Switching to Lexan (or equivalent)

Let me preface this by saying the vehicle this is for is not street legal. VIN is flagged as 'detroyed'. So it is not now, or ever will be street legal in anyway shape or form. It's life will be spent on a trailer or on track, *possibly* occasional car show. 

That being said, my 98 BMW 328is has a cracked windshield, it'll pass tech locally (they are trying really hard to get kids to come to the track), but if I travel anywhere with it, it will not pass tech. Is this a time to consider lexan (or equivalent) or just stick with basic glass?

The only reason I am thinking about it is because it needs to get rear lexan installed (previously had thin plastic that was poorly installed and badly damaged), and since it may be getting done in my yard, getting the windshield done at the same time makes sense since it saves me having to arange getting them out again OR trailering it to town to unload at the glass shop.

What say the hive? Most every thing I find online is people trying to do weight reduction on street legal stuff and being told its not worth it, or to stay glass because crash safety, or legality.

lexan is like kleexex, its a brand not a particular item. Lexan is a brand of PMMA (acrylic) and works okay but longevity wise you want PC (polycarbonate) as its tough and more UV resistant. 

I made my hatch out of PC from a giant sheet of it from Lowes, works great!

We have something on the site that might help: Replacing a Glass Windshield With Plastic.

I go with glass:

Living in the desert the polycarbonate quickly gets scratched.

As for weight you're looking at 5-10lbs tops.

This completely my personal opinion; in 37yrs of racing I've never seen an incident where having poly vs glass would have saved a life. If you're buying something in the name of safety there's a better return on investment elsewhere.....again my opinion.

With that said there's nothing wrong with buying a stronger windshield.....................for me the care and feeding isn't worth it.

So now is the time to make the switch to polycarbonate. Reading the article and it outlines exactly what I wanted to know if it would be worth it or not. I think I will be checking with the glass shop about the cost on also swapping the windshield out for polycarbonate when getting the rear window done.

In reply to DjGreggieP :

Cool, glad that the piece helped. 

Just to let you know...  you NEED to support the windshield VERY well or it will flex and distort at speed and can be quite annoying.

It's not any cheaper than a glass windshield.

A 4x8 lexan sheet thick enough for a windshield is going to cost more than glass.  It will also need straps to reinforce it, and it will scratch if you even look at it sideways and you can pretty much forget wipers if you ever plan on driving it in rain.  Once you drill the frame up for screws, it may be challenging to switch back to glass.  I personally wouldn't use lexan for a windscreen, but I have done a lot of side and rear installations and it's fine for that, as long as you're not a perfectionist - it takes a lot of wear really fast.

I have polycarbonate windows all around (rear screen and 4 doors), but I stuck with a conventional auto-glass windshield just to avoid the headaches. The local Safelite guys can pop in a new windshield for just a couple of hundred bucks, so it's not too big a deal if it chips /cracks. 

You can buy a lexan in different thicknesses, and if you get it in the thickness similar to what the glass was you will save weight and have something fairly rigid. And to add to the durability you can spec it with something called marguard which is a coating that resists scratches. I had one on an excavator and it was treated very poorly, scratched with branches, and the wipers were used on it from time to time but it held up very well.

I've had a couple of cars with plastic windows (not counting my old British stuff with removable side curtains. (Jensen CV8 had rear sides as plastic stock and my TVR Grantura Mk 3 had a complete rear window in plexi/perspex

The problem is that it will eventually fog and need replacement again and some will get brittle in UV and have a tendency to crack.

I always prefer safety glass windshields though.

I had to install clips for the rear window on the TVR - the GRP shell would lift at speed, threatening to allow wind in over the windshield (which I dealt with using a tensioned tie down rod to hold the roof down). It would have blown the rear window out in no time.

Went back to glass as well. Much lower pita factor. 

I agree on not using it for the windshield.  IME race car windshields get dirty very quickly, and you have to be really careful cleaning polycarbonate/lexan/whatever-it-is not to scratch it.