notbob Posted April 12, 2017 Report Share Posted April 12, 2017 Put a rear window in Shad. The side quarters also are in. Side exhaust, so shouldn't have issues with fumes in cabin. Debating whether to put in 2 vent holes in the rear window or not. Have read various articles. Some people say not to do it, some say to do it. Then there is location - some say towards the bottom because of the air that rolls over the top of the car, down the window, some say towards the top because it will pull the air from the car as opposed to hitting the low pressure air at the bottom? I thought about taping a handful of strings at various spots and drive around to see where they end up before cutting them out, but would like to hear your thoughts? Quote Link to comment Share on other sites More sharing options...
Ogren-Engineering Posted April 12, 2017 Report Share Posted April 12, 2017 No holes Try the ribbons. Iuse them a lot and they help. Quote Link to comment Share on other sites More sharing options...
tneker Posted April 12, 2017 Report Share Posted April 12, 2017 Was just pondering the same thing.......... We have not previously run lexan on side and rear windows. Does rear lexan tend to fog in humid situations like rain etc. We have a blower for front defrost, but no provisions for rear. Quote Link to comment Share on other sites More sharing options...
skierman64 Posted April 12, 2017 Report Share Posted April 12, 2017 (edited) We've always run lexan (except when it was banned in side windows in 2014) and never had an issue with fogging, and we've run some soggy races. We don't have holes, it just lets the rain in. The side windows create enough vacuum to keep air moving through the cabin. Edited April 12, 2017 by skierman64 1 Quote Link to comment Share on other sites More sharing options...
pintodave Posted April 12, 2017 Report Share Posted April 12, 2017 No holes in Camaro @ Daytona. We were doing the chump mandated 130 without issue. As skierman said, you should get enough evac from the side plus air on outside of window 1 Quote Link to comment Share on other sites More sharing options...
TiredBirds Posted April 13, 2017 Report Share Posted April 13, 2017 We are going to hang a Lexan "hatch" on our Firebird, no holes. once the cabin fills up with air (pressurizes) you shouldn't have an issue. Quote Link to comment Share on other sites More sharing options...
Technical Advisory Committee Chris Huggins Posted April 13, 2017 Technical Advisory Committee Report Share Posted April 13, 2017 (edited) No holes! Edited April 13, 2017 by Huggy 3 Quote Link to comment Share on other sites More sharing options...
notbob Posted April 13, 2017 Author Report Share Posted April 13, 2017 Huggy, For a true hatch back like a civic, where the fire can come straight up the back and get sucked in, I agree with no holes there... but not necessarily for other cars. I know alot of E30, E36 and others have multiple holes in theirs. Right, wrong, whatever, but within the rules. As always, I do appreciate the safety aspect and you can never bring too much attention to it! I think for now, I am going to run some strings and put a camera there, do some laps at track day and see what the strings and camera tell me on whether the window stays put, bows in or out and go from there. Quote Link to comment Share on other sites More sharing options...
skierman64 Posted April 13, 2017 Report Share Posted April 13, 2017 (edited) 2 hours ago, TiredBirds said: We are going to hang a Lexan "hatch" on our Firebird, no holes. once the cabin fills up with air (pressurizes) you shouldn't have an issue. Unless a Firebird has way different aero that most other cars, I think the pressure in the cabin of the car with no side door windows but installed rear side windows and a rear window is less than the ambient outside air pressure not greater. In other words the cabin of the car doesn't "pressurize" Edited April 13, 2017 by skierman64 1 Quote Link to comment Share on other sites More sharing options...
Technical Advisory Committee Chris Huggins Posted April 13, 2017 Technical Advisory Committee Report Share Posted April 13, 2017 E30 with no side or rear windows gets the back of your helmet/seat/suit wet if driven quickly in the rain. Quote Link to comment Share on other sites More sharing options...
