Coolent Temp for Bracket Racing

[cgmach1]

Jay or anyone else here that bracket races, what temp do you guys like to stage the car at?  160, 180?  I've been staging at around 160 but I'm not sure if that is the best temp horsepower wise and for engine longevity.  Also, what do you use for temp control?  Stat or just restrict the flow some?

[jayb]

I always use a 160 degree thermostat.  I will often stage the car with a low coolant temp, because it will usually go faster that way.  I guess I don't like to stage over 180, because the temp can rise too much during the burnout and on the starting line.   150-160 is real typical for me.  If I'm below the thermostat opening temperature when I stage, by the time I hit the line the temp has come up to 160 and everything is good.

[Rory428]

I like to be pretty cool as well. I don`t run a thermostat on either car, and ideally, I`d like to be about 145F at the starting line, but thats kinda tough to do in real life, especially in the warm summer temps. Realistically, I am usually about 140-145 in the burnout box, and 160ish on the starting line. With driving up the returm road, getting the ET slip, and driving back to the pits, I`m usually up to 185-190, sometimes closer to 200 if traffic is heavy in the pits. Since I don`t have a generator to charge the battery between rounds, I perfer not to run the water pump any more than neccasary. After a run, I usually spray down the rad with water in a garden sprayer, and run the water pump for a few minites to get the temp down to 140, then turn off the pump, and spray the rad again. If its a good day, and I`m going some rounds, I will often flush the rad in the water cool down area in  a hot lap situation. My Fairmont has a V6 Firebird aluminum rad, the Mustang uses a stock 5.9 rad, both have Moroso electric water pump drives, although a CSR, Mezirere, (or maybe a Jay Brown/CVR ) electric pump are on the wish list. The Fairmont has a fiberglass FlexALite fan on the Edelbrock water pump, the Mustang uses a stock aluminum reverse rotation 5.0 pump, and a single cheapo electric rad fan. Both cars have a single battery and stock alternator, and have no trouble going thru a 2 day weekend without any re charging, although if a buddy next to me has his generator handy, I may borrow it for 1/2 hour if I feel it is a good idea on a hectic hot lap day, or if its getting dark, and I need to use the headlights.

[cgmach1]

Thanks for the replies guys.  It seems I'm doing something similar to both of you in trying to hit the line at around 160.  I've been just cutting the center of the stat out to restrict the flow a little and it seems to keep work in the same way you both are doing.  Jay might remember from an earlier post of mine that I've had a problem cracking #1 cylinder a couple of times and just wanted to make sure I'm not screwing something up that is easy to change.  Thanks again.

[Faron]

Rounds or ET's ?, Having been in Many 6-9 final round finals , consistency is the key , not necessarily low temps , you will go faster , BUT if you cant maintain that temp after say 3rd round , your going to be guessing your dial in , My mustang runs a 10th faster the first time run ( no heat soak ) after that it settles down to 1-3 hundredths max variance , I like to be at 160 at burnout time and at that temp its easy to stay at 180 or less , BIG radiator , Alt, Elec , water pump , NO Thermostat !! in 90 degree weather trying to run the car at 140 is almost pointless ( unless you run Alcohol ) a portable generator , and a garden Sprayer ( to mist the radiator ) on the Hottest days , get in a routine and stick with it

[fe66comet]

So actually what would be the most efficient target temperature all around? I would think at a certain point itemization becomes an issue and low combustion temps would give you incomplete burn, especially wit alcohol?

[Qikbbstang]

I understand NASCAR teams run their motors scalding hot. Obviously the less cooling required the smaller the air-flow into and through the grille and the better the aero package = part of the advantages of the Ford FR9 race motor. But still the teams run high water and coolent temps over 200F.  It's no secret that low coolent temps accelerate cylinder wear and my own logic says if there is wear its costing power.  Then again a cold engine I guess can be tuned run with more compression then a hot engine FWTW.

[jayb]

Basic thermodynamics says that the cooler the intake charge, the more power will be produced from combustion.  So ideally you would like to have the air/fuel mix entering the cylinders at the lowest temperature possible.  Obviously there are limits to how cold you can go, but drag racers running turbos or superchargers with air to water intercoolers will pack the intercooler box with ice to get the inlet air temp as low as possible.

Running the coolant hot is fundamentally a different issue, except that with a higher coolant temperature the air/fuel mixture will tend to rise in temperature as it travels through the intake tract and into the cylinder, just due to heat transfer from the engine castings.  All the NASCAR teams make use of thermal barrier coatings to try to prevent as much heat transfer to the air/fuel mixture as possible, and of course they all run a fresh air package and an air gap style intake manifold.  My guess would be that the NASCAR guys have found the best tradeoff for racetrack performance.  Just as a guess, maybe they could pick up horsepower by running the coolant temps lower, but they would lose aerodynamic efficiency, and thus would go slower overall.

[fe66comet]

So I.would say 160 would.be a good target temp for my 445 FE?

[Qikbbstang]

Try to imagine how much heat can be imparted into a Fuel:Mixture when it's passing through an air cleaner, carb, intake manifold and intake port at 6,000+ rpm
--------By my math that over 50 intake pulses a second------that's not much time to heat up anything.

[fe66comet]

I do have an air gap intake and was planning on a valley pan if it will clear my roller lifters. With the 19/30 two row aluminum radiator I have and a aluminum 1000 CFM oil cooler I think keeping the engine warm is more of a concern. OH yeah and your 55 gph water pump too.

[jayb]

Try to comprehend how much heat can be imparted into a Fuel:Mixture when it's passing through an air cleaner, carb, intake manifold and intake port at 6,000+ rpm
--------By my math that over 50 pulses a second on intake pulses------mm

The way that works is that the air molecules in contact with the walls take on the heat of the walls pretty much instantly, and as you go farther away from the walls, it takes longer and longer for the air molecules to heat up.  So the air running down the middle of the intake tract probably won't heat up at all, but the air at the periphery of the intake tract will, even with 50 pulses a second.  So, some charge temperature increase, on average, will occur.

[fe66comet]

OK might have to get the thesaurus out but I catch what you mean.

[Qikbbstang]

traveling through from air cleaner to intake valve in 1/50th of a second?....You have to remember that the heat in the metal surface of the intake tracht is being subjected to thousands of pulses per minute - it's not like one pulse fire through a heated tube.
  Like Jay said it would only be the outer boundry of the charge, and it would average out, but what a degree?...two degrees?... five degrees? ..... of heat gain on the intake charge.   Of course there's also the “chilling” effect of the rapidly evaporating fuel being introduced into the air stream that likely produces a significant change and that's cooling.
   

[Faron]

Remember the post was about BRACKET Racing , the goal is consistency , not The Most HP , at least that was my take