997 GT3 and RS Understeer! Alignment Question
05-24-2007, 11:09 AM
#151
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[QUOTE=997_GT3]
997,
My GT3 is actually very well balanced when I run about 90% of my full effort. 90% is still pretty fast but not anywhere near the limit (my limit). However, if I push the car (and myself) to carry more speed the car (or tires) give up and start to push badly. A forum like this is interesting in that we all drive the same car but we all drive it very differently. As such we will always experience very different cars in the end. The trick is to find people that are getting similar performance out of their cars at tracks that are the same or similar to the tracks that you are running on. In my opinion the Corsa's were a terrible tire for the 997 GT3 based on the way that I'm driving the car. But like many things one mans junk is another mans treasure.
I also had a 996TT and in my opinion the cars are difficult to compare. They are very different beasts and I would expect the GT3 to be quite a bit faster on most race tracks.
Originally Posted by Apex Late
After taking a hard look at the front tires I'm convinced that a good bit of the understeer comes from the channels that are present in the N spec tire. There is a little more than an inch of missing rubber with those damn things there. /QUOTE]
My car came with Corsas. I didn't have notable understeer issues at TWS except at the slow carousel turn. Perhaps the tires are playing a role in the understeer (I haven't changed anything from delivery as of yet).
I may not be driving as close to the limits as you guys though. The 997 GT3 is so superior to my 996TT that I am turning 5 seconds quicker lap times without any feeling of peril and probably not pushing the car at all.
My car came with Corsas. I didn't have notable understeer issues at TWS except at the slow carousel turn. Perhaps the tires are playing a role in the understeer (I haven't changed anything from delivery as of yet).
I may not be driving as close to the limits as you guys though. The 997 GT3 is so superior to my 996TT that I am turning 5 seconds quicker lap times without any feeling of peril and probably not pushing the car at all.
My GT3 is actually very well balanced when I run about 90% of my full effort. 90% is still pretty fast but not anywhere near the limit (my limit). However, if I push the car (and myself) to carry more speed the car (or tires) give up and start to push badly. A forum like this is interesting in that we all drive the same car but we all drive it very differently. As such we will always experience very different cars in the end. The trick is to find people that are getting similar performance out of their cars at tracks that are the same or similar to the tracks that you are running on. In my opinion the Corsa's were a terrible tire for the 997 GT3 based on the way that I'm driving the car. But like many things one mans junk is another mans treasure.
I also had a 996TT and in my opinion the cars are difficult to compare. They are very different beasts and I would expect the GT3 to be quite a bit faster on most race tracks.
05-24-2007, 11:41 AM
#152
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[QUOTE=Apex Late]
997,
My GT3 is actually very well balanced when I run about 90% of my full effort. 90% is still pretty fast but not anywhere near the limit (my limit). However, if I push the car (and myself) to carry more speed the car (or tires) give up and start to push badly. A forum like this is interesting in that we all drive the same car but we all drive it very differently. As such we will always experience very different cars in the end. The trick is to find people that are getting similar performance out of their cars at tracks that are the same or similar to the tracks that you are running on. In my opinion the Corsa's were a terrible tire for the 997 GT3 based on the way that I'm driving the car. But like many things one mans junk is another mans treasure.
I also had a 996TT and in my opinion the cars are difficult to compare. They are very different beasts and I would expect the GT3 to be quite a bit faster on most race tracks.
I agree wholeheartedly with this statement and want to add that while two drivers may have similar (very good) lap times, their styles, and therefore their setups may be very different.
Originally Posted by 997_GT3
997,
My GT3 is actually very well balanced when I run about 90% of my full effort. 90% is still pretty fast but not anywhere near the limit (my limit). However, if I push the car (and myself) to carry more speed the car (or tires) give up and start to push badly. A forum like this is interesting in that we all drive the same car but we all drive it very differently. As such we will always experience very different cars in the end. The trick is to find people that are getting similar performance out of their cars at tracks that are the same or similar to the tracks that you are running on. In my opinion the Corsa's were a terrible tire for the 997 GT3 based on the way that I'm driving the car. But like many things one mans junk is another mans treasure.
I also had a 996TT and in my opinion the cars are difficult to compare. They are very different beasts and I would expect the GT3 to be quite a bit faster on most race tracks.
05-24-2007, 12:30 PM
#153
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Apex Late....your points are well made. I'm probably not pushing the car very hard in comparison to most folks who are used to driving a more track oriented car (plus I've only have 30 track days of experience which I know is little compared to most folks on this forum).
