ZSA Motorsport

agreed both are important. i leave the factory defrost controls in there, and take out all the heat and ac elements but use the defogger for rainny days.
in my 986 grand am car, it ALL was removed, and so we used a Coolsuit helmet air blower with the hose pointed up into the vent area for the inside side of the windshield and feed air in from passenger naca duct. gives some air flow to interior but puts cool air onto the windshield and helps defogging.

M758

I ran a race at cal speedway in hail/driving rain. I run without a heater, but do duct the standard fresh air system to the inside of the windshield. I also added shaving cream to the inside of the glass. Kind of messy, but I had zero fogging.

Potomac-Greg

Rain-X.
On my face.
;-)

mrbill_fl

I'll try that! thanx (coated it then wipe it off?)

fwiw, my wiper starts lifting at 140mph, so I unbolted it for daytona..
-and I'm probably not going to run daytona in the wet...

M758

Yes smear on by hand and wipe off with paper towel to "polish" to clear.

At 125 mph rain-x and air flow worked better than the wiper on my 944 at event at Cal speedway.

Potomac-Greg

I used to use rainX on my street cars and it is amazing when "fresh." Even at highway speeds, it was better than wipers. The problem is that after the first big rain (and use of wipers) it transitions into a half-way zone where the wipers chatter really badly.

If I had the diligence to apply it regularly, I would use it on my street cars.

Cris Brady

+1 to the shaving cream. No heater/vents/fans in my 944. I use the gel type. Rub in, polish it off and no fogging.

Ritter v4.0

I'd rather have wipers and slicks in the wet than no wiper and rain tires (per below). But I'd also have RainX applied.
That said I'd have em all (and a hairdryer works great as defogger).

mclaudio

Old race car tip: hand soap as anti-fog.

Steve Watkins

Anti-fog trick - Spray brake cleaner on the inside and wipe off with clean towel/terry, your racing buddies will not believe you until they see it for themselves.

onefastviking

RainX and drive faster, the water will fly right off.

As for defog, Watkins trick works, as well as dishwashing soap but on and then not touched, just a light film tho.

racing916

You can Rain X the interior as well and it keeps the windshield from fogging up, same as shaving cream, or hand soap.