How to make sure a race car stays cool on grid

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Update by Tim Suddard to the Ford Mustang Fastback project car
Jan 20, 2023 | Ford, Mustang, cooling, Ford Mustang, Summit Racing, cooling fan, Cobra Automotive

Does a vintage race car need a cooling fan? There is some debate on the subject.

Our expert, Curt Vogt of Cobra Automotive, suggested our Mustang vintage racer did not need one. He’s based in cool Connecticut. We, however, are in Florida.

We decided that no one needs the panic of an overheating race car while sitting in grid. In our mind, the slight weight and power-robbing tendencies of a cooling fan outweigh the stressful feeling that you get when watching your temperature gauge rise while waiting to go out on track.

Summit Racing shipped us a 17-inch fan from Derale Performance. (The part No. is 18217, while it retails for less than $150.)

We’re not fans of simply strapping a fan to a radiator, though, as we like something more suited for the rigors of road racing.

We opted to make some aluminum brackets that mount the fan directly to the radiator. As long as you can weld aluminum well, this is a rather straight-forward solution.

From there, we wired the fan with a thermostatically controlled switch. We figure there’s enough to remember when racing–whether or not the fan has been turned on when returning to the paddock doesn’t need to be on that list.

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edmagoo
edmagoo New Reader
1/20/23 2:47 p.m.

The fan on my race car is wired to be on all the time. Why is that wrong?

Tom1200
Tom1200 UberDork
1/20/23 2:59 p.m.

In reply to edmagoo :

It's not. In theory you are sapping power but it is not enough to truly make a difference for most of us. It may shorten the life of the fan motor though but it may not make a difference at all.

I use the stock fan on my Datsun; it's a lightweight 4 blade plastic. I ran without one for a while but had to many instances where we had slow pace laps or had a full course yellow and the temps started to climb.

 

 

 

wvumtnbkr
wvumtnbkr GRM+ Memberand PowerDork
1/20/23 3:49 p.m.

We just don't have a fan.  We shut it down when it's warmed up and stopped.  The fan was actually causing higher temps at race pace.

Olemiss540
Olemiss540 HalfDork
1/21/23 6:50 a.m.

I wired a fan in my race car. If nothing else it looks totally trick when I pop the hood after an hpde session and lean into the cab and flip the switch panel to run some cool air past my headers. 

Chick's dig it and the porsche guys think it's cool. 

Pete. (l33t FS)
Pete. (l33t FS) GRM+ Memberand MegaDork
1/21/23 8:18 a.m.
wvumtnbkr said:

We just don't have a fan.  We shut it down when it's warmed up and stopped.  The fan was actually causing higher temps at race pace.

Running the fan made my RX-7 run cooler down the backstraight at Nelson Ledges.

In theory the fan is just windmilling when off, but I have also noted that at higher speeds than I could attain at Nelson, under the right conditions, turning the fan on made system voltage go up, so it was turning into a little generator.  I thought that was kinda neat.

frenchyd
frenchyd GRM+ Memberand MegaDork
1/21/23 9:08 a.m.

Fan on race car?   Let me check the high scale professional series. 
 Formula 1? nope. 

Indy car ? nope.

NASCAR? Nope.  

Trans Am ? Nope.  
My Black Jack ? Nope. *
  The Jaguar XJS V12 ? Nope. 
 My $2000 challenge car? Nope. 
  My Jaguar V12 Tow car yeh.! 
   Hint; if the starter delays starting too long and you start getting worried.  Next time walk up to the starter and dope slap him. Explain what an engine costs and that this is a hobby not a chance to practice his OCD  

  ( actually you might avoid the need if you talk to the starter before the event).  

* my Black Jack didn't have a fan or generator.  Dead loss battery,  never once had a single issue. 

JMcD
JMcD New Reader
1/23/23 7:43 a.m.

Looks like a nice setup with two speed options for that fan. Which one did you use? 
 

I recently upgraded from a single 14" 1600 cfm fan to a dual 12" ~2500cfm full shroud setup (OEM ls1 f-body) and cooling in grid at autox events was significantly improved. 377ci SBC in a 2nd Gen Camaro.

Gimp (Forum Supporter)
Gimp (Forum Supporter) GRM+ Memberand UltraDork
1/23/23 9:26 a.m.
JMcD said:

Looks like a nice setup with two speed options for that fan. Which one did you use? 
 

