Race Car Defogger/Defroster

[JClark]

I'm sure some of you have done this already but I couldn't find any pictures or how-tos so I figured I'd post mine and maybe it'll help someone else.

When I stripped the car and did the cage last winter, I chose to leave the heater core element (but remove the giant plastic box) and eventually hook up a fan/duct setup for a defogger. Everyone that said the Fog-X stuff was "good enough" lived in Arizona and probably doesnt do as many 30*F Lime Rock mornings as I do. Regardless, I tried it and it definitely does not work well enough.

Credit goes to Jimmypet since I stole his idea.

To keep the core and lose the big plastic box, you need to make a bracket for the core to sit on (3/4"-1" above the trans tunnel). Big zip ties hold the core to the bracket.

Flow to the heater core is controlled by a solenoid on the firewall in the engine bay. It's a simple wiring job. Send power to the solenoid to STOP flow to the core.

I picked up a square to 3" duct from Pegasus, some ducting, and the in-line fan from Bimmerworld and viola:







Hard to see but this is the duct from Pegasus on the back of the core:



Here's the solenoid you're looking for:






It works great, btw.

Search words: defog, defogger, defroster, heater core

[Steve J.]

Cool.

You can even take a peice of tubing and put it at the base of the windshield, cut holes/vents in it, cap one end, and feed air in from the other. Its a simple way to get air evenly across the window.

[JClark]

I had planned to do that or hook it up to the factory ducts but my dash bar runs right underneath the opening so this was easier than cutting new ducts.

[bennyfizzle]

Hardparker

[bennyfizzle]

Your interior makes me want to gut mine sell it all and buy some sheet aluminum and gauges

[BobWright]

Jesse

Ummmmm...I think I am going to keep the stock unit in mine for now......any regrets taking yours out? I am gutting the car now...what fun....THIS IS...the job I was born to do....tear a car apart and not have to put it back together......

[JClark]

If by stock unit, you mean the giant plastic heater box, then no, no regrets in removing it.

To keep it you also have to keep the body control module in the center console AND the heater control panel. Clutter bugs me so this was an easy fix. The duct fan blows harder and hotter than the stock unit ever did.

[JGood325]

I've heard of people talking about running tubes from the trans tunnel as well (heat via exhaust). I guess the problem with this would be fumes?

[Michael9218]

I've heard of people talking about running tubes from the trans tunnel as well (heat via exhaust). I guess the problem with this would be fumes?

I think the solution you're referring to is to run a duct to the passenger side of the tunnel, but it stays in the interior, so exhaust fumes would not be an issue. The problem I would see with this would be that you would have to wait until the floor gets hot from the exhaust under the car. And then I don't know how much effect it would have.

[Michael9218]

JClark,

Interesting solution. Weren't you able to tie in that ducting to the factory dash defrost vents?

[magnetic1]

I think the solution you're referring to is to run a duct to the passenger side of the tunnel, but it stays in the interior, so exhaust fumes would not be an issue. The problem I would see with this would be that you would have to wait until the floor gets hot from the exhaust under the car. And then I don't know how much effect it would have.

That did not work for me at all. It seemed to make things worse actually.

I now just use shampoo on the inside of my windshield...

[JClark]

JClark,

Interesting solution. Weren't you able to tie in that ducting to the factory dash defrost vents?

That was the original plan, but my cage's dash bar runs right under the factory vents.

[BobWright]

That did not work for me at all. It seemed to make things worse actually.

I now just use shampoo on the inside of my windshield...

any particular BRAND Bryan....or just go VO5 and save !!......

[magnetic1]

any particular BRAND Bryan....or just go VO5 and save !!......

It's Eric!

Dunno what I use, it's whatever the wife packs me in my travel pack

[BobWright]

Oppps....sorry Eric.....I was skimming and mistook you for Bryan Watts......

[saem3]

I think the solution you're referring to is to run a duct to the passenger side of the tunnel, but it stays in the interior, so exhaust fumes would not be an issue. The problem I would see with this would be that you would have to wait until the floor gets hot from the exhaust under the car. And then I don't know how much effect it would have.

This set up has worked well for me. Now, I do have all of the Motec goodies down there pumping out heat on their own too....

Steve E.

[endoforce5]

I have a rear defrost unit out of an E-30 convertible that is lightweight and also works very well. No need to have the heat exchanger and fluid in the cockpit.

[Simon C]

Can I ask a few clarification questions please. Could you explain how you sealed the pipework back through the firewall? I am assuming that the solenoid is run off one of the toggle switches on your center panel along with the fan? Thanks for the help as I am in the middle of doing this right now.

[davesnavy]

Oppps....sorry Eric.....I was skimming and mistook you for Bryan Watts......

Yeah, they look a lot alike. Easy to confuse the two.

[boro92]

I know it's not exactly what you're looking for, but has anyone considered buffing dish washing soap into the windshield on the inside?
It's a diver's trick to prevent fogging in lenses. I actually do that on my eyewear and swim goggles as well...works excellent! /ghettoracing

[yokoseiki]

I know it's not exactly what you're looking for, but has anyone considered buffing dish washing soap into the windshield on the inside?
It's a diver's trick to prevent fogging in lenses. I actually do that on my eyewear and swim goggles as well...works excellent! /ghettoracing

Dawn is supposed to work yes.

I made a defroster using some marine fans and the diff cooler as the heater core.

[kenndoggy]

Why not eliminate all of it and just mount a 12V heater to the dash?

[smeyer1116]

Why not eliminate all of it and just mount a 12V heater to the dash?

I tried that, just not enough heat or volume to be effective. Shampoo works really well.

[dradernh]

Why not eliminate all of it and just mount a...

...heated windscreen: http://www.heatedwindscreen.com/acat...ndscreens.html?

Granted, they're not cheap by the time you have one installed & working, but pushing a button for a totally clear windscreen is very nice. I really didn't care for the results produced by the OEM heater core/dishsoap arrangement I previously used.