Horsepower = Heat?

[RICK LAKE]

DocDirk Doc Has this problem been going one since day 1? Is the motor new or does it have 2-3 thousand miles on it? What is the thermostat opening #. Do you see a 20-30 degree drop in the temp gauge when the thermostat opens? 50/50 coolant in the cars coolant system? That is a big motor in a small space. 225 is not that crazy of a number on hot days. Try this, do a heavy taping of your hood latches to hold open the back of the hood and give the hot air a place to go, Go for your normal road run and see how hot the motor gets with this opening. If the temps are alot lower than there is no problem with the motor. You need to fine a way to help remove the hot air under the hood. Heat wrap on the headers is a good start. Get yourself a infrared gun for temp readings and check the radiator from top to bottom on both sides and see what the readings are. I have added 2 4" bildge fans to help remove hot air when racing. This has helped to lower temps. Is your radiator straight up and down or at a 30 degree angle? If it is at an angle you may want to add a splitter in the opening to help the air get directed through the whole radiator. ERA sells the with their cars. Rick L. Ps Doc I looked to your pulleys and the water pump is smaller than the crank. This is a undersize setup. The coolant flow for your motor may not be enough. I ran a set of March pulleys on my FE an the water pump was spinning too slow. This was with a high flow pump. Crank pulley and water pump need to be 1-1. Are they March? I was told the same thing from March about the problem of overheating was EVERYTHING but their pulleys. I changed radiators, thermostats to a Dodge larger one, only the connection to the waterpump and radiator are rubber, to stop and collaspe on the lines, removed the intake and cleaned out the ports on the manifold of flashing where the coolant flows. I ended up going with stock size upper and lower pulleys from ASP to stop the heating issues. Both pulleys are about 6" ASP builds custom pulleys and ships them in 24 hours. I have had no issue with over heating for the last 5 years. A also went from a 452, 9.2 compression motor to a 482 with 10.5 and over 100+ added HP and torque. Rick

[undy]

I fought this for a couple years and here's what I found..

If your 4 row is brass it won't do as good a job as a 2/3 row fluidine/Be Cool or Griffin with the 1" or 1 1/4" tubes.

Ensure your water pump pulley isn't under-driven. March under-drives their crap and hurts our coolant challenged Cobras.

Make sure you run a "performance" T-STAT, such as Mr. Gasket (robertshaw made). They will flow more, under all conditions.

You can bypass the external water pump bypass for additional cooling as long as you modify the thermostat.

Ensure your puller fan is fully shrouded.

Ensure the inlet of your radiator is fully shrouded, all the way to the "mouth" at the front of the car. You WILL recirc hot air from the cooling fan's outlet if you don't at idle in traffic.

Flexalite drastically OVER-RATES their fans' CFM capabilities. "Professional grade" fans, such as Spal, tend to have true ratings.

Ensure your timing and fuel mixtures are correct. Lean conditions and incorrect timing can aggravate coolant temps.

***most important!! Make sure your electrical system is up to the task of hi-amp draw fans. Alternators/wiring and rugulators (read: Painless wiring harnesses) are NOT usually up to the task with under-sized conductors. With the usual accessories running at idle, check your voltage to and at the fan. Mine was 10.2 volts before I straightened things out!

Dave

[Tom Kirkham]

Originally Posted by undy

Ensure your puller fan is fully shrouded.

Ensure the inlet of your radiator is fully shrouded, all the way to the "mouth" at the front of the car. You WILL recirc hot air from the cooling fan's outlet if you don't at idle in traffic.

Ensure your timing and fuel mixtures are correct. Lean conditions and incorrect timing can aggravate coolant temps.

Dave

What Dave said is spot on. It is important to make sure ALL of the air flow goes through the rad.

Most engine builders set the timing on the engine very lazy. They do this to prevent the engine from detonating. You need to set your timing to come in quick and aggressive, yet still not detonate. With the timing retarded your engine will run hot and sluggish. This is a balancing act and you will need to drive the car and tune it.

