Knackered old Porsche with loads of miles - 996 content

[Slippydiff]

Excellent progress

"But tomorrow morning is a setup morning and it's equal height all the way around so the damper lengths are good, it just wants a bit more spring preload as these are way softer than the previous options!"

Must be getting older ...
May I ask what rates you're running now ? I'm currently in the process of having some dampers built and I'm trying to use the softest rates possible.

I ran these with 65 N/mm rears and 30 N/mm fronts. They were hugely impressive, but I'd like to go softer still ...

Pre rebuild for road use ... :







Did you go for the wider option 11" and 8.5" Alleggeritas ?

[poppopbangbang]

Slippydiff said:

Excellent progress


Must be getting older ...
May I ask what rates you're running now ? I'm currently in the process of having some dampers built and I'm trying to use the softest rates possible.

I ran these with 65 N/mm rears and 30 N/mm fronts. They were hugely impressive, but I'd like to go softer still ...

I'm definitely getting older Lovely dampers by the way! I'm now at 80N/mm rear and 40N/mm front. Down from 100N/mm rear and 50N/mm front. I would also like to try softer and have some 35/70's as option but I think I'm approaching the limit for the R&T damper at that point as they have a lot less oil capacity in them vs a remote res option.

Slippydiff said:

Did you go for the wider option 11" and 8.5" Alleggeritas ?

I did yes, are you on the same? If so what tyre size are you running? 285 rears are getting hard to find now!

[Mallone]

poppopbangbang said:

Slippydiff said:

Excellent progress


Must be getting older ...
May I ask what rates you're running now ? I'm currently in the process of having some dampers built and I'm trying to use the softest rates possible.

I ran these with 65 N/mm rears and 30 N/mm fronts. They were hugely impressive, but I'd like to go softer still ...

I'm definitely getting older Lovely dampers by the way! I'm now at 80N/mm rear and 40N/mm front. Down from 100N/mm rear and 50N/mm front. I would also like to try softer and have some 35/70's as option but I think I'm approaching the limit for the R&T damper at that point as they have a lot less oil capacity in them vs a remote res option.

Useful info. Could either of you make any recommendations for spring suppliers? Currently weighing up options for a set of 996 GT3 Bilstein dampers that are going to get a rebuild and would be nice to have alternatives to the Porsche OEM springs that are looking quite pricey...

[poppopbangbang]

Mallone said:

Useful info. Could either of you make any recommendations for spring suppliers? Currently weighing up options for a set of 996 GT3 Bilstein dampers that are going to get a rebuild and would be nice to have alternatives to the Porsche OEM springs that are looking quite pricey...

Order straight out the Eibach motorsport catalogue (which can be downloaded here https://eibach.com/us/file/710-Complete+Motorsport... whilst Eibach UK in Leicester don't sell direct to public, eibachshop.co.uk (part of POTN) will happily take the order and it will be shipped from Leicester. Their stock is good so there isn't much you can't get next day.

Note you'll need to know the diameter, free length and rate that you want. Free length and diameter you can work out from what you currently have with a steel rule and a pair of calipers (or very likely Google!), I'm afraid I've never seen standard GT3 suspension to help with that one

[Slippydiff]

poppopbangbang said:

Mallone said:

Useful info. Could either of you make any recommendations for spring suppliers? Currently weighing up options for a set of 996 GT3 Bilstein dampers that are going to get a rebuild and would be nice to have alternatives to the Porsche OEM springs that are looking quite pricey...

Order straight out the Eibach motorsport catalogue (which can be downloaded here https://eibach.com/us/file/710-Complete+Motorsport... whilst Eibach UK in Leicester don't sell direct to public, eibachshop.co.uk (part of POTN) will happily take the order and it will be shipped from Leicester. Their stock is good so there isn't much you can't get next day.

Note you'll need to know the diameter, free length and rate that you want. Free length and diameter you can work out from what you currently have with a steel rule and a pair of calipers (or very likely Google!), I'm afraid I've never seen standard GT3 suspension to help with that one

IIRC the rears are some weird diameter items made by H&R. Added to which they’re progressive items too.
Will post images of them when I can find them on my PC

I fitted new OE items (springs) to Bilstein UK refurbished OE dampers, the car drove beautifully

Edit to add images.

