Knackered old Porsche with loads of miles - 996 content

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It's actually even easier than that chaps..... I'm not sure about the latest ones but my head unit (that is around three years old) has the 3.5MM "Remote" jack on the back and Sony haven't changed the multiplexing on the stalk since 1999 so it's plug and play

I quite like the idea of having a period correct stalk so this seems a good option.

Now I just have to decide what I'm doing for a dash display as I don't want to do AIM again (absolutely nothing wrong with it, it's blindingly good kit just way OTT for what the car is now), could do a Racetech Dash 4 mounted on the wheel, or make a little CAN display with a 1" OLED and a Teensy board or just ignore that requirement and do some shift lights..... it's only really the shift lights that I miss but oil temp, accurate coolant temp etc. are all really useful things to have....

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I can indeed! Apologies for the delay in replying.

My "Prime" fronts are: 0800.250.0250 = 8" Free Length, 2.5" Diameter, 250lbs/in

Rears are: 0800.250.0525 = 8" Free Length, 2.5" Diameter, 525 lbs/in.

In metric that's 44N/mm front and 92N/mm front.

The caveat to this is that my R&Ts aren't standard. I believe these will go on the standard setup with the weird top mount puck thing that retains the OE bearing assembly but I'm not 100% sure as mine have always run with a conventional/proper front spring perch. I'd measure the Ohlins supplied top mount bits for you to check but they went in the recycling several years ago I'll try and find some stock Ohlins springs to confirm.

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For reference this is my top mount setup on the front:





I run an axial thrust bearing under the spring platform which avoids the springs binding at extremes of motion and makes adjustment far easier. Eibach call this a Torsion Release Bearing (https://eibach.com/us/c-119-motorsport-springs-accessories-race-spring-accessories-torsion-release-bearings.html).

Edited by poppopbangbang on Friday 16th June 23:57

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Mikeeb said:

I assume there’s a steel or steel/ptfe type spherical bearing in those mounts? Where did you get the mounts or are they something you had made?

Ta

Yep there's a spherical in there. They're Elephant Racings standard C4/Turbo camber adjustable top mounts. They're very nicely done including some custom seals on the spherical which is a really nice (and expensive to have made!) touch.

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Slippydiff said:

No worries on the delay, I'm sure you're plenty busy enough without having to check up on your various PH threads everyday !!

That's great information thankyou
Some nice mods you've carried out to the Ohlins to make them to your spec.

I'm trying to keep my car as compliant as possible, so whilst I really like the idea of the Elephant top mounts, I don't want to run spherical bearings (been there, done that, they're a step too far on our hopeless road surfaces these days) so I'll be using the stock top mounts, but possibly going to have to adapt the Ohlins top spring perch to suit 65mm ID springs or find some 70mm ID springs to the specs I need.

In their infinite wisdom Ohlins use 70mm ID front springs and 65mm ID items for the rear



Any reason you went from 70mm ID front springs to the 65mm ID items ? Better availability/more options ?

Were those top spring platforms custom made items you produced specifically for the 65mm ID springs ?

My Ohlins started out as one of the first few sets made which were on 65mm front and rear hence the 65mm upper spring perch etc. as I already had 65mm springs. I think these upper platforms were some I had kicking around from something else and I just machined the bore out to suit the Ohlins damper rod..... they're a common thing though and readily available from plenty of places. I think it would be pretty hard to use these with a standard top mount though as the large Ohlins top mount forms the interface with the standard top mount bearing.

I might have some 70mm front springs in the garage that will work for you and will be cheap, let me have a look this evening.

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Border89 said:

Never seen those thrust bearings before but they make loads of sense - do you run one set per shock or do you have one at each end of the spring? I get that one is probably enough, but given your belt and braces approach to maintenance I can see value in there being redundancy in case one end seizes up...

