Corvette ZO6 vs Porsche 997 GT3 RS

[JYODER240]

My bet is with equal tires, the Porsche would still handle better, but the Z06's better ability to get its power to the ground on corner exits would give it the time advantage.? That said, I still want the 911, though I take nothing away from the Z06.? It's quite a machine.

If anything I would think that the 911 would be better at getting power to the ground. It has alot more weight over the rear tires. After all thats the 911 mantra, "Slow in, fast out".

[Raza]

If anything I would think that the 911 would be better at getting power to the ground. It has alot more weight over the rear tires. After all thats the 911 mantra, "Slow in, fast out".

Yes, but this time is what the RS ran on those tires; it has no place to go.  The Z06, having the extra grip, will be able to put more power on the ground when exiting corners, the area in which I surmise the Corvette lost the most time.  I have no doubt that the RS is faster in the corner, but the Z06's extra power isn't making it any faster on the default tires.  If you go to grippier tires, you get more time at WOT. 

[JYODER240]

Yes, but this time is what the RS ran on those tires; it has no place to go.? The Z06, having the extra grip, will be able to put more power on the ground when exiting corners, the area in which I surmise the Corvette lost the most time.? I have no doubt that the RS is faster in the corner, but the Z06's extra power isn't making it any faster on the default tires.? If you go to grippier tires, you get more time at WOT.?

I misunderstood what you were trying to say in your original post, nevermind.

[Nethead]

ChrisV:  The Nethead here has shit on my heel from stomping you in the head. 
Now that that is settled, on to the full statement I made and not an excerpt out of context:
"ChrisV would have us believe that the low 400 HP Porsche GT3 beat the low 500 HP Corvette Z06 strictly because of its tires.  I'm sure neither of you are that brand blind...right?  There are tires and there are tires but I've never seen a set that's worth 100 horsepower on cars that have very high performance tires to begin with."
Whether you admit it or not, the Z06 has great tires.  The GT3 has fabulous tires, at least for a dry track.  But the difference between "great" and "fabulous" does not make up the difference of around 100 horsepower--even if the Porsche's tires are as wide as the Z06's (anyone got the figures on that?), which ain't likely even in a GT3.
There's more to the parity in speed than tires alone.  I presume both these cars have upper and lower A-arm independent suspensions, but the Porsche uses coil springs and the Z06 uses transverse leaf springs.  The Corvette has good weight distribution front to rear; the Porsche has great weight distribution front to rear, at least for a dry track.  The Porsche brakes later going into a curve; the Corvette accelerates harder coming out of a curve, as would be expected with its approximately 100 horsepower advantage. 
The fastest laps of both were nearly equal, although that roughly half-second advantage of the GT3 is admittedly several car lengths at the speeds these cars were attaining on that track.  One has more engine, one has more suspension.  What the driver reported sounds like what anyone should expect; and no one should be shocked--or upset--at those quite predictable results.
Did anyone get the prices in Germany for these cars?

[VetteZ06]

So what do you think would happen if the Corvette had "fantastic" tires?

[Eye of the Tiger]

So what do you think would happen if the Corvette had "fantastic" tires?

It would asplode

[VetteZ06]

Ah, yes. Makes perfect sense.

[southdiver1]

