Edgy01

Did you ever notice that the rear grill on the 997 opens to the rear, while those slots on the 996 are open to the front. OCBen, and others,--what's going on with that? When the tail is up, what's going on differently now on the 997 from the 996?

yemenmocha

One is functional, the other is just bling?

Gaspasser19

I'm not sure I understand what you mean. The louvers on my 996 open to the back.

ADias

OCBen is correct. What I read (somewhere) was that in the lean days of the 996 development the designers almost did not get an OK for a moveable spoiler and designed the slats facing forward to increase drag. When they got the OK for the moveable spoiler they still kept the design. The 997 is the correct one.

WCE

996 design lets WAY too much water in - 997 improved on this problem!

Edgy01

What I think you'll find is that on the 996 the louvers are designed to allow air to be rammed in from the direction of travel, while on the 997 the louvers, opening to the rear, allow the air to be PULLED out of the engine area to enter the slipstream, rather than to upset it. This may be, as stated earlier, part of their windtunnel testing to clean up that area of the car. It's this sort of subtle engineering work that shows the level of detail going on with these things (like the fact that the tails go up higher on the cabriolet models than the coupes).

OCBen

I'm not so sure that's what's going on here, Dan.

True, it's a low pressure zone as the airstream goes over the louvered panel. Now if the pressure inside the engine bay were greater than the pressure over the panel, yes, air would flow out the louvers.

But, as you know, the engine bay is fully exposed underneath to the airstream flowing underneath the car. This large opening likely produces a lower pressure zone than the pressure zone over the louvers, and will thus cause air to be drawn inside the engine bay through the louver openings because of this pressure differential.

This is another reason why covering up the engine bay underneath with aftermarket gadgets will definitely upset the balance of thermal management of the engine.

Ucube

I think I'll have to go check out a 996 to recall what the rear louvers look like.

Rob in WA

I have a really hard time believing that. Especially after the face lift in MY02.

I always figured it was to increase airflow to the engine. Then in 997 they determined it wasn't needed.

Coochas

I never noticed the difference....I guess I'm not 'vane' enough.

ADias

Page 258 Leffingwell's Porsche Sixty Years: "... We were not allowed to even think of a moving spoiler..." Pinky Lai remembered. ... "One day in the wind tunnel, we cut one of the grille louver panels and put it on backward. Suddenly the aerodynamic changed".

OCBen

Wow, they were doing this by trial and error?

They should have hired an aerodynamicist who could have predicted precisely how it would work and why, and saved themselves a lot of time and frustration and money in the long run. Maybe they couldn't afford to hire one at the time. Doubtful. Or maybe they were just too stubborn to admit they needed a specialist here. I'm sure they have one now, or at least a consultant on retainer.

Rob in WA

I don't doubt that.

I just can't see PAG leaving the louvers faciing forward to increase drag unlesss there is some other reason behind it or the drag is needed w/the spoiler up. As I said, especially after MY02.

ADias

Those were lean years for PAG. I can very well imagine casts being made for a fixed cover and adapted to a moveable spoiler. The 996FL major change was the headlights succumbing to customer criticism. IMO a bad decision, as the drooped headlight design is a bad fix - at least the former were original.

Rob in WA

You know this Tony, it wasn't just the headlights that changed in MY02.

A few other changes:

- 20 more hp, 3.4l vs 3.6l
- more torque at a lower rpm (thanks to VarioCam Plus)
- Better aerodynamics (20% less front lift and 40% less rear lift)
- 20% stiffer chassis
- added a glovebox
- improved oiling
- improved engine cooling
- improved suspension
- revised exhaust

Why not flip the louvers on the spoiler around if they are unnessarily increasing drag.

It just doesn't make sense.