Knackered old Porsche with loads of miles - 996 content
Discussion
Well it's about back together after this unplanned bit of down time. Just waiting on some discs which should be here in the morning - which is good because it has to go and earn its keep on Thursday!
Carbon laminated floor is on and far more stable than it ever was as a bit of plastic:
Nut and bolting it in place of plastic hope is a good mod!
All the Lobros have been stripped, cleaned and crack tested, then rebuilt with fresh CV2
New front caliper hard lines as these get a bit of a kicking due to their location:
Corners back on just waiting for discs:
And the engine bay has had a wipe over:
Along with that it has had new TREs, I've changed the Powerflex gearbox mounting bush for the new upspec'd version (which they kindly supplied FOC, excellent customer service), rebuilt the front outer CVs and finally got around to fitting an external power connector to charge the battery if it's ever needed.
Time to pile some miles on it now!
Carbon laminated floor is on and far more stable than it ever was as a bit of plastic:
Nut and bolting it in place of plastic hope is a good mod!
All the Lobros have been stripped, cleaned and crack tested, then rebuilt with fresh CV2
New front caliper hard lines as these get a bit of a kicking due to their location:
Corners back on just waiting for discs:
And the engine bay has had a wipe over:
Along with that it has had new TREs, I've changed the Powerflex gearbox mounting bush for the new upspec'd version (which they kindly supplied FOC, excellent customer service), rebuilt the front outer CVs and finally got around to fitting an external power connector to charge the battery if it's ever needed.
Time to pile some miles on it now!
leglessAlex said:
Christ, 5kg per corner! That must make a massive difference to how it drives?
Yes I've had to make some changes to damper settings to account for the reduced mass, the amount of kinetic energy in the unsprung corner is now significantly less even though the wheel/tyre package is larger. The rears are 9.95KG and the fronts are 7.9KG vs 14.7KG and 12.8KG (including spacer, which is probably a bit unfair counting it but it was part of the wheel as I needed them to get the offsets required). Totals up at 19.3KG! The dampers are clearly having a much better time of things than they were. It always amazes me how wheel weight affects things.
There is now very little else to do on the car for the foreseeable aside from drive it. However I am working on new front discs as I believe there are some gains to be had here. I was originally going to go for an off the shelf floating setup but all of them are based around a motorsport bobbin type design which is fine on a race car but can be noisy on a road car, there are also much better ways to do it these days - every F1 team has gone to spline drive discs now which provide the float in the spline rather than via a number of individual bobbins, it's lighter, has less component count, fewer failure points and reduces vibration over a bobbin setup. This is what I'm in the process of putting together at the moment:
You can see how the entire disc floats within the bell with a limit plate on the rear face. Float is then determined by the clearances in the bell and the there is no stuck or misaligned bobbin failure mode possible. It also does away with needing a number of lock nuts on the disc/bell assembly and the load is passed through the disc in a radial fashion rather than the load being carried by a number of cap heads in shear, this also means the failure mode of the disc cracking around the mounting holes is removed as there are no mounting holes. As they will be 350mm X 34mm 997 Turbo size they'll also fit all the 997 Turbos and be a good upgrade for 996 Turbo, C4S etc. replacement discs are also way cheaper than Alcon, PFC etc. as no need for new bobbins or fasteners and there are less machining operations on the disc itself, which is good if you do the sort of miles I do!
Considering the astounding amount of work and attention that's gone into your car it's surprising you waited so long to switch to (much!) lighter wheels.
Did you not think the weight saving was going to be as significant as 20kg, or was there some other reason why you never changed them before now? It would seem to my layman's understanding to be one of the first places to seek a bit of weight reduction and damping improvement, given what are always told about unsprung weight.
Did you not think the weight saving was going to be as significant as 20kg, or was there some other reason why you never changed them before now? It would seem to my layman's understanding to be one of the first places to seek a bit of weight reduction and damping improvement, given what are always told about unsprung weight.
loudlashadjuster said:
Considering the astounding amount of work and attention that's gone into your car it's surprising you waited so long to switch to (much!) lighter wheels.
Did you not think the weight saving was going to be as significant as 20kg, or was there some other reason why you never changed them before now? It would seem to my layman's understanding to be one of the first places to seek a bit of weight reduction and damping improvement, given what are always told about unsprung weight.
Because I want it to look as standard as possible, its not quite so stealth on aftermarket wheels! I'm now investigating if I can have some spun alluminiun outers made for the original GT3 centres and use these with a Ti or similar spacer to get as close to these wheel weights as possible. The steering wheel is a similar thing, it proved the concept but I'm now looking at how to machine a spacer for the original wheel (which is off being retrimmed) to put it in the same position. Did you not think the weight saving was going to be as significant as 20kg, or was there some other reason why you never changed them before now? It would seem to my layman's understanding to be one of the first places to seek a bit of weight reduction and damping improvement, given what are always told about unsprung weight.
Subtle is a win here really so many things on the car are the least attention grabbing option, calipers in original silver are a good example. At a glance it looks like a standard old 996
poppopbangbang said:
Chris Stott said:
11's on the rear 
What are the sizes and off sets of the new wheels?
They are 18's. 8.5" fronts with an ET40 offset and a 235 profile tyre, 11" and ET63 on the rear with a 295 profile tyre. What are the sizes and off sets of the new wheels?
If you fancied making two spacers I'd be happy to take the second off your hands for a reasonable contribution- from Carnewal they are £much, so whilst tempted I have never got one. That of course is assuming that a PPBB version would not be £muchplus, of course.
Is the choice of 997 air box for performance or aesthetic reasons?
Is the choice of 997 air box for performance or aesthetic reasons?
Dammit said:
If you fancied making two spacers I'd be happy to take the second off your hands for a reasonable contribution- from Carnewal they are £much, so whilst tempted I have never got one. That of course is assuming that a PPBB version would not be £muchplus, of course.
Is the choice of 997 air box for performance or aesthetic reasons?
I will see about doing a run, I think the Carnewal ones are cast hence why they are so much money (trying to recoup tooling costs etc. for a casting over a small run is pretty painful). I was thinking of doing a billet item with the splines wire eroded as whilst this is more per item than a casting there is no tooling cost associated with it so overall it is much less costly if you're only making a handful of them. Once trimmed in leather they should look really OEM. Is the choice of 997 air box for performance or aesthetic reasons?
The 997 airbox is meant to flow a little more than the 996 one, it probably does but the difference is small. It was one of those things I wanted to do because the same airbox was used on the 3.8 so remove it as a possible loss by using the bit from the OEM application of the same/greater capacity. It is way more aesthetically pleasing in the bay too
poppopbangbang said:
Subtle is a win here really so many things on the car are the least attention grabbing option, calipers in original silver are a good example. At a glance it looks like a standard old 996
Fair point. Not sure it would make much difference at 180kph though. In the dark. Rigged for 'silent running' 
Dammit said:
If you fancied making two spacers I'd be happy to take the second off your hands for a reasonable contribution- from Carnewal they are £much, so whilst tempted I have never got one. That of course is assuming that a PPBB version would not be £muchplus, of course.
Another one here interested in a steering wheel spacer. I have 10.5 inch rears on my 996 nb. I have replaced my 2 piece wheels with 18 inch 997 wheels and the weight saving is immense.
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