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Discussion Starter #1
I have a track day fox making 330 whp. It's a dedicated track day car/AI wanna-be. I recently moved from California to Texas, and summers are just a bit different out here. If you know, you need no explanation. If you don't know, no explanation is possible. The only A/C I need is from my cool suit system, shirt, and Cool-a-clava. I intend to race this thing in the Summer. Do or Die.

In 80 degree temps, the car runs 220-230+. I want that down to 210 or better. (I tried shifting at 5K, did not help).

The current cooling set up is a boxed radiator (in front, not behind), 21lb radiator cap, Huge dual electric fan, and a 180 thermostat, and an Edelbrock water pump. The radiator is an "SVE" radiator, measuring 2" thick. Coolant is Prestone antifreeze - it has a corrosion inhibitor, the car sits a lot. So far, I haven't even had to fill out a tech sheet on track in Texas. Freedom. It also has a gigantic overflow tank from Moroso. And an oil cooler from Mishimoto.

The hood is not ventilated. I'm either going to go with a stock hood and 3 vents from Trackspecmotorsports.com, or a tiger racing hood.

And a 3" radiator from Griffen Thermal products looks really good. Will and 3" radiator help me or hurt me? Too thick?

What have you done that has made your car run cool on track? What am I missing?
 

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On track, the fan isn't doing anything to cool the car. The cooling is completely a function of the air speed through the radiator from the vehicle speed. Given that, if you have a shroud on the back of the radiator for the fan, that is going to create a lot of restriction at speed. The back of the shroud needs flappers on it. These will be pulled shut from the vacuum that the fans creates, but at speed, the positive airflow through the radiator will push them open allowing more airflow. For track use, you shouldn't really need a fan at all.

http://st.hotrod.com/uploads/sites/21/1997/08/p121068_image_large.jpg

Make sure that your bumper cover has a Cobra grille insert, so that air can get to the radiator from headlight height. This makes a significant difference as it is the highest pressure point on the front of the car.

http://image.mustangandfords.com/f/72105982+w650+h433+re0+cr1+ar0+st0/1993-ford-mustang-new-cobra-grille.jpg

Venting the hood in the correct location (just behind the radiator, but not far back) will help cooling a lot.

230 degrees is perfectly fine engine coolant temperature for track use.
 

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Discussion Starter #3
Jack, you are right in assuming that my shroud isn't ventilated. That's now on the list. 220-230 in 80-degree temps may not translate well in 100 degrees at 110% humidity. I do drive the car to the track so I'll modify the shroud and keep the fans. I wasn't aware that 220-230 is normal. But I'd rather overkill and be forced to change thermostats than have a track day ruined because of cooling issues.

I did trim the insert location quite a bit, but I don't have the cobra insert. I was thinking of various bumper cover mods to scoop more air from the front of the car, like a Cobra R cover or something like that.

Thanks for jumping in. I have almost your entire catalog under the car, (Minus the K-member). Cheers.
 

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If your engine is running at a temperature higher than the thermostat temperature, then it doesn't have enough cooling capacity. In that case, if you switch to a lower temperature thermostat, the only affect will be that the car runs at too low of a temperature when used at low loads. Since the thermostat is already 100% open when the car is at high load, the thermostat can't have any affect on what temperature the car runs at. It will make a slight difference in how long it takes the car to run at too high of a temperature. Maybe half a lap. The moral of this is that for track use, there is almost never any reason to change the thermostat temperature, unless of course you like destroying your engine on the street driving around at 160F.

Look at the link below. Down the page linked, there are pressure distribution maps of a car in the side view. You want all of your radiator vents to be in the high pressure area (+). If you try to vent air into the radiator from the bottom, this won't work since it is probably a low pressure area (see images in the link). The exception to this is if you have the OEM plastic air dam under the radiator core support. There will be high pressure in front of this and low pressure behind it. This is why the factory draws air into the radiator from just in front of it.

Aerodynamics
 

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Discussion Starter #5
I have a 180 Thermostat in there now. The car runs and cruises at 195-200 which is what I have the fans set at. (fans come on from the ECT sensor, not a radiator probe). So that means that I don't have enough cooling capacity as you say. If it ran at 180 then I would change it to a 195-degree thermostat. So cooling capacity. If the shroud was ventilated, it might run/cruise cooler. As it stands now, even at highway speeds, the ECT drops when the fans come on. To me, that's a clear indication that I need those louvers you mentioned.

From the link you posted, -to simplify- more holes in the front to increase airflow from high-pressure areas in front of the car to low-pressure areas on the hood. From what I know that's about 20" back from the front of the hood. Vents in the hood have other benefits of course, like reducing high-speed lift, etc.

