"Some racers believe that a warm engine makes more power than a cold engine; others think that a warm engine is more consistent. In fact, heat is the enemy of performance. An engine will make more power if you run it cold - and it can still be consistent.
The ritual of warming an engine is a holdover from the days when we ran "molasses" in our engines. Back when racers used 20W-50 and 10W30 mineral based oil, there was a valid reason to warm an engine. Those thick oils caused big pumping losses. In contrast today's off the shelf synthetics oils do not need an extended warm-up. Even on a freezing morning all you need to do is take the chill off. Futher heating of synthetic oil makes no difference, it just needlessly puts heat into an internal combustion engine.
Our dyno and track results have repeatedly shown that a drag racing engine runs best with thin oil and cold water.
In pro-stock a stone-cold engine is best. We have also dyno tested literally hundreds of sportsman engines, and it appears that a coolant temp. of around 120 degrees at the start of a run is ideal.
I recognize that pro-stock teams have the luxury of 90 minutes between runs and that it is tough for a sportsman racer to keep the engine cool during round robin eliminations. That's just another reason to have an effective cooling system and to refrain from putting unnecessary heat in an engine by warming it up.
I've watched racers warm their engines, then turn off the electric pump and fan to keep the heat in the engine. Instead, leave the pump and fan running to pull heat out of the cyl heads, which need to be cool. You won't pull much heat out of the oil 'cause it's sitting in the pan.

My recomendations to sportsman racers are to use synthetic oil and run your engine as cool as you can."

(Credit David Reher)

There's a lot more to the article, like btu's generated during a run, and that he likes the engine to be a maximum of 150 degrees after the run. But that's the jest of it. Enjoy it for what it's worth.

SteveW

I know you've got your sh!t together and you're a winner, but read the whole article. Along with making more power he's discussing longer engine life which might help you out. He doesn't mention block fillers, but I'm sure they use them in the pro-stock engines. The whole article including btu's etc. was based on gasoline. Your alcohol cools things off, so does N2O for those who like that. I need an electric water pump and fan for the '66. At Sac. raceway last w/e we used a hose to try and cool things down, and all we cooled was the radiator. It's a lot hotter there than at searspoint on a Weds. night.

Those pro stock guys arent concerned about making a motor live 250+ passes, all they are worried about is 8, maybe 9, then they tear them down and freshen them up.

Perhaps the motor would make more power with a real low temperature, but from what I have seen, and have heard from a couple of big name circle track engine builders, it is just as hard on them to be too cold as it is to be too hot.

That being said, I use synthetic in the engine, tranny, and rear end... chassis grease too!

My car runs best stone cold. I'll run the electric fan and water pump until the engine is cool to the touch, then get it to the line with as little running (sometimes pushing) as possible. Fire it up, do a burnout, and run it. This is what -my- car likes best.

Now, THAT being said.

Engines make the most power with warm, thinner oil and cooler air/fuel temperatures. Thinner oil takes less horsepower to pump, and cooler air/fuel mixtures are more dense.

An intake tract that is cool, will not heat the fuel mixture as much as it travels through the ports... but higher temperatures will vaporize more of the fuel, so your mileage may vary. Alcohol runs extremely rich, so there is a LOT more of it to vaporize. As it vaporizes, it absorbs heat from its surroundings, making those surroundings cooler. Intakes on alcohol engines will often be COLD to the touch while they are running. It's pretty neat! Alcohol engines generally need more engine temperature than their gasoline counterparts to help vaporize all that additional fuel.

Moral of the story, with if you use conventional oil, be SURE that the oil is warm before making a run... especially if the clearances in the engine are fairly tight. Thick oil in an FE engine run at the strip cold is a SURE FIRE recipe for spun bearings... especially if those oil mods haven't been done!

Good Luck!

Shell
Ladyracer

Rob, how long have you run alcohol in your car and do you like it better than gas?

quote:

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Originally posted by Ken&Shell:

Rob, how long have you run alcohol in your car and do you like it better than gas?

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2 full seasons and half of another.

And I really love the stinky stuff
Without it, I would never be able to run multiple classes (the motor would get way to hot). Plus, it is easier for me to be consistent with it than when I ran gasoline.

Keeping heat in the combustion chamber is what makes power. Note that an iron headed motor will make more power than an aluminum one all things being equal. I know of a guy that tested a big block chevy on a dyno and then changed nothing but the block, switched to an aluminum block. With no other changes he lost 60hp.

That's why I posted the article. Not to argue but just to get to the truth. I would consider Mr. Reher an expert and he thinks cool engines (including the combustion chambers) with thin oil make more h.p.. Your theory is sound if the engine is tuned not to be on the verge of detonation, which is where an engine will make max. h.p. Remember he's talking about "sportsman" engines, not just ProStock engines, and Reher-Morrison sells a ton of them. I'd like to hear what other racers have experienced in the real world of "drag racing", like N2OMike, Rob, Shell, Jim, TomP and Alex. Thanks for your input. I'm not disagreeing with you, I'm just not sure.

I talked to Wayne Torkleson after noticing they set the valves before firing the engine,ran it for under a minute, then set the valves again before warming it up.

The tall deck height aluminum block and big aluminum heads, long aluminum rockers etc... all grow more than the valve lash.

160* = 6.504
168* = 6.504
180* = 6.500

But, then during the third round of elims, I screwed up and staged at 150* (had a really big problem right before then) (dont ask), and it slowed to a 6.53 (on a 6.50 dial). Needless to say, I lost.

104.73
104.68
104.77

oops, looked at my log book today