cockpit heat abatement

[captzoom]

Today on the Se7ens board a question was posted about how to cut down on cabin heat. I posted a note saying how I had configured my car for Texas summer use. It was then suggested by a fellow Westfield owner that I start a thread on the subject here. So, in the hopes that others will also post their ideas, here's what I sent to the Se7ens group, along with some pictures (mostly shot during construction a few years ago):

 

Don't know if it'll work on a Caterham, but my Westfield is cool enough in the cockpit, even though an 80 degree day here would be considered almost cold. Typical summertime here runs mid-high 90's, so it was built to cope.

 

I covered the firewall, rear bulkhead panel, trans tunnel sides and top with ThermoTec foil/ceramic fiber insulation (glued in place to the aluminum sheet); the vertical firewall face and the trans tunnel top and sides were insulated on both inside and outside surfaces. There is a considerable amount of heat radiated from the differential, so the rear bulkhead is insulated. I placed stainless steel boat ventilator louvers on the lower area of the front side panels adjacent to the exhaust headers, and had the exhaust headers inside the bodywork coated in and out with JetHot ceramic coating.

 

A major improvement was made by incorporating fresh air vents from the front of the car into each footwell. These were constructed using flexible stainless steel tubing (insulated where it passes near the exhaust) and controlled using 5.0 Mustang throttle bodies (had a few of these laying around) mounted to the firewall and operated by bicycle shifter levers/cables.

 

Additional comfort was provided by constructing my seat backs using a poly mesh fabric. A very lightweight composite duct system pipes fresh air from above the tunnel in the cockpit to the seat backs, boosted by banks of computer cooling fans.

 

The Westfield bonnet has a pair of triangular vents on its top side which eject engine heat. These outlets are the source of most of my discomfort since I run a minimal aeroscreen rather than a full windshield and the hot air flows over my forehead and top of my head at speed. Maybe I need a cap made out of the ThermoTec stuff. If I were a bit shorter I could probably avoid this.

 

My floor panels are bare aluminum, no carpet or mats, and the cockpit side panels, tunnel and rear bulkhead have only a glued-on thin vinyl covering, with only the ThermoTec foil material beneath it.

 

http://www.usa7s.com/aspnetforum/upload/296341518_DSCN4731.JPG

 

http://www.usa7s.com/aspnetforum/upload/64418459_DSCN4829.JPG

 

http://www.usa7s.com/aspnetforum/upload/1008788489_DSCN4838.JPG

 

http://www.usa7s.com/aspnetforum/upload/810945004_DSCN5258.JPG

 

http://www.usa7s.com/aspnetforum/upload/432752585_DSCN3581.JPG

 

http://www.usa7s.com/aspnetforum/upload/1557471549_DSCN3591.JPG

 

http://www.usa7s.com/aspnetforum/upload/1083131252_fr qtr02.jpg

 

http://www.usa7s.com/aspnetforum/upload/2005071080_Headers02.jpg

 

http://www.usa7s.com/aspnetforum/upload/1369083378_RRSE2k_constr025.jpg

 

http://www.usa7s.com/aspnetforum/upload/1090144633_RSvent control.jpg

 

http://www.usa7s.com/aspnetforum/upload/403076346_RSvent footwell.jpg

 

http://www.usa7s.com/aspnetforum/upload/659962101_RSvent inlet.jpg

 

http://www.usa7s.com/aspnetforum/upload/1501884310_RSvent valve.jpg

 

http://www.usa7s.com/aspnetforum/upload/1790694357_LSvent valve.jpg

 

http://www.usa7s.com/aspnetforum/upload/1670297221_DSCN2463.JPG</p><p> </p><p> http://www.usa7s.com/aspnetforum/upload/1636672411_dshaft4.jpg

[JohnCh]

It was then suggested by a fellow Westfield owner that I start a thread on the subject here.

 

Guilty of the prompting. Thanks for posting the pics. Definitley some out of the norm mods to beat the heat!

 

One question from the photos: What is the access port for that is located behind the right front wheel?

 

Thanks,

John

[manik]

I've had the pleasure of riding in Rob's Westie. I was unable to tell that the exhaust header, collector or outlet pipe from the Honda engine were but inches from my person. Very impressive insulation!

