HereIam

So, shamefully... I'm a driver with no real mechanical understanding beyond knowing the importance of having an excellent mechanic

Help me understand this point...
Why do Porsches have seemingly lower HP, but are so powerful?

I have friends with American muscle who boast about their huge HP, but I know my Porsches are "faster." Right now I have a friend with a 700hp pickup who's dying to race me because he's confident he can "eat my Boxster for breakfast." While I wouldn't be surprised if 3 1/2 times the HP will overpower my little go-cart, I know his victory will not be as amazing as he anticipates.

Aside from the obvious power/weight ratio factor...what makes Porsche's "unimpressive" HP so much more powerful than other cars with a lot higher HP numbers??

P.S.
"My X is better than a Porsche"
Ever heard this? The thing they fail to recognize is Porsche is always their measuring stick.

MDamen

Pound per horsepower is a big indicator of 0 to 60 times. Compare those numbers for your car and your buddy's. Gearing also has a big impact on acceleration.

Amber Gramps

Your Porsche has a tall first gear and a relatively weak clutch. It wasn't made to accelerate, it was made to go fast.

Steve Weiner-Rennsport Systems

Good question and quite complicated due to a plethora of variables.

First, SAE (US) & DIN (Euro) HP ratings are not the same so one must be certain when comparing apples to oranges. There are conversions for each that are available such as this one: http://www.statman.info/conversions/power.html

Second, vehicle weight and gearing play huge roles in how a car accelerates to a given speed. Beyond 100 MPH, aero factors begin to be very important for top speeds.

Lastly, Porsche's power measurements are done in Pferdestärke (abbreviated as PS) measured on an engine dyno so the above tool might help you understand and factor the differences.

HereIam

Great answers. Thanks guys!

I've also learned there's a bit of marketing and politics involved in this, too...
~Sometimes HP has been exaggerated to promote sales, as in early muscle cars.
~Sometimes HP has been underrated to cope with safety and environmental lobbying.

Amber Gramps

I assure you there were also lots of cars who had understated horsepower to help keep the cost of insuring them down.

HereIam

So I guess we'll just have to drag race to determine who has the most HP

TheDatanator

Lets not forget German horses are inherently more powerful. One German horse = 1.25 'regular' horses. Some have speculated German horsepower is measured in Clydesdales....true story.

Edward

I think that weight distribution and parasitic losses play a role, as well.

As for weight distribution, roughly 65% of the 911's static weight is over the rear axle which can translate to better transfer to the tarmac with tires firmly gripping asphalt. And when under acceleration, even more weight bias goes rearward right where you want it: over those fat tires that hurl the car forward instead of spinning over blacktop. Sidenote: ever see powerful FWD cars spin tires even under modest acceleration? American muscle isn't this bad, but comparatively speaking, the rear end is pretty dang light which makes lighting up the tires really easy with HP. Other Sidenote: our rear-weight bias also makes hard braking in a 911 akin to throughout out an anchor

Moreover, the modest power (by today's standards) put out by our 911s are mitigated by their more direct output to halfshafts straight out of the tranny (well, technically the diff, but they're mated). Compare this to typical American muscle that goes through a driveshaft, a few joints, then to diff, then to shafts, all of which adds to parasitic loss.

...and all that other good stuff you folks mentioned

Edward

Drisump

Those big displacement/big horse power trucks are pretty potent off the line...most Porsche's couldn't compare. That's not their thing, high speed maneuvering is. I have a friend with a 993 TT that duked it out with one of those trucks and won...but not by as much as you might expect. Cheers

TerrySmith

If you bought your Porsche to win drag races, you have the wrong car. You should take it to a road course track on a DE day and compare lap times. The more the curves, the better the Boxster will do.

Which is more fun to drive on the twisties with the top down, a truck or a Boxster?

BTW, don't race on the street or even at a DE event.

JCP911S

Heck... I'll weigh into this mess...

HP is a theoretical calculated number.... originally it was used in Britain to measure the work potential of a steam engine. and then used for Automobiles as a tax mechanism... cars of larger weight and displacement were typically purchased by wealthier people, and subject to more registration taxes ( so "horsepower" was like "net income")

Torque is the actual measure of "work" in foot-pounds. The real performance of a car is determined by the torque delivered from the powered tires to the ground at any point in time.

Drisump

"Horse power sells cars and torque wins races"....I'm not sure who said it, for whatever reason I think it might be Enzo Ferrari (high HP, low torque cars).