Only one per spring, two is just doubling the failure mode. The nice thing is they fail by binding/locking up at which point you are no worse off than when the spring was just sat against the upper spring perch as standard. I bin them every year in road use, although if you didn't run through winter they'd likely last far longer.

They are very cheap and very available from the vast majority of bearing suppliers so as a yearly consumable they add little to the cost of running the car.

To make adjustment far easier and avoid the springs binding at large steering deflections, especially on cars with sub optimal pickup points (like the C4) they are highly recommended.

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It had a visit to Centre Gravity yesterday and spent some time with the resident suspension wizard





I am over the moon with their work and how it now drives, there is a lot of compliance and damper travel which it didn't have before and the balance of the car is far more ideal for its new role as a GT car.

Weights are also pretty impressive:



That's with full fuel, which on this car is 97L so minus fuel but with all other fluids (and a jack/spare oil etc.) it's circa 1375KG. I added 16KG of aircon system etc. since the last time it was weighed so the carbon wings etc. are definitely keeping the overall mass down.

I really can't rate CG highly enough, their level of experience and understanding of how the elements within a suspension system interact and operate is unmatched in my experience and I would encourage anyone who is adding some new bits or wanting to refresh their current setup to speak to them about setup!

There's only a few bits left to do on it now, and it's officially back on the road having clocked up 75 miles or so yesterday. Nothing fell off so I'm considering first shakedown a huge success

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Slippydiff said:

That would be great if you could, as I'm fast running out of options for the rates I want in 70mm ID springs ...

This is what I have in stock:



2 Off - ERS-D-200-70-040 - Metric Spring, 200MM free length, 70MM Diameter, 40N/MM Rate.

2 Off - 0800.250.0525 - Imperial Spring, 8"/200MM free length, 2.5" Diameter, 92N/MM Rate.

I'll drop you a message through your profile in case they're of interest.

Slippydiff said:

Has the added compliance come as a result of the overhaul of the suspension components and/or the damper refresh and a spring rate change ? or the tweaks Chris/Pete at CG did to the car ?
In my experience running large cambers seems to reduce the tyre's ability to cushion the ride and provide a decent primary ride, add in low ride heights that are too low and things can get pretty crashy.

All of the above really, there was plenty of 100,000 mile old stuff in there which had some play/noise, fresh dampers always help, the drop in spring rate has calmed everything down and the work Chris/Pete have done has tied it all together and made it work well. It's certainly not some over soft, roly poly thing as it has the odd polybush in the arms, spherical bearing front top mounts etc. etc. but it has absolutely no fizziness to it and very little NVH beyond tyre noise, which on a wide rear on a 911 is standard operating procedure It has proper poise to and the stability and lack of GT3 style nervousness is just superb on UK roads, very settled across mid corner bumps and primary ride is far improved (which I think is likely a result of having a lot more droop than before).

Basically, I reckon I've about cracked the best setup for a very performance orientated 996 road car i.e. something you can send down a B road without bits decking out or your fillings falling out whilst being arrow straight and planted at speed on the motorway!

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One from C&M today, first proper run out somewhere in it since I rebuilt it!



Happy to report all systems working as they should including the E-Aircon. The new suspension setup is so much better, took the Fosse home to experiment over choppy B road surfaces and it is so much more well behaved, stable and grippy!

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Thanks for the great feedback chaps - genuinely making me blush

Great failure today though:



Drivers side window regulator made a bad noise and that was that, never seen this failure mode before as the cable has jumped off the pulley and bound up on the metal work. Likely fixable but it was a rubbish pattern part that had gone in during lockdown when no OEM ones were in stock. I actually had a spare for the Boxster (as it has a lazy window drop) so pilfered that for the 996 and all is well again. Window regs are one of those jobs where the first time seems to take ages of dicking around getting it all to line up but subsequent ones are an hour at most

I also had this big chunk of Shadowfoam in stock:



One of the jobs I've wanted to do for ages was make a Froot tidy / carrier so with a bit of scalpeling:





OE tool rool, jack, jack handle, emergency tyre weld, jump pack, tyre inflator and a litre of Millers finest now have a proper home!

