997 GT3 Gen1 clubsport

[Steve Rance]

Balancing that chap at the front must be one large splitter! Thanks for the heads up on the diff. I'm expecting bad news. Thankfully motorsport parts are not horrifically expensive. I think I'm going to hold off big aero changes. My aim is to keep the car as standard as possible. We got the 996 going pretty well without any aero changes.

[fioran0]

Thanks for the car comments etc. Its fun doing it which is the main thing. LOL at the fuzzy slippers. Ive got one part of the photo at least :P

Steve, had a look at the pictures on the site. Looks nice, I'm liking the bold colour.

The aero comment was as much because I think the 997.1 looks tough as nails in Cup form. It wears the lid, wing and front end incredibly well and turns a car that I don't much care for the looks of into one that I do. But beauty is in the eye of the beholder so each to their own on that one.

I don't want to bog this thread down with a massive post but one option for your PASM conundrum that could be worth considering is simply trying harder springs. One of the fundamental issues with those sorts of systems is that as delivered they are unable to operate as a damper/spring combo should in either mode. The spring rate tries to bridge the two settings and thus the system fails at doing either. In regular mode you have a shock that cannot control the spring properly, in sport mode (or whatever designation is used) you have a spring that is too soft for the damper - and are thus driving on the shock. Its logical and clear why its terrible from an operational point of view if one thinks about what its being asked to do.

Ive never tried on the Porsche set up but increasing the spring rate made a huge difference on another similar system ( this using magnetorheological fluid as the shock control).
In regular suspension mode the car was of course now much worse - it bounced around even more than it did before - but in sport mode it drove just wonderfully. The spring was finally contributing as it should leaving the damper able to do its actual job. The car just remained in sport permanently and nothing else was required.

Alternatively one could have went the path of selecting a softer spring and matching it more closely to the damper when in regular mode. This would have rendered Sport mode unusable but created a workable normal setting.
In this particular case sport mode and the accompanying rate was no where near being too hard. I actually felt the car was more comfortable after the spring change in permanent sport mode than it had been originally when in regular mode (with the softer springs) as a result of the reduced bounce..

[Trev450]

Interesting options for PASM, Neil. I don't think you will convince Steve its worth keeping in a hundred years though. He appears to hate it with a real passion.

[fioran0]

Oh don't get me wrong. PASM is really quite $h!t3 but the reasons why are simple to understand if one thinks about it.

All I was suggesting was that selecting a spring rate that allowed one mode to work properly (rather than neither working properly) may be sufficient to resolve (some) of the issues with it.

I haven't done this on a Porsche PASM system so the unknown of whether the damper itself is any good remains. In the end it may prove to be a rather nasty little damper even once everything is working properly and the whole thing is rendered futile, the parts fit only for the bin.

[Trev450]

I appreciate where you are coming from. The system appears to be easily confused and too slow to react to the driver's inputs.

I was just commenting that there could be a relatively simple fix other than tossing the whole lot in the bin and going passive.

[skijumper]

Congrats on your purchase! putting in Motorsport plates into the LSD in a 997 is only a part fix as the ramps in these cars are 28/40.
To get a better locking diff you need to go with Guard Transmission's 40/60 ramps which give the same LSD as fitted to the 996 GT3's.
Your looking at about $1,700. The difference with this LSD is amazing, braking hard in the wet from high speed is a huge improvement.
If you intend tracking your car Guards is definitely the way to go. The difference in the gearing between the 996 and 997 is only marginal,
IMO the gearing is way to long on these cars, which was only properly addressed in the 3.8 RS.
,

[skijumper]

Congrats on your purchase! putting in Motorsport plates into the LSD in a 997 is only a part fix as the ramps in these cars are 28/40.
To get a better locking diff you need to go with Guard Transmission's 40/60 ramps which give the same LSD as fitted to the 996 GT3's.
Your looking at about $1,700. The difference with this LSD is amazing, braking hard in the wet from high speed is a huge improvement.
If you intend tracking your car Guards is definitely the way to go. The difference in the gearing between the 996 and 997 is only marginal,
IMO the gearing is way to long on these cars, which was only properly addressed in the 3.8 RS.
,

[GreatPretender]

Steve Rance said:

Balancing that chap at the front must be one large splitter! Thanks for the heads up on the diff. I'm expecting bad news. Thankfully motorsport parts are not horrifically expensive. I think I'm going to hold off big aero changes. My aim is to keep the car as standard as possible. We got the 996 going pretty well without any aero changes.

