997 GT3 and RS Understeer! Alignment Question
05-08-2007, 05:05 PM
#46
Question guys: alignment is so important for proper handling, why does Porsche send these cars out with alignments so far out of spec? I can see small errors, but major differences side to side?? Is it the shipping that plays a part in these errors... the way they're tied down, for example?
I'm sure Porsche knows that track guys will make alignment changes after delivery, but that doesn't mean you ship cars out that barely go straight. It is, after all, a road car. Some owners will drive it out of the dealership and assume it's handling properly. IMO, it should be delivered very close to proper spec.
Also, why can't I get my sig to show up? TIA
I'm sure Porsche knows that track guys will make alignment changes after delivery, but that doesn't mean you ship cars out that barely go straight. It is, after all, a road car. Some owners will drive it out of the dealership and assume it's handling properly. IMO, it should be delivered very close to proper spec.
Also, why can't I get my sig to show up? TIA
05-08-2007, 05:06 PM
#47
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Originally Posted by Bob Rouleau
Hmmm I am reluctant to lower the car since I have enough trouble getting into gas stations and parking lots. My neighborhood has speed bumps and dips. I will be condemned to have to follow Apex.
I wonder if the PASM PSS9 kit would help with the understeer problem. I am suspicious of the roll bars. My observation is that initial turn in is good. The push comes mid corner and thereafter. Is this a result of the shocks getting stiffer (PASM has a reaction time after all)? My previous experience was that shocks can have a dramatic effect on handling. I once tried race shocks and springs. Talk about STIFF!. I decided to use softer springs. Guess what, the car was just aas STIFF. The difference between a 1200 lb spring and an 800 lb spring was masked by the shocks.
I wonder if the PASM PSS9 kit would help with the understeer problem. I am suspicious of the roll bars. My observation is that initial turn in is good. The push comes mid corner and thereafter. Is this a result of the shocks getting stiffer (PASM has a reaction time after all)? My previous experience was that shocks can have a dramatic effect on handling. I once tried race shocks and springs. Talk about STIFF!. I decided to use softer springs. Guess what, the car was just aas STIFF. The difference between a 1200 lb spring and an 800 lb spring was masked by the shocks.
05-08-2007, 05:06 PM
#48
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Originally Posted by Bob Rouleau
Hmmm I am reluctant to lower the car since I have enough trouble getting into gas stations and parking lots. My neighborhood has speed bumps and dips. I will be condemned to have to follow Apex.
I wonder if the PASM PSS9 kit would help with the understeer problem. I am suspicious of the roll bars. My observation is that initial turn in is good. The push comes mid corner and thereafter. Is this a result of the shocks getting stiffer (PASM has a reaction time after all)? My previous experience was that shocks can have a dramatic effect on handling. I once tried race shocks and springs. Talk about STIFF!. I decided to use softer springs. Guess what, the car was just aas STIFF. The difference between a 1200 lb spring and an 800 lb spring was masked by the shocks.
I wonder if the PASM PSS9 kit would help with the understeer problem. I am suspicious of the roll bars. My observation is that initial turn in is good. The push comes mid corner and thereafter. Is this a result of the shocks getting stiffer (PASM has a reaction time after all)? My previous experience was that shocks can have a dramatic effect on handling. I once tried race shocks and springs. Talk about STIFF!. I decided to use softer springs. Guess what, the car was just aas STIFF. The difference between a 1200 lb spring and an 800 lb spring was masked by the shocks.
I was talking with some guys in the US today and they suggested that all of us will likely end up in the aftermarket world where shocks and springs are concerned. The PASM system will likely not suit our needs for the heavy track guys. Its a shame that the 996 got us used to just doing a set-up and hitting the track. It seems that Motons and the bits that Unitah suggested will likely be "standard equipment" on our cars in the coming months.
With reference to PSS9's I had them on my Turbo and I liked them quite a bit. BUT I think that for the difference I would likely just go to the Moton's and get something industrial strength. Just my $.02
05-08-2007, 05:07 PM
#49
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Originally Posted by Unitah
Interesting, now, what would the benefit be of deactivating the PASM system?
they are defeating PASM to put traditional coil over, moton, jrz and the like on the car.
i dont know if that's better or not, i am just passing info in that PASM can be turned off and coil over installed.
05-08-2007, 05:10 PM
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Originally Posted by supercup
Motorsport setting for my 997 Cup car are:
Basic settings for Michelin slick tyres (as delivered)
Front axle Rear axle Left/right Left/right
Ride height 77 mm 115 mm
Camber - 4° - 4°
Toe setting(total) 0´ + 34´
Anti-roll bar 75° 45°
Main spring 100 - 60 - 260 120 - 60 - 260
Helper spring 75 - 60 - 43 60 - 60 - 40
The sway bars on the Cup are blade type - but for reference 90 degrees is full soft and 0 degrees is full stiff. So you can see the front bar is fairly soft and the rear bar is 1/2 way.