Rear damper/spring :



Front springs. One is a Mk2 GT3 item (the shorter one ...) the other a Mk1.



Mk1 and Mk 2 upper rear spring seats differ too. Blue item is Mk1, gold is Mk2 (and yes, I was fitting Mk2 springs onto a Mk1,and no they didn't fit ...)

Long story, but Porsche GB had said the Mk1 front and rear springs were no longer available. I bought the Mk2 items and the gold rear upper spring seats, they were fine, but the fronts were waaay too short and low ... :



Refurbed Bilsteins :



Tip, don't buy the spring seats or locking rings off Porsche (they're 993 items) Bilstein can supply them and they're waaaay cheaper than your local OPC, and the same applies to the anti-roll bar droplink brackets

Edited by Slippydiff on Tuesday 28th February 01:15

[Slippydiff]

poppopbangbang said:

I did yes, are you on the same? If so what tyre size are you running? 285 rears are getting hard to find now!

I’m thinking of lashing out on a set, but it looks like OZ are phasing them out/ceasing production, so availability is proving problematical currently.

Tyre availability is a ‘mare too.
I’m on stock C2 “Carrera” 5 spokes in 8” & 10” widths, seemingly the lightest OE 18” 996 wheels available.

I’m running 235/295 Michelin PS4S, which look a bit over tyred on the 8’s and 10’s, but they’ll fit better on 8.5 & 11’s.

I really want to try a set of Continental Extreme Contact Sports, but they’re US market only, despite being E marked ...
I spoke to Continental UK about getting a set, but they were adamant they were US supplied only ...

https://m.tirerack.com/tires/continental-extremeco...

Scroll down to the sizes tab and you’ll see the make a 285/30/18 and a 225/40/18 ...

[HughG]

PPBB you are obviously on the 285 side of the 285/265 fence. Was that always the case even when economy was a priority? I don’t find rear grip a problem with 265s.

Edited by HughG on Tuesday 28th February 10:45

[Fast Bug]

I run 295 on the back of mine

[ATM]

Ignoring 0.5 inch rim sizes

285 30 - not many options - need 10 inch minimum rim really
265 35 - lots to choose from - not sure you can stretch these on rims wider than 10 inch
275 35 - lots to choose from - fit fine on 10 and 11 inch
295 30 - lots to choose from - need 11 inch rim really - will go on 10 but look bloated

[poppopbangbang]

Great info and pics!

Slippydiff said:

IIRC the rears are some weird diameter items made by H&R. Added to which they’re progressive items too.
Will post images of them when I can find them on my PC

Guessing it's the same upper dia as the standard spring to retain the standard dimensions top mount but with a 2.5" lower? I think Elephant Racing do a top mount that converts it to a standard 2.5 top and bottom. You could probably even use the Ohlins upper spring perch to do the same job on the standard top mounts...

Slippydiff said:

Mk1 and Mk 2 upper rear spring seats differ too. Blue item is Mk1, gold is Mk2 (and yes, I was fitting Mk2 springs onto a Mk1,and no they didn't fit ...)

They look pretty simple to draw up and have a few made should anyone be properly stuck....it looks like the MK2 spring and platform is a good 40mm shorter than the Mk1 as a combination between the perch height and the spring itself!

[poppopbangbang]

HughG said:

PPBB you are obviously on the 285 side of the 285/265 fence. Was that always the case even when economy was a priority? I don’t find rear grip a problem with 265s.

It was built to run a 285 AD08R rear on an 11" rim so 265 was never an option due to the rim width for me. Unfortunately Yoko then stopped selling AD08R in the UK/EU above 255 due to the drive by noise regs and it being a pretty rare size.

[poppopbangbang]

Slippydiff said:

I’m thinking of lashing out on a set, but it looks like OZ are phasing them out/ceasing production, so availability is proving problematical currently.

I still have a good relationship with OZ from buying pallets of single seater wheels for several years so happy to ask and find out what the deal is. There is a lot of stuff going on long lead times at the moment but I believe it's energy/raw material related rather than a push to thin the range.