TiredBirds Posted April 13, 2017 Report Share Posted April 13, 2017 58 minutes ago, skierman64 said: Unless a Firebird has way different aero that most other cars, I think the pressure in the cabin of the car with no side door windows but installed rear side windows and a rear window is less than the ambient outside air pressure not greater. In other words the cabin of the car doesn't "pressurize" bad choice of words... the cabin will be full of air, thus create a barrier. You wouldn't need "vents" out back. 1 Quote Link to comment Share on other sites More sharing options...
pintodave Posted April 13, 2017 Report Share Posted April 13, 2017 Even with no back window the Camaro was never bad about sucking in outside air (due to the shape and lack of back doors I'd assume), but with the a-pillar lexan and a back window, there was virtually no air movement inside the car and definitely no fumes. It was quite nice. Surprisingly I did not find it any hotter or more uncomfortable than normal, I guess “hot is hot” at that point so unless you have a hose directly pointed at you, you probably don’t notice much interior cabin cooling with or without a back window. Quote Link to comment Share on other sites More sharing options...
theblue Posted April 14, 2017 Report Share Posted April 14, 2017 while on the topic. what about holes in rear bumpers? good or bad? Quote Link to comment Share on other sites More sharing options...
enginerd Posted April 14, 2017 Report Share Posted April 14, 2017 18 minutes ago, theblue said: while on the topic. what about holes in rear bumpers? good or bad? This car is so fast it needs a parachute! And it has holes in the rear bumper, so I say holes = good. 3 Quote Link to comment Share on other sites More sharing options...
theblue Posted April 14, 2017 Report Share Posted April 14, 2017 I was hoping for more science Quote Link to comment Share on other sites More sharing options...
enginerd Posted April 14, 2017 Report Share Posted April 14, 2017 5 minutes ago, theblue said: I was hoping for more science Holes in the bumper are like the Blipshift "+5 HP" stickers that I put on my ECU cover And for the science.... it depends 'bigly' on the shape of your bumper and what the air is doing underneath your car. For the e30 design, cutting holes in the rear bumper won't affect the airflow. I don't know about other cars though. 1 Quote Link to comment Share on other sites More sharing options...
theblue Posted April 14, 2017 Report Share Posted April 14, 2017 yeah, I've been looking at E36 racecars and trying to decide if there is any value. Quote Link to comment Share on other sites More sharing options...
pintodave Posted April 15, 2017 Report Share Posted April 15, 2017 Me thinks a lot of the aero shtuff we ponder over don't mean sheeeeeeeaaaatttt.... You'll gain more by making sure you have a perfect 14 hours. 2 Quote Link to comment Share on other sites More sharing options...
enginerd Posted April 15, 2017 Report Share Posted April 15, 2017 15 minutes ago, pintodave said: You'll gain more by making sure you have a perfect 14 hours. What if I told you.... having a perfect 14 hours and pondering aero aren't mutually exclusive? 1 Quote Link to comment Share on other sites More sharing options...
dogtired Posted April 15, 2017 Report Share Posted April 15, 2017 This one time at band camp..... I fell out a E36... as I couldn't no longer stand.... fumes, dem fumes... but, I got some A1 treatment from the EMTs at VIR... Quote Link to comment Share on other sites More sharing options...
revvhappy Posted April 15, 2017 Report Share Posted April 15, 2017 It must be something about VIR. My first 24 hour race was there and 45 minutes into my first stint I called in to say that I was done - I've never felt so awful driving a car. Quote Link to comment Share on other sites More sharing options...
pintodave Posted April 15, 2017 Report Share Posted April 15, 2017 10 hours ago, enginerd said: What if I told you.... having a perfect 14 hours and pondering aero aren't mutually exclusive? Indeed. Pondering is one thing. But your time is a limited resource. If you have 8 hours to spend on a Saturday working on the car, 8 hours invested in preventative maintenance and race strategy might yield better dividends than spending 8 hours on aero But then again, 8 hours spent on a completely different activity could be more productive than all listed above 2 Quote Link to comment Share on other sites More sharing options...
skierman64 Posted April 17, 2017 Report Share Posted April 17, 2017 On 4/15/2017 at 0:10 AM, dogtired said: This one time at band camp..... I fell out a E36... as I couldn't no longer stand.... fumes, dem fumes... but, I got some A1 treatment from the EMTs at VIR... The trunk and air outlets (inlets) need to be sealed to keep exhaust fumes out of the cabin. Quote Link to comment Share on other sites More sharing options...
pintodave Posted April 17, 2017 Report Share Posted April 17, 2017 On 4/15/2017 at 1:10 AM, dogtired said: This one time at band camp..... I fell out a E36... as I couldn't no longer stand.... fumes, dem fumes... but, I got some A1 treatment from the EMTs at VIR... So fumes is the new code word for Budweiser? 1 Quote Link to comment Share on other sites More sharing options...
wvumtnbkr Posted April 17, 2017 Report Share Posted April 17, 2017 43 minutes ago, pintodave said: So fumes is the new code word for Budweiser? no, I think "A1 treatment" is the new code word for Budweiser. 4 Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.