I'll need to process that link when I have some sleep. Good info there.
 

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FWIW, I put the Track Spec Motorsports GT2 Center Vent on my 86. We mounted it so that it straddles the MM STB. Came out great and the "wedge" shape matches the hood.

 

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In my experience and from what I've gathered, it's REALLY hard to keep these things cool on a hot track day if you also insist on having functioning air conditioning, because that condenser sits out there in front and restricts air flow through the radiator. You can run an SN95-style condenser that flows better, (search for tech on how), or forego A/C altogether in which case keeping the engine cool seem to simply no longer be an issue.
 

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Since you are in Houston you could always try running E85 or a mix of super unlead pump gas and E85. You'll have to tune accordingly if you use full blown E85. Based on my experience, you can mix up to a 50/50 mix of the E85 and 93 octane super unlead without issues but every car is going to be different. It definitely makes a difference when it comes to the cooling system.
 

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Discussion Starter #9
Since you are in Houston you could always try running E85 or a mix of super unlead pump gas and E85. You'll have to tune accordingly if you use full blown E85. Based on my experience, you can mix up to a 50/50 mix of the E85 and 93 octane super unlead without issues but every car is going to be different. It definitely makes a difference when it comes to the cooling system.
E85 is out of my knowledge base. Just a guess, the larger tuning window from e-85 means EGTs can be lowered...somehow. I'd have to spend a few hours reading up on this. As it stands now, 110 is available at the pump, and I have an extremely capable tuning solution in the car now. Pro-M Efi. Changing tunes is a few clicks away.
 

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FWIW, I put the Track Spec Motorsports GT2 Center Vent on my 86. We mounted it so that it straddles the MM STB. Came out great and the "wedge" shape matches the hood.

I ordered a set of these with the e36 side vents as well. I also have 3" radiator coming and ordered some rubber louvers from summit to place into my fan shroud, (1.30$ apiece wow).

So what I have learned so far, 1) Get oil temps under control, huge oil cooler. 2) A larger radiator will help. 3) the fan shroud can be restrictive, either eliminate it or ventilate it. 4) Boxing the radiator is important, don't forget to box the top from the top of the radiator. 5) Vent the hood is high speed, low-pressure areas behind the radiator. 6)running a higher pressure radiator cap raises the boiling point of the coolant, add that to a water wetter additive or equivalent and it's a good combo. 7)Shift a bit lower to decrease water pump cavitation 8) lower EGTs with timing or fuel 9) 230-240 degree coolant temp is normal 10) 240 oil temp is normal.



Here are some pics from Ryan Waltons AI car. From FB. His set up is quite efficient. He runs his PS fluid through his Transmission cooler in the radiator, which could make the two fluids the same temp. I've seen guys use sandwich coolers, I run a finned tube cooler myself.
 

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E85 is out of my knowledge base. Just a guess, the larger tuning window from e-85 means EGTs can be lowered...somehow. I'd have to spend a few hours reading up on this. As it stands now, 110 is available at the pump, and I have an extremely capable tuning solution in the car now. Pro-M Efi. Changing tunes is a few clicks away.
In that case you would just need to add about 30% fuel and then play with the timing. You'll want to make sure you have enough fuel pump to support the extra fuel too. You should be able to add more timing and you should not see a big change in power. I know it is vastly different but I use it in a supercharged car that gets hot lapped at the dragstrip and it made all the difference in the world in that thing. I actually have the opposite problem, I have to start it up and let it run to warm up in the staging lanes because the temp gauge is stuck in the basement most of the time.
 

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have you ever raced the car on a cool day, if so did you still have cooling issues?

i'm guessing the car was dyno tuned since you mentioned 330whp
 

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Discussion Starter #14
have you ever raced the car on a cool day, if so did you still have cooling issues?

i'm guessing the car was dyno tuned since you mentioned 330whp
It's been on a dyno, but not dyno tuned. The out of the box tune from Pro-m Works great. I did fatten WOT up a bit. 12.4-12.7. I haven't touched timing yet. The numbers it made for my combo are right where they should be. It's a 302 with TFS HCI, CIA, 75MM TB, Shortie headers, Windage tray, crank scraper, Roadracing oil pan. No AC, no Smog pump.

On cool days the car runs cooler. I could go over every change made to the cooling and what the results were but that would take too long. The big show stopper came on 90-degree day at Buttonwillow, the water (water and Redline) started to boil out of the stock overflow tank I had at the time. And I was losing coolant that way. I also had a Black Magic fan, and a 1 bar cap.