 

I should also point out that Rob's design and implementation of the seats & fans is really phenomenal. You cam also just make out some very handy side compartments for the driver and passenger's wallet, cell phone, etc.

 

 

tm

[captzoom]

John, access panel is for the oil filter (visible in shot of engine/headers before side panel installation).

 

Thank for all compliments.

 

rgds, Rob

[gjslutz]

Great design ideas and build. Too many great ideas not to share, thanks. The areo-shield looks great, purchased or built?

 

GAry

[southwind25]

yeah, we thought a nice little NACA duct from the side into the footwell would be of help..buit not sure if this is a good place for an inlet or not? dont want to start cutting into things if it wont work. we have our headers wrapped and insulation on the footwell.. but the feet still do get warm!

[11Budlite]

Rob,

 

Lot's of nice ideas and details. Thanks for sharing! :thumbs:

 

Bruce :7drive:

[captzoom]

I considered NACA inlets into the footwells but instead chose to bring fresh air from the front of the car to avoid debris from the front tires and heat from proximity to exhaust system on pax side. The NACA inlet seen in the nose of my car delivers cool air to the engine air filter.

 

Since the pix were taken I have added copper window screen to the fresh air ducts (clamped under the rubber 45-degree elbows where they slip over the flexble stainless tubing) to keep road debris, insects, flying squirrels, etc out of the footwells.

 

Putting NACA ducts through the side panels on the Westfield is somewhat more difficult than on a Lotus/Cat/Birkin because of the triple-wall construction. There is the fibreglass exterior skin, a semi-stressed aluminum panel attached to the outboard side of the frame tubes, and a thin unstressed aly interior covering panel inboard of the frame tubes. The space between these panels would be another good location for insulation, but the air gap between them, combined with a heat-reflective shield attached to the outer skin behind the exhaust/catalytic converter system made me think additional insulation here would be unneccessary (see Manik's comments for testimonial confirmation). Picture below.

 

My experience is that a lot of heat comes into the cockpit up the sides of the car from underneath, and is further heated en route by the side-mounted exhaust. It seems worse when running a full windscreen. This phenomonon was especially evident in previous 7s with V8 engines because there was an exhaust pipe on my side of the car. Since I am usually solo in my Westfield I run a half tonneau cover, which should help some. Has anyone else noticed this problem and found a good fix?

 

The aeroscreen on my car is a Westfield part, specified as clear acrylic rather than the dark tinted stuff they normally supply, so my inspection and registration stickers are visible to keep the police happy.

 

http://www.usa7s.com/aspnetforum/upload/1070912184_xhst02.jpg

[JohnK]

Many thanks for the rationals, descriptions and pics - It's always helpful to see how other people have approached common problems - and have the opportunity to admire nice pieces of work :-) .

[pksurveyor]

Thank you for sharing your success in reducing the oven effect in a 7. You have given me many ideas for my soon to be built 2008 Caterham (when it finishes the trip across the pond).

[slngsht]

I've been using reflectix to cover the footwell area and it worked well. You can find it at hardware stores, and it looks like bubble wrap, except it's outer skin is aluminum.

 

It's designed for duct insulation and it works pretty well.

 

Before I ripped the car apart, I had covered the passenger compartment side (as opposed to the driveshaft side) of the tunnel panels. All the panels were completely cool (like the car is not running) after driving.

[slngsht]

captzoom, as others have said, thank you for your detailed description of what you have done. Posts like these really add value to the forum :thumbs:

[slomove]

You guys....and I thought I am doing crazy things to get rid of the heat.

 

some of my experiments:

 

- using the aluminized "bubble wrap" Mazda mentioned to insulate the firewall and accessible footwell surfaces: helps a bit, is cheap and easy to remove.

http://www.usa7s.com/aspnetforum/upload/814818760_Battery2.jpg

 

- wrapping the exhaust headers with glass fabric tape and then aluminum foil duct tape: helps a bit but the first hour of driving and burning off the aluminum duct tape adhesive is not healthy. Fortunately the wrap is holding up for 3 years now.

 

- sealing all the cracks, holes and crevices between the engine and the cockpit with silicone and duct tape: quite efficient. If that is not done properly all the other measures will fail. Just a 3/8" hole or equivalent will pass a LOT of hot air.

