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Author Topic:   Best engine temp for drag racing...
steve'66
Gearhead

Posts: 8826
From: Sonoma,CA,USA
Registered: Mar 2000

posted 08-09-2001 08:38 PM     Click Here to See the Profile for steve'66   Click Here to Email steve'66     Edit/Delete Message   Reply w/Quote
I don't claim to be an expert, but there is a very interesting article in the latest National Dragster written by David Reher, of Reher Morrison Racing engines and the crew chief of the Reher-Morrison Pro Stock car. I don't want to type the whole thing, but here are the interesting points.

"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

[This message has been edited by steve'66 (edited 08-09-2001).]

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JAAZZY
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Posts: 777
From: Bay Area, CA
Registered: Apr 2001

posted 08-09-2001 08:58 PM     Click Here to See the Profile for JAAZZY     Edit/Delete Message   Reply w/Quote
So what you're trying to say is that if someone like myslf employs these principals not only will I redlight thinking about it but I'll also miss a gear looking at the temp gauge!

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Just Jim
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Posts: 381
From: So Cal
Registered: Feb 2000

posted 08-09-2001 09:52 PM     Click Here to See the Profile for Just Jim     Edit/Delete Message   Reply w/Quote
Yup.That's what would happen to me also.Another red eye. The theory sounds good but won't work in the real world of "little guy" racing,IMO.

------------------
"Just Falcon Around"
1962 Falcon 351W
1958 Morris Minor 289

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chips67
Gearhead

Posts: 651
From: louisville, ky, usa
Registered: Jul 2001

posted 08-09-2001 09:57 PM     Click Here to See the Profile for chips67   Click Here to Email chips67     Edit/Delete Message   Reply w/Quote
i think my car likes to be cold, or just starting to warm up. the thing is i drive to the track so if i wanna be cold i have to leave real early and bring a novel. then i get one cold pass, which your first pass is usually your worst anyway, then i get in a huge line of cars. by the time my lanes are called i sit idling for at least 10 minutes so the car is full operating temperature and i run the same. then as the night wears on my car is hot, the air gets cool and what i get in hp i lose in traction so the car still runs about the same. i just wish i had two identical cars that i could get to the track early....maybe take a bus back to pick up the other one....then be the only one there that day. i could pratice a couple laps with one, get in the cold car and run my best time. also id like a heated track and industial airconditioners blowing on each side of my lane as i make a pass. i think with all this in about a month of practice and tuning i might find out what my car is capable of. i think a full moon would be nice too, take some weight off but i dont know how bad that would affect traction. can you tell its past my bedtime?

------------------
67 coupe, 650dp and rpm intake on 5.0 with afr 165 heads, 4 speed, 4.11's.....best so far is [email protected] in 1/8 mile with 1.91 60ft. time.

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kid vishus
Gearhead

Posts: 6098
From: middle of NC
Registered: Oct 2000

posted 08-09-2001 10:06 PM     Click Here to See the Profile for kid vishus   Click Here to Email kid vishus     Edit/Delete Message   Reply w/Quote
My car runs faster with heat in the motor. Even with the 5W-20 synthetic oil I run, it goes faster when the water temp is around 170*. Probably due to the fact it is on alcohol.

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steve'66
Gearhead

Posts: 8826
From: Sonoma,CA,USA
Registered: Mar 2000

posted 08-09-2001 10:46 PM     Click Here to See the Profile for steve'66   Click Here to Email steve'66     Edit/Delete Message   Reply w/Quote
Rob,

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.

SteveW

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clevelandstyle
Gearhead

Posts: 1035
From: Connersville, IN
Registered: Jul 2001

posted 08-09-2001 11:30 PM     Click Here to See the Profile for clevelandstyle     Edit/Delete Message   Reply w/Quote
I find it hard to believe that it is good to run an engine dead cold, but hot isn't good either.
I was at a Fun Ford Weekend at IRP many years ago. It was in mid March and the weather was about 35 degrees. BURR! I saw more engines blow up at that race in one day than I have ever seen at one race. If I recall, there were five engines blown. I'm talking BOOM! Oil all over the place. My theory, for what ever it's worth, is that racers were running there engines dead cold. It may not mean anything, but that's my opinion.

