What's the best defroster/defogging recommendation

#1

I competed in the recent BMWCCA “monsoon” club race at Roebling earlier this month and had a heck of a time with visibility. I had used some rain-x anti fog and it worked for a short while but it was not good result. On previous occasions I have used a light layer of soap on the inside to reduce fogging and again was not totally pleased with the result. There was a gentlemen at the race that was using a 12v hair dryer as a defogger in his E36.

Are there any other defroster/defogging alternatives that anyone can recommend?

#2

other than shampoo/chewing tobacco on the inside of the windshield?

here’s what turner did, i am thinking of something similar:

#3

kishg wrote:

[quote]other than shampoo/chewing tobacco on the inside of the windshield?

here’s what turner did, i am thinking of something similar:

[/quote]

Can’t quite make out what you are showing. Do you have any aditional pictures or information or maybe a link?

#4

link to full size pic is http://www.turnermotorsport.com/image/gallery/forsale/gs-e46-m3/IMG_7480.JPG
the duct there is picking up hot air from the trans tunnel and ducting it to the windshield.

#5

That seems to me to be less than an optimal solution. I’d think that a lot of moisture would be directed at the windshield in the rain. A better idea would be to come up with a way of getting hot air from the HVAC box to the windshield. A dash bar makes that more difficult, but I’m playing around with a couple of ideas for that.

#6

This looks kind of like what I’ve been thinking of…

Tap into the heat at the trans tunnel, 3" hose, 3" fan in the middle, 3" hose to drivers side windshield base.

#7

Indy jim and I wear at the sane race, in my 5er. Jim and our buddy ran over to walmart ,bought a hairdrier and an inverter that we straped to the dash. Im not kidding. It wasn’t great but it was good enough for us to finish the enduro! I would use it again if I ever race in the rain , which I probally wont!

#8

how would moisture get there jim? its just picking up heat from the trans tunnel and ducting it. there’s no opening to the outside. or do you mean water would collect in the foot well through the window? i’ve deleted the heater core, so that’s not an option any longer.

#9

scottmc wrote:

[quote]This looks kind of like what I’ve been thinking of…

Tap into the heat at the trans tunnel, 3" hose, 3" fan in the middle, 3" hose to drivers side windshield base.[/quote]

exactly.

#10

kishg wrote:

The fact that there is no opening is not really clear from the picture. I can’t think that air is as warm as it would be with a heater core.

Glad I’ve got a heater core.

#11

its probably not as warm but should serve the defog purpose. you don’t want an opening due to the obvious water issue as well as allowing exhaust gases inside the car.

#12

kishg wrote:

If you are driving in the wet, water sprays up against the entire bottom of the car. Including the transmission tunnel. I had water coming into the car via a torn shift boot last March at Road Atlanta when we were engaged in amphibious racing. So I’d expect a transmission tunnel defogger to wet the windshield when racing in the rain.

If you took the heater core out, you can put it back in.

#13

jlevie wrote:

[quote]kishg wrote:

If you are driving in the wet, water sprays up against the entire bottom of the car. Including the transmission tunnel. I had water coming into the car via a torn shift boot last March at Road Atlanta when we were engaged in amphibious racing. So I’d expect a transmission tunnel defogger to wet the windshield when racing in the rain.

If you took the heater core out, you can put it back in.[/quote]

how does water get into the car when there’s no opening? up here we get a lot of wet days and i’ve never experienced water coming in to that section of the car. through the window i’ve had the passenger seat get slightly wet but that’s about it.

#14

kishg wrote:

[quote]jlevie wrote:

[quote]kishg wrote:

If you are driving in the wet, water sprays up against the entire bottom of the car. Including the transmission tunnel. I had water coming into the car via a torn shift boot last March at Road Atlanta when we were engaged in amphibious racing. So I’d expect a transmission tunnel defogger to wet the windshield when racing in the rain.

If you took the heater core out, you can put it back in.[/quote]

how does water get into the car when there’s no opening? up here we get a lot of wet days and i’ve never experienced water coming in to that section of the car. through the window i’ve had the passenger seat get slightly wet but that’s about it.[/quote]
The transmission tunnel is open to the ground, unless you leave the heat shield in and don’t go through it. But in that case there’d be no air flow from the tunnel.

I’ve figured out a way to get flow from the HVAC box up through the dash vents. It might not work quite as well as what BMW engineered, but it will be better than nothing. Now I just have to fabricate the part.

#15

Jim,
they’re saying that the vertical pipe just butts up against the tunnel - it doesn’t go through it at all.
bruce

#16

In that case, never mind.

#17

right. the metal fitting there is just up against the tunnel on the interior of the car. the metal there gets pretty hot with the heat from the exhaust. a small 3" fan on the other side of that ducting will pull the heated air up and vent onto the windshield.

i’ve also thought about re-using a rear defroster from a vert. has anyone tried this?

#18

jlevie wrote:

[quote]
I’ve figured out a way to get flow from the HVAC box up through the dash vents. It might not work quite as well as what BMW engineered, but it will be better than nothing. Now I just have to fabricate the part.[/quote]

any pictures or sketches available?

#19

Pictures will be posted once I get it built.

#20

Here’s a solution I kinda like. Guy says it’s worked fine for him in the NorthEast for the last 3-5 years. See post 23 of the below thread.

http://forums.bimmerforums.com/forum/showthread.php?t=916770

Since last year’s rules didn’t permit such, I came up with a way of trimming the defrost ducting to appear that the dash bar goes through it. It also required a little creativeness with the heater-A/C box also. Hopefully I’ll get to see how well it works this year.

I’d definitely prefer a lighter weight solution that works when it’s supposed to. The thing I don’t like about the heater core in the cabin is when it lets go. I’ve heard of people getting their feet burned if the heater core encloser isn’t fairly water snug and providing a drainage route away from the driver’s feet.

Is the Turner application just an idea yet to be proven? How well does it really work? How long does it take to warm up before there’s a sufficient warm air source avialable? Obviously, if you can ditch the heater core, there’s one less thing to go wrong.