winovin

Juan's post has triggered my memory - I don't think the tolerance is +/- 10% - that is too wide a range, and frankly, I don't see such a variance being possible with the same components.

+/- 10hp seems more reasonable.

Steve in FL

It's +/- 5%, or so I recall being told once upon a time.

jyoteen

That sounds about right. I know I was catching up to a GT3 this past weekend at Buttonwillow, so I must have gotten a strong motor.

Ghost Rider

jyoteen,
That reminds me I was playing with a GT3 in traffic one day and then on the highway, another user here, and I didn't have any problems keeping up with him.... hmmm must be a group of mystery C4S's out there..
I've probably got an extra factory supercharger stuck in there somewhere under the hood since my car was a late in the year build it was probably just an extra part laying around they decided to get rid of when cleaning house...

jumper5836

dyno it

JimB

I can see how an engine can make less than specified HP but it's not at all clear how it can make more. You can make a mistake in manufacturing and reduce performance but I doubt you can make one and increase it. I suspect by +/- 10 hp they really mean -10 hp. Just a thought. I don't mean to bust your bubble Ghost.

winovin

JimB,

I think the way an engine can make more than it's rated power is if the rated power is conservative (i.e. stating the rated power as an average of observed outputs).

Having said that, I still find it hard to believe that the variation could be more than 20hp (i.e. 320 +/- 10hp).

Further, not sure if this was speculation or an explanation, but the original article I read about this said something about the stronger engines going into the heavier cars, such as convertibles and C4s. As I said, not sure if the article stated this as an explanation, or whether it was just speculation.

Paul

fahren affair

the guys at mckenna porsche recounted a story of the meridian metallic carrera no one wanted, but every salesman that drove it swore it was faster than a 'normal' car. they dynoed it at 345 hp (3.6L) which is a little more than +5% ....recompense for a hard to sell color?

nsxtbone

Well I am the victim of racing ghost rider. I must correct Ken in his story
as he was not correct. His story was slightly off and I appreciate
ken's lie to spare me the emabaressment of our race. He beat me
by 15 car lengths or more from 60-145. It was like my car was pulling
a boat while racing ken., Clearly the nsx is a pos and has no business racing this car. I have only owned my 02 nsx for a month but have been beaten by many cars including civics,taurus,escorts and even a woman in a wheel chair who smoked me off the line. Not only did he smoke my car but after we got off the highway and stopped at the next light a hot woman jumped out of the car with huge ***** and hugged ken calling him the greatest while her ugly fat friend wanted me. lastly ken you mentioned that there is no skill mashing the throttle on the highway but clearly you are a better driver then me and other nsx owners. remember when you smoked the nsx in your auto g-35. My conclusion of you being a better driver then me starts with your probe beating my prelude/then your boxster killing my s2000 and now your c4s smoking my nsx.
I assume when we are 65 your 4 volt motorized scooter will kill my scooter.your pencil is even better then mine and I believe your father can beat mine up
I bow to your greatness. Well I got to get back to work

Bob Rouleau

As far as I know Porsche does run every engine on the dyno for break in and testing. The Spec is minus 0 plus (something) percent. I am pretty sure the spec is -0 +10 percent. There is no way Porsche would sell an engine making less than its rated power. The rating is designed to allow for engines that are below some threshold and the advertised spec is set such than no engine is ever less. Given the degree of precision these days I am confident that the majority of engines in Porsche cars are above spec and it is the rare one which is at or close to spec.

About Gas - I'm in Canada. It was a charity event put on by Pirelli. They recruited PCA instructors to take celebs around the test track at high speeds. They also supplied free tires which was a good thing.

The track is an oval (you can see it at PMG.com), one mile on a side. The turns are banked steeply and you don't have to lift at speeds below around 200 MPH. Each "ride" was 4 laps. I was amazed at how much gas I used running flat out constantly. I could run about one hour before heading for fuel. The first tank was Gulf 92 octane and my car was clocked at 161.72 MPH average speed. The next tank I filled with Petrocan 94 octane and my speed went up to 170.93 MPH. I don't think heat was a factor it was a cool day and I got better speed after the first hour. I also discovered a trick about banked turns, get really really close to the wall and your car picks up speed. Some aerodynamic effect the car gets quieter and goes faster. My passenger (another instructor) remarked "Bob do you realize your mirror is only 2 inches off the wall?". He was right but no way was I going to look over to see it! This was in a 2000 Boxster S on fresh P 0 Rossos compliments of Pirelli. We learned one other thing than day, a 993 TT was capable of a sustained 300 KPH but don't try it on R compound tires. They are not designed for sustained high speeds!

Oh year, how to freak out the celeb? Drive onto the banking and take your hands off the wheel at 170 MPH. Since this is a 996 forum, you'll be pleased to know that a 996 C2 press car was lapping at 179 MPH. Bothe the boxster S and the 996 exceeded specs in that regard.

Best,

JimB

Paul,
I would agree if I believed that Porsche was building engines with a 20 or 30 hp variation and that they picked a number in the middle to publish knowing that some would be high and some would be low. I seriously doubt that that is the case. I certainly hope it's not. With modern manufacturing techniques now in use, I suspect that 99% are within a 1% range and that the others are on the low side. Actually I would hope that 99.99% are within 1% and the +/- is caused by variation in the dyno. But who knows.
Jim

jyoteen

sometimes, that additional power is made by the combination of the right parts. That's why a lot of race teams spend $$$$$ trying to find that elusive perfect camshaft or perfect piston, because by itself, it may not do anything, but a combination thereof may produce noticable gains.

This is pretty evident in spec series, where a slightest advantage can mean running midpack or ahead of the field.

Ghost Rider

nsxtbone,

That was pretty funny. As you know, this thread isn't about whose car is faster, but rather that published numbers, either from magazines, or even from Porsche don't seem to be jiiving in this instance, and of course how the so-called "experts" are often quite wrong...

Bob Rouleau,

I'm going to have the oppotunity to put this C4S on the high bank ovals of our local speedway in a couple of months. I'll report back my findings, although I might just have to remove my mirrors altogether so I can get even closer... There is an aerospace engineering term for the flow of air near a surface, and I suspect near the wall, I think it was called laminar flow and it had different characteristics, although that was 20 years ago and I don't remember much about those classes anymore...

jyoteen,

Maybe I just got the right parts! The NSX driver reported a puff of smoke out of the exhaust between 4th and 5th gears, don't know if that means anything or not, I'm still burning what I think is a higher amount of oil than normal for an engine with 5000+ miles on it now, but who knows, I still think it is the mystery "Orange Plug" upgrade that is secretly worth 20HP!

All,

A friend of mine got an R32 which I checked out yesterday, looks like a fun little car, can't wait to see it at the track.

nsxtbone

Hey no problem. Next time let me know ahead of time when you want to race rather then taking off while we are entering the highway and when almost I catch up claim I am getting smaller in your mirror? Also letting me know would give me time to roll up my windows, put my top on and turn my a/c off. Heck now I am excited that Acura must have lied to us owners about how fast our cars are also!!!!!!

redcab

NSXTBONE -
thanks for keeping our collective big heads in check!