In reading other forums and articles you often hear about the cars HP and then the HP at the wheels. I do not recall seeing anyone mention this on Rennlist. Does anyone know what the HP is at the wheels for the 997 and 997s?

 

As a general rule on the P-cars. reduce the advertised HP by 15% on a 6 speed and 19% on a TIP. I know for a fact that the 15% holds true on the 6 speed. You may need to deduct slightly more for the automatic. AWD are also reduced more than the RWD.

 

Is the gear box in the 996 the same as in the 997? If not, will the losses be the same?

 

Losses will be the same. The have been no changes in the manual gear boxes that will either reduce or increase the power loss going through it.

 

So, unfortunately no progress in that area. Any idea how these gear boxes compare to other manufacturers?

 

i would assume that compared to other cars with the traditional front engine/rear drive setup, the 911 would have less drivetrain loss. basicall,y since there is no long drive shaft transferring the power to the wheels, i would think that there is less loss of hp at the wheels. but i dont know much

 

You have to remember that the amount of loss in power and torque is directly effected by many things. These include the number of parts, the weight and size of the parts, the number of unions and their angle and any hydrolic or other Non-mechanical and drect connections between the crank and the wheels. In the case of a 6 speed, there is a direct connections You are either drirectly connected between the flywheel and the wheels, or you are not. This assumes your pressure plate is working as desgned.

 

In addition, the straight axle cars with front engine lose alot of power through the drivetrains particularly when they raise the backend of the car. This is caused because of the increase in the angle of the driveshaft to the tranny.

 

You are right, I should have said, no progress in the area of power losses for the gear box, but I can see progress in weight, size, tolerances and so response. Do you have any comparison data in that area: weight, size.....

Regarding the font motor, rear wheel drive: I can see more losses, not perse due to the longer shaft, but also in response time. The long shaft will twist before it will transport the torque. That is not directly a loss, but very important in the area of response.

I was trying to compare with front wheel drive with front motor, as that is more close. 15% is the statement for the 997, what are others doing?

 

There is very little difference in drivetrain loss (if any) between the RWD Porsche and a FWD front engine car. Both have minimal drivetrain angles. As far as weight, you would be amazed as to how much weight effects the response to a cars power. For instance, a weight difference of 30 pounds on a 3,000 pound car with 300 HP will effect the performance of the car the same as a 5 HP change. So find a way to reduce the car's weight by 180 pounds and it is like adding 30 more HP. You might have noticed that you car's performance is considerably less when you carry a passenger with you.

 

Yep, that is why I keep my car empty and have the non-S version. I'm gaining about 10 HP on personal weight, 10 HP while I have hardly any stuff in the car, and 10 HP as my fuel tank is normall half full :-)). So a total of 30 HP.

Interesting enough Porsche mentions in the manuals that they test the acceleration with a certain load, and that is to my opion one of the reasons others can find easily better numbers, besides the influence of weather and so on. If you put a tiny test driver in, the numbers will look good.

Still the question: what kind of weight gain did they get between the 996 and 997?

 

2005 997's curb weight is 3.075 and the 99 C2's is 2,910. That's a 165 lbs difference. Therefore, using the example of weight to HP noted above, the 99 with HP of 296 and the 2005 with HP of 325 actually have a weight to power ratio difference of about 10 hp. The 997 has 1 HP for every 9.46 ponds and the 99-996 c2 has 9.83 pounds for every 1 HP.

 

My 997S dynoed at 317 at the wheels. (GT3 had 353)

 

You need to be carefull with dyno numbers. Depending on what dyno is used and what adjustments are made, the results can vary tremendously. The SAE WHP of a stock 2004 GT3 is 325 and the 355 HP 997S is 300. Only by using the SAE standards can you come close to fairly comparable results. You could take you car to a mustang dyno and they would show your 997S as having close to 360 whp and would swear up and down that that is accurate.

Bottom line is, dynos are only good to compare apples to apples for perfromance improvements. It doesn't matter what the results show, but only that they are consistant.

 

1999 i agree completely