just wondering if anyone can tell me the specs on front downforce of a 1999 996 c2?
my car handles fine, but at higher speeds the car doesnt feel 100% planted, could this be another issue??
again, its not terribly obvious, but enough to wonder if an aftermarket bumper with better downforce design is worth it.


also, the tires have less than 1000km on them (Michelin super sports) and all the parts under the car are in great condition, very little wear except the stab bar bushings.

 

Akshun,
those of us that have changed the suspension to a lowered more sporty/firm stance have found that the "floaty feeling" you mention has completely cured.
I suppose that an aero package or aggressive lower front lid under the bumper may work to some extent, but the suspension is really the trick.
Pete

 

Also looks like an aftermarket front bumper and side skirts on the car. Maybe add ons for the bumper...but great Pete's think alike. Suspension is where the truth is.

 

Stock, it doesn't have enough downforce to negate lift. 996.2 restyle cut the amount of lift in half from the 996.1. BTW, it was not just the front bumper that cut it down, the rear quarter panels are actually slight different on the 996.2 as well as the lower rear bumper contour helped reduce lift significantly. Consider investing in a 996.1 GT3/aerokit front bumper, side skirts and rear decklid/wing...or just sell it and upgrade to another car (996.2, aerokit car or GT3).

 

I would agree with Pete...and Pete for that matter on the suspension front, but like...well...Pete mentioned, it looks like you've added front and side downforce, but no added downforce to the rear(at least from the angle of your photo). Now I don't know at what kind of speed you're experiencing this "not planted" feeling, or if its front end lift or the back end is dancing around(perhaps you could expand on this), but without providing some compensating downforce to the rear end you are throwing off the overall aerodynamic balance that Porsche engineers worked a lot of hours in the wind tunnel to create. Just because there is a lot of weight hanging off the back end, doesn't mean that things won't get a bit hairy at 120+ when the car is biased towards front downforce. Just something to consider in the discussion.

 

Does the 996.2 require a suspension upgrade, to improve downforce? or does the new front bumper and rear enough?

 

I didn't do any aero changes on my 99' C2, but did change out the stock suspension to the US MO3O which did not lower my Porsche, but did improve the 'floatiness' mentioned.

 

I have a Guards Red 996.1 Taco wing i could sell. This wing negates lift.
See link in my signature. I have upgraded to a full CUP wing.

 

+996

Change the suspension and the difference will be huge.

 

-Maybe I have not spent enough time at speed, but never noticed any floating of mine.....

 

Agreed. Mine was rock solid and planted, even before I added the aero kit.

 

I'm also looking into suspension lowering
What is the least expensive
Version ?

 

I put H&R sport springs on my '00 C2 and these lowered it by about 1" all around. This is the cheapest route, unless you want to go with coilovers.

DO

 

Ok, so far great responses and much appreciated info.
I originally said "planted" and i guess my wording was a little off, i should have said "floating" feel in the front end at highway speeds(120km and up).
it is mild, but still, i m not getting the rock solid feel that some have mentioned.

My suspension is factory original and lm guessing that after 14 years it wont perform the same as it once did. I am not the original owner, so i wouldnt know.
I have considered the ROW M030 suspension, which has been advertised for really good prices, or the Bilstein Pss10's.
I have heard good things about both set-ups, but i like the fact that Bilsteins are adjustable as i have 19" wheels and i really dont want to lower the car and have it rub against the tires.
im adding some new bushings to the stabilizer bars this weekend and hoping i feel some improvement.

 

Akshun,
From the picture in your avatar, I can 100% confirm that the front spoiler lips and side skirts are from TechArt and were an add-on by a previous owner when the car was relatively new (Tech Art has not offered these pieces for quite some time). I can confirm this because I have those same exact pieces on my '99 coupe.
The recommendations from above to get a rear spoiler are also spot on correct. You have a LOT of front end down force now, which is NOT being compensated in the rear so the car is "floaty" at high speeds.

Sadly, the offer made above to sell you a Taco spoiler will prove incorrect. Not because there is anything wrong with the advice or the spoiler or the individual who offered it. The factory Taco spoiler will absolutely NOT work on a cabriolet. Porsche never offered it because the metal convertible top "boot" rises up and back when cycled, and would contact the spoiler very hard.

Porsche offered a 'Basket Handle" rear spoiler for cabriolet owners who wanted an aero kit. It was lower and thinner than the Taco spoiler.

Yes, the suspension ideas offered will also help plant your car even more, but they probably won't give you enough clearance for the 19" wheels. You will likely have to pick one or the other.

Your real issue is needing a proper rear spoiler, or removing the front spoiler lips.