I've had several people ask for my opinion on how the Corvette and the Porsche compare to one another, since i have both, and I recently addressed this with the posting below, on the Corvette forum. I thought I'd add it here, too.

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First, in comparing Porsche to Corvette, realize that Corvettes vary. That said there really isn't much difference between a C6 and a C5 so I'm going to lump all of them into one category (and yes I know HP varies from 345 to 505).

Similarly, Porsche Carreras (they haven't officially been called 911s since 9/11) vary, but again the 996 (sold through 05) and the 997 (since) are derivative -- one after the other just like the C5 and C6 were. Again HP varies, from 320 to about 455.

Finally, there is a substantial cost element, not quite but nearly 2:1. My ā€˜vette stickered at $51k new and '07 'vettes go from $50K +/- to around $75K for a full house ZO6. Porsches vary even more, from a supposed base of around $70k (never seen one less than $80k on my dealer's lot through - mine stickered at $87.8) to way over $140K.

That said, my comments comparing stock '02 ZO6 ($51k, 405 HP, 3185 lbs) to stock 04 Carrera ($87k, 320 HP, 3054 lbs) are fair, in think: both were models on sale for roughly the same time period and represent their Marqueā€™s best on a contemporary basis.

1) Overall design: Not even close. The Porsche of far better. I am talking about design, not engineering. Remember Porsche Design is one of the most prestigious design studios in the world, designing everything from table lamps (I have one in my office, very good) to watches, to other companies' cars.
The Porsche is supreme among every car I have ever considered in its near perfection of design, layout, tradeoffs of one conflicting characteristic versus another, etc. Ergonomics are flawless. There are no blind spots at all. Suspension and chassis dynamics are near perfection under all circumstances. And that Tiptronic automatic transmission -- it can read minds (at least mine). The 'vette on the other hand is well styled but the interior is not as well laid out: I fit well in the 'vette, but in the Porsche I feel like I'm in a car designed just for me. A big part of this: I think every part in the Porsche Carrera was designed for the Porsche Carrera, not for use across a whole line of cars from Cavalier to Avalanche.

2) Engineering. The 'vette is better. Yeah, I'm going to get Porschephils coming down on me hard, but people don't give GM credit for its engineering. The LS V8s are among the best passenger car engines ever designed: light weight, small packaging, durable, gobs of torque down low and lots of power up top, and surprisingly good fuel economy. Pushrods have huge advantages and GM maximizes them all, as well as some annoying downsides, which GM minimizes brilliantly. The ā€˜vetteā€™s chassis and suspension are world class, which considering the car's use of transverse leaf springs, is amazing.
The Porsche Engineering isn't bad, mind you. Getting between 320 and 415 HP from 3.6 to 3.8 liters, normally aspirated and with low emissions, takes some innovation (particularly given that Porsche horses seem to each just a bit bigger than GM's). Making a rear engine car handle well is very difficult (ask any owner of a 911 from the 60s) and has been done brilliantly, including taking advantage of the rear weight bias for traction. But Porsche does it all by letting things get real expensive. A 415 HP (flywheel) 3.8 Porsche GT3 engine is a work of art and engineering but expensive as the dickens: expensive materials and expensive machining, etc. itā€™s glamorous, but the engineer in me realizes: its also damn expensive, too.
By contrast, a 430 HP LS3 used in everything from a Chevy truck to the ā€˜08 Corvette, is a $6000 commodity crate engine made from standard industrial materials on a truly mass, mass production line: there is nothing exotic or even advanced in its design: itā€™s a dull, low-tech engine, but damn effective, inexpensive one.
I'm not knocking the Porsche's engineering: its makes few mistakes, but GM really understands the adage: "An engineer is a person who can build for a dollar what any damn fool can build for three dollars."

3) Build quality. Not even close. The Porsche is the best built car I have ever owned, better than Mercedes and Audis, etc. The 'vette is put together well where it counts (engine, drivetrain, chassis) but the body is so-so and the interior almost seems like it was built by Fisher-Price.

4) Handling. The Porsche handles better than the 'vette, especially at speeds below 60 mph andin tight turns. It has much better transient dynamics particularly at low speeds, never feeling either heavy or light, or uncontrolled. It reacts better under combinations of hard braking and hard cornering and on rough roads. It power steers more easily and controllably. The 'vette has to be manhandled to be fast -- the Porsche just has to be pointed. The Porsche also rides slightly better than a standard ā€˜vette, by a small margin (both cars are available in certain models with run flats, and both suffer ride degradation as a result).

5) Corning ability. The vette is better, particularly on sweeping bends. It has just a bit more grip, although the difference is small.