If it's any use, I was quoted £650 on average to have the diff removed and re-built with cup plates. All the usual suspects in the south east were much of a muchness, price-wise.

It's the car's only Achilles heel though. PASM I can take or leave, tbh. Oh, and the sat nav is worse than useless

[pete a]

This is aimed at Steve and Neil or anyone else who is really clued up on the mechanics of the car.


All this talk of Pasm being rubbish and the diffs being naff, genuine question is this only really relevant for hard track use?

I only drive mine on the road, the hardest driving I do is stuff like The alpine assault with petrolhead nirvana, is the standard set up sufficient in your opinion for this sort of road use or would the mentioned upgrades be of benefit.

So far I've not been disappointed with the car in any way.

[GreatPretender]

pete a said:

This is aimed at Steve and Neil or anyone else who is really clued up on the mechanics of the car.


All this talk of Pasm being rubbish and the diffs being naff, genuine question is this only really relevant for hard track use?

I only drive mine on the road, the hardest driving I do is stuff like The alpine assault with petrolhead nirvana, is the standard set up sufficient in your opinion for this sort of road use or would the mentioned upgrades be of benefit.

So far I've not been disappointed with the car in any way.

The standard diff is chocolate. If you've got anything over a few thousand miles on the car, the chances are the unit won't be working at all (i.e. it's effectively open). Test it by reversing on full lock. If the car is reluctant to move or makes any graunching noises, then you still have some lock-up. I suspect however the car will reverse as smooth as butter (i.e. no diff locking).

PASM however is generally fine for road use, but not perfect. For me it's too soft as standard and unusable on hard, which leaves me in a damping no man's land most of the time unless I'm on the track.

[Cunno]

GreatPretender said:

If it's any use, I was quoted £650 on average to have the diff removed and re-built with cup plates. All the usual suspects in the south east were much of a muchness, price-wise.

It's the car's only Achilles heel though. PASM I can take or leave, tbh. Oh, and the sat nav is worse than useless

Don't forget if your using on track the below

ABS unit is a bit of a pain
Gear ratios
Diff
PASM
Exhaust Noise
Break disc cracking
Rear break pad wear is a joke as ABS can't fully be turned off
Engine and gear box mount

All could have been better IMO.

P.S £650 for diff plates is a good price, did that include fitting?

[ttdan]

fioran0 said:

Thanks for the car comments etc. Its fun doing it which is the main thing. LOL at the fuzzy slippers. Ive got one part of the photo at least :P

Steve, had a look at the pictures on the site. Looks nice, I'm liking the bold colour.

The aero comment was as much because I think the 997.1 looks tough as nails in Cup form. It wears the lid, wing and front end incredibly well and turns a car that I don't much care for the looks of into one that I do. But beauty is in the eye of the beholder so each to their own on that one.

I don't want to bog this thread down with a massive post but one option for your PASM conundrum that could be worth considering is simply trying harder springs. One of the fundamental issues with those sorts of systems is that as delivered they are unable to operate as a damper/spring combo should in either mode. The spring rate tries to bridge the two settings and thus the system fails at doing either. In regular mode you have a shock that cannot control the spring properly, in sport mode (or whatever designation is used) you have a spring that is too soft for the damper - and are thus driving on the shock. Its logical and clear why its terrible from an operational point of view if one thinks about what its being asked to do.

Ive never tried on the Porsche set up but increasing the spring rate made a huge difference on another similar system ( this using magnetorheological fluid as the shock control).
In regular suspension mode the car was of course now much worse - it bounced around even more than it did before - but in sport mode it drove just wonderfully. The spring was finally contributing as it should leaving the damper able to do its actual job. The car just remained in sport permanently and nothing else was required.

