Hot Feet

[MBEARDEN]

After driving the Birkin this weekend in 90 degree temps I was reminded how hot my feet get. I have lined as much of the firewall as possible with Eastwood Thermo-coustic insulation which has helped a lot. Also under the floor. How much trouble is it to remove the console? Most of the heat seems to be high in the console. I can't help but think that a lot of the heat is trapped under the hood...all of the little rear facing louvers don't seem to let much air out.

 

A couple of thoughts...

 

1 a row of forward facing louvers down the sides of the hood or a horizontial boat vent.

 

2 a pop-up vent in front of the windshield to force outside air into the footwell...something like on older pickups.

 

3 there does not seem to be enough room to bring a hose from the front of the grill to the footwell.

 

4 I remember from having a Miata someone sold a thin airscoop the velcrowed to the windshield frame to force air into the cockpit.

 

Any thoughts

Edited May 22, 2012 by MBEARDEN

[Kitcat]

Switching to Brooklands really cooled down my Caterham's cockpit. Still hot, just not AS hot. Better wind flow over body too.

[pi7ot]

I have read about the heat in the foot wells but I don't notice.

I have a hole in the foot well to access the top starter mounting bolt but that's it for non standard ventilation.

 

Maybe a NACA duct on the side panel?

 

m

[turboeric]

4 I remember from having a Miata someone sold a thin airscoop the velcrowed to the windshield frame to force air into the cockpit.

 

Any thoughts

 

http://www.coolbreezescoop.com/servlet/StoreFront

 

A useful device, although it relies on the groove in the weather seal on top of the windscreen header.

[pksurveyor]

Is your exhaust wrapped or coated? It makes a difference.

[MBEARDEN]

Exhaust is wrapped. My heater valve is shut off ...but I think it may not be totally closed off. I plan to get a shutoff valve.

 

I searched and found the Cool-Breeze...I sent a message to the inventor...not sure how it would mount...it did an amazing job cooling the Miata.

Edited May 22, 2012 by MBEARDEN
added

[Ian7]

get some of this:

 

https://www.pegasusautoracing.com/productselection.asp?Product=3620

 

run it from inside the nosecone, around the radiator, back to a hole in the bulkhead in front of your feet

 

if you drive in the rain a lot, put a loop in it and a small drain hole at the low point in the loop

[wemtd]

if you haven't already seen it, his thread may be worth a look:

http://usa7s.com/vb/showthread.php?t=2612&highlight=footwell+heat&page=2

 

cheers

[BirkinBernie]

The tunnel in my Birkin used to get so hot it would almost burn my leg. So when I had the engine out one time I lined the transmission tunnel and footbox with heavy foil backed foam insulation. I bought it at a local insulation shop so don't have a trade name. The seams are sealed with aluminum tape. Also, make sure that any air leaks around the pedal box and steering shaft are sealed tight. This made a world of difference. Even in the Texas heat the surface of the tunnel remains at a reasonable temp. And sealing out airflow from under the hood made really big difference. Oh, and I had the headers coated too.

 

HTH,

Bernie

[BruceBowker]

I only jet coated my headers and it seems to have made a noticeable difference.

[MBEARDEN]

Birnie's solution is probably the ultimate answer...however I hope to never have to pull the engine and trans...I wonder how much trouble it would be to pull the console and insulate the inside.

[MichaelD]

1. Jet Coat Headers - only with a no modified motor. My 216 HP Zetec burned off the coating in three days. So I needed additional insulation.

 

2. Covered footwells with self adhesive reflective heat guard.

 

3. Pack all around trans tunnel to prevent hot air from blowing down the tunnel.

 

This lowered my footwell temps by 40 degrees. Measured with dual cooking thermoters in each footwell on 93 degree day. Temps measured before mods and after mods at same outside temp.

[locost7018]

MichaelD, how did you "pack all around the tunnel"? I assume you have an independent rear end so the prop shaft does not move up and down. I have a live axle so my diff moves. I guess the tranny does not move that much. Russ

[MichaelD]

I used 4" thick foam rubber and simply stuffed it all around the trans. This blocked all hot air from flowing down the tunnel. It was no where near the drive shaft.

