What makes the .2 "S" so freakin' fast?
#61
06-02-2009, 07:34 AM
I added the 996 Tequipment Bar to mine, forgot to weigh it before install, but it was not heavy at all. I also removed my rear seat backs and I am sure that they cancelled each other out.
#62
06-02-2009, 07:40 AM
http://e-partssales.com/Merchant2/me...e=997seatsroll
It says that it only weighs 26lbs, I am sure that is without the sliders.
I have these seats for the track, 996 GT3 Euro CS
http://e-partssales.com/Merchant2/me...e=997seatsroll
If that is what you are thinking of ordering on your car, I say go for it. I would have bought those seats for my car, however they were about 6 months behind my schedule (and I picked the 996 seats up for $2600 for the pair).
#63
06-02-2009, 07:41 AM
Join Date: Apr 2004
Location: North Dakota
Posts: 9,541
Rep Power: 502 
We still haven't gotten any official figures on the weight. I'm surprised no one has come up with that yet.
Based on the car and driver that I just got in the mail...
The 2010 GT3 is 3250
The 09 Boxster S is 3220
The 997S has got to be at least those numbers... Probably heavier.
As far as skill coming into play with a roll on...
Despite the fact that the Greeks haven't done anything noteworthy in history since before Christ was born, I'm convinced I could teach one to just floor it and do a shift or two with no problems
Highway roll ons are about the easiest thing you do when it comes to motorsports. I'm living proof of that as I'm mildly retarded when it comes to driving.
#64
06-02-2009, 07:42 AM
Join Date: Apr 2004
Location: North Dakota
Posts: 9,541
Rep Power: 502
I would guess it's at least 25 pounds. No?
#67
06-02-2009, 08:00 AM
Join Date: Apr 2004
Location: North Dakota
Posts: 9,541
Rep Power: 502 I picked it up once before it was installed but I never weighed it. It had some heft to it, but I wouldn't call it heavy either.
#68
06-02-2009, 10:01 AM
I was with a buddy at Sebring today. He's got an 09 S. We didn't really get much of an opportunity to mix it up on the track, but we did do a few roll ons on the way home. The cars were pretty much dead even. How is this possible? I have at least 120hp on him with my supercharger. I have run other cars with similar HP ratings to mine and the runs were very close. How is the .2 "S" able to match this performance with such a HP deficit. I was very impressed to say the least. Are they way under rated at 385?
The 997S.2 PDK has a 7-speed 'box so I'm assuming the gears are more closely stacked than the 6-speed. In essence, this allows the engine to stay in its optimal 'zone' for more of the time. If you can constantly run the engine at or near peak power then it's imparting more energy to the vehicle and will give better results than one that's being used further down the power curve.
What we need to do to 'prove' what's going on is to graph the actual 'thrust' the engine gives the 2 cars, yours and the PDK car, between the speeds at which you started and finished your side-by-side runs. This is easily done if we have a flywheel torque curve and a full set of gear and final drive ratios for both cars. The thrust (in lbs) imparted on the vehicle at any given moment can then be calculated by:
torque (lb-ft) x ratio of the gear the car is in x the ratio of the final drive / rolling radius of the rear wheels in feet. As we're all aware (and as mentioned above) there will also be losses due to friction in the drivetrain but we can only estimate these.
If we graph the thrust on the cars v. the speed of the car in, say, 500rpm intervals, we'll get a picture of the performance being imparted by the engine. If we compare these graphs and the vehicles' weights, we'll get our answers as to why the 997S.2 is apparently so fast.
Whilst we can use the factory torque graph to do this for the 997S.2, we unfortunately don't know how much energy is lost to friction - this can only be estimated. Also we have no flywheel torque curve for your car. The torque curve on your dyno plot isn't 'torque at the wheels' as this is gear dependent and is always several times engine torque. What it is is a calculated set of figures based on the wheel HP and rpm of the engine. Effectively it's what the engine torque curve would be if the wheel HP were, in fact, the flywheel HP. It's like a torque curve including the transmission losses but calculated, not measured. As it's all we have, then it will have to do!
What we have to decide is how much percentage of the energy produced by the 997S.2 engine we will assume to be lost to friction. Historically, 15% was considered about right for 2WD 997s. Unless Porsche has developed a much more efficient, less power hungry, transmission for 997.2 then this will also have to do.
I'll try to do the math over next weekend and hopefully put up some graphs next week. Then, fingers crossed, we'll have you an answer!
All I need you to confirm is if your car is still running standard gear and final drive ratios?
#69
06-02-2009, 10:14 AM
Registered User
Join Date: Aug 2004
Location: Chicagoland
Posts: 2,134
Rep Power: 122 I have a hunch that this is most likely down to gearing/weight. In theory we can do some calculations and graphs to prove the point. However we have some problems as 1) your car is non-standard and we don't have a flywheel torque curve and 2) we don't know the transmission loss percentage for a 997S.2 PDK. (More later).
The 997S.2 PDK has a 7-speed 'box so I'm assuming the gears are more closely stacked than the 6-speed. In essence, this allows the engine to stay in its optimal 'zone' for more of the time. If you can constantly run the engine at or near peak power then it's imparting more energy to the vehicle and will give better results than one that's being used further down the power curve.
