user 729082021

I'm in Colorado and considering making the switch from my Audi B8 S4 to a 997. I was curious about the hit in HP for the NA 911's. My understanding is that it's ~3%/1000', so up here that is easily a 15-20% loss in HP. My S4 is supercharged and I do have a smaller pulley and tune which I believe makes this altitude hit much, much less dramatic. I've never timed mine, but know similar S4's are low 4 seconds for 0-60 all day long.

Wondering if anyone has experience driving a 997 from low to high altitudes and what they noticed in power.

wportervt

I am in Denver and while I've never driven mine at sea level to compare I can tell you that I do feel like it is down in power when I'm driving up in the mountains (i.e. going over Vail Pass) compared to down here. With that said the 997 still has more than enough power for me up there and I don't feel like I'm missing out on anything!

Dennis C

I'm also in Colorado. I moved here from the midwest in 2010, so I went from less than 1,000 feet of elevation to about 8,000 feet of elevation. When I made the move, I had a 996 Carrera 4S and a Cayenne S. Both were normally aspirated. I currently have a 997 turbo and a supercharged Audi SQ5. I think you can easily see how I feel about this based on the cars that I bought!

The 996 C4S has less power than the 997 (rated at 320 HP). That being said, it was perfectly fine for normal driving. If you are somebody who really demands high performance, then you'll want forced induction at altitude.

I do miss the sound of the normally aspirated flat 6 engine, but the boost more than makes up for it.

user 729082021

Thanks for the replies. I'd really want a 997 C4S (I don't want a turbo for various reasons), and would be happy if it was even a little slower than my S4, but a lot slower would be sad.

Dennis C

I think that normally aspirated 997s are rated in the mid 4 second range from 0 - 60 at sea level. At elevation, it's going to be worse. That being said, Porsches don't really shine in drag races. They shine on a twisty mountain road.

user 729082021

Totally agree, though the S4 is no slouch and I'll pee myself before that thing lets go up my regular mountain drive.

wportervt

I just picked up a 2006 C4S this summer and having come from an '89 3.2 Carrera I never feel this car is lacking for power. Let me know if you want to meet up to take a spin someday and you can judge for yourself!

user 729082021

That's a real generous offer! I thought I'd just bother prestige when they get one in.

jennifer911

WE have a 997 C4 408 HP power kit engine (Carrera 4 GTS model) and often climb over California’s 10,000 foot Tioga pass when on holidays. Going from west to east to the height of the pass the road grades are much like Colorado in that the grade is about 4%. On the other hand, traveling from east to west the road climbs steep as hell up to the top of the pass. This is where we notice the power peak ebb away somewhat. However, that being said there is still plenty left and we have never had trouble passing Ma and Pa Kettle and others in lumbering camper trucks a dozen at a stretch.

One thing about driving at high altitude, is the engine will not ping even on the crummy California gas. This returns some lost engine power, because when pushing the engine hard the knock sensors are not busy retarding the timing.

Here in my corner of Canada we don’t have much and live in mud huts, but we do have exceptionally fine premium 94 octane gasoline made from only the best dead dinosaurs, without any whiff of corny stuff. Elegantly dressed sommeliers carefully pour the nectar into the gas tank from beautiful cut crystal carafes at our gas stations by the way.

fc3

I owned a B8 S4 for several years, modified with APR pulley and tune. I've had a 997.2 C4S for about a year now and don't feel I am lacking anything in the power department in comparison.

Hula

Another check-in from Denver. Picked up a 997.2 C4S a couple of weeks ago. It's replacing my 955TT as my Denver to Vail ski lift. I was thundering up Mount Evans today. Highest paved road in North America at 14,130 feet. Also tried to break Buddy Lazier's record up the Central City Parkway. I'll need more talent before I'll need more power. A lot more talent.

user 729082021

Where are you located? What altitude?

user 729082021

Ha! In colorado the only swill we can get is 91.

fc3

Louisville CO, just a hair over 5280

Happy to let you try a side by side test w/your B8 sometime if you want

user 729082021

I have an appointment on thursday with a local dealer to drive a 996 C4S on Thursday, real curious what the butt dyno will register with that. Those 996's sure are the red-headed step children of the 911's, but some are available at a steal. I know the 997 would be a bit more powerful, so this will be a decent benchmark.