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!
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
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
mmcd87 said:
Epic car OP. Is there a reason you went to Autofarm for the engine build over Hartech or similar? Are they local to you?
Autofarm built my last engine (which is now owned by Jethro from Evo) which was faultless so it was only sensible they built this one for me. Their work is exceptionaly good and they are engine builders rather than reconditioners meaning the support around them is far more geared towards the bespoke than the same again. Whilst they are very well known for their air-cooled work there doesn't seem to be the same awareness of them in water cooler circles, I would strongly recommend anyone considering a water cooled build speak to them as I and many others have found their approach and ability to be head and shoulders above a lot of other Porsche specialists. 
Krikkit said:
Haven't looked at this in a couple of months, what a great couple of pages!
New wheels (outside and in) both look great, good choices.
I love the carbon-strenthened parts, is it something that needs special gear? (I'm thinking the undertray more than the uprights) I've often encountered plastic parts which are vulnerable underneath the car and could do with reinforcing, but never know quite how to do it. I presume you wet-lay the twill and brush with resin, then dry with a heat gun?
The new wheels (external) have grown on me a lot over the past few weeks. I'm also massively impressed with how the AD08 tyre does in the wet it is so much better than an R888. New wheels (outside and in) both look great, good choices.
I love the carbon-strenthened parts, is it something that needs special gear? (I'm thinking the undertray more than the uprights) I've often encountered plastic parts which are vulnerable underneath the car and could do with reinforcing, but never know quite how to do it. I presume you wet-lay the twill and brush with resin, then dry with a heat gun?
There are no special tools required to do the trays. Just make sure they are well keyed with an 80 grit or similar paper to make sure there is a good surface for the adhesive to key to, you can then wet lay onto it accordingly. It's even easier to use pre-preg to do it, with a thin bonding layer between the first layer and the tray but you need a big tent or oven to set it which I unfortunately don't have.
CornedBeef said:
Hows the Porsche doing PPBB? I've got a vested interested after this pushed me to buy mine!
I may have made a few more upgrades 
I'll report in full shortly but for the most part I have just continued to pile miles onto it and enjoy it. It continues to be an incredible bit of kit!DELETED: Comment made by a member who's account has been deleted.
I did have FVD manifolds on mine but recently changed them for cheapy Chinese ones and noticed absolutely no difference in performance, which is not surprising as the Chinese ones are a good copy of the FVD ones. The Chinese ones are so cheap they can be a yearly service item! The silencers on mine are a copy of the D911 style ones (with no flexi in them like the Dansk have) done by a local exhaust manufacturer. They are fairly low loss and probably a bit OTT for most people but i don't find them bad. They've been serviced once by chopping the ends off and repacking them and are still goings strong. There are a lot of people using the D911 ones and they don't seem to be bad at all, certainly not for the money. I don't have cats on mine as I run quite lean AFR at part throttle high RPM cruise and this would damage most cats pretty quickly, to give you some idea my engine runs at Lambda 1-1.1 at 125mph cruise. Mine has a set of simple decat pipes (no X-over or similar). Replacing the standard cats with lower loss cats or removing them all together does seem to give quite a bump in performance.
Accelebrate said:
Do they howl like my R888Rs* do?
They are a lot better than 888s for road noise. They are still noisey compared to a more all round tyre but they don't howl like 888s do, just make a low "a wheel bearing has failed" rumble - Also surprisingly good at the moment, I guess a softer compound isn't a terrible thing in cooler weather.
DELETED: Comment made by a member who's account has been deleted.
If you remove the Cats then it will fail the MOT, no two ways about it. It is also probably not long until cats go the way of DPFs and it becomes illegal to run without them. It's no problem for me to do an MOT prep each year but I appreciate not everyone is lucky enough to have a ramp etc. available to them so realistically a set of very good quality 200 cell cats (100s will be borderline for MOT) is the way to go as they'll be much less of a restriction than the OE cats and can stay on the car. I'll try - I intend to carry on running this car until we're not allowed to anymore!