Regarding the Corsas, I was just thinking that if more tire is missing on the front of the n-spec MPSC due to the rain channels relative to the rears this alone might create a understeering situation. The Corsas have a symetrical front tire to back tire pattern which might make them more balanced even though they are non-grippy and crappy tires when compared to MPSCs . Perhaps the regular MPSCs (without the larger rain channels) will be more balanced.
I haven't tried MPSC's on my GT3. I will after the Corsas wear out. The MPSC's were definitely the tire to go with on the pig (my 996TT).....cheers.
Regarding the Corsas, I was just thinking that if more tire is missing on the front of the n-spec MPSC due to the rain channels relative to the rears this alone might create a understeering situation. The Corsas have a symetrical front tire to back tire pattern which might make them more balanced even though they are non-grippy and crappy tires when compared to MPSCs . Perhaps the regular MPSCs (without the larger rain channels) will be more balanced.
I haven't tried MPSC's on my GT3. I will after the Corsas wear out. The MPSC's were definitely the tire to go with on the pig (my 996TT).....cheers.
05-24-2007, 12:40 PM
#154
work around the problem
I am also still experiencing more corner exit understeer under full aproach driving than I like (espeacially in slower corners like 180's) and also would love to find a technical solution for that in order to be 100% happy with the car. For tirewear reasons alone I have to say.
But after being frustrated at first (even though laptimes were good compared to ex996GT3) things got better because you actually can do something yourself on the matter. I was able to reduce the push by driving a bit more V than U in the turns, which allows you to be earlier on full thottle with a straighter car. Because there is no turn-in understeer, especially not if you brake into the turn, this works very well and gives you a great speed overall.
Slow-in/fast-out is actually not a novelty for fast Porsche driving, right?
But after being frustrated at first (even though laptimes were good compared to ex996GT3) things got better because you actually can do something yourself on the matter. I was able to reduce the push by driving a bit more V than U in the turns, which allows you to be earlier on full thottle with a straighter car. Because there is no turn-in understeer, especially not if you brake into the turn, this works very well and gives you a great speed overall.
Slow-in/fast-out is actually not a novelty for fast Porsche driving, right?
05-24-2007, 06:09 PM
#156
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"What's in a name? That which we call a rose by any other name would smell as sweet."
In my case it was the only handle that I could think of on short notice its not a representation of my driving style
In my case it was the only handle that I could think of on short notice its not a representation of my driving style
05-24-2007, 06:14 PM
#157
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.
Just noticed this post.
You are incorrect.
We spent a few hours at our local dealer working on this. We have removed the PASM module from the car and reintroduced all of the computers to the Gateway. We choose to not look for the PASM module.
The car now thinks it is no longer there.
No faults
No errors
No lights
We frequently scan the car to make sure nothing has popped up.
This is about as clean a procedure as it gets.
05-24-2007, 06:33 PM
#159
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Originally Posted by Bob Rouleau
Update - Three days of tracking the RS and I am happy to report that the car now handles well, sharp turn in and no understeer except in slow corners - which is typical of all 911s. With the settings below the car ran with the big dogs (finally!). It was especially impressive for stability in the infamous McLaren (turns 1-2-3). The car was planted - perhaps the big *** wing did it but the car was confidence inspiring in what is normally a butt clenching complex.
Front Rear
Toe 0 16 mins per wheel
Camber neg 2.5 neg 2.0
Caster 8 deg
Sways Full soft Full stiff
Wing Max angle
Height Factory spec.
At Le Circuit the car was a pleasure to drive and quick. I will probably fiddle some more but this set-up works quite well. Ran Michelin Cups 19 inch N 0 spec 32 lbs F 34lbs rear hot pressure.
Now for 18 inch rims so I can use the stickier Cups which are not the N0 Spec.
Best,
Front Rear
Toe 0 16 mins per wheel
Camber neg 2.5 neg 2.0
Caster 8 deg
Sways Full soft Full stiff
Wing Max angle
Height Factory spec.
At Le Circuit the car was a pleasure to drive and quick. I will probably fiddle some more but this set-up works quite well. Ran Michelin Cups 19 inch N 0 spec 32 lbs F 34lbs rear hot pressure.
Now for 18 inch rims so I can use the stickier Cups which are not the N0 Spec.
Best,
OTOH, I'm running your specs and my first track day proved that the car was too biased for oversteer. Note that (i) I have the regular 3 which might be slightly less grippy out back and (ii) I'm sure I don't have your skills.
For now I'll get a bit more rear camber, a bit less front camber and get some seat time in.
For 997_GT3, in the carousel at TWS I was getting no push with these specs. It was incredible frankly, b/c *everything* pushes in the carousel. It was a revelation. . . though T2 was a bit scary.
