180, or even a 150 degree opening thermostat in your car. The operating temp during "performance" driving will be higher than the opening temperature of your thermostat.

If you had an oversized radiator, the fans programed to come on at 180, then in most "performance" driving situations the coolant temp would be around 182-185 regardless if your thermostat opened at 160 or 180. The 180 degree operating temp would give you a very slight power advantage over a 200 degree operating temp.

I hope this helps to dispell the belief that a lower opening temp thermostat somehow magicly creats more Horsepower all by itself.

Jim

 

Thanks for the information. Do you have any idea why Hypertech suggest that you purchase the PowerStat along with the Hypertech Programmer? Maybe it's just great marketing. Thanks again

 

I'm currently in Texas. 100 degree weather. My C5 runs 180 degrees on the interstate at 80/85 MPH. I'm running a Hypertech 160. If I was running a 192 thermostat it would never run below 192. My fan temps have been lowered but shut off at 185, so they're only running in town or when I'm doing some very aggresive driving. The lower operating temp of the thermostat will make a difference.

Bob
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I believe the Programmer will allow you to lower the temps at which your fans come on (among other things). Without lowering this temperature threshold, a lower temp thermostat will do very little towards lowering your operating temps in city stop and go driving. On the highway, however, you will se a big drop in temps. I have a 160 and cruising speed gives me an operating temp of 171° all day long.

 

Why are you going with Hypertech? The consensus seems to be that they don't do much for a vette, but change fan temps and up the redline. You can't even change the gear ratio with them, much less get a good performance tune.

 

I think I should have done more research. After reading through some of the other postings, it looks like lot of members lean towards the Predator vs Hypertech.

 

Nothing will compare to a good tuner. I wouldn't use either one. Just my opinion.

Bob
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Hypertech Programmer for fan control, and 160 stat is perfect combo. :yesnod:

 

There was a big write-up on this subject in the GM High Tech Performance Mag a while back testing all the stats. It was concluded that that the LS1 reached optimal peak performance output at 178 degrees and they selected the 180 stat, which is why I got it. Colder is not always better, especially when you depend on the heat to create the expansion of the aluminum needed to help seal the piston rings, etc. If you would like more info on the article I'll look it up in my stack of mags, just IM me and let me know.