Should I have specced PASM on my 991?
Should I have specced PASM on my 991?
Author
Discussion

Ady128

Original Poster:

537 posts

173 months

Tuesday 10th July 2012
quotequote all
I have been driving my 1st 911 for 3 weeks now; a new 991 Cab. Having previously owned 2 Boxsters I find the 991 feels like a big lump and not as nimble. It's certainly quicker and handles reasonably well but I wonder if I should have opted for PASM and also wonder could I have it fitted by my OPC? And qould it cost a fortune?

SFO

5,190 posts

213 months

Tuesday 10th July 2012
quotequote all
991 Cab is about 120 kilos heavier than a 981, so will be less nimble. Clearly the rear engine also produces different driving dynamics.

PASM will not necessarily make it more nimble, but it will cost a fortune to retrofit, if it's even possible.

Perhaps put on 5mm spacers?

535dBoy

474 posts

228 months

Tuesday 10th July 2012
quotequote all
I'm getting confused between PASM and PDCC on the 911

What is the difference ?

When I specced a 911s cab on the configurator (to £123k!) I saw PDCC not PASM

Ady128

Original Poster:

537 posts

173 months

Tuesday 10th July 2012
quotequote all
It's standard on the S.

535dBoy

474 posts

228 months

Tuesday 10th July 2012
quotequote all
Ady128 said:
It's standard on the S.
I see

So what does PDCC do over PASM then!?

Edited by 535dBoy on Tuesday 10th July 15:02

Ady128

Original Poster:

537 posts

173 months

Tuesday 10th July 2012
quotequote all
I think it makes you corner flat rather than leaning. I don't think I'd have gone for that though. I think Porsches should handle ok as they are.

SFO

5,190 posts

213 months

Tuesday 10th July 2012
quotequote all
Ady128 said:
I think it makes you corner flat rather than leaning. I don't think I'd have gone for that though. I think Porsches should handle ok as they are.
you can only spec PDCC on the S

BnB

1,059 posts

205 months

Tuesday 10th July 2012
quotequote all
No you can't cheaply retrofit PASM through OPC, though you could go aftermarket.

If comfort as well as mass is part of your beef, then, before you go to those lengths I strongly suggest you take the simple step of setting your tyres to comfort pressures (or just letting out some air). And if that doesn't work the easiest and most effective solution (which will also improve handling and NVH) is to switch to some Michelin Pilot Super Sports tyres - quieter, smoother and grippier. You can't get N-rated yet but you don't need N-rated to meet the new car warranty. Don't let anyone on here tell you otherwise. My OPC fitted mine.

nickfrog

25,405 posts

247 months

Tuesday 10th July 2012
quotequote all
The issue is structural really. A low polar moment of inertia car like the Boxster will always feel more "nimble" than a higher polar moment of inertia like the 911, where a big part of the weight is still outside the space between the axles.

A little work on toe and camber can help up to a point but adaptive dampers or reduced roll won't make much difference.

GrahamSaunders

211 posts

197 months

Tuesday 10th July 2012
quotequote all
Agree with comment above. You could get the GEO tweaked more towards a track/fast road setup and that will improve initial turn-in response. I have a 997 GT3 and the set-up makes a huge different to the handling and the feel. It shouldn't cost much to get it done or affect warranty etc.

Moosh

1,122 posts

251 months

Tuesday 10th July 2012
quotequote all
I would drive it for a while before you spend any cash. It can take a little while to get use to the rear engine weight over the back axle and does take a different style of driving.

Ady128

Original Poster:

537 posts

173 months

Tuesday 10th July 2012
quotequote all
Yes, good idea. I've yet to have my Silverstone course.

Asterix

24,438 posts

258 months

Tuesday 10th July 2012
quotequote all
Not surprised it feels a bit lumpen after a Boxster - as said, get the geo sorted and make sure it has appropriate rubber at the right TPs - that will help a bit.

BnB

1,059 posts

205 months

Tuesday 10th July 2012
quotequote all
Ady128 said:
Yes, good idea. I've yet to have my Silverstone course.
You will learn a great deal about weight transfer on this course and come away better equipped to make the most of your wonderful car. Especially, trail braking into a corner with the correct delicacy and smoothness to load the front wheels for optimum turn-in, followed by a smooth, progressive throttle from the apex. See how I used the word "smooth" twice there. Others here will agree this is the essence.

nickfrog

25,405 posts

247 months

Tuesday 10th July 2012
quotequote all
Yep, the slower it feels, the quicker it is usually.

MaxAndRuby

6,792 posts

262 months

Wednesday 11th July 2012
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Moosh said:
I would drive it for a while before you spend any cash. It can take a little while to get use to the rear engine weight over the back axle and does take a different style of driving.
yes

Tony 1234

3,465 posts

257 months

Wednesday 11th July 2012
quotequote all
Moosh said:
I would drive it for a while before you spend any cash. It can take a little while to get use to the rear engine weight over the back axle and does take a different style of driving.
That's just the point, a 991S doesn't feel like a rear engine car at all smile drive a 997 fast into a corner and it want's to go straight on unlike a 991


Edited by Tony 1234 on Wednesday 11th July 14:03

anonymous-user

84 months

Wednesday 11th July 2012
quotequote all
nickfrog said:
The issue is structural really. A low polar moment of inertia car like the Boxster will always feel more "nimble" than a higher polar moment of inertia like the 911, where a big part of the weight is still outside the space between the axles.

A little work on toe and camber can help up to a point but adaptive dampers or reduced roll won't make much difference.
This is a good summary of the fundamental difference between these two chassis. Less weight and lower polar moment of inertia = more nimble