LeMons windshield defroster options

We were testing the LeMons RX7 on Sunday in the rain and had some serious visibility issues from fogging. I don't love the idea of relying on chemical treatments, but it's option one.

Option 2: Hookup the airbox etc again - pros: it works. Cons: heavy and more to go wrong. Heats the cockpit too.

Option 3: Electric heater matrix - Pros: light and only heats the windshield. Cons: expense, but it's a safety issue. http://www.frostfighter.com/clear-view-defrosters-legacy.htm

Any experience? All my other events have been dry - so fogging hasn't been an issue.

I can tell you that I am a little upset we removed our heater core in our 2nd gen rx7 for leChump races.

The heater core worked awesome! The electric defroster grid we added to the windshield didn't seem to do much at all.

I am thinking about re-engineering the heater core and fan to be able to swap in and out depending if it a wet race or not.

In the old days they used little rubber bladed fans.

Anything to increase airflow will help.

iceracer wrote: In the old days they used little rubber bladed fans. Anything to increase airflow will help.

I remember our school bus (50s-60s) used small fans to assist in keeping the windshield fog free.

Fog-x and a bilge blower pulling in ambient-temp air works for us. Pitching it sideways and letting an on rush of air come in from the passenger side window also works extremely well.

Jc Whitney used to sell a blower that plugged into a cigarette lighter for the front windshield of AC VW Beetles. Maybe they still do.

In reply to JohnRW1621:

We tried one of those.

I think the main issue is that the Windows are wide open. Most fans don't work well without a ton of flow and some heat.

Another vote for the bilge fan. We picked one up cheap and had it pull air from a hose out the passenger window and ducted through a piece of plastic gutter liquid nailed to the bottom of the dash out couple holes cut at the base of the windshield.

Edit. This was in an open late model stock car. The bilge fan moves a lot of air.

Secret Option 4: Remove windshield.

THe "pro" way to go that I'm sure you can fabricate yourself once you see what it is: http://www.bimmerworld.com/Safety-Race-Interior/Battery-Electrical/BimmerWorld-Front-Windshield-Defroster-Kit.html

The way I went once with good results - you get used to it really quickly so vision isn't an issue but it sucks when you have to replace the window: http://www.frostfighter.com/clear-view-defrosters-legacy.htm?gclid=COS-58qj088CFY1ahgod5x8KwA

Wrap a rag around your hand and wipe it off during the straight-aways

What about a heater core in a box with a fan and duct - basically a custom airbox - with an on/off switch? A heater core and fan weighs what - five pounds? Skip the second McRib and you're at a wash for weight. I bet you could re-use the factory blower and heater core and defrost vent. Pop rivets and zip ties and some aluminum flashing could make you the box, duct connector, and mount it to your firewall.

trigun7469 wrote: Wrap a rag around your hand and wipe it off during the straight-aways

You laugh but a "rag on a stick" was the most effective tool I had for the E30 of Doom for it's first season.

Damp cloth with Dawn dishwashing liquid (not too much) Soak the soap through the cloth. wring out the cloth, then wipe inside of windshield with cloth.

Huckleberry wrote:

trigun7469 wrote: Wrap a rag around your hand and wipe it off during the straight-aways

You laugh but a "rag on a stick" was the most effective tool I had for the E30 of Doom for it's first season.

I had one too since the defrosters on our buses were awful with a standing load. They were also effective crowd control tools.

Interesting thread. The big question... Is this a safety concern...?

Can you route the exhaust to blow on the inside of your windshield? But do it after the muffler so it's not too loud.

I used straight exhaust to heat up my '73 Beetle. I just carried extra Extra Strength Excedrine in the glove box.

Is it too simplistic to have radiator tubing/hose run under the base of the windshield (inside). A small Walmart 12v fan to blow the heated air across it?

I build a portable system in a five gallon pail. I installed the biggest fan and heater element that would fit and duct taped the openings. I ran a couple ducts up to the windshield. It really pumped out the hot air. I bungeed the bucket to the passenger side floor.

My experience is that the 12 volt heaters are useless unless they are huge and will then tax your electrical system.

I took a piece of downspout and capped one end and then put slots in it and mounted it across the base of the windshield. We ran a duct over to the passinger side mirror and duct taped it to it . Worked really well once we got the size of the slots in the downspout sized properly. Later on we ran the duct to a cobbled together air box made of aluminum that had a heater core in it that was fed air by the same duct taped to the mirror. That worked really well and was easily removable if we wanted to. We would usually just loop the heater core hose in the engin compartment and conect the two ends of the lines running to the heater core to seal them up as well. It could be hooled up in 5 minuts if the motor was not hot. WIth a hot motor is was a SOB to hook it up. I was going to put valves in but never got to it.

The model T or the A had an air box on the exhaust manifold Air came in the front, heated by the manifold and routed to the inside of the car.

We used the factory heater core and a boat bilge blower in the Lemons car. It did a outstanding job and the weight penalty was minimal.

iceracer wrote: The model T or the A had an air box on the exhaust manifold Air came in the front, heated by the manifold and routed to the inside of the car.

Air cooled VW's use the exhaust for heat. Or the heat generated by it anyway.

A little rust/rot in the right place will lead to severe headaches and sleepiness!

RX-7s are tough, the considerable exhaust heat causes any water on the car floor to vaporize, which then condenses on the windshield. Nothing wrong with running the stock heater core and fan to clear the windshield. Just make sure it's in excellent condition and is mounted so it can't be chafed. I have tied a shop rag to a back scratcher so the driver could reach the windshield without loosening the belts.

I'm a big fan of leaving the original heater box, or at least part of it. Works pretty good as a supplementary cooling system as well, and really, in a car with no windows, I really don't notice the extra heat inside the car.