I found the toe setting front and rear on my 996 Cup and my 996 GT2 and GT3's was 0 - 10' total (0-5' per side) in the front and 34' - 40' total (17' - 20' per side). Caster in all cases needed to be in stock setting.
With stock tires it would seem like -3 degrees would be a good start with 0' of front toe and 34' of rear toe, stock caster, with front bar 1 off full soft and the rear bar in the middle (or if only 4 holes, 1 off full stiff). Ride height will play a roll as well.
I am interested to hear what you guys try and what seems to work.
JCM
Basic settings for Michelin slick tyres (as delivered)
Front axle Rear axle Left/right Left/right
Ride height 77 mm 115 mm
Camber - 4° - 4°
Toe setting(total) 0´ + 34´
Anti-roll bar 75° 45°
Main spring 100 - 60 - 260 120 - 60 - 260
Helper spring 75 - 60 - 43 60 - 60 - 40
The sway bars on the Cup are blade type - but for reference 90 degrees is full soft and 0 degrees is full stiff. So you can see the front bar is fairly soft and the rear bar is 1/2 way.
I found the toe setting front and rear on my 996 Cup and my 996 GT2 and GT3's was 0 - 10' total (0-5' per side) in the front and 34' - 40' total (17' - 20' per side). Caster in all cases needed to be in stock setting.
With stock tires it would seem like -3 degrees would be a good start with 0' of front toe and 34' of rear toe, stock caster, with front bar 1 off full soft and the rear bar in the middle (or if only 4 holes, 1 off full stiff). Ride height will play a roll as well.
I am interested to hear what you guys try and what seems to work.
JCM
R+C
05-08-2007, 05:18 PM
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Originally Posted by Apex Late
I was given the exact same information today. 
BUT I would like to get as much out of the stock parts as I can before starting the upgrade process. That being said I'm sure that these purchases will not be too far in the future.
BUT I would like to get as much out of the stock parts as I can before starting the upgrade process. That being said I'm sure that these purchases will not be too far in the future.
05-08-2007, 05:22 PM
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Originally Posted by mooty
if you are referring to why AWE is doing it....
they are defeating PASM to put traditional coil over, moton, jrz and the like on the car.
i dont know if that's better or not, i am just passing info in that PASM can be turned off and coil over installed.
they are defeating PASM to put traditional coil over, moton, jrz and the like on the car.
i dont know if that's better or not, i am just passing info in that PASM can be turned off and coil over installed.
I don't think it's a big deal, but the error code will be read out by your porsche dealer depending on what service you are having done.
05-08-2007, 05:40 PM
#53
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When this began, I thought PASM was a good idea, track stiff and more supple on the way home. UGH. I hope there is a better way than replacing the suspension.
Frayed - working on the driver is always a good strategy but fighting push gets old fast. I can't believe that PAG has dumbed down the car this much. I wonder if the PASM program is flashable. Asato the spring/bar/shock effects, my (probably flawed) theory is as follows. At turn in the shocks are relatively soft and the soft roll bar allows for good grip at initiation. Once the weight transfers the electrons wake up and stiffen the shocks like mad. The greater roll stiffness in front causes the car to push. On the other hand, greater roll stiffness in the back should cancel that out .. but it doesn't! Next event I might try disconnecting the bar in front like we do in the rain to see what effect it has.
best,
Frayed - working on the driver is always a good strategy but fighting push gets old fast. I can't believe that PAG has dumbed down the car this much. I wonder if the PASM program is flashable. Asato the spring/bar/shock effects, my (probably flawed) theory is as follows. At turn in the shocks are relatively soft and the soft roll bar allows for good grip at initiation. Once the weight transfers the electrons wake up and stiffen the shocks like mad. The greater roll stiffness in front causes the car to push. On the other hand, greater roll stiffness in the back should cancel that out .. but it doesn't! Next event I might try disconnecting the bar in front like we do in the rain to see what effect it has.
best,
05-08-2007, 05:50 PM
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Originally Posted by TTRob
Question guys: alignment is so important for proper handling, why does Porsche send these cars out with alignments so far out of spec? I can see small errors, but major differences side to side?? Is it the shipping that plays a part in these errors... the way they're tied down, for example?