I also saw some track video of my car from the back, for that day and under certain conditions, like after Closing the throttle at 5-6k for a big break zone, wisps of vapor could be seen exiting both sides of my exhaust. Looked like steam. I ran a test for combustion gases in the coolant, and that came back negative. We guess that the lower intake manifold was loose and pulling coolant into the intake. We retorqued the lowers and the problem has not returned, to my knowledge.:idunno: TO me the sequence for this event was: Water escaping through the lower intake gasket under extreme vacuum conditions that cause air pockets to form in the water passages, which led to a boilover.

Anyway, after that, I changed to a 21psi cap and put antifreeze in there to keep the coolant from boiling (and apparently it actually freezes in Houston on occasion). Double Overkill. Then we switched to a huge dual fan off a truck, put in a huge overflow can and ran it. And that where we are today.
 

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here's some info on what i did years back to cool my turbo setup http://forums.corral.net/forums/10142010-post23.html

part of which was trimming the headlight support (not sure if yours is still on there) as it blocks lot of air flow to the top of the radiator. i think a small cowl hood would help although you can probably get some 1/4" spacers and raise the back of your stock one and see if helps. make sure the rubber seal at the firewall is gone too as that can help get some airflow. again, not sure of all the details on your end, so just throwing it out there for what its worth.

pk
 

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Water Wetter is most likely the cause of the water getting into the engine. Since WW lowers the surface tension of the water, the water can creep through gaps between gaskets and mating surfaces that it can't without WW in the coolant. You need to make sure that your hose clamps are extra tight with it.

If the radiator cap gasket is worn out or the ring it seals on in the radiator isn't properly formed, coolant can prematurely start coming out of the overflow. This makes it seem like the coolant is overheated, but it really isn't.

If you are turning the engine enough rpm to cavitate the water pump, install an under drive WP pulley. I may have some lying around.

Don't vent the hood at the back. This is a high pressure zone. High pressure in front and high pressure in the rear, equals zero air flow. It will stop all air from flowing through the radiator at speed. It allows the engine to cool better when the car is near stopped because the it increases convection cooling and allows the fan to move more air through the radiator.
 

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Discussion Starter #17
Jack, that's interesting. Water wetter can cause the coolant to creep through gaskets. Makes sense, I had to put two clamps on the coolant neck to solve minor leaks, and there were other minor leaks that came from connections, even reinstalled the WP. I switched to a higher quality hose set and that seemed to solve that problem, (Mishimoto). That answers a lot of questions.

As far as the vents, right, I understood that part. Hence the "cowl induction" hood. I'll put the vents in the low-pressure areas. That link you posted cleared that up for me.

As far as the underdrive pullies, I actually went BACK to the stock pulley, That might have been part of the equation I hadn't thought of. This past weekend at MSR I bled they system between runs and it was full, but there were minor air bubbles here and there. Do you have any hard data on when or what rpm these pumps cavitate? I trust your experience of course.
 

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here's some info on what i did years back to cool my turbo setup http://forums.corral.net/forums/10142010-post23.html

part of which was trimming the headlight support (not sure if yours is still on there) as it blocks lot of air flow to the top of the radiator. i think a small cowl hood would help although you can probably get some 1/4" spacers and raise the back of your stock one and see if helps. make sure the rubber seal at the firewall is gone too as that can help get some airflow. again, not sure of all the details on your end, so just throwing it out there for what its worth.

pk
I went into the front bumper with a razor myself, cleaned quite a bit out. I think part of my problem is because the radiator is boxed from the front, and that scoop is removed, its halfway between a top breather and a bottom breather. The solution, of course, is to vent the hood and put some sort of lip on the front bumper cover to scoop more air into the radiator. And Box the top of the radiator as well.
 

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Over 10 years ago we did some testing on this. In the photo below, you can see the water pressure gauge mounted in top center of the gauge cluster. We moved around the sending unit to look at pressures at different points in the system and with different pulley combinations. I don't remember the pulley combination that we ended up using. I can check.

http://www.maximummotorsports.com/Assets/cars/racecar/large/Maximum_91_AI_Racecar_Buildup-074_LG.jpg

One other thing that can be an issue on a Fox Mustang. The upper radiator hose is the high point in the system, not the radiator cap. This makes it very difficult to get all of the air out of the system. See the photo below. Install a 24lbs cap on the radiator and install a 21lbs cap on the assembly in the upper radiator hose. Now you can completely bleed the system. Only connect an overflow hose to the top radiator cap.I think we bought the inline radiator cap tube from Moroso.

http://www.maximummotorsports.com/Assets/cars/racecar/large/Maximum_91_AI_Racecar_Buildup-054_LG.jpg

If you watch the video linked below, you can see the water pressure gauge. Basically at any engine rpm above 3,500 it is pegged. 40 psi +

 
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