Not sure if it will fit on the "regular" 991. The door looks a little more concave, I may be wrong.

 

Good stuff, thanks for doing some photoshop on that image.
I don't think Porsche has changed the shape of the doors on the 991 just for 1 model... it would be very, very costly to do so.
In the past they've used the same dye's moulds, tooling etc but did use a different light weight material for the doors etc of the GT3 Cup car... same dimensions though.

But I guess we'll find out soon enough if the mirrors fit... I see them in my future, soon!

 

I couldn't wait 12-13 months...I would jump off a cliff!!!
A right of passage- I can accept that!

I too was wondering about switching the tires too after the OEM are out. A big consensus is the MPSS but from what I gather its the C & Cs crew, nobody from C4s because the sizing is different right?

Ahhhhh the confusion....

 

+1 !!!

-I love them so much I might just get a set of black out wheels to match! (I have a guards red c4s with aerokit cup pkg on order) AHHHH so excited!!!

 

+1 Slippery Slope

-meds? You guys need to ask the Pharmacists!!! Any around?

...Ahem...how can I help you?

 

Question.....

Does the regular C4 (non S) have the same rear body width as the 4S?

 

It is my understanding that it does. The difference are more related to performance. Interior and exterior are the same.

The main differences are engine and breaks. Oh and the S models have PTV and PASM. I think thats it, but I could be wrong...

 

Kenshin, funny you have the same specs that I am dying to get the ***** to order. Guards Red w/ aerokit cup package!!
And oh yeah, it appears we have the same career

 

I have faith that Michelin will eventually come out with a closer (if not exact) size for the rear.

 

Yeah I hear ya, I'm actually looking to do it before I even take the car on the road for the 1st time... I just really, really hate Pirelli's.

The stock sizes are;
C2 = Front 8.5 x 19 235/40 ZR19 Rear 11 x 19 285/35 ZR 19
C2S = Front 8.5 x 20 245/35 ZR20 Rear 11 x 20 295/30 ZR 20

C4 = Front 8.5 x 19 235/40 ZR19 Rear 11 x 19 295/35 ZR 19
C4S = Front 8.5 x 20 245/35 ZR20 Rear 11 x 20 305/30 ZR 20

The Sport Techno (regardless of 991 model) = Front 9 x 20 245/35 ZR20 Rear 11.5 x 20 305/30 ZR20

OK now if you check on both the US and Canadian Porsche configurator and tech specs it will give you different sizes than listed above... it's wrong!
You actually have to go to the individual model info pages to get the right psecs, crazy I know but that's the way it is.

With the awd you can't just change tire sizes because outside of throwing the ECU, ABS, speedo etc, etc. out of whack (same on 2wd 991's) it will also destroy your awd system... while having killed your warranty at the same time!

Soooo you need to take into consideration the rotaions per mile, hight of the side wall, tire circumference, if a larger tires will still clears the inside suspension components, the outside fender etc. etc.

Now most assume that the rotations per mile of the front tire/wheel would be the same as in the back... makes total sence to me too... ehmmmm it's not!
Yep Porsche has engineered into their specs a way to ensure we wear out our tires regardless of driving style, PDCC etc.
The stock difference between the front and rear for a C4/S is 13 rotations per mile...

So when you start playing with different sizes you have to take into account all the above mentioned, this of course really narrows your choices...
There is however a factory variable of 4% that you can play within and not effect the above mentioned systems negatively.

Michelin PSS tires jump from 295's to 335's so if I want to go bigger than my stock 305's I HAVE to go with 265/35R20 front and 335/30R20 rear.
This gives a rotation per mile difference of 16 (instead of OEM 13), the side wall will be 10mm higher, the speedo will read 2,7% faster, stick out at the fender side by 15mm, inside towards the suspension by an extra 15mm, fill out the wheel well by 10mm... but it fits on an 11.5" rim.
In order to reduce some of these figures one can change the tire from "performance" pressure (OEM setting) to "comfort" as this will actually lower the rations per mile by decreasing the sidewall size/height at the contact patch... so from that point of view it will work.

However it is really pushing things both from a spec point of view as well esthetically..
So I'm leaning towards going with the Dunlop Sport Maxx GT which comes in 265/35R20 and 325/30R20.
It doesn't sound like much of a difference but with this set up there's only a 6mm sidewall increase and instead of 16 r.p.mile it's 10.. so 3 less than stock as apposed to 6 more than stock with the Michelin PSS.
Al the other figures are much closer to OEM specs as well.

The last part of this equasion is the size differences between tire manufactures... The 335/30 Michelin is only 10mm difference on paper from the 325 Dunlop... well actually the PSS tread width is 13" compared to the Dunlop's being 11.5... that's a whopping 1.5 inches on a tires which on paper are only 10mm apart... and that's just one example.

Sooo it does get complicated, but for me that's where the challenge lies... pushing the envelop while staying within the set parameters.
OK hooker and blow till the wheels come may sound better... but that brings with it a whole bunch of other problems hehehe (joking).

Hahahaha I'm sure this looooong answer is not what you where expecting... me neither!




Short answer... yes!

 

Great info Sid!!

 

Jeez Sid, you wrote all that! My head is spinning, and I have only had one martini!

Big dilemma with the Turbos as well. Attached is a picture of a 2009 OEM Spec'd tire size on 19 inch GT2 8.5 front wheels with stock shocks, but with CMS springs:



The OD's matched up with the correct OEM recommendations within the tolerances allowed. However, when driven at speed and conviction look what happens. Although when street driving there isn't an issue....its when physics take over and distort reality...less than 3 days on these tires...meaning 6 to 7 hours of hard track driving.

 

I'm addressing the issue though....

 

Yeah it's enough to make your head spin independent of alcohol intake!
But I'm in the middle of this so it actually helped writing it out like that (rather than copious amounts of categorized numbers...).

You sure did a number on those tires, damn!
You're lucky you didn't get a blow out with that type of damage.
Yep, perfect example that everything is connected to everything...looks like you've got a pretty good solution though, very nice!

Cheers.

 

Sid,

I must have missed something in all of that. I understand that you don't like the stock rubber. First question is why? Second question is why the bigger tires? I assume that there are true equivalent sized tires from Michelin and othere- arn't there? Why not go with those? Sorry if you answered this before, but I know next to zip about tire and that was, I hate to say it, fascinating and educational!
Thanks in advance