 

- Duct the nosecone into the footwell (picture below): I was disppointed. No significant change.http://www.usa7s.com/aspnetforum/upload/300708814_ventfunnel.jpg

 

- Footwell bottom louver: Disppointing. May have some effect but not worthwhile:

http://www.usa7s.com/aspnetforum/upload/1412907654_footventlouver.jpg

 

- By far the best improvement so far was a fresh air vent from the bonnet side with a reversed boat louver. The air flow can be felt and it flushes the stagnant hot air from the footwells:

 

http://www.usa7s.com/aspnetforum/upload/391741_AirVent2.jpg

http://www.usa7s.com/aspnetforum/upload/1342358358_AirBox2.jpg

http://www.usa7s.com/aspnetforum/upload/1177971570_AirBox1.jpg

 

The high intake position of this louver prevents it from sucking in hot air from the exhaust. Also, I have been driving in pouring rain for hours (PNW 2007) but for some strange reason there was no water dripping into footwells.

 

Gert

[captzoom]

Concur sealing all gap and holes btwn engine compt and cockpit is very important. Should be done at rear bulkhead and tunnel too (including shifter and handbrake. This is basic, but worth repeating.

 

I don't think cloth duct tape is a useful product for this work, aluminum foil tape is better though not as good as forming a piece of aluminum to make a seal.

 

In the same category (IMHO) using Reflectix is a less permanent fix than buying the good stuff from ThermoTec or equivalent. The material is much more expensive, but this is a job you do not want to have to do over...worth the higher materials cost up front. (Probably works a lot better too and is approved for use in aircraft firewalls, which should tell you something.)

 

Rob

[jcab]

Rob-

This is a beautiful car, with lots of original solutions and ideas--congratulations. I'm beginning the process of building a Westfield using a Honda S2000 powerplant, so I'm REALLY interested in your build photos, etc.--might save me some headaches.

If you wouldn't mind, could I contact you for info/help/advice as I proceed with my build?

If yes, then should I use this forum, or some other means?

Thanks,

jcab

[snookwheel]

Rob-

This is a beautiful carjcab

 

I agree.

[007 FSR]

Living on the Gold Coast of Australia we have fairly warm weather; bit Florida -Southern California like - so have some hot days amongst generally very nice weather.

 

I am not quite there re cooling and have used aluminum foil between tunnel and carpet plus a heat shield made of alloy heat sheild stuff as per pic. This seems to be quite effective!

 

http://i57.photobucket.com/albums/g202/fraserwill/P5270038.jpg

 

I do like the idea of throttle bodies as air controlers as the winter are brisk 50 to 60 F and I will not want any additional cool air in the footwells, as VERY happy with current set up for a winter blatt around the the hills in my backyard. I intend to take the air to be ducted into the footwells from the sides of my radiator . I have enough space around the sides of the radiator to make a small flattened plastic funnel. I don't seem to have any engine cooling problems, so think this would be OK!

http://i57.photobucket.com/albums/g202/fraserwill/charlton023-1.jpg

 

 

I already have a NACA duct for my cold air box on the side so can't use that area even though in an aerodynamic sense it is a high pressure spot!

http://i57.photobucket.com/albums/g202/fraserwill/IMGP4233.jpg

Edited December 5, 2009 by 007 FSR

[timax]

Will , have you tried the gold foil stuff? Its expensive at about $80 for a 1x2 foot piece. Out at one of the state rounds I noticed many of the top cars had engine bays or fire walls covered in this stuff. I'm in Sydney and don't have my Clubbie yet but i'm already researching the heat problem. Its harder to deal with than the cold. Like anything its the combination of ideas that will work over just 1 product or treatment.

Tim

[Dave W]

I just used 5/8" contruction foam glued to the tunnel, foot wells and sides. Probably less then $10, and less then 2 lbs. No heat problems at all. besides adding insulation, make sure you are getting the heat out of the engine bay.

Dave W

Edited December 8, 2009 by Dave W

[soareyes]

This last summer I decided I needed to finally do something about my cockpit heat problem. However, being a procrastinator at heart, I never followed through. I took a drive last weekend and my heat problem seems to have taken care of itself! Unfortunately now I have a cold cockpit problem in its place, but I have a feeling that too will take care of itself in a few months.

 

 

 

Sorry, couldn't resist!