997.1 GT3 on passives vs 996.2 GT3 - Page 1 - 911/Carrera GT - PistonHeads UK

Hi all, As per title really. Anyone driven a 997.1 GT3 on passives and a 996.2 GT3? Specifically interested in track experience, and how they compare / contrast? Thanks for any comments and feedback. Cheers Slodge

slodge said: Hi all, As per title really. Anyone driven a 997.1 GT3 on passives and a 996.2 GT3? Specifically interested in track experience, and how they compare / contrast? Thanks for any comments and feedback. Cheers Slodge I like your thinking

http://www.pistonheads.com/gassing/topic.asp?t=997...

mrdemon said: http://www.pistonheads.com/gassing/topic.asp?t=997... You're slipping, you missed tthe perfect opportunity to have "GT3 pop" there mrdemon said: Upgrade a Gt3 suspension, surly not ;-) I suspect you meant surely btw (surly is what you consider me to be)

7.1 RS on aftermarket passives (sorry can't remember which ones) vs 6.2 non-RS with aero mods and KW Mantheys = very evenly matched with 2 race drivers of very similar ability. The 7 nibbled a fraction of time out of the 6 on high speed aero-friendly direction changes and the 7 has a bit more torque lower down so has a little more grunt out of low speed corners but otherwise v little in it. Both cars have inherently outstanding chassis. The 7 just needs a proper damper to make it shine.

I have a lot of experience driving both on the circuit. The 997 chassis is stiffer and more able than the 996 which as the spring/shock rate increases will flex diagonally along it's axis. This makes the car more 'mobile' and it requires a slightly more animated driving style. This observation is made at the very margin of grip level at 10/10ths and is quite subtle. There is no light and day difference. With passive, the 997 is far more predictable and responds well to being 'worked' from turn in to apex. In active form the car is horrible and at the margin of grip vague and - in my experience - dangerous. Active suspension in this guise has no place on a serious track car. In short, with passive fitted and with equally accomplished set up's the 997 is very slightly quicker than the 996 but feels less flustered when it's 10/10ths performance is exploited. As the chassis tuning stakes get higher and one gets closer to cup levels of chassis tuning - lighter weight, slicks, extreme geometry etc.. the gap starts to widen but as 'tuned' road car level there is very little in it. I tuned road car trim, of the two, i prefer to drive the 996. it's just more fun. If i were racing, I'll take the 997. it's quicker with the sequential and the composed nature of the chassis free's up more of a driver's capacity to concentrate on race craft.

So, talking track toys here not carrera cup championship ambition . Steve, please indulge me a little, i know this has been done a few times but what's the issue with PASM in this context . Is it too slow to react? Is it fast enough in the hardware but programmed poorly? (Asking because recents been reading about TPC racing's PASM upgrade module) Are the dampers themselves just not as good? If the dampers' job is to keep the tyre on the tarmac then the theory of an active suspension has to be admired, essentially with a passive system you are adjusting for a best compromise where as active is in theory letting you have the proverbial cake and eating it. So where is it falling short of expectations? This is a sincere question btw not a PH poke.

Harris / Steve - thanks for taking the time to post up your experiences. Most useful indeed and has helped my thinking! Cheers Slodge

ttdan said: So, talking track toys here not carrera cup championship ambition . Steve, please indulge me a little, i know this has been done a few times but what's the issue with PASM in this context . Is it too slow to react? Is it fast enough in the hardware but programmed poorly? (Asking because recents been reading about TPC racing's PASM upgrade module) Are the dampers themselves just not as good? If the dampers' job is to keep the tyre on the tarmac then the theory of an active suspension has to be admired, essentially with a passive system you are adjusting for a best compromise where as active is in theory letting you have the proverbial cake and eating it. So where is it falling short of expectations? this is a sincere question btw not a PH poke. No problem in short. A passive damper behaves constantly so a driver knows exactly what to expect from it and can trim the car with confidence on a trail all the way to the apex. An active damper is not by it's nature constant. Its adds a variable which the driver has to then drive around. On the 997 the resistance rate increase as the driver loads the nose of the car at the on turn in which makes it a lot harder to counter understeer - so the driver applies more brake pressure to counter it and ( because the shock resistance rate is a variable ). This greatly increases the risk of oversteer before the apex. And - unlike the passive 997GT3 which will telegraph the onset of oversteer in this situation well in advance - the onset is at an advanced stage before the driver is aware of it. Because of this, I find the active 997 GT3 the most difficult and uncommunicative of all the Gt3's ( including Cup cars ) that I have driven.