ChrisV:? The Nethead here has shit on my heel from stomping you in the head.?
Now that that is settled, on to the full statement I made and not an excerpt out of context:
"ChrisV would have us believe that the low 400 HP Porsche GT3 beat the low 500 HP Corvette Z06 strictly because of its tires.? I'm sure neither of you are that brand blind...right?? There are tires and there are tires but I've never seen a set that's worth 100 horsepower on cars that have very high performance tires to begin with."
Whether you admit it or not, the Z06 has great tires.? The GT3 has fabulous tires, at least for a dry track.? But the difference between "great" and "fabulous" does not make up the difference of around 100 horsepower--even if the Porsche's tires are as wide as the Z06's (anyone got the figures on that?), which ain't likely even in a GT3.
There's more to the parity in speed than tires alone.? I presume both these cars have upper and lower A-arm independent suspensions, but the Porsche uses coil springs and the Z06 uses transverse leaf springs.? The Corvette has good weight distribution front to rear; the Porsche has great weight distribution front to rear, at least for a dry track.? The Porsche brakes later going into a curve; the Corvette accelerates harder coming out of a curve, as would be expected with its approximately 100 horsepower advantage.?
The fastest laps of both were nearly equal, although that roughly half-second advantage of the GT3 is admittedly several car lengths at the speeds these cars were attaining on that track.? One has more engine, one has more suspension.? What the driver reported sounds like what anyone should expect; and no one should be shocked--or upset--at those quite predictable results.
Did anyone get the prices in Germany for these cars?

The GT3 in Germany is 110.878,00  Euros. The Z06 in America is 70K USD. At todays exchange rate, that makes the Corvette 54,110.4883 Euros. The GT3 is more then twice as much as the Corvette. Even if you tack on, lets say, 20 grand for shipping and such, the Vette is still a bargin.
And given how close the times were and given the fact that the testor attributed the slower cornering TO THE TIRES, it is LOGICAL to say that with BETTER RUBBER, the Vette can make FASTER TIMES.
It is pretty easy.

[565]

ChrisV:? ? I presume both these cars have upper and lower A-arm independent suspensions, but the Porsche uses coil springs and the Z06 uses transverse leaf springs.? The Corvette has good weight distribution front to rear; the Porsche has great weight distribution front to rear, at least for a dry track.? One has more engine, one has more suspension.?

You presumed incorrectly.  The Z06 uses upper and lower A arm independent suspensions all around.  The Porsche makes due with MacPherson front strut design.  A MacPherson strut design is a fundementally flawed setup that has trouble keeping the wheels at a consistent angle to the ground at extreme suspension travel.  The primary purpose of the MacPherson design is to save space and cut costs on mainstream sedans.  The 911 uses a multilink rear design as well.  In terms of sheer design, the 911 uses a much more mainstream setup than the Z06's race car like double wishbone all around suspension setup.  That said, execution in suspensions is as important as design (if not more so), and the 911 makes the most of it's inferior setup with extremely good tuning. 

Also as with all 911's the GT3 has an extremely flawed weight distribution compared to the nearly ideal 50/50 of the Z06.  Not enough weight over the front wheels cause all recent 911's to understeer on turn in.  Also too much weight overhanging the rear wheels causes unpredictable oversteer characteristics.

The 911 has always been an extremely odd design that no other sportscar manufacture has bothered to emulate.  It's astonishing that Porsche engineerings have managed to make it as capable as it is.

I believe that Jeremy Clarkson said it best.  "The engine's in the wrong place, but instead of fixing it, Porshce engineers have stubbornly tried to engineer around the problem."

The 911 is truly an example of the triumph of sheer will and determination over common sense.

[Raghavan]

The 911 is good, but as they put more and more power into it, it's going to have trouble with the engine in the rear.

[ro51092]

You presumed incorrectly.  The Z06 uses upper and lower A arm independent suspensions all around.  The Porsche makes due with MacPherson front strut design.  A MacPherson strut design is a fundementally flawed setup that has trouble keeping the wheels at a consistent angle to the ground at extreme suspension travel.  The primary purpose of the MacPherson design is to save space and cut costs on mainstream sedans.  The 911 uses a multilink rear design as well.  In terms of sheer design, the 911 uses a much more mainstream setup than the Z06's race car like double wishbone all around suspension setup.  That said, execution in suspensions is as important as design (if not more so), and the 911 makes the most of it's inferior setup with extremely good tuning. 

Also as with all 911's the GT3 has an extremely flawed weight distribution compared to the nearly ideal 50/50 of the Z06.  Not enough weight over the front wheels cause all recent 911's to understeer on turn in.  Also too much weight overhanging the rear wheels causes unpredictable oversteer characteristics.

