Road racing on the track w/o a thermostat

[Van]

In order for my car to dominate the race, I need every ounce of torque, so I run it between 3500 to 6500RPM. During a twenty minute period I begin to see the coolant temp rise to near the red line, so I need to short shift to cool it off a little, but it is usually not capable of getting back into it as there is usually only two laps to go. My question is might we see lower temps after we ditch the thermostat?
Mods are: Koyo Race radiator, 14 LBS radiator cap, 7qt motor oil sump, 1qt oil cooler

 

[Another MkIII]

Do you still have the undercover? I believe this makes a difference with airflow through the radiator, but I'm not certain.
-AM3

 

[Dan_Gyoba]

You may actually see higher temps without the thermostat, since the coolant won't be spending enough time in the radiator to shed heat. That might also be the problem that it's having once things get hot.

Make sure that the radiator is getting the airflow that it needs, and that you're not needlessly keeping heat under the hood. The undercover DOES help force air through the radiator, as does the fan shroud.

 

[ATL88Supra]

what fans do you have? also if you are hitting the redline on the water temps you are boiling over and losing water

 

[gsxr141]

try adding some "redline water wetter". it helps lower the temp.

 

[Mikael_7m]

You may actually see higher temps without the thermostat, since the coolant won't be spending enough time in the radiator to shed heat. That might also be the problem that it's having once things get hot.

Pretty sure his water temp on track will be over ~190 Fahrenheit so the thermostat will be open the whole time anyway...

 

[IndigoMKII]

Do you have all the air dams and such?

Have you thought of hooking up sprayers directed at the radiator? Something to spray a mist of water onto the front of the radiator might help cool it.

 

[Van]

Do you still have the undercover? I believe this makes a difference with airflow through the radiator, but I'm not certain.
-AM3

Yes I do have the under covers on the car...

You may actually see higher temps without the thermostat, since the coolant won't be spending enough time in the radiator to shed heat. That might also be the problem that it's having once things get hot.
It was suggested at the track that the car be fitted w/a 16 Lbs radiator cap...

Make sure that the radiator is getting the airflow that it needs, and that you're not needlessly keeping heat under the hood. The undercover DOES help force air through the radiator, as does the fan shroud.

I also run a fan shroud and have a 2800 CFM fan fitted through a thermostat (190 degree) and relay. It was suggested that the car not have a fan and shroud when running on the track, as it isn't needed...

what fans do you have? also if you are hitting the redline on the water temps you are boiling over and losing water

Got close to 220 degrees all day long... Didn't boil over, but the car was driven at under 90 MPH in 5th to cool it down...

try adding some "redline water wetter". it helps lower the temp.

Some at the track also don't use anything else; that and water...

Pretty sure his water temp on track will be over ~190 Fahrenheit so the thermostat will be open the whole time anyway...

Yes just below 220 all day... On Auto Meter gauge

Do you have all the air dams and such?
Yes

Have you thought of hooking up sprayers directed at the radiator? Something to spray a mist of water onto the front of the radiator might help cool it.

Never thought to do that. I'm going to hook up the 1 Gal surge tank to the Koyo Race radiator, put on the 16 Lbs radiator cap and see what happens...

 

[Poodles]

On a track, where you're spending lots of time at high RPM.... You're probably cavitating the water pump and not getting the flow you need. Paging IJ...

 

[OfnaRcR4]

Hmm how would you fix that?

 

[toyotanos]

IJ added an electric water pump to supplement the factory mechanical one at low and high engine rpms. It was a tight fit, but he said it improved his cooling all around. iirc, the mechanical pump starts to cavitate around 6-7krpm, and he spun his to 8000.

 

[Nick M]

A track has nothing to do with a fan shroud. The shroud is used to pull air across the entire radiator core for more cooling. Removing the shroud reduces cooling capacity. The thermostat is not wide open at 190. The temperature rating for any thermostat is when it starts to open. 190 degree thermostat starts to open at....190 degrees. The long block of the 7M causes problems to the rear of the block with coolant flow. The coolant cavitates on a 7M, even a stock Cressida.

 

[supraguy@aol]

So, would an increase in water pump pulley diameter help in lowering the rotation speed of an oem pump, in order to keep it out of high rpm caviation(in a racing situation)?

 

[Nick M]

Do you still have the undercover? I believe this makes a difference with airflow through the radiator, but I'm not certain.
-AM3

It develops low pressure behind the radiator, forcing air through it rather than around the nose of the car.

 

[Nick M]

If the pulley is under driven, then yes, the speed of the impeller will slow down. I would be more concerned with volume of coolant making it to the rear.

 

[OfnaRcR4]

Do you have your fans on while you are racing? When at speed it can actually hinder flow. Try a stock fan.

 

[Poodles]

Also looking at your build thread, you have the oil cooler between the radiator and intercooler. Could be blocking flow there. Also looks like you have a stock intercooler (forgot what power you're running or boost levels, but that might be an issue here too).

 

[Van]

If the pulley is under driven, then yes, the speed of the impeller will slow down. I would be more concerned with volume of coolant making it to the rear.

There is just so much to digest here! I even started reading more about this subject online. Whew!
What can I say... Start messing with the stock set-up and here I am, lost in too much information.
I also got confused reading this: http://www.arrowheadradiator.com/14...apability_in_high-performance_automobiles.htm

Do you have your fans on while you are racing? When at speed it can actually hinder flow. Try a stock fan.

I was told to take off the fan and shroud after I get to the track, or trailer it in... I rather not have to do either, but I may try their and your suggestion to see what results from it.

Also looking at your build thread, you have the oil cooler between the radiator and intercooler. Could be blocking flow there. Also looks like you have a stock intercooler (forgot what power you're running or boost levels, but that might be an issue here too).

It is a stock intercooler. The car makes 280hp/288tq at the wheels, on 13 psi, stock CT 26, BIC DDP and the Blitz dual SBC is set between 10-11psi. I don't know what the wheel Hp/Tq actually was on the track.

 

[Van]

Poodles,
You and "bloodasp" both say that the placement of the oil cooler is an obstruction. I agree and will consult with my buddy at VIP Performance to get suggestions for alternative placement or different oil cooler.

 

[Poodles]

Keep in mind the Turbo-A ran the oil cooler behind the crash bar and it had cutouts and a vent in front to get air to it

Can also run the oil cooler on the sides where the fog lights go (if you have them removed).