Slippydiff said:

Tyre availability is a ‘mare too.

In GT3 sizes absolutely, AD08R was my absolute go to and the car loved them but alas no more!

Slippydiff said:

I really want to try a set of Continental Extreme Contact Sports, but they’re US market only, despite being E marked ...
I spoke to Continental UK about getting a set, but they were adamant they were US supplied only ...

https://m.tirerack.com/tires/continental-extremeco...

These look like they could be an excellent option! I don't have much to do with Conti's tyre side of things but let me see if I can get a steer on what the chances are of these making their way over the pond.

[Slippydiff]

poppopbangbang said:

These look like they could be an excellent option! I don't have much to do with Conti's tyre side of things but let me see if I can get a steer on what the chances are of these making their way over the pond.

They’re not cheap, but with Michelin seemingly slowly ceasing production of the 285/30/18 rears (never available as Supersports or PS4S) and now only available in PS2 or Cup 2 Connect format l, the Contis look to be a viable option. In The States they come with a 30k mile warranty too ... (which is probably why they’re not available in Europe)
I’ve an acquaintance that ships automotive parts from all over the globe to the UK, and has freight forwarding companies he uses on both the East and West coast.
His comment was that shipping tyres isn’t cheap, as they’re not space efficient and they’re heavy.

If you could establish the situation with regards to the OZ’s, it would be much appreciated.
I’ve spoken to at least 8-10 retailers and most have come back with differing answers as to when (if) production will re-commence.

Design 911 said April/May. Demon Tweeks said they couldn’t get a date, but OZ had said they may not manufacture them again, others said June/July, and several said 3-4 months ...

I’m not fussed about what colour they are, just as long as they’re the 11 ET63 & 8.5 ET40

More on the stock 996 GT3 front strut top mounts, they’re all alloy and equipped with spherical bearings. I’ll dig an image out that shows the spring seat diameter.

Edit to add image :



The top spring seat can be seen on the left, the depth of the boss that locates the ID of the spring isn't large, but it does the job admirably.

The three securing studs can be pressed or hammered out and moved to the alternate holes in the top mount, to enable it to be rotated and provide an increase in camber up to 3.5 (iirc) degrees, additionally the coffin arm is split and shimming this can enable up to 4.5 degrees of camber (and possibly more)

Edited by Slippydiff on Wednesday 1st March 00:14

[Mallone]

Slippydiff said:

poppopbangbang said:

Mallone said:

Useful info. Could either of you make any recommendations for spring suppliers? Currently weighing up options for a set of 996 GT3 Bilstein dampers that are going to get a rebuild and would be nice to have alternatives to the Porsche OEM springs that are looking quite pricey...

Order straight out the Eibach motorsport catalogue (which can be downloaded here https://eibach.com/us/file/710-Complete+Motorsport... whilst Eibach UK in Leicester don't sell direct to public, eibachshop.co.uk (part of POTN) will happily take the order and it will be shipped from Leicester. Their stock is good so there isn't much you can't get next day.

Note you'll need to know the diameter, free length and rate that you want. Free length and diameter you can work out from what you currently have with a steel rule and a pair of calipers (or very likely Google!), I'm afraid I've never seen standard GT3 suspension to help with that one

IIRC the rears are some weird diameter items made by H&R. Added to which they’re progressive items too.
Will post images of them when I can find them on my PC

I fitted new OE items (springs) to Bilstein UK refurbished OE dampers, the car drove beautifully

Edit to add images.

Rear damper/spring :



Front springs. One is a Mk2 GT3 item (the shorter one ...) the other a Mk1.



Mk1 and Mk 2 upper rear spring seats differ too. Blue item is Mk1, gold is Mk2 (and yes, I was fitting Mk2 springs onto a Mk1,and no they didn't fit ...)

Long story, but Porsche GB had said the Mk1 front and rear springs were no longer available. I bought the Mk2 items and the gold rear upper spring seats, they were fine, but the fronts were waaay too short and low ... :



Refurbed Bilsteins :



Tip, don't buy the spring seats or locking rings off Porsche (they're 993 items) Bilstein can supply them and they're waaaay cheaper than your local OPC, and the same applies to the anti-roll bar droplink brackets

Thanks both. Very, very, useful info.