Steve, Do you have a recommendation for active dampers that work well particularly with the 997 GT3 chassis or is it best to go with the ones that the Indy has experience of setting up / recommends? I put Ohlins and Powerflex Black Series bushes on my 996 GT3 and loved them so may well go for same damper and solid bushes for the 7 unless there is a better trodden path? Cheers Slodge

Presumably you mean passive? I'd go high end. Moton, JRZ, etc.. Also, it nice to have as much control as possible - providing it is well set up for you. Whatever you do make sure that the company but whatever you do make sure that whoever you buy them from have experience in setting up GT3's before you buy. Otherwise you will be on a hiding to nothing on bump and rebound set up. Guys who really know what they are doing around GT3's like Red line racing, Tech 9, Parr, Neinmeister, JZM etc..

Steve Rance said: Presumably you mean passive? Yes passive! Need coffee. Thanks for the info. Cheers Slodge

A Pleasure

slodge said: Steve, I put Ohlins and Powerflex Black Series bushes on my 996 GT3 and loved them so may well go for same damper and solid bushes for the 7 unless there is a better trodden path? Cheers Slodge Polyurethane should not be found anywhere near suspension components. Ever. The better path is called rose-joints. If you are going as far as fitting passive suspension on a 997 GT3 you may as well do it properly and fit rose-joints. I have Manthey RSR bits on my Mk1 CS (Olaf's old personal car) and I don't find them a problem for the limited road miles that I do. Polyurethane is work of the devil. It falls appart after a while and does not perform the same duties even as the original bonded Porsche rubber bushes. It is well and trully crap. Ask any suspension engineer and see what they say...

Steve Rance said: No problem in short. A passive damper behaves constantly so a driver knows exactly what to expect from it and can trim the car with confidence on a trail all the way to the apex. An active damper is not by it's nature constant. Its adds a variable which the driver has to then drive around. On the 997 the resistance rate increase as the driver loads the nose of the car at the on turn in which makes it a lot harder to counter understeer - so the driver applies more brake pressure to counter it and ( because the shock resistance rate is a variable ). This greatly increases the risk of oversteer before the apex. And - unlike the passive 997GT3 which will telegraph the onset of oversteer in this situation well in advance - the onset is at an advanced stage before the driver is aware of it. Because of this, I find the active 997 GT3 the most difficult and uncommunicative of all the Gt3's ( including Cup cars ) that I have driven. Cheers for that explanation. Would love to try a passive set up on my gen 2 at some point.

Cheburator mk2 said: slodge said: Steve, I put Ohlins and Powerflex Black Series bushes on my 996 GT3 and loved them so may well go for same damper and solid bushes for the 7 unless there is a better trodden path? Cheers Slodge Polyurethane should not be found anywhere near suspension components. Ever. The better path is called rose-joints. If you are going as far as fitting passive suspension on a 997 GT3 you may as well do it properly and fit rose-joints. I have Manthey RSR bits on my Mk1 CS (Olaf's old personal car) and I don't find them a problem for the limited road miles that I do. Polyurethane is work of the devil. It falls appart after a while and does not perform the same duties even as the original bonded Porsche rubber bushes. It is well and trully crap. Ask any suspension engineer and see what they say... Hi there, Don't sit on the fence, tell us how you really feel about Polyurethane! Yes I'd agree (although I thought they were better than the Porsche OEM bushes) which is why I want to go solid / rose jointed next time. I had several of the bushes replaced under warranty, they have held up since then. Hope you are enjoying the Mk1, must be awesome with the Manthey bits on it! Cheers Slodge Edited by slodge on Tuesday 4th November 21:11