6) Acceleration. As they have always been since the 911-ā€˜vette rivalry began, Corvettes are a faster at the track: base C5s were quicker to 60, to 100, etc., through the quarter than base 996s were. The newer C6s are just a tad faster than the newer 997s. The ZO6 is faster than the GT3 or the Turbo, etc. On paper (e.g., Car and Driver road test) the difference is slight, but . . .
The 'vetteis much faster in daily driving than you would think based on car magazine tests. To see this,look at the "street start" (5-60) times reported: the Porsche loses a lot compared to 0-60 times: to get those you rev it to 4500 and drop the clutch, otherwise it loses nearly a full second in 0-60 time; the 'vette loses much less if you do a ā€œstreet start.ā€. That's torque at work; you feel that every day on the street.

7) Top speed, remarkably similar, year to year, model to model.

8) Braking. Overall, about the same.

9) Daily driving. I drove the 'vette daily (near stock, or with only headers and a Maggie SCr) to work every day for two years. It was fine. ThePorschehowever, is a jewel, the best daily driver I have ever had.

10) Features: my Carrera is near bottom of the line and my 'vette was top of the line at the time I bought it. Both have effective features that count: ABS, traction control, stability control that work well. Good AC, sound systems, power windows, etc. The vette (and vette's in general) have more gimmicks (heads up display, tire pressure monitors, etc.). Porsches offer extra cost options that are endless -- if you pay -- including a $9000, 100% all leather[/i] interior you want to eat, its so flawless, and custom this and custom thats like adjustable suspensions and ceramic brakes and . . . All that is piffle. It's a tie here.

11 Styling. A matter of personal taste. The Porsche is simple, pure, and I like it a lot more today than when I bought it. The 'vette looks dramatic, but then that's what I want with it.

12 Class, cachet, image, etc. The Porsche has more of whatever it is. Both attractattention and get manylooks, although I think anymore my 'vette does so because of the mods and the"if God owned a hot rod this would be its exhaust note" sound.
The Porschegets attention. Itā€™s always valet parked up front. You can tell a lot of drivers notice it. But it also attractsannoying young kids in tricked out, loud but not very fast Civics and Integras and Eclipses with "fart mufflers"; young professionals in 350Zs who seem to suffer terrible cases of "Porsche envy"; BMW M3 owners who want to make sure you realize why their car is superior to a Porsche, and the occasion SOB in an old Camry who cuts you off simply to **** you off just because you are in a shiny Porsche and he's in an old beater.

13 Confidence or whatever. Porsche is the standard of comparison around the world. 350z owners point out they get nearly as much of everything as a Porsche offers for 1/3 the price; M3 owners talk endlessly about how their based-on-a-family sedan car is really faster than a Carrera; Eclipse owners have lots of comparisons or how similar the two are, Mitsi Evo owners point out how their car is very close to being a 4-door Porsche, ā€˜vette owners point out they got more performance for half the price, etc., and on and on . . . . Porsche owners -- well, I doubt many Carrera owners longing look at an M3 or a ā€˜vette and wish they had made that choice . . .

14) Hobby/hot rodding. You can have fun modifying both, and in either case roughly double stock power without making it so extreme you canā€™t enjoy it on the street. That said, Iā€™d pick the ā€˜vette as the mod fun for a hobby-hot rodding base (Well, I did, didnā€™t I?). Aftermarket parts for the vette cost much less (about 3:1 ratio) compared to the Porsche, and selection is wider than for any other brand or type of car ā€“ wider even than for very popular Japanese cars like Civics, Eclipses, etc.
Then there is driveability of a modded car. Iā€™ve never ridden in a 700 HP RUF, but I have ridden in Porsches modified by competent local schops to be 2x stock power (700 HP) and they felt extreme: rough riding, noise and vibration, minor unevenness, etc. What I like about my ā€˜vette is that at exactly 2x stock power (810 to 405 flywheel based on 703 vs. 351 stock RWHP) it idles and rides and cugs along in traffic and on hot days just[/i] like[/i] stock: in my mind itā€™s not really fun, or a real challenge, unless you modify it so you can use it every[/i] day.

If I had to pick just one: the Porsche. Sorry to say it, but much as I love my 'vette and GM, I cannot tolerate the notion of not having a Porsche daily driver for the rest of my life. I actuallyrevised my retirement budget and plans for a new one every four-five years.

 

Your anaylsis of the two cars pro and con is the best I have ever read. I found it very interesting.

My only question is what are the huge advatanges to push rod engines other than GM has the tooling already so their capital cost to build a more modern engine is alot less.