I'm sure Porsche knows that track guys will make alignment changes after delivery, but that doesn't mean you ship cars out that barely go straight. It is, after all, a road car. Some owners will drive it out of the dealership and assume it's handling properly. IMO, it should be delivered very close to proper spec.
Also, why can't I get my sig to show up? TIA
I'm sure Porsche knows that track guys will make alignment changes after delivery, but that doesn't mean you ship cars out that barely go straight. It is, after all, a road car. Some owners will drive it out of the dealership and assume it's handling properly. IMO, it should be delivered very close to proper spec.
Also, why can't I get my sig to show up? TIA
best,
05-08-2007, 05:53 PM
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Originally Posted by frayed
Just as an FYI on the PASM issue. The protocol posted will eliminate the error light but an error code is still stored in the controller. It's the high tech solution to putting electrical tape over the idiot light.
I don't think it's a big deal, but the error code will be read out by your porsche dealer depending on what service you are having done.
I don't think it's a big deal, but the error code will be read out by your porsche dealer depending on what service you are having done.
ming, we are f'd.
05-08-2007, 05:57 PM
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On the topic of ride height. We are all talking about how much to lower the car from stock but that assumes that the stock figures for ride height are all standard. This seams unreasonable given that all of the other values on the suspensions of our various cars were different. So I went looking for what the ride height should be in stock positon. This is what I got:
Vehicle height
Note
The following values relate to the empty weight, i.e. full fuel tank/fluid reservoirs, vehicle with tools, but without driver or additional weights!
Vehicle height 911 GT3/911 GT3 RS (997) RoW/USA
Front axle
Height with 19-inch wheels
→ Adjustment value: 108 mm+ 5 mm- 0 mm → :
From road contact surface to lower edge of hexagon-head bolt of cross-member threaded connection to the body.
Rear axle
Height with 19-inch wheels
→ Adjustment value: 133 mm+ 5 mm- 0 mm → :
From wheel contact surface to the locating bore in the rear-axle side section (between toe and camber eccentrics).
Permitted transverse inclination of the vehicle: Max. difference in height, left to right = 5 mm.
Max. wheel-load difference from right to left on front and rear axle is 15 kg.
SO to revise the ride height figures from my earlier set-up post the ride height front should read 96 mm (actual height) for the front axle and 121 mm (actual height) for the rear axel.
Unitah, using this information can you confirm these figures?
Vehicle height
Note
The following values relate to the empty weight, i.e. full fuel tank/fluid reservoirs, vehicle with tools, but without driver or additional weights!
Vehicle height 911 GT3/911 GT3 RS (997) RoW/USA
Front axle
Height with 19-inch wheels
→ Adjustment value: 108 mm+ 5 mm- 0 mm → :
From road contact surface to lower edge of hexagon-head bolt of cross-member threaded connection to the body.
Rear axle
Height with 19-inch wheels
→ Adjustment value: 133 mm+ 5 mm- 0 mm → :
From wheel contact surface to the locating bore in the rear-axle side section (between toe and camber eccentrics).
Permitted transverse inclination of the vehicle: Max. difference in height, left to right = 5 mm.
Max. wheel-load difference from right to left on front and rear axle is 15 kg.
SO to revise the ride height figures from my earlier set-up post the ride height front should read 96 mm (actual height) for the front axle and 121 mm (actual height) for the rear axel.
Unitah, using this information can you confirm these figures?
05-08-2007, 06:22 PM
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Originally Posted by Bob Rouleau
! Next event I might try disconnecting the bar in front like we do in the rain to see what effect it has.
best,
best,
At this stage, you may be overthinking this. I'm not a PASM fan but blaming it (which plays with shock valving affecting mainly transitions) for mid corner push is premature IMO.
My money is still on the bars. WTF was PAG thinking when they sent a car to us that pushes this bad, with only one hole of adjustement? That's crazy.
05-08-2007, 06:27 PM
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Apex Late,
OK, here is what I have. I took the measurements before reading your last post, so, I went to your original request of the fender. I am NOT happy with the results because it seems as though my car is leaning, hahaha.
Data:
-Measurements taken inside perfectly flat and level garage.
-1/2 tank of fuel
-no driver
-GT3 seats (-about 50 lbs) + 997 RS Cage (+ 37 lbs)(for weight and balance purposes)
Left Front: 25 5/8"
Right Front: 25 7/8"
Left Rear: 26 1/8"
Right Rear: 26 3/8"
OK, here is what I have. I took the measurements before reading your last post, so, I went to your original request of the fender. I am NOT happy with the results because it seems as though my car is leaning, hahaha.
Data:
-Measurements taken inside perfectly flat and level garage.
