Plexi / polycarbonate windows FS

[NigelStu]

I figured this would be the best place to put this since it really just applies to racers, but if anyone feels it should be moved to the for sale section, let me know (or move it).

I bought a 3/8" thick 4x8 sheet of Makrolon GP (general purpose clear polycarbonate) to make windows for my ChumpCar, and was able to arrange the pieces so that had enough left over to make a 2nd set. This is for a coupe, includes rear window and rear side windows.

Tight fit to the openings, these will need to be drilled and riveted in and potentially trimmed a bit (due to vehicle build variance).

If rules require removing glass, or allow it, and you want to drop some weight this would be a good move.

$100 for the set of 3 pieces
$60 for just the 2 side windows
$50 for just the rear window
Plus shipping

Obviously, shipping the rear window is going to be a bit of a pain due to the size (aprox 52" xx 30")

I made templates for the WDWs, so if there seems to be a some interest, I could always make more. Lots of interest, I could do a group buy of some sort.


Pics of the windows, in various stages attached.



Ben

[djjerme]

I would be interested.. what is approx shipping to 97212. Or perhaps would you share the pattern?

[Kershaw]

you cut them out by hand? lol ouch. cnc is a lot easier and for the time saved, very cost effective.

good prices though, this stuff isnt cheap.

[NigelStu]

DJ - I'll look into prices for shipping, might not happen until this weekend. I look into the template bit as well since making those took the largest amount of time (and shipping a tube with the templates would be much easier!) - Ideally, I'd like to have 1 piece templates, currently the rear wdw is 3 poster-boards taped together. If I can source some larger sheets, I could go that route.

Kershaw - jig saw with a smooth-cut wood blade - made pretty quick work of it. The little bit of trimming/shaping to get the fit to the car took majority the time. I would completely agree about a CNC machine, but my little garage-shop doesn't have one of those yet!

[NigelStu]

Looks like shipping for the WDW set should be ~$25


Of if I can get at least 4 people who want templates, I can do a set of those for $25 shipped wherever. Those will take me a bit since it looks like I'll need to order a roll of poster board large enough to make the rear window 1 piece.

[Luis325]

Are you using any spacers for the side windows? How are they attached?

[KenC]

Good prices.

Can I ask why you're running them at all? Our lemons/chump car just runs the windshield.

[NigelStu]

Luis - no spacers, I used large head rivets with backing washers to attach - I'll post up some pics of the finished install later.

Ken - Its all for aerodynamics. windshield and roof with no side or rear windows creates a ton of drag. With 2 trips to Road America and one to Michigan International Speedway this year, we will be hitting speeds plenty high enough for aero drag to come into play. We were topping 110 at Nelson Ledges (I think 112.4 was highest), I'm expecting (hoping?) the car is capable of 125+ at RA. Any advantage we can get on the big track, I'm going to take. Its all about fun, but I still have this over-powering competitive nature.... :D

Secondary reason, also aero related, is improving aero on the car should improve MPG on track and when towing. I was VERY surprised that towing MPG was approximately 3 MPG worse than when I'm towing my Spec Miata - same truck load, BMW is only ~100lbs heavier than the miata. Reduction in MPG was primarily due to the extra Aero drag the BMW has.

[KenC]

It really makes that much drag?

Our car will hit 140+ on the back straight at PIR.

[jandress]

Didn't realize there was that much drag created by not having rear glass/plexi whatever. I would have though that it would be less drag wide open, but an aero specialist I am not.

[djjerme]

All I know is someone complained when an unnamed PRO3 car showed up with venting holes cut in the rear plexi window... Said it was an aerodynamic advantage, and that was the reason they ran faster. :S

[NigelStu]

^
Controlled airflow outlet will definitely help. There is a formula somewhere based on inlet opening size that gives the optimum outlet size...

Aerodynamics are cool. Minimizing flow separation and wake/vacuum areas is key. Taking the rear windows out of the car effectively changes the shape of the back half the car from a wedge to a box.

[jandress]

Im in for templates please