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Why do you have these vertical steel pieces over the rear window?
I assume with all bolts arround it it would not go anywhere?
I can answer that.
Back in the 80s I built an SCCA GT3 VW Scirocco and installed a rear plastic window.
Mine had rivets & washers holding it in all around the window.
After 1 race I found tiny stress fractures all around the rear window coming from where the rivets were.
I added 2 vertical straps to help hold the window in.
I glued felt on the underside of my straps to help protect the plastic.
Plastic rear windows are not as strong(nor as rigid) as OEM glass.
I'm sure Jason's plastic is MUCH better than I could find at Builder Square 35 years ago.
Why do you have these vertical steel pieces over the rear window?
I assume with all bolts arround it it would not go anywhere?
The straps, 1/8 thick alum are there to provide structure to the Lexan to keep it from flexing, each strap has 2 fasteners that attach into the Lexan. Without the central attachment points, the Lexan is very floppy and my concern was over time the constant bowing and flexing would lead to stress on the periphery fasteners and eventual failure.
The structure is now pretty rigid…. I think the construction of the windshield itself plays a role, mine is just a flat sheet and has not been formed, I bet if you bought a fabricated piece that was formed to the actual windshield, that curvature would add strength and the flexing may be minimized.
In any event, the rear windshield will see a fair amount of force, it is something that should be overbuilt because the consequences of failure are not acceptable.
I can answer that.
Back in the 80s I built an SCCA GT3 VW Scirocco and installed a rear plastic window.
Mine had rivets & washers holding it in all around the window.
After 1 race I found tiny stress fractures all around the rear window coming from where the rivets were.
I added 2 vertical straps to help hold the window in.
I glued felt on the underside of my straps to help protect the plastic.
Plastic rear windows are not as strong(nor as rigid) as OEM glass.
I'm sure Jason's plastic is MUCH better than I could find at Builder Square 35 years ago.
When you use bolts the attach the window, all the load is distributed along a very tiny overall area, a fraction of the window perimeter as a whole. Using a high quality window weld bonding agent along the whole perimeter of the window will increase its strength immensely with the downside of no removal ability. I will say that being able to remove the rear window is a nice feature. With that said, if you are using thin flat lexan, as you know, the straps are still a necessity due to the lack of rigidity . We are using OEM GT3RS lexan which is "domed" like factory glass and when glued in is very stiff almost rivaling that of the glass window. No straps are necessary there. A friend is using this same window glued in on his track car without straps and no issues.
Jason, out of curiosity, did you measure the thickness of the lexan you used? What brand is it? The RS lexan window is 4mm thick and 7lbs. OEM Glass is 16lbs.
John - the lexan is from professional plastics and is 1/8 in thick. Didn't weigh the completed setup with straps so not much help in comparo.
1st track day done, 3 sessions at Thompson. By the way, before seeing the track I had driven the car all of about 100 feet, so we are trial by firing it.
The car did not break ! That was really the goal of the day. I wanted to be able to sufficiently incrementally push to make sure the car did not have any inherent weaknesses, specifically with the work I did and am really happy with the results. All the aero and lexan stayed on, the brakes worked and only had a period of weird pedal feel which was probably due to me not bedding them in properly and after that felt really good and by the end of the day, my confidence level in the car is about a million times greater than when I started.
The car was harder to drive, I am not sure yet how much of this is due to the rust that has accumulated on my driving skills after being out of the car so long and how much is attributed to setup but this was the first step in a process of refinement and the car had to perform to move past it. I think the best time of the day was in the 1:21's, about 2 seconds slower than my PB at Thompson. I am actually really encouraged that off the trailer after such a long time away at the car and so many new parts to only be 2 seconds away, there is a lot of potential and I am really excited to start really leaning into her.
Very cool! I gotta believe it will take some number of sessions to get the suspension dialed in. Awesome job getting to this point. Super stoked to watch the progress.
Dude! Only 2 seconds off from your PB? That's fantastic! I remember from the other videos you were really pushing it so to be that close after all the work done I'm expecting you to be 2 seconds faster than you PB at least as you gain more confidence and dial stuff in. Congrats on getting all this done. It's been a process.
06-28-2022 | 08:33 PM