[JohnK]

Under-hood heat is a problem. Knowing this beforehand I did a lot of work to eliminate it and succeeded mostly, but I'm concerned that the temperature inside the engine bay is going to shorten the life of the electrical components. Insulation is a good way to protect things, but I think getting the heat OUT of the car is the key and there's not a simple way to do that. Wrapping the exhaust does that, A reverse-NACA duct I put on one panel does dump a lot of heat out of the car, but it could use another on the other side just behind the headers (and making and fitting these is a LOT of work). Someone wrote that Caterham & Birkin louvers on the top rear of the bonnet happen to be in a high pressure area, so while they look like they'd vent really well, they don't.

 

One thing I did which helped the ENGINE was to seal up the area in the nose so that all the air hitting the front of the car goes through the radiator and only the radiator. At Paul Snyder's direction I also covered the chin of the car with sheet that routes the air flow at the nose even better - and out the reverse NACA duct.

 

Details, and you can see http://www.usa7s.com/vb/showthread.php?t=7421:

I covered with insulation all the walls in the engine bay, the tunnel, wrapped the exhaust and put a reverse NACA duct on one side of the body (and planning on doing the other side), put some gaps in the joint between the dash and the bonnet. My feet don't get even warm but there's a lot of heat being dumped in my lap. All this tells me it's really hot on the other side of the dash. In my car the bonnet is fiberglass and punching a hole in it would probably weaken it considerably.

[timax]

Don't under estimate how hot a Gearbox will get.

I use ZIRCOFLEX as used by F1 on the tunnel. And also a gearbox oil cooler. Made a difference. Backward facing vents on the side of the car at the rear of the engine bay will help in getting air out also.

[WestTexasS2K]

Does sealing the air flow around the Trans over heat the Trans? I would think it needs that air.

 

We have had good luck with Jet Coatings on headers making much power than 216hp. Did you cure them the way they tell you when you installed it. It will burn right off if you don't do the curing process.

[MBEARDEN]

Just a thought ...but has anyone driven their car with the hood left off to see if the heat is being trapped by the hood?

[scannon]

Just a thought ...but has anyone driven their car with the hood left off to see if the heat is being trapped by the hood?

 

When I was having overheating problems with my first radiator I did a couple of track sessions with the bonnet off the car. It didn't make any difference on the overheating problem. I don't recall any difference in cabin temp but that was a few years ago.

 

When I changed from a windshield to the Brooklands screens I noticed hot air coming over the hood between the screens. Holding a hand above the screens I found much cooler air up there. I had never felt hot air coming over the top of the windshield.

 

When I first built the car the footwell heat was unbearable. The turbo and downpipe are directly in front of the driver's footwell and my feet were getting cooked. The bare aluminum transmission tunnel was too hot to touch.

 

I installed the foil and foam pre-cut insulation from Sevens & Elevens on the outside of the footwell and tunnel. The foil quickly delaminated on the foot well and the difference in heat level was minimal. I then constructed a stand off sheet aluminum heat shield an inch in front of the footwell and applied spacecraft multi-level insulation (MLI) on the cockpit side of the footwell and transmission tunnel.

 

The MLI was scraps I got from work and is very lightweight and effective. As a test I taped a 6" square on the bare aluminum transmission tunnel. After a drive on a hot day you could lay your palm on the MLI and it was just warm while the bare aluminum was too hot to touch. The MLI was then glued to the back of the carpet when I installed it on the floor and sides of the cockpit.

 

One other thing I did was to stuff foam rubber in the gap between the footwells and the outer skin of the body to keep heat from flowing through there and heating the left side of the cockpit.

 

The end result of this is a footwell that is slightly warm on a hot day but still cool enough that I can drive comfortably with sandals or driving shoes.

[Mondo]

Hey John,

I checked your pics but didnt see one in regards to sealing the front so air came thru the radiator. Maybe you can post some pics.

My car doesn't overheat, even in the hot Central Valley. But I do. I haven't figured out a way to seal the driver's footwell box... especially since I have an electrical pedal assembly that moves a rod forward/backward thru the front of the box.

I was thinking of an opening at the rear of the hood bulge... or a couple vents on the flat portions of the hood (to the sides/rear of bulge) to let the hot air out. The pressure coming into the footwell leads me to believe the air would be forced out of these types of vents.

Or do you think they have to be closer to the front, like Westfield's one piece hood.

Edited May 27, 2012 by Mondo