Lets talk heat management in race cars

Im probably overthinking this. 

Im trying to build in some driver comfort in the rebuild of the nascar. As im overweight and live in the south, heat is an issue. Now, coolsuits and such are great, but id like a more comprehensive solution. 

What id like to do is shield heat from the drivers compartment. 

In the mid to late 80s when this was built as a cup car (from what is left when i bought it) there was an aluminum shield above the exhaust with some thermo tec mat on top, airspace, floopan, airspace, and another piece of aluminum with thermo tec mat. The mat is pretty degraded at this point, and will need replacement. And it looks similar to the thermo tec mat that i saw at the used nascar store, but im not certain that's actually what it was. This shielding was only from the front edge of the seat to the bottom of the firewall.

Im thinking of replicating this on both sides (driver and passenger) and then continuing it to the rear bulkhead. Would this be worthwhile? I figure the exhaust runs under the seats, so extra there cant hurt. 

I also am wondering if using the dei floor and tunnel shield over the entirety of the underside of the floor and firewall would be a good idea. It would take up some if not all of the airspace between the shields. 

What about something on the interior side of the firewall? Extra shielding?

Just were is the point of diminishing returns? Is airspace better, or more insulation? What am i not thinking of? Any better stuff to use than others? 

My main goal is to keep the passengers as cool as possible as long as possible in a tube frame race car. If needed, ill add air directing ducts or a coolsuit. But that is step two if step one isn't enough. 

Recently built a door for fire testing.  It passed.  To save the seals, we lined around them with this stuff https://smile.amazon.com/Lynn-Manufacturing-Temperature-Superwool-Furnaces/dp/B077VRS14X/ (choose your thickness, there are several available)

The door not lined with this stuff was glowing red hot (dark cherry to medium cherry red) while the stuff lined with the superwool was not showing any temp change.

1800F on one side, no temp change on the other.  No gap between, we literally stuffed it in as much as possible, so you'd be able to sandwich it with a steel plate or something to prevent any damage to it.

High ambient temperatures don't help, that's for sure.
Drivers overheat because they're exerting themselves while wearing head-to-toe insulation.

You need a coolshirt to pull the heat of of the driver since they're so well insulated.

We just recently bought a 12v freezer (with refrigerant and a compressor, not peltier) that we now use as a coolshirt box.  The ice lasted longer but at the race where ambient temps outside in the shade were 104 we still needed a new bag of ice every hour.  Hopefully the next race has saner temps so we can judge the new freezer a little better.

In reply to Mr_Asa :

So, you filled the hollow door with that stuff, or laminated it to the large vertical surface? Its a hell of a lot cheaper than the thermo tec stuff!!

Honsch: i am almost certain to wind up with a coolshirt or something. Having not run full sessions in a fire suit before, im not sure how ill cope. Especially since god saw fit to equip me with no self cooling ability to speak of. Im hoping controlling the cockpit ambient will help though. 

In reply to Dusterbd13-michael :

Save your pennies and buy a coolshirt setup with the added helmet cooling tube. It is really easy to overheat when you are fully suited properly.

In reply to Dusterbd13-michael :

Filled the hollow door.  About the bottom foot of it or so.

Insulation and air flow  are good, but a cool shirt is another level of comfort. 
 

I built a cool shirt setup for our Lemon's team. It was not super spendy. A cooler, a boat bilge pump, tubing, fittings, cotton T-shirts, and a good sewing machine is all you need. I have a parts list around somewhere. 

Cool seats.

Works pretty well.  Lots of tubing sewn into the seat with fishing line hooked up to a bilge pump in a cooler.

Cheap and works very well to take the edge off.

In reply to wvumtnbkr :

That is brilliant. I was looking at alternatives to coolshirt stuff as i couldn't bear their prices. but cooling the seat, that is next level. No extra lines to get tangled in, no extra time to get hooked up and I bet you can pre cool it. Did you just do the back and sides?

I've never used a cooled seat, but have spoken to plenty of endurance racing teams that have.  Feedback is that they are better than nothing and cheap, but nothing close to a coolshirt set up.  Keep in mind that with coolshirt you have those tubes pressed right up against your skin.  With the seat, there's an insulated layer between you and the tubes.  I use a coolshirt and absolutely love it.

imgon said:

That is brilliant. I was looking at alternatives to coolshirt stuff as i couldn't bear their prices

There are some pretty nice, not expensive and easy to do DIY cool shirt vids online. 

Another thing that helps is airflow to the driver. After all, you need that heat to go somewhere and if the air is stagnant you'll just reach equilibrium.  I used to have a NACA duct in the triangle window of my Miata door with the output aimed at my chest. It really illustrates how good those "submerged ducts" are and made a big difference in comfort. 