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Amherst
Gearhead

Posts: 255
From: Amherst, WI, USA
Registered: Aug 2000

posted 08-10-2001 12:23 AM     Click Here to See the Profile for Amherst   Click Here to Email Amherst     Edit/Delete Message   Reply w/Quote
Steve - Does he talk about cooling the engine any other way? You always see racers with their hoods open, which makes perfect sence. If you had a box fan and power, could you cool the block that way while the radiator fan and water pump were running? Just a thought. Maybe pull your other car along side and plug in a dc converter, and point the box fan towards the motor.

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Doc
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Posts: 466
From: Redwood City, Ca. USA
Registered: Jan 2001

posted 08-10-2001 02:35 AM     Click Here to See the Profile for Doc   Click Here to Email Doc     Edit/Delete Message   Reply w/Quote
We were joking about a large free standing air conditioner mounted in the back of a pickup with ducting so we could pick the car up on the return road and tow it back to the lanes, cooling while going for the next round. This would shoot your cars street status in the pooper with the other racers though not to mention the cost .

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kid vishus
Gearhead

Posts: 6098
From: middle of NC
Registered: Oct 2000

posted 08-10-2001 02:40 PM     Click Here to See the Profile for kid vishus   Click Here to Email kid vishus     Edit/Delete Message   Reply w/Quote
Not to be argumentative, but I have seen the effects of what running a cold motor does to the life exptancy. It is hard on them. I still periodicaly help out an IMCA open wheeler that runs alcohol. 2 seasons ago they put a big (426 ci SBC) in it and put it on alcohol. It ran great, but had no heat in the motor ever. Halfway thru the seaon it started to lose power. We pulled it out and took it apart. The cylinders were scarred terrible. We honed it, put new rings in it, and put in a 190* thermostat. The motor finally got some heat in it, ran harder than before, and at the end of the season it still looked like new inside.

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.

Steve, thanx, I just wish I had my sh** together as much as it appears. If it werent for that "luck bunny" that rides on my shoulder, I would be first round fodder durn near every week.

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steve'66
Gearhead

Posts: 8826
From: Sonoma,CA,USA
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posted 08-10-2001 05:58 PM     Click Here to See the Profile for steve'66   Click Here to Email steve'66     Edit/Delete Message   Reply w/Quote
One thing he eluded to is that pro-stock engines are right on the verge of detonation, and that increased heat in the motor will cause a meltdown.
And that other (sportsman) engines can run higher compression and more spark advance at lower engine temps. That makes sense

SteveW

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n2oMike
Gearhead

Posts: 2419
From: Spencer, WV
Registered: Jan 2001

posted 08-11-2001 06:27 PM     Click Here to See the Profile for n2oMike   Click Here to Email n2oMike     Edit/Delete Message   Reply w/Quote
Conventional oils need a good bit of heat to thin out and flow well. Running a stone cold engine at the strip on straight 50W dinosaur juice is asking for trouble.

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!

------------------
Mike Burch
66 mustang real street
302 4-speed 289 heads
10.63 @ 129.3
http://www.geocities.com/motorcitymustang/cmml/cmml_mburch.html
http://www.fortunecity.com/silverstone/healey/367

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Ken&Shell
Gearhead

Posts: 706
From: Mocksville, NC
Registered: May 2000

posted 08-13-2001 07:14 PM     Click Here to See the Profile for Ken&Shell   Click Here to Email Ken&Shell     Edit/Delete Message   Reply w/Quote
I try to maintain consist temp in my car at the track. I like my car about 140 at the line but as someone mentioned, you get down to round robin in the later rounds you can not get your engine cooled back down to that temp in the little time you get between rounds. That's why I try to find an "even" temp to run my car at so I can consistently have the same conditions (barring weather and atmosperic conditions) each and every pass. Therefore, I usually am sitting close to 160 to 165 degree at the line each time I make a pass.

Shell
Ladyracer

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

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kid vishus
Gearhead

Posts: 6098
From: middle of NC
Registered: Oct 2000

posted 08-13-2001 07:44 PM     Click Here to See the Profile for kid vishus   Click Here to Email kid vishus     Edit/Delete Message   Reply w/Quote
quote:
Originally posted by Ken&Shell:

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


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.

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TomP
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Posts: 5761
From: Delta BC Canada
Registered: Dec 99

posted 08-13-2001 07:59 PM     Click Here to See the Profile for TomP   Click Here to Email TomP     Edit/Delete Message   Reply w/Quote
With my teensy rad it's tough to maintain anything below 150.

I did notice that when Bobby DeArmond made that historic 9 second Stocker run at Mission that they had ice on the intake and a temperature guage sitting on the bottom pin right until he had to go to the burnout box. In bracket racing you'd need a crew person to help, the car gets pushed ,not driven.