I recently upgraded from a single 14" 1600 cfm fan to a dual 12" ~2500cfm full shroud setup (OEM ls1 f-body) and cooling in grid at autox events was significantly improved. 377ci SBC in a 2nd Gen Camaro.

2nd gen? Cooling improvements? 377ci?

 

 

And you owned a 318ti?  I may need a DNA test.

frenchyd
frenchyd GRM+ Memberand MegaDork
1/23/23 9:54 a.m.

Keeping cool can also be achieved with the use of E85. 

GameboyRMH
GameboyRMH GRM+ Memberand MegaDork
1/23/23 10:07 a.m.

I would only consider not putting a radiator fan on a car if it were a dedicated serious-business race car, ideally with pit crew ready to run out with leafblowers. Even F1 cars are fitted with fans at times, just never for qualifying or the race. They're super convenient for all kinds of situations where you want to run the engine, and even a low-flowing lightweight slim fan is worlds better at keeping temperatures under control at a standstill than nothing at all.

frenchyd said:

* my Black Jack didn't have a fan or generator.  Dead loss battery,  never once had a single issue. 

Interesting, you rarely see this kind of setup outside of karts or landspeed cars. How long could it run between charges and what kind of voltage range would it run on?

wspohn
wspohn SuperDork
1/23/23 10:07 a.m.

I used a fan on the race cars as sitting in pregrid watching your engine getting hotter and hotter when there are delays in the start are very nervous making.  Turn off a hot high compression race engine and sometimes they don't start again.  Fans address that

frenchyd
frenchyd GRM+ Memberand MegaDork
1/23/23 10:53 a.m.

In reply to GameboyRMH :

I normally would plug a charger in at night but it never was an issue. It was possible to run the car the whole weekend  off one charge.  
  The Black Jack had 13-1 compression  4.17 stroke. 999 CFM carbs, and pretty snarfy camshafts. Plus I would crank the engine over until I had pressure on the gauge before starting. Then flick the fuel pumps on until the float bowls filled, ignition and start. 
        Regarding F1 cars remember they have to preheat the coolant before they can even crank the engine over.   I'm guessing they start with temps near 220 in order to have sufficient clearances. 
    Us less than bazzilonairs  start our cars at ambient temperature. 
      One reason fans aren't used in pro series is because they block the free flow of air once moving.  Oh the fan may pull air through the radiator when stationary but at speed it probably is doing more blocking than cooling.  
        I make sure all air in the front of the car is  required to go through the radiator rather than around it by proper sealing .   Then once past the radiator it has as clear a path to escape as I can make.  Cooling those headers and block on the way out.  
 

frenchyd
frenchyd GRM+ Memberand MegaDork
1/23/23 10:54 a.m.

Yes it was a dedicated race car. The Green car right behind was the DeMar   ( a Devin body, tubular chassis ) which I had restored  and race prepared. 
   It too never had fans or a charging system.  
small block,  Hilborn fuel injection, Aluminum heads, big Roller camshafts and as much as 430 cubic inches.   
     Again typically we'd charge the battery overnight but occasionally not.   Even running the enduro's Sunday afternoon  plenty of battery.   
  There was also a Lotus 11  LeMans series 2 that I prepared running without a fan or generator. 

 

* picture at Elkart Lake the Hurry  Downs 

frenchyd
frenchyd GRM+ Memberand MegaDork
1/23/23 11:02 a.m.

In reply to wspohn :

Almost never was an issue even with extended grid time.   Only once in the Bahamas did it even approach 230 and under that all was good.  
 Remember we carried a lot of oil. And that was typically barely off the peg  when we started rolling. 

JMcD
JMcD New Reader
1/23/23 2:58 p.m.

In reply to Gimp (Forum Supporter) :

Lol. Apparently my screen name isn't sufficiently close to my email address, haha. Josh here with the CAM-T 81 Camaro. I think I still have a set of 318ti camber shims you gave me a long time ago. Need to pass them along to someone who can put them to good use.

Gimp (Forum Supporter)
Gimp (Forum Supporter) GRM+ Memberand UltraDork
1/23/23 3:27 p.m.
JMcD said:

In reply to Gimp (Forum Supporter) :

Lol. Apparently my screen name isn't sufficiently close to my email address, haha. Josh here with the CAM-T 81 Camaro. I think I still have a set of 318ti camber shims you gave me a long time ago. Need to pass them along to someone who can put them to good use.

Well DUH on me.

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