Eg civic hatch and no rear glass or hatch....

 We're building an endurance  racing EG hatch,the one with the silly fold down tailgate and separate hatch glass.

 Question is regarding backdrafting fumes etc running without any of the rear side windows,hatch glass or tailgate in place.

 I can see it back drafting with just the hatch section left open,but I'm thinking/hoping that  with air flow thru the rear windows openings that it might break the suction.

 Anyone have experience with this scenerio?

 Thanks.

The case you should be comparing to is a convertible with the top down. You usually wind up with some recirculation toward the back of the drivers head. It will be reduced with a roof and no side windows/hatch, but you may still get some fumes in the cabin. Fix it with a NACA duct mounted in the A-post notches and a hose blowing toward the driver.

Thanks,I think I'll add a sealed bulkhead  behind thw main hoop for added fire/fume protection

Why not just put Lexan in place of those windows?

 The EG civic hatch has a separate upper glass hatch and a lower fold down tailgate.

 Pain in the neck to try and build a hinged lexan hatch with it being so curved that seals and isn't flopping at the edges at 120+ mph

 Leaving it all open means diving in to sort a wiring/fuel related issue is a piece of cake.

We have an EG hatch and run lexan on the rear.  The side windows were easy.  For the back we made a frame out of some thin round stock.  We basically bent it by hand.  The lexan is sandwiched between inner bars and outer bars (rules require the outer bars) and zip tied around the edges.  It has pins on the tailgate that secure it.  It works pretty good.  The cool shirt cooler is back there so it gets opened every pitstop.  It has survived 7 Chump races.

Here are a few pictures to better explain.

The frame.

In reply to logdog :

Very nice work