@slippydiff - I know you know your way around these cars, but my own research on these springs and perches contradicts yours - at least based on the different spring lengths/spring perches you pointed out in your (very useful) images.

The 996 Katalog (and my conversation with Porsche parts yesterday) suggests that the original Mk1 GT3 springs are still available, in stock in the UK right now (though around £600 for a full set. Ugh.) and that the shorter one in your image is the MK1 spring, not a MK2 one as you'd suggested, and should be paired with the yellow spring perch.

As far as I can work out it is 996.313.531.91 for the front springs, 996.333.531.91 for the rear, on a 996 GT3 MK1. The rear springs should be paired with 996.333.529.90 (the yellow spring perch). For reference, my research suggests the spring rates on the MK1 GT3 springs are 35N/mm for the fronts and 65N/mm for the rears.







Have I got the wrong end of the stick? Have Porsche?

poppopbangbang said:

They look pretty simple to draw up and have a few made should anyone be properly stuck....it looks like the MK2 spring and platform is a good 40mm shorter than the Mk1 as a combination between the perch height and the spring itself!

I've got to replace a full set of front and rear spring perches as part of this rebuild so if you fancy jumping on a lathe and sorting some out that would be much appreciated!

PS. Apologies for the thread derail!

Edited by Mallone on Wednesday 1st March 14:44

[Slippydiff]

No, you haven’t got the wrong end of the stick
There was more to the story regarding trying to fit Mk 2 springs to a Mk 1, but I didn’t want to de-rail Pop’s thread any further with my ramblings

I did the that suspension refurb on my Mk 1GT3 back in 2014 ... but I bought the Mk 2 springs and spring seats at least 4 or 5 months before I undertook the work, and I bought the Mk 2 items because my local OPC told me the Nk 1 springs weren’t currently available, and neither was there a date scheduled for their production ...

After I’d fitted the Mk 2 springs and seats to the car, I rang up my local OPC to establish when/if the Mk 1 items would be available again, only to be told they’d become available a couple of weeks previously...

They ordered the springs in and I sold the brand new Mk 2 springs and seats on here ...

[Mallone]

Slippydiff said:

No, you haven’t got the wrong end of the stick
There was more to the story regarding trying to fit Mk 2 springs to a Mk 1, but I didn’t want to de-rail Pop’s thread any further with my ramblings

I did the that suspension refurb on my Mk 1GT3 back in 2014 ... but I bought the Mk 2 springs and spring seats at least 4 or 5 months before I undertook the work, and I bought the Mk 2 items because my local OPC told me the Nk 1 springs weren’t currently available, and neither was there a date scheduled for their production ...

After I’d fitted the Mk 2 springs and seats to the car, I rang up my local OPC to establish when/if the Mk 1 items would be available again, only to be told they’d become available a couple of weeks previously...

They ordered the springs in and I sold the brand new Mk 2 springs and seats on here ...

Ahhhhh! Makes more sense now. Thanks for confirming. Case closed. Thread derail over!

[poppopbangbang]

Good thread derail though! I hope google indexes PH as that's absolutely going to be of benefit to someone in the future

So latest update, it's not a big one I'm afraid....

Wheels have had a proper going over and clean, they've come up amazingly well so very pleased with that. Hats off to OZ they're harder wearing than the Braids on the Cayenne!



Dragons Blood is an amazing but particularly stinky wheel cleaner!



And the rest of the assortment of bodywork fasteners and clips have arrived:



Including some fresh side repeaters as they've been in and out one too many times for 20 odd year old plastic

So that's it now, it's off to the bodyshop - likely to be there for a few weeks then once back there's a couple of days of putting back together to do/final assembly.

With a bit of luck it'll be back together for Easter - I'll update you all when there's something to show

[WojaWabbit]

poppopbangbang said:

The winter mods are well under way with air-con going back on it in the form of e-AC as part of testing for another project I'm involved in, I've been considering re-airconing the car for a while as it's not like it mostly runs at night anymore! Aim with this is just to maintain ambient temperature inside the car (ACO style ) so just one heat exchanger is going in the nose - big props to the ally rads that went in many years ago and are still in great condition!



