Having done a modicum of consumer marketing, let me see if I can explain what I think I know :-)

To a consumer, the existing hp number generally has a relatively simple and consistent meaning. The more hp my car has, the faster I can go. To a lesser extent, consumers may look at torque numbers and say more torque means I can pull more, or something like that, but hp is the primary number.

If we were to give them your average power from idle-redline measurement, what would it mean? What is drivability? How do you convey to the consumer that because you can drive a Camaro at 1500 rpm comfortably that it is more driveable than an S2000? How do you communicate that different driving styles will be demanded?

I'm not saying that you can't communicate these things, but the effort outweighs the benefits - by far IMO. For readers of an enthusiast magazine, such a measurement would be more reasonable, because the magazine already tells us things about drivability and required driving styles, not to mention the fact that the readers of said magazines are far more interested in learning about these things.

As a comparative example, look at crash test scores in the U.S. The raw data is vastly interesting to me. We can see g-forces imposed on various body parts and correlate that with known injury thresholds. But even communicating the g-loads is too much for the consumer, the results have to be reduced to a simple 5-point "star" system that averages together results from all 4 measurement areas (2 leg, torso and head). More stars means safer - it has to be that simple to appeal to the masses. And if it doesn't appeal to the masses (or isn't required by law), the vast majority of car makers won't do it.

Of course, now I'm so off topic (not only for this thread, but for this forum) I think I should call it quits with an encouragement to pursue a means of evaluating cars on the criteria you've brought up.

UL

 

Since net power and net acceleration on a given platform is the issue. Why not just advertise scientific 0-60, 1/4mile and top speed times. Or better still acceleration times for each gear in the optimal bands.

I agree with the marketing viewpoint in that one number is simpler to grasp for the mass market. The average job wants simple, gearheads like us want results. Preferably fast results.

 

How about simple peak horsepower too weight ratio, or is that to simple?

Make............Weight..HP......Ratio (H/W)
Insight.........1805....70......0.039
CRX.............2167....108.....0.050
MR2 Spyder......2195....138.....0.063
Accord..........3105....200.....0.064
Miata...........2387....155.....0.065
Civic...........2440....160.....0.066
CRX+SC..........2177....151.....0.069
Chrysler 300M...3585....253.....0.071
Acura CL........3500....260.....0.074
Z3..............2960....225.....0.076
Elise...........1550....118.....0.076
s2000...........2809....240.....0.085
Boxster S.......2900....250.....0.086
Acura NSX.......3069....290.....0.094
Mustang.........3300....320.....0.097
BMW M3..........3415....333.....0.098
Corvette........3300....345.....0.105
Corvette Z06....3210....385.....0.120
s2000+SC........2829....340.....0.120
Ferrari 360.....3065....400.....0.131
Viper...........3424....450.....0.131
Porsch 911......3131....415.....0.133
Lamborghini.....3583....550.....0.154

Well it's a thought anyhow... I guess we could Integrate the horsepower curve and divide it by the piston linear velocity... OR maybe it's best to just drive the car. Anyone have a Lamborghini for a test drive?

-Mike
Kindly reminding all of you to KISS (Keep it simple...).

 

Glad you guys appreciated that. I do have that in an Excel sheet if anyone would like it. The best text book I've got, UL is Engines: An Introduction by John L. Lumley; Cambridge University Press, 1999. Taylor's two volume set is still used, but I don't like the intensive empirical equations. I'm not sure about emissions books, though.

This started off as a "disgust assignment" to myself. The Technical Specialists in Car Powertrain NVH [where I work at FoMoCo] aren't that knowledgeable about engines, per se, so I started listing the nicer engines and began to wonder "of all the 'basic' info available to us, what metrics would be the best indicators of performance?" Connecting rod length to stroke ratio would also be of prime interest as it relates to bmep, but who knows what they are for most of these engines. The Honda engine info is readily available, however. I never made it available to them... I'd also like to do the same for motorcycle engines [my favorite], but more data will be needed to distinguish one from another like valve sizes, lift, degrees overlap

I do plan on plotting the data to scientifically come up with correlations based upon the sketchy data that I have. I'll make one Excel sheet and repost this and all who are interested will receive it in their e-mail.

I would like to see a sight that would have this kind of information readily available with links to excellent magazines, like RACE TECH http://www.racetechmag.com as well as links to SAE [Society of Automotive Engineers] which has an excellent library. I know few would appreciate it, but we, the few, would like it.

Other comments:

I vacilate from torque to bhp is the true measurement. 'Power' is loosely described as Torque in engine dyno development at GMPD's John Juriga [Mgr who was responsible for the LS-6] when I worked for him back in the early 90's. BMEP is the best measure I know of, but average power from, say, 1,000 rpm to engine redline would be of interest. I'd also like to know the average torque as well as torque at the wheels and thrust curves. I was disappointed that Honda did not release as much gear head info with the intro of the S2K as they did with the ITR. I know they are two different market/mindsets, but I could go either way with the vehicles as both are remarkable for similar and dissimilar reasons.

The consumer has been dumbed down from years of "HydroSlop" transmissions and "VarioCam" Valvetrains. I have to give Toyota props for VVTL [Variable Valve Timing & Lift]. It's an accurate acronym. VTEC is rather confusing, but we all are familiar with it. Everyone wants a simplified number to tell them everything about the engine. Hell, today who even cares about the engine? Peak numbers are great for marketing types who understand precious little. But until I see drag coefficients [that's ground for another discussion], bhp and torque curves, bmep and bsfc curves, torque at wheels, thrust and drag curves and power to weight numbers little is known about the machine. The same can be said about vehicle dynamics as well, yet fewer still comprehend the basics of that.

Today I commented that few knew what bhp was and when some disagreed I asked. Rhetorically, of course. None could answer correctly, though a few had an idea. Sad.

 

Couldn't agree with you more Chui. I'll have to check out Lumley's book, Obert is very tough reading for someone who has forgotten most of his thermo :-)

BTW, on rod length, I haven't had a chance to get a really accurate measurement yet, but the F20C rods are about 154 mm in length (center to center). Hell of a rod ratio, eh?

UL

 

Being an engineer I love all of the engineering data but other factors need to be considered in determining what is a great engine. Namely the sounds and vibrations felt by the driver. Have you ever listened to a Ferrari 360 engine at 8000+ rpm? It positively shrieks! Closest sound to an F1 engine for the street.

Plus a true gearhead sometimes just likes to look at the engine. Man, I wish I had a Ford Shogun V6 near my sofa.

Manufacturers releasing detailed data would be great but it ain't gonna happen. This data would confuse 99.9% of the population (not an exageration) and every single car salesman. Sheesh, most people are suprised to hear the S2K is not FWD.

 

Interesting assessment, babylou. Especially since I also am doing some sound quality stuff at the moment! I've ridden in a 360 Modena and it does shriek at speed. I absolutely love it. Actually, all the engines listed sound great, though I've not heard the 996 GT3 or E46 M3 I have heard versions of those engines and I absolutely love them.

UL, thanks for the conrod length info. I'll make a few phone calls to area dealerships to see if they have that info for the Porsche, BMW and Ferrari engines. If so, I'll add that to the list and see what correlations arise when compared to bmep.