Alternatively one could have went the path of selecting a softer spring and matching it more closely to the damper when in regular mode. This would have rendered Sport mode unusable but created a workable normal setting.
In this particular case sport mode and the accompanying rate was no where near being too hard. I actually felt the car was more comfortable after the spring change in permanent sport mode than it had been originally when in regular mode (with the softer springs) as a result of the reduced bounce..

With PASM the dampers are supposedly not two distinct settings, soft and hard, they are two variable range settings, soft range and hard range. There is an overlap between the two also. So, how does this differ from having passive dampers that are themselves adjustable with say ten different settings? I can't imagine the PASM damper operates much outside the range of any manually adjustable damper. Maybe a mod for pasm where the rate is just set rather than left to vary. A nice 10 way click dial on the dash will do :-) Steve's comments a few weeks ago was bemoaning the unpredictable nature rather than the ability to control the spring.

[nxi20]

ttdan said:

With PASM the dampers are supposedly not two distinct settings, soft and hard, they are two variable range settings, soft range and hard range. There is an overlap between the two also. So, how does this differ from having passive dampers that are themselves adjustable with say ten different settings? I can't imagine the PASM damper operates much outside the range of any manually adjustable damper. Maybe a mod for pasm where the rate is just set rather than left to vary. A nice 10 way click dial on the dash will do :-) Steve's comments a few weeks ago was bemoaning the unpredictable nature rather than the ability to control the spring.

In my very limited experience of PASM on the 997.1 GT3, the real problem seems to arise just as you are really leaning on the car & asking the maximum of the dampers. It feels as though the computer controlling the damping runs out of ideas & falls back into a default "when in doubt, just make it as stiff as possible" mode. Dynamic variable damping is always going to be a compromise (I think it's generally agreed that the 997.1 was too road-biased) & IMO has no place on a track car.

[fioran0]

ttdan said:

With PASM the dampers are supposedly not two distinct settings, soft and hard, they are two variable range settings, soft range and hard range. There is an overlap between the two also. So, how does this differ from having passive dampers that are themselves adjustable with say ten different settings? I can't imagine the PASM damper operates much outside the range of any manually adjustable damper. Maybe a mod for pasm where the rate is just set rather than left to vary. A nice 10 way click dial on the dash will do :-) Steve's comments a few weeks ago was bemoaning the unpredictable nature rather than the ability to control the spring.

The PASM setup feels very much to me like the spring rate is placed between the soft and hard ranges. This makes sense from a technical perspective when you look at what they are trying to achieve - its the only logical way to approach it - but unfortunately it also responds as logically as one would expect in this circumstance.
In soft mode the damper cannot quite deal with the spring while in hard mode the damper is now too much for the spring. As a result neither are effective

This is all no different from the limitations of a manually adjustable damper. With an improper spring and damper valve configuration then no amount of adjustment is going to set the car up well (hence the need for a revalve if you change spring rate).
Likewise If the range of adjustment offered by the damper is designed to allow it to take a variety of spring rates (think RSR) then its easily possible to adjust the damper out with the window of the current spring. The car will not drive well until you adjust it back into the setting range appropriate for the selected spring.

The elephant in the room with all of these dual mode suspensions is that your spring rate is always your spring rate. You cannot, by adjusting a shock, make a hard spring behave like a soft one and vice versa.

As I said, I have no experience trying this with Porsche PASM but on Ferrari, ditching the idea of a soft and hard mode, picking a spring that matched one rather than trying to accommodate both and then leaving it in that mode worked perfectly. Again this is not that big a leap of logic.
In that case we picked the hard mode (Race) to be default option. Running in normal mode was even bouncier than it had been prior to the change (of course since the damper had even less chance of controlling the increased spring) but Race mode was now perfect. It was also more comfortable than either mode had been prior to the spring rate swap since the options before the change had been bouncy or crashy.

