Is there value in a defroster in a roadster without a top?

[Slider]

Running the duct work today, and got to thinking... Why would I want a defroster in a car with no top? I believe that if both sides of the window are the same temp, then frost shouldn't occur? With that thought in mind, I think I may just route the ducting that was intended for the defroster vents back into the footbox as well. Looking to see if there are any dissenting views on this. I live in ND, so heat is a must, but can't figure out the logic of a defroster for the windshield (Unless I put a top on at a later date, upon which I will install them at that time)

Comments and thoughts are sure appreciated?

[bansheekev]

I am omitting mine and have talked to others that have omitted theirs for the same reason (no top)...

Kevin

[seagull81]

I have never had any issues without them. BUT, be sure to RainEx both sides of the windshield in case you hit some rain.

[MHCobra]

Slider,
Unlike these other guys, I live in the "north country" like you(central MN). I don't have defrosters & have driven in temps as low as 25 degrees and I've never had a problem.

Mike

[Slider]

Excellent. I think this solidifies it for me. Extra heat to the footbox for me!

[mrmustang]

For those of you who drive the cars all the time,yes, defrosters are not a bad thing to have. I say this as I have a tendency to take the wife out to dinner in my Cobras, or stay later at a friends house over the summer. As such, you do get a build up of dew or haze on both sides of the windshield, making the use of a working defroster a good thing. Even with rainex on both sides of the windshield, you still end up with this same build up. Wiping it with a rag helps, but only for a few moments and things fog right back up. So, if you live in an area where you get condensation build up, then I do suggest you install the duct work. You'll thank me down the road.


Bill S.

[Dan Babb]

One morning I was cruising along and it was cool with some moisture in the air. I would go down a hill and the temp got about 15degrees cooler. When I went up in elevation, the temp warmed back up (instantly). Whole window instantly fogged up and I was driving blind. Happened a few times that morning. Wish I had the vents in the body to install defrosters.

[Cobradavid]

I agree with Bill S. Like what Dan said, I've experienced sudden temperature/humidity changes on cool mornings. It doesn't happen very often, but when it does I'm glad to have the defog vents.

David

[Scott Zackowski]

I have to agree with Dan and David. As a fellow North Carolinian, where the climate is humid, I have heard of the windows fogging up just pulling out of the garage on a cool morning or evening. The conventional wisdom is that you don't need a defroster if topless, but as stated I have heard several stories to the contrary.

For my build, I am going with defroster vents.


Scott

FFR 7304, Mk4

[Don DePontee]

I have them going into my current build, they do work like Bill and Dave have mentioned. It's better to have them than not.
Here is an item I bought from Richard at North Racers (one of our vendors here) which is a fiberglass defroster plenum to keep things clean behinds the dash.
http://www.northracecars.com/OtherItems.html
Don

[lakercr]

Im not sure what the process will be to get your car licensed and on the road, but up here in Winnipeg, functioning windshield defrosters will be required to pass inspection before I can get my plate. Something to consider?

On a related note, I've owned british sports cars for ~25 years, and would strongly suggest you install defrosters for the reasons mentioned above.

[Mesa Mike]

I built my FFR Roadster in 2000 while living in San Francisco. I moved to Arizona 7 years ago. Now there is two extremes, dry and warm/hot and mild and wet. I routed my defrost vents back into the foot box on each side. In both California and Arizona I have used the heater/vents many, many times. I have never experienced a foggy windshield, but I have enjoyed the warmth of the heater in both states. My opinion is: without a top you don't need defroster, with a top possible.

[CraigS]

I have had an APE hardtop since 07 and drive all year around. I don't know why but I have never needed a defroster. I thought like you, no defrost equals extra foot heat. MAybe you should install the vents etc and hang some hose but not connect to the heater. That way, if you ever find you need them it would be fairly easy to connect.

[t d]

In Pa (2010) defrosters were required for enhanced inspection. I would talk with the shop that will do the inspection. Yes I use mine. Great on a rainy day or VERY humid day.