E-AC compressor in the nose on the PAS side to balance the driver and move a little more mass forwards. There is quite a bit of HVH research required here so we'll see what its like on solid mounts first.



The system will use the standard 996 evaporator and expansion valve with a boggo aftermarket dryer. Lines are fabbed up to suit the install with one entering through the standard point in the arch and the other through a spare bung in the nose. Bit of wiring work to do but nothing too major due to the convenient battery location and the fact the car already has a SuperB fitted that is quite happy with big transient currents etc.

PPBB (apologies to those expecting an update!), harking back to this post, would a custom a/c condenser in the style of the centre/gt3 rad be more efficient for the main coolant rads, leaving them with unrestricted airflow? Or would any potential gains be outweighed by the cost and hassle compared to your 'almost oem' set up (not including the e-a/c bit!)?

[poppopbangbang]

WojaWabbit said:

PPBB (apologies to those expecting an update!), harking back to this post, would a custom a/c condenser in the style of the centre/gt3 rad be more efficient for the main coolant rads, leaving them with unrestricted airflow? Or would any potential gains be outweighed by the cost and hassle compared to your 'almost oem' set up (not including the e-a/c bit!)?

The problem is the centre rad area is pretty tight and whilst you could get an aircon rad in front of the centre rad getting the hard lines out of it would be need some bespoke bits as the bend radius is tighter than achievable with flexi and you're still facing having half the condenser area if not a bit less than using a standard condenser coupled with the loss of performance from the centre rad..... plus you really do need fans on an aircon condenser for zero vehicle speed conditions.

The option of using just one OEM condenser in front of one rad is about the best middle zone and it works especially well with an e-aircon compressor in the nose as the pipe runs are super, super short compared to the engine mounted compressor hence far lower losses in transit (you get a lot of heat transfer to atmosphere from long runs of hard line!).

Anything is doable so it's entirely possible to get an aircon rad in the middle and if you got rid of the centre coolant rad probably with a couple of little SPALs on it but I think it would be a lot of work for little pay off...

[WojaWabbit]

poppopbangbang said:

WojaWabbit said:

PPBB (apologies to those expecting an update!), harking back to this post, would a custom a/c condenser in the style of the centre/gt3 rad be more efficient for the main coolant rads, leaving them with unrestricted airflow? Or would any potential gains be outweighed by the cost and hassle compared to your 'almost oem' set up (not including the e-a/c bit!)?

The problem is the centre rad area is pretty tight and whilst you could get an aircon rad in front of the centre rad getting the hard lines out of it would be need some bespoke bits as the bend radius is tighter than achievable with flexi and you're still facing having half the condenser area if not a bit less than using a standard condenser coupled with the loss of performance from the centre rad..... plus you really do need fans on an aircon condenser for zero vehicle speed conditions.

The option of using just one OEM condenser in front of one rad is about the best middle zone and it works especially well with an e-aircon compressor in the nose as the pipe runs are super, super short compared to the engine mounted compressor hence far lower losses in transit (you get a lot of heat transfer to atmosphere from long runs of hard line!).

Anything is doable so it's entirely possible to get an aircon rad in the middle and if you got rid of the centre coolant rad probably with a couple of little SPALs on it but I think it would be a lot of work for little pay off...

I don't currently have the centre rad, and given the cost of the rad and kit, and also the cost of replacing the oem condensers on each side, was thinking I could bin them and use a single centre mount universal condenser (29"x15"). That would hopefully give improved cooling for the main rads, while maintaining at least some a/c. The a/c would be a lower priority than on-track cooling tbh, so as long as it could maintain a degree (no pun intended!) of comfort I think I'd be happy.

Making up the pipes shouldn't be an issue, the techs at my work are wizards with pipe and tubing so as long as I could source the correct fittings we should be good. Rear-mounted fans on a bracket are a good idea, I hadn't thought that far ahead!

Regarding the heat loss on the long hard line runs, I thought the lines between the condenser and evap would be the ones to consider - which won't be very long... or are the return line temps relevant enough to affect post-compressor temps? Lower in, lower out I guess!