It may be that the PASM shock and setup turns out to be a POS even when trying this out, or that the self adjusting behaviour is still too much to bare.

[Trev450]

pete a said:

This is aimed at Steve and Neil or anyone else who is really clued up on the mechanics of the car.


All this talk of Pasm being rubbish and the diffs being naff, genuine question is this only really relevant for hard track use?

I only drive mine on the road, the hardest driving I do is stuff like The alpine assault with petrolhead nirvana, is the standard set up sufficient in your opinion for this sort of road use or would the mentioned upgrades be of benefit.

So far I've not been disappointed with the car in any way.

For road use the PASM is fine in 'soft' mode. As already mentioned, however, the diff is next to useless as an LSD for the reasons already covered. If you are happy with the way the car feels, though, and don't intend to track it, leave the diff alone.

[Steve Rance]

Thanks for the input guys. First, let me clarify the main issues that i have with PASM. It's a reactive variable damping rate and that means; Firstly, its difficult to predict exactly what the car is going to do the nearer to 10/10th you get which is the last thing you want as a driver. Secondly, It fights a driver trying to load the nose of the car on a trail in slow and medium corners which - again - makes things unpleasantly difficult near the limit. Thirdly, as Neil says, the spring rate cannot be paired to the ideal shock rate because there are two modes which are too extreme to work to. The first two factors turn what should be a supreme and delicate track car into a potentially dangerous one. The third…. well it's just useless. Thats without looking at the actual control of the PASM dampers - which is probably not ideal either. The spring rate - as Neil says is key. Without the very high grip factor of slicks, there is scope for a nice compromise between road and track for the rates. The dampers will then be set up with two primary settings . One which will be a dry track set up and the other which will be a wet track set up/ road use (although obviously there is scope for the full spectrum in-between)
. Both will operate at the opposite ends of the effective working range of the spring rates selected. This will (should) provide a lovely stable, reliable and predictable platform for the chassis to work from on the road and track. This will (should) allow me to trail in on a later brake and get on the throttle earlier on the apex - with the car reacting to my inputs rather than the other way around.

The diff will almost certainly be fitted with a motorsport pack with 40:60 or 50:70 ramping. Top mounts will probably be changed with the dampers and motorsport control arms fitted. Brakes will probably be 997 Cup fronts with paged yellow pads and a hard pad material on the rear. We found a way of running pretty high degrees of front camber without needing a motorsport ABS unit on the 996 so we have the same aim on the 997. The only thing that concerns me now is rear braking 'interference'. I don't want it so need to do some research here. Does anyone know the score? If I turn traction off will there be ABS interference only? What does the sport button do when the dampers are thrown away? noisy exhausts have no interest to me so if it doesn't help the car's performance, I'd rather not have it on. Will I need to switch it on to stop rear braking interference?

I'll probably go with the BBS one piece track wheels with no other external clues ( aero ) that the car is not standard - although the geo my give it away to the trained eye.

[braddo]

Steve, there are 3 buttons:

1. Dampers/PASM - pressing it changes the dampers to the harder setting.
2. Sport - this apparently sharpens throttle response, lets the exhaust valves open a bit earlier and, possibly, loosens the traction control settings?
3. TC - traction control. My understanding is that off means off, which would leave you with just ABS.


I'll be following this thread with interest.

Edited by braddo on Tuesday 16th December 16:26

[Richie200]

Hi Steve, really great thread and look forward to how your project progresses. I have recently bought a Gen1 RS which has H&R passives fitted. The Sports button had absolutely no effect when I pressed it. This may be slightly different with a less modified car (mine also has an Akrapovic exhaust). I will look a little deeper into exactly what has been done to my car and report back; it could be a case of it has just been fully deactivated.
Keep up the good work

[Steve Rance]

Thank you for taking the trouble to reply gentlemen. That is useful info.

[DT398]

I'm wondering if I owned that for a while. Does the reg start with "R" and end with "Z"? Awesome piece of kit, even if it wasn't the one I had (spec looks identical). I only sold it to get an RS.....