Hi,
I'm sorry, but I have to chime in here, probably to the chagrin of a few...
A Dyno can be a very precise tool, but more often than not, is used in a most
imprecise way. There are so many variables affecting the outcome of a Dyno that very few shops even consider, let alone control.
Fuel Quality, Alternator Load, Tire Make, Model, Pressure and Temperature, Heat Soak (Engine, Tranny, Fluids), Advance Curves, Ambient Temperature, Barometric Pressure, etc. are all variables which have
definite effect on the results.
A simple XY Graph, without controlling and matching these variables, means
NOTHING!. And, an XY Graph without a set of Baseline #s mean even less than that.
Most Dyno Shops are in the
Feel Good business, they invest $25k in a Rolling Road, maybe another $1k in minimal software and generate lots of
Happy Graphs for their Happy Customers who all rush out to tell their friends which generates more business for the Dyno Shop. The Dyno-Jet has been the best friend the Aftermarket ever had.
But, there's an old addage in testing:
Garbage IN... Garbage OUT. Automakers do dyno runs which cost them an average of $25k per run, do you really think that plopping down $50-$100 bucks at your local Dyno Shop can yield results which are just as accurate?
You may choose to believe that the variables I've mentioned have minimal effect, but they are well within the values of the reported gains. In other words, if a varable has a 10 HP effect, and your gains show 10 HP, without knowing whether that variable was present or not, you cannot attribute the gains to the Mod - you are within the degree of error of the testing. Multiple runs don't confirm anything either if the same inaccuracies are present and unaccounted for.
edevlin remarks how flat the torque curve is. Well, what does the Stock torque curve look like? Don't you think that Porsche realizes that a flat torque curve through the mid-ranges is desirable too? Perhaps their torque curve is even more flat - we don't know.
The Dyno Shop I've used has very intricate software which monitors the sensors, electrical loads, and ECU in addition to what the rear wheels are doing. It measures temperatures to the 0.0X°. But, they charge $700 for a run too. Their results are reproducible almost every time.
Then there's the variation in the cars themselves. It's not unusual to see variations in power of 10% or more between the various cars coming off the line, they don't all produce exactly what the Sales Brochure describes, in fact, that number on the Sales Brochure represents the minimum numbers a car will produce.
Remember the MOPAR and FORD Muscle Car brochures of the late '60's? They reported numbers, for Insurance purposes, which were sometimes underestimated by as much as 125HP in the case of the Hemis and Cobra Jet engines. If you're making a Dyno Graph comparison to those published numbers, it's quite possible that you're not having any real increase at all.
The interesting thing about these latest Dyno Graphs isn't the HP or Torque, but the AF graphs. The car is running very Rich and this means that all the fuel is not being combusted. Running Rich robs power and/or leaves power unrealized as the unburnt fuel is expelled out the exhaust. Also, it runs lean at low rpms, again, unusual.
But, in the end, there are no gains to be had except those which were overlooked, for a variety of purposes, by the Manufacturer.
Honda holds a lot of their engines potential back because their strength in the Marketplace has always been Reliability and Range (MPG). This means that there's a lot of potential to unlock, if you don't mind sacrificing those things Honda designed the engine to preserve. Civics and such demonstrate huge Dyno gains because of this.
But, Porsche designed and markets this car as a
Sports Car. It already has one of the highest HP/Displacement ratios out there. There just isn't a lot to be found by just reprogramming the software.
If you add Intake, Exhaust and Cams, then it's a whole different story, and different engine. But, absent this, aftermarket chips can't hope to gain more than 10HP. You can alter the curves, change the Power Bands, but for the most part, it's not usually worth the money invested, or the reliability lost...
Happy Motoring!... Jim'99
Hybrid Mode