Frankly romping through the nice to have jobs now the car is back together. Next job is the new dash display which will replace the AIM one I used to run, this should match the general look and feel of the 996 far better.

Also had some time to put some miles on it, clocked up 375 miles to Wales and back, did the old Evo Triangle and was very gutted to see that not only is the Sportsman now closed but also it's covered with average speed cameras. I am so very pleased with the new spring rates and setup, over broken road surfaces and general B roads it is superb - yes it's lost a touch of track capability but it's such a small amount vs the usability it now has on the ever worsening UK roads!

No issues to report on the run out bar a panel making an annoying buzzing in the back..... better make sure I put all the fasteners back into that!





Oh and in other news I have a new whiteboard in the workshop:



Upcycling and all that!

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nebpor said:

snotrag said:

Lovely, lovely, bump eating suspension travel

Exactly! It's what is needed on our roads these days.

It's not coincidental that the current ride height is very, very similar to that which the GT3 Tarmac rally boys are running

Ten years ago when the car was used for European Autoroutes more than anything else it was much less of a consideration and the ability to do a few sighting laps etc. at the destination also had an impact on some of the choices made but these days with the cars more GT orientated setup and the focus on all round usability regardless of country I am very, very happy with the suspension setup. Being able to properly thump some big bumps mid corner without the car reacting badly is very pleasing indeed!

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Heaveho said:

What do you do about security on something like this? I'm 20 years invested in a modified Evo 8 and st myself every time it's out of sight. As much as I've spent on that, I'm nowhere near as deep in as you must be with this, are you happy just to park it and walk away, or is the security as high tech as the rest of it?

Obviously not asking for specifics, as that would defeat the object, just interested in your mindset about how to protect it.

It's well insured on an agreed value and I have a very good relationship with my insurer, it's protected as much as something like this realistically can be and it's tracked as one would expect. These days most things are nicked by breaking into a house and stealing keys or by relay attacks on keyless entry/start vehicles. The 996 is realistically too old for this generation of thieves I'm certainly not careless with it but as with all things if someone REALLY wants it there are ways that they'll get it.

When all is said and done I built it to use it and a chunk of the spend is in the R&D not the bits, in short I can always build another one was the worst to happen..... but I'd rather it didn't!

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Chris Stott said:

However, the ride height is pretty much stock… might be M030 height, but it’s nowhere near where a GT3 would sit.

You say that like it's a bad thing? Whilst a 996.1 GT3 is great on a track (and I've done enough miles in one ) they are a total dick on UK roads with a tendancy to follow camber changes and take chunks out the front splitter on big bumps / car park ramps. This car is all about function, the form is secondary - think of it like a tarmac rally car rather than a track car

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Filibuster said:

1. To my eyes, the rear axle could do with some spacers. Did you contemplate them? Would they have messed up the whole chassis set up?

Definitely no room for spacers on this one



It's actually relying on the camber change under compression to get the tyre under the arch at full compression!

Filibuster said:

2. Did you ever consider a ducktail? I thinks this would suit your car very well indeed, much more so after it’s new designation as a GT

I'm rather a fan of the original Mk1 Aero Kit / GT3 rear wing and they're a rare thing now having only existed for a couple of model years. No plans to change it as if you can't see the wing in the rear view mirror is it even worth having one?

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dome said:

Long time lurker and all that.

Suffice to say I've always been a 911 fan and have loved this thread. The car keeps getting better and better.

After looking at 6 996s in Scotland over the last few weeks I did the right thing and bought the cheapest one. Which also turned out to be the best one!

This is lovely! Well purchased

Makes me wish I'd done something more interesting than my monochrome 911

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Slippydiff said:

Did you get my email Matt ? Apologies it was a bit of an “essay” ...

I've just found it in my spam! Apologies I'll reply ASAP.