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jkilroy
Gearhead

Posts: 1808
From: Vicksburg, MS
Registered: Dec 99

posted 08-14-2001 08:31 AM     Click Here to See the Profile for jkilroy   Click Here to Email jkilroy     Edit/Delete Message   Reply w/Quote
Didn't we just cover this topic? Warm engine, cool air, that is the combo you want. The production of heat is what makes power in the first place, heat is not bad in itself. Most people feel that a cool engine runs harder because of the effects of cooling the intake charge. Note the previous story about ice on the intake. Something we have all seen many times.

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.

------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"

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steve'66
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Posts: 8826
From: Sonoma,CA,USA
Registered: Mar 2000

posted 08-14-2001 10:19 PM     Click Here to See the Profile for steve'66   Click Here to Email steve'66     Edit/Delete Message   Reply w/Quote
Jay,

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.

SteveW

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TomP
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Posts: 5761
From: Delta BC Canada
Registered: Dec 99

posted 08-15-2001 12:23 AM     Click Here to See the Profile for TomP   Click Here to Email TomP     Edit/Delete Message   Reply w/Quote
Yessiree , Reher sells enough engines to know not to advise customers wrongly. The aluminum block will lose power because the clearances all expand, more deck clearance lowers compression, but if it can be compensated for it wouldn't be a problem.

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TomP
Gearhead

Posts: 5761
From: Delta BC Canada
Registered: Dec 99

posted 08-15-2001 12:29 AM     Click Here to See the Profile for TomP   Click Here to Email TomP     Edit/Delete Message   Reply w/Quote
on the alloy block deal....

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.

They set the cold motor near zero lash, get some heat in it then shut it off before the pushrods fall out,and finally set lash at regular specs.

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jkilroy
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Posts: 1808
From: Vicksburg, MS
Registered: Dec 99

posted 08-15-2001 08:23 AM     Click Here to See the Profile for jkilroy   Click Here to Email jkilroy     Edit/Delete Message   Reply w/Quote
Push rods falling out, man would that be a pain in the *** ! Is this only an issue on the huge tall deck pro-mod motors? I don't remember anyone talking about that problem with any other aluminum blocks, like a ZL-1 BBC's for example.

------------------
Jay Kilroy
68' Fastback GT 390
"No such thing as a cam thats too big"

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bluestreek
Gearhead

Posts: 1724
From: Athens,GA
Registered: Jul 2001

posted 08-15-2001 01:16 PM     Click Here to See the Profile for bluestreek   Click Here to Email bluestreek     Edit/Delete Message   Reply w/Quote
Don't mean to change the subject but...
I didn't read anything about fuel jetting when running at cooler temps.. A cold motor can take advantage of a lot more fuel when it's cold.. I noticed the other day after I increased my jet sizes, that the engine idles better and is much more radical when I crank it and run it cold now.. It sounds like it's gonna blow the darn Flowmasters apart!!

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kid vishus
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Posts: 6098
From: middle of NC
Registered: Oct 2000

posted 08-15-2001 03:17 PM     Click Here to See the Profile for kid vishus   Click Here to Email kid vishus     Edit/Delete Message   Reply w/Quote
With my motor being on alcohol, it's not affected very much at all by water temp. Example,, last week I staged during time runs with the motor at diferrent temps to see if it made any diferrence.

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.

So based off last weeks experiance, with my car being on alcohol, more heat is less of a detriment than not enuff.

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bluestreek
Gearhead

Posts: 1724
From: Athens,GA
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posted 08-15-2001 06:42 PM     Click Here to See the Profile for bluestreek   Click Here to Email bluestreek     Edit/Delete Message   Reply w/Quote
Kid,
How did your mph compare for the runs?? Would that mean that any alcohol engine just runs better when it's say 160-170 degrees, or does it mean that your A/F ratio and ignition is tweaked for that temperature ???

Just curious..I know nuthing about alcohol.

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kid vishus
Gearhead

Posts: 6098
From: middle of NC
Registered: Oct 2000

posted 08-15-2001 07:11 PM     Click Here to See the Profile for kid vishus   Click Here to Email kid vishus     Edit/Delete Message   Reply w/Quote
The mph was down almost .6 (104.19) on the 6.53 pass. It was real consistent on the others.

104.73
104.68
104.77

oops, looked at my log book today

[This message has been edited by kid vishus (edited 08-16-2001).]

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