What we need to do to 'prove' what's going on is to graph the actual 'thrust' the engine gives the 2 cars, yours and the PDK car, between the speeds at which you started and finished your side-by-side runs. This is easily done if we have a flywheel torque curve and a full set of gear and final drive ratios for both cars. The thrust (in lbs) imparted on the vehicle at any given moment can then be calculated by:
torque (lb-ft) x ratio of the gear the car is in x the ratio of the final drive / rolling radius of the rear wheels in feet. As we're all aware (and as mentioned above) there will also be losses due to friction in the drivetrain but we can only estimate these.
If we graph the thrust on the cars v. the speed of the car in, say, 500rpm intervals, we'll get a picture of the performance being imparted by the engine. If we compare these graphs and the vehicles' weights, we'll get our answers as to why the 997S.2 is apparently so fast.
Whilst we can use the factory torque graph to do this for the 997S.2, we unfortunately don't know how much energy is lost to friction - this can only be estimated. Also we have no flywheel torque curve for your car. The torque curve on your dyno plot isn't 'torque at the wheels' as this is gear dependent and is always several times engine torque. What it is is a calculated set of figures based on the wheel HP and rpm of the engine. Effectively it's what the engine torque curve would be if the wheel HP were, in fact, the flywheel HP. It's like a torque curve including the transmission losses but calculated, not measured. As it's all we have, then it will have to do!
What we have to decide is how much percentage of the energy produced by the 997S.2 engine we will assume to be lost to friction. Historically, 15% was considered about right for 2WD 997s. Unless Porsche has developed a much more efficient, less power hungry, transmission for 997.2 then this will also have to do.
I'll try to do the math over next weekend and hopefully put up some graphs next week. Then, fingers crossed, we'll have you an answer!
All I need you to confirm is if your car is still running standard gear and final drive ratios?
The 997S.2 PDK has a 7-speed 'box so I'm assuming the gears are more closely stacked than the 6-speed. In essence, this allows the engine to stay in its optimal 'zone' for more of the time. If you can constantly run the engine at or near peak power then it's imparting more energy to the vehicle and will give better results than one that's being used further down the power curve.
What we need to do to 'prove' what's going on is to graph the actual 'thrust' the engine gives the 2 cars, yours and the PDK car, between the speeds at which you started and finished your side-by-side runs. This is easily done if we have a flywheel torque curve and a full set of gear and final drive ratios for both cars. The thrust (in lbs) imparted on the vehicle at any given moment can then be calculated by:
torque (lb-ft) x ratio of the gear the car is in x the ratio of the final drive / rolling radius of the rear wheels in feet. As we're all aware (and as mentioned above) there will also be losses due to friction in the drivetrain but we can only estimate these.
If we graph the thrust on the cars v. the speed of the car in, say, 500rpm intervals, we'll get a picture of the performance being imparted by the engine. If we compare these graphs and the vehicles' weights, we'll get our answers as to why the 997S.2 is apparently so fast.
Whilst we can use the factory torque graph to do this for the 997S.2, we unfortunately don't know how much energy is lost to friction - this can only be estimated. Also we have no flywheel torque curve for your car. The torque curve on your dyno plot isn't 'torque at the wheels' as this is gear dependent and is always several times engine torque. What it is is a calculated set of figures based on the wheel HP and rpm of the engine. Effectively it's what the engine torque curve would be if the wheel HP were, in fact, the flywheel HP. It's like a torque curve including the transmission losses but calculated, not measured. As it's all we have, then it will have to do!
What we have to decide is how much percentage of the energy produced by the 997S.2 engine we will assume to be lost to friction. Historically, 15% was considered about right for 2WD 997s. Unless Porsche has developed a much more efficient, less power hungry, transmission for 997.2 then this will also have to do.
I'll try to do the math over next weekend and hopefully put up some graphs next week. Then, fingers crossed, we'll have you an answer!
All I need you to confirm is if your car is still running standard gear and final drive ratios?
#70
06-02-2009, 11:15 AM
I think Dog should trade in the European sports car for an American "straight line" muscle car...I hear the new Dodge Challenger SRT8 is pretty fast in a straight line...
#71
06-02-2009, 12:08 PM
Dog, lets weight my 09 997S and let do some drag racing. We could do something fun and official at Desoto Dragway in Bradenton on HWY64 or Suneshine in Clearwater...it is not far at all.
#72
06-02-2009, 01:12 PM
Join Date: Apr 2004
Location: North Dakota
Posts: 9,541
Rep Power: 502 If I remember right Mr. "I'm getting moved up to the yellow class next time", the last we drove together I got a point by from you before the safety pin and never saw you again for the rest of the session. Not bad for a guy in a 996 who doesn't know how to turn left or right
#73
06-02-2009, 01:21 PM
Join Date: Apr 2004
Location: North Dakota
Posts: 9,541
Rep Power: 502 As far as drag racing... Are you out of your mind? My 6speed vs your PDK with launch control... I can already tell you how that would turn out
We could find a nice quiet place to do a couple rolls though.
#75
06-02-2009, 01:51 PM
The 997S is indeed a very fast car, and all those Gustav videos are another proof of how fast this car can be compared to +420hp beasts.