I spent a considerable amount of time searching on the forums yesterday but couldn't find an easy answer. Looking for dyno charts or peak figures. I would like to klnow the difference between the two and also the numbers they put out. I saw one post about a dyno day where C2s were putting out around 285-295 whp...

Any info is appreciated. Seems like not too many p-car owners visit the dyno or they don't post their numbers.

Thank you

 

Nobody?

 

some of tuner threads such as the "awe exhaust" thread have dyno info. Otherwise, I don't think many owners are tuning their cars beyond suspension and exhaust options. (and mostly to make the cars better track cars) There are not many porsche forums either, compared to ford and chevy or "import" tuner forums. Those always seems to have scads of dyno data!

 

Thanks John. What I am looking for actualy is to determine the following:

-Are the C4 and C4s engines underrated from the factory or do they produce 325 hp and 345 hp as claimed by porsche?
-I am also interested in the difference in power AWD cars are puting vs RWD...

Example, we know that the BMW 335 really produces around 330 hp and not 300 hp as the manufacturer claims. Also, dyno stats show that the 335xi actualy produces slightly more power at the engine than the 335. BMW probably did this to offset the AWD losses...

I was just interested in gathering some data on porsches...

 

I'd be curious too. The c2s feels like more than 345 to me.

 

There are strict legal requirements in Europe for engines to be very close to the rated output - I would imagine the same is true in North America. Add to this that every Porsche engine is tested for power output on a test rig prior to going in a car and you can be very sure they're all within a very few HP of the nominal rated output.

I'd also be very interested to know why people think BMW is producing engines that are illegal. That's probably just more bad dyno practice giving meaningless results.

 

that is a tall order! From what we have been discussing, here and on other forums, is that dyno data is rarely interchangeable and can have some pretty large variations. For a turbo BMW motor, it is pretty easy to tell the computer to just "add" a little boost to offset the added drag and weight of a AWD system. With a normally aspirated motor, that would cost money to do. "Chips" and similar electronic tuning are not as fruitful without a nice wastegate and turbo! I would have to say that I doubt that the AWD models are tuned any different than 2wd porsches. For example, the recent C&D test of a base 911 put up similar accel times as a C4S that they tested in the next months mag. If anything the AWD seemed a bit slower than expected. (the 1/4 mile data was about the same as the 2wd model, and should have had a bigger benefit due to the extra HP) Now, some of this may be due to the advantage the DSG tranny, but I doubt it. (the claims of millisecond shifts never seem to outweigh the launch and weight disadvantages) I would be more inclined to believe that the drag and extra 200lbs on the C4S were the culprit, and negated the HP advantage.
I have also been a bit skeptical on the 335 power numbers, since they should make the care significantly faster than an E46 M3...which they are not. It should actually make them faster than the E92 M3, which they are not. According to some dynos, they have 20-30 more BHP than the E46 M and about 70 more lb/ft of torque in a similar weight vehicle!! It is therefore shocking that the 335 cannot get through a 1/4 quicker or at a higher trap speed than an M3. So, I would agree with other members and take the dyno data with a grain of salt.

 

Any info is appreciated. Seems like not too many p-car owners visit the dyno or they don't post their numbers.

Thank you[/quote]

There have been a # of dyno threads. Go to the search feature and you'll get all kinds of info - some good and some total BS (as on any forum). I think that you'll quickly find that there is extreme variability determined by which dyno, which operator, temperature, humidity, blah blah blah. I'd like to think that the charts from awe, fabspeed, and others are accurate - you be the judge. You can easily contact these guys at their web sites:
http://www.awe-tuning.com or www.fabspeed.com

 

From various threads and post I have seen, the factor for converting crankshaft to rear wheel horsepower is 80% or 83% to 84% for all wheel drive or two wheel drive, respectively. This is not a scientific study.

 

The engines in a 997.1 C2 and C4 produce the same amount of power at the crank, 325. The engines in a 997.1 C2S and C4S produce the same amount of power at the crank, 355, unless the option X51 package was ordered then the engines are rated at 381hp.

I would imagine that there is a little more loss of power at the wheels on the 4 wheel drive versions, but I doubt it is a major loss.

As for the 335's push 330hp on a 300hp rated engine, I would think that this has come from bad dyno testing, or incorrect calculations. I doubt that anyone has pulled an engine and tested it at the crank, as well if BMW was producing 330hp they would be selling it as such. Remember the age old saying;

Horsepower sells cars, Torque wins races!

 

Many 335s have been shown to put down 290-295 at the wheels on dyno jets. Dyno jets happen to give the highest numbers but a 300hp car usualy puts out around 250-270 at the wheels not around 300... This has been fairly well documented. I don't own a 335, neither am I planning to buy one ... So I have no interest on spreading false truths

 

There have been a # of dyno threads. Go to the search feature and you'll get all kinds of info - some good and some total BS (as on any forum). I think that you'll quickly find that there is extreme variability determined by which dyno, which operator, temperature, humidity, blah blah blah. I'd like to think that the charts from awe, fabspeed, and others are accurate - you be the judge. You can easily contact these guys at their web sites:
http://www.awe-tuning.com or www.fabspeed.com [/quote]

Did a lot of searching prior to posting. Saw some dyno threads but the subjects seemed to be more baseline vs mods... I will take another look. Thank you.

 

John, the problem with a 335 in a 335 vs E46 M3 race is the lack of a limited slip differential. Hooking up with all that power with the skiny rear tires and no limited slip is a real prob... Power is nothing if you don't have traction.

 

If that is the case it would mean that the porsche AWD system is fairly efficient. I know that on the newest 997s, porsche switched to an electronic system instead of a viscous coupling based system... This is one of the areas that interests me. I want to learn more about the Porsche AWD system if possible.

Thank you all for your participation. Any input is welcome.

 

True true. My 335 xi with Dinan V2 and exhaust mods put down 337 rwhp at altitude (Denver). With all the fudge factors we figures crank HP to be a little over 400, meaning the stock engine would have to be around 325. There is no doubt the modified 335xi is way torqueier than both the M3's and my 997 (targa) C4s, at least IMHO.

This is my first Porsche. I find the real life power curve way different than the BMW. It might be because the amazing PDK smooths everything out so much.