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Chris Stott said:

It’s only a bad thing aesthetically… as I said, I don’t doubt it’s perfect, dynamically… but 996’s just look better at GT3 ride height.

I think they look better at Carrera Cup ride height with split rims and a shed load of negative camber but again that's a function of the use case



I'll absolutely have an old Carrera Cup car at some point, I think they represent mega value vs a road car GT3 even when one considers the drama the sequential built in a road car gearbox casing brings from a servicing perspective. They were also the only road car based race car I've ever been around that ground the trailing edge of the side skirts down during general use

[poppopbangbang]

As mentioned previously I wanted to replace the AIM display / logger (G Dash / Evo 5) that had been in the car for sometime. Whilst it's a great bit of kit it was way OTT for the use case of the car and looked a little too motorsport plonked in front of the standard clocks for the cars new GT Car aspirations.

I've been researching who does a small CANBus capable display for a while and hadn't found much that could go in relatively unobstrusively but spotted that Germany based CANChecked had updated their 52mm gauge display to have a few extra capabilities that made it fit the bill, so I got one ordered up!

Key requirements were abiliy to brand it with a splash screen, have sufficent control on the layout so it matched the colour and design influence of the 996 interior, had configurable CAN (as surprisingly no one has done a proper decode of the Mk1 996 CANbus which only exists proerly in the C4 ) and supported a basic shift light.

First job was to decode the CAN, I'd done this previously but wanted more channels that I'd had on the AIM (specifically all four wheel speeds and both PPS):



Using an OTS Shiftec CAN Analyser to work out the scaling required to get SIC units out of the raw CANbus data. Some things like RPM are simple 1:1 scalings and some things like coolant temp are proper OEM levels of dicking around to get two decimal places from three numbers.

With that done I made a splash screen in GIMP that matched the wallpaper on the head unit:



All the data comes across a treat and the ability to change text colour etc. on the display layout means it doesn't stand out too much against the stanard orange on black LCDs:



The display layout is pretty configurable with bar charts etc.



As well as having math channels etc. to support selected gear calculation etc. It's got a bit of logging on it (albeit proper bare bones!) and is really very impressive for the cost of it. Configuration is via a web browser and Wifi connection which is something I'm very not keen on but it works well enough for the short and basic config required for something like this, plus it's pretty impressive having Wifi, a web server, a DHCP client etc. built into a 52mm gauge

Very pleased it works as planned as it was the least obvious option I could find without making something from scratch! Plan is to install it in an Autometer column pod:



Which is currently on its way from the States. I'll post an updated when it's all in and I've had chance to use it in anger!

[poppopbangbang]

I've not been happy with the brake pedal feel now things are a little bedded as it just seemed a touch on the soft side. Clearly some air stuck in the ABS valve block and I've got all the gear to bleed it properly so how hard can it be?

Well how's this for a bodge!



All because Durametric is somehow broken in the latest version an no longer runs the boost pump when commanded which makes carrying out the "book" process to do this impossible. When faced with a take it to Porsche, find out if a £200 Chinese diagnostic thing that promises ABS bleed functionality really does or bodge a solution I picked the latter. So here we have an EZ Bleed at 20PSI (off the A2s spare ) with a bench power supply directly feeding the PSM/ABS Pump with a vacuum bleeder on the calipers........ It worked

The process was pressure up the master cylinder res, apply vacuum at the bleed nipple then power the boost pump as the nipple was cracked. About 200ml of fluid was pulled through each caliper to make absolutely sure all the air was out.

So if anyone is stuck for bleeding their C4 or Turbo then this is a workable solution!

This is one of the last bits of the final commissioning process really, I'm waiting on a few final bits that need to go on but it's about at 500 miles in for the post build bolt check and then it's ready for some proper use

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DanG355 said:

Another long term follower of this thread now into a 996…

Lovely motor car Excellent choice and that looks like an absolute peach!