Sorry for the lack of update chaps! As a few have mentioned above I have been crazy busy recently (as it always is at this time of year) including spending some time in Australia to sort out an F1, which ended up on the news:
And I've done the very sensible thing of buying a Peugeot to do a spot of racing in (I'll do a thread on this later once I've got it up to my spec):
But back to the most important thing, the Porsche. Well.... drumroll please..... I have done absolutely nothing to it aside from drive it, It's due a set of rears shortly although I may refit the standard wheels for winter as they have relatively fresh PS2 on them although it has been amazingly good on the AD08s even with rain and standing water. The rear drive shafts/lobros are coming up to life but there is a set of rebuilt shafts in the workshop ready to go on at service which is only 2K miles or so off now, I should cover that before Xmas so during the Xmas break I will get it up on the ramp and swap shafts/do a minor service (it only needs engine oil, oil filter, fuel filters and a wipe over this time around).
Despite the fact it has been very cold recently the tiny Super B battery doesn't seem fussed at all and the car continues to crank way quicker than it ever did on an LA battery, the little Lithiums are amazing really as the battery is only 3KG!
I'm considering putting a bigger tank in it to the point that the CAD is already done and the bag quoted on but it is going to be quite a big job as it involves dropping the standard tank and modifying the front bulkhead. I'm not really sure it is necessary but it would give it around 130L of fuel capacity and delete the second filler which would be a nice touch, it would also provide some usable space in the front for stores..... I'll ponder this over Xmas and decide
Expect a bigger and more detailed update next month including my decision on the fuel cell
And I've done the very sensible thing of buying a Peugeot to do a spot of racing in (I'll do a thread on this later once I've got it up to my spec):
But back to the most important thing, the Porsche. Well.... drumroll please..... I have done absolutely nothing to it aside from drive it, It's due a set of rears shortly although I may refit the standard wheels for winter as they have relatively fresh PS2 on them although it has been amazingly good on the AD08s even with rain and standing water. The rear drive shafts/lobros are coming up to life but there is a set of rebuilt shafts in the workshop ready to go on at service which is only 2K miles or so off now, I should cover that before Xmas so during the Xmas break I will get it up on the ramp and swap shafts/do a minor service (it only needs engine oil, oil filter, fuel filters and a wipe over this time around).
Despite the fact it has been very cold recently the tiny Super B battery doesn't seem fussed at all and the car continues to crank way quicker than it ever did on an LA battery, the little Lithiums are amazing really as the battery is only 3KG!
I'm considering putting a bigger tank in it to the point that the CAD is already done and the bag quoted on but it is going to be quite a big job as it involves dropping the standard tank and modifying the front bulkhead. I'm not really sure it is necessary but it would give it around 130L of fuel capacity and delete the second filler which would be a nice touch, it would also provide some usable space in the front for stores..... I'll ponder this over Xmas and decide
Expect a bigger and more detailed update next month including my decision on the fuel cell
RM said:
Ah! So you were the creator of my second favourite 996 (Jethro's arena red one), as well as my favourite. Great thread. It would be interesting to learn more about your old 996 too though.
It would appear so My old one was a bit rough around the edges (much like my current one! ) but mechanically it was very good with a 3.4L Autofarm motor (there was no 3.7 at the time), Bilstein PSS9s and a fruity exhaust along with the GT3 rep seats. I also did a shed load of miles in this car putting 40K on it over the course of a year. It was very good but a C2 wasn't what I wanted by the end of the 40K miles and I went off to buy a Mk1 GT3 instead. However a couple of test drives and a weekend with one showed that whilst it was an extremely capable car in the right conditions those conditions weren't that common and actually as a road car it was quite compromised which made me think about a narrow body C4 as that combined the narrow body that I really like with 4WD........ and here we are today Gassing Station | Readers' Cars | Top of Page | What's New | My Stuff