-1/2 tank of fuel
-no driver
-GT3 seats (-about 50 lbs) + 997 RS Cage (+ 37 lbs)(for weight and balance purposes)
Left Front: 25 5/8"
Right Front: 25 7/8"
Left Rear: 26 1/8"
Right Rear: 26 3/8"
05-08-2007, 06:34 PM
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"Bob/Unitah,
This is what I think so far:
Front camber -3.0
Front Caster Max
Front 1/8 toe out (total toe)
Front sway bar full soft
Front ride height lower by 12 mm
Rear camber -2.5
Rear caster Max
Rear 1/8 toe in (total toe)
Rear sway bar full stiff (or one from full stiff depending on preference)
Rear ride height lower by 12 mm
8 degree attack angle on the spoiler with a cup spoiler on the front (no brake duct version to reduce the air flow further at high speed) These are available from Gert and my only concern would be brake cooling. That being said I think that there is more air going under the 997 than the 996 because of the cooling holes and the reduced front lip. Just a thought based on Unitah's high speed comments.
Unitah, does this jive with what you were thinking? The only thing that I'm not final on is the rear camber. I may choose to run even less camber in the rear."
Here is what I am going to shoot for........
Front camber -3.0
Front Caster Max
Front 1/8 toe OUT EACH SIDE
Front sway bar middle position
Front ride height lower 1/2"
Rear camber -2.75
Rear 1/8 toe IN EACH SIDE
Rear sway bar full stiff
Rear ride height lower by 1/2"
Wing: 8° AOA
Cup Car front Splitter (do you have a part number for this????)
Rear Cup Car toe links
Solid motor mounts (leaving tranny mount Cadillac sponge rubber for now)
After the above, then on to round 3:
-get rid of heavy *** exhaust system: straight pipes baby!!! hahaha
-LWFW / Clutch
-Solid cup car tranny mount
-?Cup car gears or final drive ratio
-and lastly: if I am still unsatisfied --> conversion to full RSR suspension system with all solid, spherical uniballs and fully adjustable shocks. Removing every last bit of rubber from the suspension system.
This is what I think so far:
Front camber -3.0
Front Caster Max
Front 1/8 toe out (total toe)
Front sway bar full soft
Front ride height lower by 12 mm
Rear camber -2.5
Rear caster Max
Rear 1/8 toe in (total toe)
Rear sway bar full stiff (or one from full stiff depending on preference)
Rear ride height lower by 12 mm
8 degree attack angle on the spoiler with a cup spoiler on the front (no brake duct version to reduce the air flow further at high speed) These are available from Gert and my only concern would be brake cooling. That being said I think that there is more air going under the 997 than the 996 because of the cooling holes and the reduced front lip. Just a thought based on Unitah's high speed comments.
Unitah, does this jive with what you were thinking? The only thing that I'm not final on is the rear camber. I may choose to run even less camber in the rear."
Here is what I am going to shoot for........
Front camber -3.0
Front Caster Max
Front 1/8 toe OUT EACH SIDE
Front sway bar middle position
Front ride height lower 1/2"
Rear camber -2.75
Rear 1/8 toe IN EACH SIDE
Rear sway bar full stiff
Rear ride height lower by 1/2"
Wing: 8° AOA
Cup Car front Splitter (do you have a part number for this????)
Rear Cup Car toe links
Solid motor mounts (leaving tranny mount Cadillac sponge rubber for now)
After the above, then on to round 3:
-get rid of heavy *** exhaust system: straight pipes baby!!! hahaha
-LWFW / Clutch
-Solid cup car tranny mount
-?Cup car gears or final drive ratio
-and lastly: if I am still unsatisfied --> conversion to full RSR suspension system with all solid, spherical uniballs and fully adjustable shocks. Removing every last bit of rubber from the suspension system.
05-08-2007, 07:05 PM
#60
my 2 cents...when i went from 996 GT3 to 997S i was prepared for the typical stock set up 996 understeer. before getting it aligned at www.euautowerks.com i slapped on my 18 inch FIKSES with MPSC and hit the track. the car was awful,understeer.. oversteer awful...when i put the stock 19 inch wheels on with the stock PS2 it felt like a dream. no understeer very neutral. i think you just need to find the front end set up that the tires that come on the car like..whatever camber,toe whatever...i think it will then work better. play with it until you make the right set up work..take lotsa notes and have a good driver and knowledgeable suspension guy with you. thats what i did with my 996GT3 and thats what i would do if i were you...new cars take time to set up..seems like the rear is good...the front will come too
P.S my lotus Exige S is awesome right out of the box SUCKERS!!!!
P.S my lotus Exige S is awesome right out of the box SUCKERS!!!!