05-24-2007, 06:38 PM
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Originally Posted by Mike/A.W.E.
Just noticed this post.
You are incorrect.
We spent a few hours at our local dealer working on this. We have removed the PASM module from the car and reintroduced all of the computers to the Gateway. We choose to not look for the PASM module.
The car now thinks it is no longer there.
No faults
No errors
No lights
We frequently scan the car to make sure nothing has popped up.
This is about as clean a procedure as it gets.
You are incorrect.
We spent a few hours at our local dealer working on this. We have removed the PASM module from the car and reintroduced all of the computers to the Gateway. We choose to not look for the PASM module.
The car now thinks it is no longer there.
No faults
No errors
No lights
We frequently scan the car to make sure nothing has popped up.
This is about as clean a procedure as it gets.
My confidence in the folks who told me this (won't name names) is shaken anyway, as I've been trying to buy some go fast parts and have been getting the run around for literally months. Seats, bar, linkages etc. I'm done with them.
05-24-2007, 06:39 PM
#161
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throttlesteer - Comments about understeer from Apex Late, Racerron and myself are relative to our 996GT3s. One of the corners where we cursed the understeering nature of the 997GT3/RS (before finding the right set-up) is best executed as a kind of a V as you describe. We turn in early, constant speed- then lift to rotate and accelerate. Until I tweaked alignment I watch a well driven 996GT3 on 18 inch cups motor away from me in that corner using the same technique as I was. Apex has tried some decidely untidy techniques to deal with the problem (grin) but untimately found that an "anti-understeer" alignment was needed.
Re: 19 inch wheels. Perhaps they are needed to clear the ceramic rotors - but I doubt it since the cup race cars run PCCB with 18 inch wheels. I think it is a "bling" factor more than anything else. With the cast iron rotors, 18 inch wheels work fine. In fact wheels from a 993TT fit!
I also agree that the big rain grooves in the 19 inch N spec tires reduce grip considerably. That's why I am going with 18 inch wheels. I am also pretty sure that rubber is lighter than metal which is why I don't think much of 19 inch wheels in the first place.
Best,
Re: 19 inch wheels. Perhaps they are needed to clear the ceramic rotors - but I doubt it since the cup race cars run PCCB with 18 inch wheels. I think it is a "bling" factor more than anything else. With the cast iron rotors, 18 inch wheels work fine. In fact wheels from a 993TT fit!
I also agree that the big rain grooves in the 19 inch N spec tires reduce grip considerably. That's why I am going with 18 inch wheels. I am also pretty sure that rubber is lighter than metal which is why I don't think much of 19 inch wheels in the first place.
Best,
05-24-2007, 06:40 PM
#162
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Originally Posted by Porsche997gt
I see a lot of people switching back to 18". I thought Porsche putted 19" so it could clear the bigger brakes... 
05-24-2007, 06:46 PM
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Originally Posted by Mike/A.W.E.
Just noticed this post.
You are incorrect.
We spent a few hours at our local dealer working on this. We have removed the PASM module from the car and reintroduced all of the computers to the Gateway. We choose to not look for the PASM module.
The car now thinks it is no longer there.
No faults
No errors
No lights
We frequently scan the car to make sure nothing has popped up.
This is about as clean a procedure as it gets.
You are incorrect.
We spent a few hours at our local dealer working on this. We have removed the PASM module from the car and reintroduced all of the computers to the Gateway. We choose to not look for the PASM module.
The car now thinks it is no longer there.
No faults
No errors
No lights
We frequently scan the car to make sure nothing has popped up.
This is about as clean a procedure as it gets.
Is the procedure that you posted a while ago still up to date? We are going through this right now and any advise would be greatly appreciated.
grussell@ushorizon.com
05-24-2007, 07:03 PM
#164
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Originally Posted by Porsche997gt
I see a lot of people switching back to 18". I thought Porsche putted 19" so it could clear the bigger brakes...
05-24-2007, 07:09 PM
#165
Originally Posted by grussell
Mike,
Is the procedure that you posted a while ago still up to date? We are going through this right now and any advise would be greatly appreciated.
grussell@ushorizon.com
Is the procedure that you posted a while ago still up to date? We are going through this right now and any advise would be greatly appreciated.
grussell@ushorizon.com
Let me know how you make out.
We have had our Moton's on for a few weeks now. Zero issues and the car handles vastly better than the OEM.
Low speed compression is amazing. Car does not wallow through high speed corners. It's compliant and NOT harsh. The finest suspension we have ever installed on a car.