Rear windows down?

[green_henry]

I noticed in the track photo thread that sometimes the rear windows are down -- emphasis on sometimes, because the same drivers/cars have them up in other track photos. Out of habit, I rarely drive with the rear windows down under any circumstances. For those of you who have rolled them down at the track, was there a specific reason?

 

[jeffreylyon]

Some governing bodies require that they are up. Some folks think that lowering them lowers the CG enough to take the trouble.

 

[green_henry]

Ok, lower center-of-gravity kinda makes sense, but isn't the drag increased? I don't know, but my butt dyno says yes, lol. I guess it wouldn't matter on a slower auto-X course but could on a road course -- and maybe that's why the photos are inconsistent? Down for auto-X, up for road?

 

[XR650R]

Ok, lower center-of-gravity kinda makes sense, but isn't the drag increased? I don't know, but my butt dyno says yes, lol. I guess it wouldn't matter on a slower auto-X course but could on a road course -- and maybe that's why the photos are inconsistent? Down for auto-X, up for road?

That makes sense. In auto-x, several pounds of glass are lower. That helps with CoG.

 

[kivnul]

For autox, I keep them down when it is hot out as I tend to keep the AC off the whole day. Some clubs/organizations have a rule that windows must be either 100% up or down, no in between. As our back windows do not go all the way down, the windows would need to stay up.

 

[WannabeST]

In HPDE events, many organizations require them down. Incase of a crash or rollover so they can pull you out faster.
A couple aerodynamic companies have tested the windows up vs down aero argument. While the windows up is more aerodynamic, the difference is marginal. Most results show that once the cabin gets filled with air, it tends to just block out any new air from coming inside the cabin. I usually run the heater to the windshield to help get rid of some engine heat and the cabin doesn't get too hot with the windows down, even in hotter track days.

 

[green_henry]

In HPDE events, many organizations require them down. Incase of a crash or rollover so they can pull you out faster.
A couple aerodynamic companies have tested the windows up vs down aero argument. While the windows up is more aerodynamic, the difference is marginal. Most results show that once the cabin gets filled with air, it tends to just block out any new air from coming inside the cabin. I usually run the heater to the windshield to help get rid of some engine heat and the cabin doesn't get too hot with the windows down, even in hotter track days.

I run the heater with the center vents closed and the side vents pointed out the window -- love that they rotate fully.

 

[Woods247]

Some tracks won’t allow them to be down because they only go half way. Typically the rule is all the way down or all the way up. Most HPDE orgs and track safety crews require the front windows to be all the way down for HPDE so they can access the interior of the car easier in an emergency.

I prefer my rear windows down to help with buffeting over 110mph. It gets bad.

 

[cidsamuth]

My FiST is track dedicated, and I run a lot of HPDEs. I have never seen one require the rear windows down or up or even mention them. The only rule that is hard and fast is that windows must be down where there's an occupant, i.e. the driver's window is always down and the pax/front is down with a rider. I can't get a straight answer on whether the pax/front needs to be down with no rider, so I just put it down to avoid the trouble.

As for aero and CG, I'm betting any change is marginal, as mentioned.

 

[Woods247]

I track a lot too but mostly in the SE. Some tracks like AMP require the windows to be all the way down or all the way up. Others like Road Atlanta, Barber, CMS, CMP, Roebling and VIR don’t care. Orgs have their own rules and depending on their relationship with the track they can decide if windows are up/down (I’ve helped make these decisions for orgs during wet weather events lol). For example, I’m a Driving Club at Road Atlanta member and they could care less about anything as long as you pay up. Almost all of those guys drive windows up AC on except for those of us who have dedicated track cars. Every other HPDE org I’ve driven with wants them down for point byes and easier access for safety crews if the driver needs to be extracted. I see a lot moving to turn signals or hands now though.

Windows up absolutely helps the car accelerate quicker from around 115mph up. My interior is just too loud and hot for me even with a Coolshirt, helmet and earplugs. And if I’m upside down I’d like the option to get out without dealing with side window glass. Just sharing experience and definitely not trying to come across as a douche.

 

[kevinatfms]

Rear windows down to reduce buffeting. Its horrible on the Fiesta at speed.

Fronts are always down, even in the rain, as required by the event organizer.

 

[green_henry]

Yes, front windows down at Thunderhill (West) and Sears Point as well, but I've never had buffeting issues, which is what prompted the thread -- but don't think I've ever topped 90 mph at either. As much as I'd like to try the track in the rain, not willing to get the Recaros soaking wet.

 

[Woods247]

Buffeting is almost unbearable at 100mph and over with the rear up and front down. Those metal “rally vents” with holes don’t work at those speeds either. Gotta roll all four down.