[DocDirk]

Originally Posted by RICK LAKE

DocDirk Doc Has this problem been going one since day 1? Is the motor new or does it have 2-3 thousand miles on it? What is the thermostat opening #. Do you see a 20-30 degree drop in the temp gauge when the thermostat opens? 50/50 coolant in the cars coolant system? That is a big motor in a small space. 225 is not that crazy of a number on hot days. Try this, do a heavy taping of your hood latches to hold open the back of the hood and give the hot air a place to go, Go for your normal road run and see how hot the motor gets with this opening. If the temps are alot lower than there is no problem with the motor. You need to fine a way to help remove the hot air under the hood. Heat wrap on the headers is a good start. Get yourself a infrared gun for temp readings and check the radiator from top to bottom on both sides and see what the readings are. I have added 2 4" bildge fans to help remove hot air when racing. This has helped to lower temps. Is your radiator straight up and down or at a 30 degree angle? If it is at an angle you may want to add a splitter in the opening to help the air get directed through the whole radiator. ERA sells the with their cars. Rick L. Ps Doc I looked to your pulleys and the water pump is smaller than the crank. This is a undersize setup. The coolant flow for your motor may not be enough. I ran a set of March pulleys on my FE an the water pump was spinning too slow. This was with a high flow pump. Crank pulley and water pump need to be 1-1. Are they March? I was told the same thing from March about the problem of overheating was EVERYTHING but their pulleys. I changed radiators, thermostats to a Dodge larger one, only the connection to the waterpump and radiator are rubber, to stop and collaspe on the lines, removed the intake and cleaned out the ports on the manifold of flashing where the coolant flows. I ended up going with stock size upper and lower pulleys from ASP to stop the heating issues. Both pulleys are about 6" ASP builds custom pulleys and ships them in 24 hours. I have had no issue with over heating for the last 5 years. A also went from a 452, 9.2 compression motor to a 482 with 10.5 and over 100+ added HP and torque. Rick

Rick, the motor has only about 7.5 hours on it, including initial engine dyno. The temperature smoothly climbs to 185-190 while I'm driving at any steady forward velocity over 35 mph, and stays there. I run a 180 degree pro thermostat. Within a few blocks of city driving it begins rising and steadily does so until I pull it over to cool off. Earlier in the year it rose to 235 but I've not allowed that lately, pulling it over if I reach 225. Yes, I'm using March pulleys and the water pump pulley is smaller than the crank pulley. It seems to me that would INCREASE the water pump RPM's vs the crank, and increase output?? Wouldn't a smaller pump pulley turn the water pump more often per crank revolution? I'm confused why equal sized pulleys would increase rather than decrease water pump output per engine RPM? (Unless the higher pulley ratio of a smaller water pump pulley would be pushing TOO much water through the radiator without giving it time to cool off...I have heard of that but only due to running without a thermostat.....) I have a larger than usual scoop on the hood and have yet to isolate the passenger compartment from the engine compartment, so a LOT of heat escapes through the footwells, perhaps the engine compartment venting is going to be worse if there is one, once I get the airflow blocked..... The radiator is straight vertical and the shroud on the fan side is completely sealed except for each side which has about 1/4" full vertical height opening. I've wondered how much sealing that opening would improve flow through the radiator. Shrouding the front makes a lot of sense. That way only external air would be drawn through the radiator. My engine has a 10.5 CR btw. I noticed you weren't so impressed with 225 temp on hot days. At what temp do I worry about hurting the engine actually? ... AND the days will be MUCH hotter in about 3 months.

Thanks for the input everyone!

Dirk

[barabar]

Doc, Arnie here. I'll give you some info that will cool. There is a rule of thumb to use when cooling engines. It is derived based on HP--500HP and below, 2 rows 1" aluminum cores, dual fans, flow 3300 cfm each, 10 gauge copper wire to each fan, complete shroud, high flow 180 degree thermostat. high flow mechanical water pump. 600HP and below----1 1/4" cores and the same criteria as above. 700HP and below---1 1/2" cores and same criteria as above. As a couple guys stated, make sure all the air pulled goes through the radiator. You might have to fabricate a shroud from the nose to the radiator. This should work all the way up to 750HP. Yes there are things you can do---Timing, water fast or slow cfm. When you get much over 750HP your not to streetable and would probably reconfigure the cooling system anyway. Good Luck.

[DocDirk]

Not sure what the size is on the radiator tubes, hoping to find if anyone has used a Flexalite or equivalent dual fan to cool their Cobra engine ??