I would add that when I drove the new C6 chasis I felt it is definelty a step up for Corvette. my only down side was the steering felt numb and uncommunicative. i bought a differenent sports car.

I will most likely buy a Z07 when they come in late 2009. I cannot pass up 700 supoercharged Hp numb steering or not.

Great job.

Lee

 

The major advantages that pushrods have is:
--- weight and friction surfaces - DOHC heads weigh more, hae more cams and more cam bearings and more cam followers, etc. (Of course you get cross flow breathing, etc., but . . . )
--- compatness. The cam and cam followers etc., are inside the V instead of on top of the heads as on a DOHC. The engine is 2-3 inches or so shorter top to bottom, and on a V engine, a couple of inches narrower: you can fit it lower in an engine bay. Pushrod engines are a bit lower than DOHC ones, but their center of gravity is much lower.
A perfect example is: compare a 4.6 liter Ford DOHC cam V8 (1998 Mustang Cobra, 305 HP) with a contemporary 5.7 liter LS1 V8 in a Camaro (1998, Z28, 305 HP) -- but take the plastic "fuel rail covers"bracketed abovethe Camaro's engine off -- they are there to make the engine look as big as the Mustang's. The Ford is huge compared to the Chevy. The Chevy also weighs about 55-60 lbs less. Basically GM traded OHCs for more displacement -- an even swap on HP, but the engine is lighter, and more compact. The downside is a bit rougher operation at high revs. But it does not seem to matter: think Lemans, Chevy versus Aston Martin all these years: pushrods get the job done.

 

Thanks Lee, a very well thought out response to my question.

Signed the other,

Lee

FYI my cars are

2006 Ferrari F430F1
2006 Lotus Elise Sport #8 of 50 built for racing
2005 Ford GT
1965 Shelby Cobra 427 kit
1999 Porsche 911 CAB
2005 Mercedes B E320
2001 Toyota Highlander
2006 Harley Davidson VROD Screaming Eagle race modified
2004 Demo Chopper one of design
2006 Honda Goldwing

 

Thanks. Nice set of cars. I have only the three right now, largely because lately we seem to prefer to buy art we can hang on the walls rather than drive on the street. I am looking for a '65-'66 Sunbeam Tiger in oroginal condition (never modified) however.

 

" The major advantages that pushrods have is:"

I gotta pipe in cause pushrod engine engineering is what I do for a living.
You missed the biggest advantage that faaaaar surpasses those you mentioned. Rocker ratio. Period. This is the biggest HP builder in a p'rod motor. You just can't get enough valve lift and you can't get it fast enough with a direct cam-on-follower engine. Physics (and cam lobe geometry limitations) just won't allow it. The saving grace that the overhead cam setups have is multiple valves per cylinder. This comes close to negating the advantage from ratio but it falls a tad short. I can design a cam that I'm happy with for any pushrod engine. For an overhead cam though, you always wish you had more to work with. The difference is that you can amplify all the dynamic parameters (lift, velocity, accel) with the rockerarm. This also can be done more cheaply because luckily, pushrod engines don't need the exotic engineering feats necessary to reach 19,000 RPMs. That because of fast valve motion.

And oh, yeah, I came into my C4 from a long line of Vettes and as I said in a recent post "The Vette is a sledgehammer but the Porsche is a nail gun".

 

Hi, Lee, very nice!
I am glad that I own a Porsche. I feel good everytime I start the car and drive off my garage.

 

Your comment is very valid from our standpoint in this forum.

I've run into this when modifying engines (you are stuck with near-factory valve lift) but never in engines that you can re-engineer, and so while I think it is valid from a hot rodder's standpoint ("I prefer modifying engines with pushrods for all the reason listed above including this one"), I didn't list it within the context of the reasons a manufacturer like GM might choose pushrods over OHCs (above) because a manufacturer seems to be able to re-engineer engines with wider spacing and bigger cam lobs as needed. During part of my career I bought and speced hundreds of stationary combustion engines (piston and turbine) every year. Engine manufacturers like Cat, GM, etc., would routinely redesign the valve gear if needed for higher lift (e.g., high-altitude versions of gasoline and diesel pump engines with more lift). That said, among piston engines I bought more GM 5.7 liter pushrod engines (based on the LT1) than anything else: they were just less expensive than the many fine OHC designs out there, and cheaper to maintain, too. One thing I never gathered really good data on but suspect is that pushrod engines probably last longer in pooor shape: with all the cams at the top of the engine if oil pressure drops a bit it would seem to be more serious than if all that is affected is the rockers as on a pushrod engine, so a pushrod engine would tend to last longer in "neglected" condition. I never saw any evidence to dispute this suspicions but never gathered hard facts to support it.