What is best for defrosting?

[Jay Laifman]

First, I recognize I need to go through all Brett's posts. I started to. But I've yet to find any final installations and conclusions.

I have a Sebring. It really HATES coldish moist mornings or evenings. The windshield REALLY wants to fog up. The car has an AC in it that isn't working anymore and needs to be updated to R134. When the AC in it used to work, I think it did ok on defrosting. But it's been a long time.

Currently, I have tried the RainX for inside, squeegys and towels and nothing really works. Kind of dangerous actually.

Here is my question. In looking for and designing a system, what is best for defrosting? Massive air flow blowing onto the windshield? Cold air? Hot air?

Thanks for any thoughts.

(Also, currently my car is still running with the Fiero GT V6. And I'm still thinking about putting in an 1835 built VW engine back in. That actually would have a big impact on the AC since the V6 probably does better with the compressor than hanging one out for the VW engine.

 

[B57-1974]

You may know this already, but it is worth mentioning. I once visited my sister in Ohio. She was complaining about her car and the fact that the windshield was always fogged up and she was constantly wiping at it. We were driving down the road at the time and I flipped the air control from recirc to outside air. The fog went away almost instantly. She was amazed. The moral of the story is that the most important factor is to get outside air blowing on the inside of the windshield. My preference is to use hot air, but many people swear that using hot air and A/C at the same time is better because A/C removes moisture from the air. I don't think it really matters too much about hot or cold, just be sure that it is not recirculated air from the inside of the car.

 

[B57-1974]

my car is still running with the Fiero GT V6. And I'm still thinking about putting in an 1835 built VW engine back in.

What are the advantages of the 1835cc over the V6? Other than not having to worry about a radiator? I have always been jealous of people that have gone through the trouble of putting a water-cooled engine in their car.

 

[letterman7]

I concur. Unless you're driving through heavy fog (or it's below freezing), a strong wash across the windshield with outside air should do it. Now, here in the great NE, if it's raining out the last thing I want turned on in my truck is heat - the defrost will hit the A/C every time and clear it out. Weirdly, the same thing works in the winter... A/C turns on with the defrost.. probably to dry the air as it's being heated. All that said, in both my cars I simply turned the fan up high and aimed it the best I could towards the screen. I didn't have upward facing dash vents linked up.. it seemed to work for the most part.. keeping the side windows cracked helped, too.

 

[Jay Laifman]

So, outside air even if it's raining or humid out?

I agree that AC seems to go on with some cars. But now that I think about it, how does that make sense? A fogged window means, I think, that the water near the glass in condensing. I think that usually means the glass is colder than the moist air around it, slowing down the speed of the molecules, pulling the water vapor together. So wouldn't it be better to heat the glass?



On the V6 back to VW, the V6 is great. Power, smoothness, reliable, and actually low mileage. Here are the three things I don't like:
(1) all that extra weight in back.
(2) that it constantly burns out mufflers because the mufflers are less than 2 feet from the exhaust manifolds, with no time to dissipate. That said, I've identified Borla and MagnaFlow options that should solve that, but might make the car too loud.
(3) Call me nuts, but also, in the back of my mind, I think about the V6 and the gas tank and today's distracted drivers and all the rear end accidents I've seen. If the car gets rear ended with the VW engine, it seems pretty unlikely to hit the gas tank. And if the air housing hits the tank, I think the air housing will crumble first. The V6 however is much closer and seems to have a higher likelihood of being pushed into the tank. That could be catastrophic.

 

[letterman7]

It's not a perfect solution, but as long as there is air moving across the screen it shouldn't condense as fast. There have been times that no matter what I couldn't see, but a little Rain-X took care of that for the next outing.

The v6... why not swap it out for a stout v4? If all the plumbing is already there, I'm sure you could find a small 2.8L or something along those lines..

 

[B57-1974]

So, outside air even if it's raining or humid out?

Yes. Every car that I have ever seen that had window fogging problems was because the operator had the vent system set on recirc instead of outside air. As for why the A/C kicks on with defrost, it is because the process of cooling the air removes moisture.

 

[Jay Laifman]

Ok. Someone posted these somewhere else. I have to pull out and build a new AC unit anyway. So I think I'm going to make a separate system to pull in and blow air on the windshield, lots of it. Using one or two of these: Turbo 4000 Series II In-Line Blowers : Attwood Marine

I think, with my Sebring, I can make a hole in the front footwell, mount one of these just outside the footwell, going into the car, and run two hoses up to my vents on the top of the dash.

It will have its own switch. Then when I do the AC, it will be its own separate system, which uses different vents anyway.

Heck, if I use two of them, and really blow a lot of air, maybe it's enough to keep me cool enough on the warm days, which might help until I get around to the AC.

Thanks for all the help.

 

[islandman]

The original owner of my car put one of those in the sides inline with his air intake, it worked but was very noisy. I've since changed my whole set-up

 

[Jay Laifman]

It's not a perfect solution, but as long as there is air moving across the screen it shouldn't condense as fast. There have been times that no matter what I couldn't see, but a little Rain-X took care of that for the next outing.

The v6... why not swap it out for a stout v4? If all the plumbing is already there, I'm sure you could find a small 2.8L or something along those lines..

I tried the inside Rain-X. It was useless then. Maybe with the blower I'm adding, it will be helpful to use Rain-X.


The V4 would still put big heavy metal up near the gas tank. So that wouldn't change that risk issue. And I don't know V4s very well, or their respective weights.

Here is a list I put together at some point for a 912 group:

2.0L 911 - 405 lbs
2.2L 911 - 380-405 lbs (magnesium case dropped weight)
POLO - 286 lbs
912 - 212 lbs - 240 lbs
Subaru - 271 lbs (2006 Forester, sohc non turbo, with flywheel, not exhaust)
914 - 311 lbs? (from questionable chart)
Raby? Type 4
Pontiac 2.8 liter V6- 345-376 lb. (for point of reference, with all extras)
VW Type 1 250-265 lbs with flywheel, muffler, carbs and all sheetmetal, dry.

 

[letterman7]

I wouldn't worry too much about getting rear ended. If we were all worried about accidents in our cars we wouldn't drive them.. if it still bothers you, look to change the gas tank to a fuel cell rather than change the engine.

 

[Jay Laifman]

Yes, valid points. I don't know if it is older age, having kids, or having kids who will drive the car. Or if it is seeing all the distracted drivers and accidents. I've driven this car for well over 30 years now. I never used really care. Now I do.

I have thought of a fuel cell. I usually assume pretty expensive to get to fit in that space. I will look into it. Thanks for reminding me.

I still may do the VW engine for now anyway. All that can happen is that I put the V6 back in. And, in the meantime, it would be a fun, educational project for my kids.

 

[Jay Laifman]

I should also add - in case anyone still cares - Since putting the V6 in the car in 1989, I purchased a 912. Full disclosure, I have a long hood 911 that I've had since 1988 (long before they rocketed up in value). I got the 912 just a few years ago (also before values spiked) because my daughter really wanted to do it as a project. I fully expected to dislike the car as an underpowered shadow of the 911. But I proved myself completely wrong. Once we got that 912 dialed in, I found I absolutely loved it. That is a jewel of an engine, and such a well balanced car. And in autox'ing it, I'm frequently faster than some 911s. That's what has also gotten me to go back to the VW engine in the Sebring. The car just seems more balance with the lighter VW engine.

We'll see. As I said, after we put in the VW engine, if we miss the V6, we'll still have everything to put back in.

But, then I also have a Rayjay turbo that used to be on the car. So we'd probably go that route before back to the V6 . . .