Pazzo009

Hi everyone,

I recently have a become a Porsche owner. I have a F10 M5 and needed something more visceral so I got a 991S coupe with the Aero kit pkg. Now I have the best of both worlds. Heres my concern. It could be me...But I had the car on brand new pavement at hit around 140mph. The car felt floaty and light at that speed. I am used to my M at those speeds it feel glued and comfortable. I cannot see despite the 991 lightweight it feeling this way at speed. I then researched tire pressures. The car was showing 34 front, and 44 rears (20's). I was the only person in the car and it was 63 degree day. I have lowered my PSI to 32 front, and 35 rear cold.

What is your take on this? Was it tire pressure you think? I will not be able to test it till next week.

kosmo

youre experiencing lift. If you intend to drive at those speeds some mods will be in order. Try getting dive planes, and possibly the grill/vent from the upcoming Gt3.
The M5 is a heavy beast.

Lastly I've noticed the lift sensation in the 991 vs the 997 to be Electic steering in the former.

Pazzo009

Thank you. The car has the Aerokit, but it does not have the Sport Suspension thus lowering it. I do not plan on lowering it either. I can't understand how a car built for speed would not have something in place to counteract that. The car has a lip, so I do not plan on putting a different lower lip on. So then all I can think is putting Canards (I guess dive planes?) on the sides of the front bumper which could add extra downforce and look cool.

So you don't think it had to due with air pressure?

Team Plutonium

To some degree it is normal, I felt that too coming from an M3, but you might wanna check your alignment, if your rear wheels are slightly toed-in the floaty effect becomes much more noticeable. In any case, some good coilovers will fix that in no time.

Pazzo009

Alignment? Okay, but I just picked up the car Tuesday night brand new. I do not want to add any suspension mods because I am leasing the car for 27 months. The only option the car is equipped with as far as beneficial in this matter would be the PDCC.

pyramid

In curiosity, what was the gas tank level?
May want to try again at full tank.

Pazzo009

3/8's

LexVan

Give your greasy tires a few hundred miles to scrub off the mold release. That will help a little too.

kosmo

if all else fails put a few bags of concrete mix in the frunk!

Pazzo009

Lol...perhaps I can attach the GT3RS wing to the front of the car?

Team Plutonium

We've seen alignments being off with brand new cars, so it wouldn't eb that unusual. I'd start with that.

ny991

Two days to 140mph. Not bad!

Pazzo009

Lol... Yeah I don't play "Just the tip" However, I'm not pushing her in the turns yet. I live in upstate NY too, so road temps have not been optimal.

John 996 TT Cab

In Germany last year I drove a 991S Coupe as fast as 183mph (295kph). Rental car and did not have any additional spoilers over dead stock. Didn't observe any instability. Earlier in 2012 I drove a rental 991 Cab as fast as 164 mph with top down but windows and windscreen up. No instability at all.

Bacura

I had a 997.2 and am waiting for my 991 very shortly. I generally don't travel at 140 mph but the car is designed for that. It is very disturbing that you found it floaty. That would be unacceptable. The last 2 years the 991 has won the drivers car award from motor trend. Randy Probst drove the crap out of them and the word "floaty" was never brought up. Either your car is defective or your driving is "off". I live not too far in Toronto. Where in gods name do you drive that fast? My licence and car would both be gone. My first 911 was a 1988 carrera 3.2. I had that car at 151 mph and have never driven that fast ever again. Even that 1988 felt solid and not floaty. Something is wrong. And I don't think it's your tire pressures. I run 1-2 psi higher than factory.