DEI floor and tunnel under the transmission tunnel, floor boards firewall etc have been working very well for me. Don't need anything on the inside walls with this stuff on the other side. 

beyond that, you need to cool the driver. This is where the cool shirt comes in. 

ttrying to figure out what to do about helmet cooling myself 

In reply to amg_rx7 (Forum Supporter) :

So using the floor and tunnel shield and aluminum shielding is all i really need? Diminishing returns from there?

All: i will move coolshirt up the must have list to just behind closed face helmet and hans

Duster, I have some ceramic material that is intended for insulating kilns (+1800deg F). I have plenty of it if you want to try a sample or test some construction methods.

I used it to fill the voids in the side-pipes on the Spiftire.

In reply to stafford1500 :

That sounds awesome! Thanks!

I need to bribe you one day soon for tube bending of that dashbar to trans tube....

A few thoughts:

Insulating the car well is significantly heavy, more so than most people are willing to put up with in a race car.  I don't actually know how much the insulation weighs compared to a coolshirt, but the coolshirt system is a lot easier to take out when it's not hot.  Are you competing in the car, or just driving it for fun?

As Keith mentions airflow is important.  My Miata had lots of airflow past the driver just with the windows open (and hard top on), my E46 not so much (even with no side windows).

Do some research into your driving suit, they are not all created equal.  Cheap and old suits are MUCH less breathable than newer and slightly more premium ones.  In particular, Sparco "hocotex" suits run much cooler.

Coolshirts are amazing.  They have 12v powered cooling engines for them now (various brands), but they're pretty expensive.  Good for an endurance car where you want it to run all day, but if you're just doing track days or sprint racing then changing out the ice is fine.  They sell SFI coolshirt underwear now too.

I have an (uncooled) helmet blower, it helps but I think it's more subjective than real cooling.  Where that's really useful, though, is for defogging the visor on cold days.

I haven't tried seat cooling, but I agree with SKJSS, there's nothing like having those tubes right up against your skin.  They work even better when the straps are tight, pressing it against you.

I agree the coolshirt is better.  However, if you wet your racesuit before driving, it works really well!  

With that and a bilge blower, you can do long stints.  Did it for years in lemons 

That said, coolshirt is more better.

Airflow is king next to a cool shirt. 

This made a big difference for me because my head and face sweat so much. Without it, I would have to leave the face shield up just so I could dry the sweat out of my eyes. 

Then the cool shirt keeps the core from overheating. 

Dusterbd13-michael said:

In reply to amg_rx7 (Forum Supporter) :

So using the floor and tunnel shield and aluminum shielding is all i really need? Diminishing returns from there?

In my experience, it was sufficient - for the heat from the mechanical bits on the car but you also need to cool the driver.
That DEI stuff I mentioned is pretty awesome. I'd try that first and evaluate before spending additional money on car related products. 
Definitely do the cool shirt too. This isn't an either/ or. Both act to make the driver more comfortable and aware 

Hey, we have a Classic Motorsports video about this.

One thing that hasn't been mentioned yet is the driver him/herself.  First and foremost, you need to be 100% hydrated when you get in the car.  That starts days before the event.  Then, at least in my opinion, the calmer and less red-misty you are the cooler you will tend to stay...both figuratively and literally.  When I first started racing, I was a bundle of nerves before I got in the car and during my stint.  I was sweating bullets before I even got in.  As experience and confidence grew, I found myself getting more and more calm.  Now, I almost find the race car to be my calm/happy place.  Steady, deep breaths, focus on what I'm doing, don't get mad when the dumbass I'm trying to pass doesn't see me and cuts me off going into a corner.  I just wait for the next one and get them then.  Yes, it's still very hot in the car, but I've found myself dealing with it much better when I'm in that "zen state" behind the wheel.  Happened to me just a few months ago.  I was running at AMP, (Atlanta Motorsports Park) so of course it's hot.  Cool shirt was not working from the moment I got in.  Shift wasn't going great initially and I found myself losing focus.  That's when I noticed the heat.  I even called in to my team to get the next driver ready early.  Then my wife got on the radio and was able to get me back into my happy place and within minutes I found myself breathing normally, relaxing and the intense heat went away.  Yeah, it was still hot.  No, I wasn't being a "hero" and toughing it out.  I genuinely felt cooler and was able to finish my shift with zero issues.

What hasn't been mentioned is ceramic coating the exhaust. This will greatly reduce the radiated heat. It can be DYI and is well worth the cost. It also protects the exhaust from corrosion. I have been ceramic coating my exhaust and heat shields on my race cars since the early 90's and have only used my cool shirt on extremely hot days.