The 911 has always been an extremely odd design that no other sportscar manufacture has bothered to emulate.  It's astonishing that Porsche engineerings have managed to make it as capable as it is.

I believe that Jeremy Clarkson said it best.  "The engine's in the wrong place, but instead of fixing it, Porshce engineers have stubbornly tried to engineer around the problem."

The 911 is truly an example of the triumph of sheer will and determination over common sense.

Which is why I love it so much

[GoCougs]

So a conundrum of sorts: pushrods and leaf springs vs. rear engine and strut/multi-link. (No brainer IMO.)

[SVT666]

So a conundrum of sorts: pushrods and leaf springs vs. rear engine and strut/multi-link. (No brainer IMO.)

Yup, pushrods and leafsprings for me.  By the way, can anyone please explain to people like me who don't quite understand how the leaf springs work (and the people who rag on the Vette for using leaf springs) exactly what they do?  Because I believe the Vette uses coil overs at all 4 corners, so what do the leafs actualy do?

[GoCougs]

Yup, pushrods and leafsprings for me.? By the way, can anyone please explain to people like me who don't quite understand how the leaf springs work (and the people who rag on the Vette for using leaf springs) exactly what they do?? Because I believe the Vette uses coil overs at all 4 corners, so what do the leafs actualy do?

Actually, no coils anywhere. The leafs (mono actually) run left to right under the car (much like a sway bar) connecting the two lower A-frames. The spring is bolted to the chassis in its center. That's it for "springs" as far as the Corvette is concerned. See the inherent issue?

[Raghavan]

Hmm, I thought they ran parallel to the body on each side of the car?

[Lebowski]

Hmm, I thought they ran parallel to the body on each side of the car?

They do on trucks, lumber wagons, and probably 99% of vehicles that have them for that matter, but not on the vette.

Douchebag.

[Raghavan]

Oh, that's a cool setup.

[JYODER240]

So a conundrum of sorts: pushrods and leaf springs vs. rear engine and strut/multi-link. (No brainer IMO.)

They're both flawed. I haven't driven a C6 or 997 but i've driven a few C5's and 996's. Its no contest the 911 is easily my favorite. It doesn't have the power of the Vette but its much more involving to drive. The C5 feels massive, and i can't stand its gearbox. I enjoy driving my Z more than the C5.

[VetteZ06]

Because I believe the Vette uses coil overs at all 4 corners, so what do the leafs actualy do?

They make the Corvette an inferior car.

[SVT_Power]

They make the Corvette an inferior car.

The fact that it's American makes it an inferior car.

[Nethead]

Transverse leaf springs were fairly common on sportscars through the 1960s.  The original Cobras (260s, then 289s) used multi-leaf transverse leaf springs combined with A-arms through 1963, which was the suspension inherited from the AC Ace that became the Cobra.  With the power (and especially the torque) available in the 427, Carroll Shelby and Pete Brock sought the more responsive and quicker-reacting coils on all four corners, along with upper and lower A-arms on all four.  The coils were a major improvement, and this was before variable-rate coils.  In fact, it was transverse leafspring independent sportscar suspensions that gave Ford engineer Fred MacPherson the idea to develop a coil spring version of that sportscar suspension way back in 1948, I believe it was.  That suspension he developed bears his name to this day. 
The Nethead here wasn't certain what suspension was underneath the GT3 (hence the "presumably")--and I stand corrected by 565--who has informed us that MacPherson struts are on the front of the GT3.  The springs are coils, as in the many BMWs that use MacPherson struts with coils.  MacPherson struts do have geometry problems at extreme suspension travel, but that's probably not an issue on pavement vehicles like it is with ORVs--even at great speed in corners, Porsches stay very flat.  BMWs, too.  But so do all really fast sportscars and racecars, many of which have very modest suspension travel limits.  And the GT3's suspension surely works--down 100 horsepower, not benefiting from the Z06's 50-50 weight distribution, and not benefiting from the Z06's racecar-like suspension, the GT3 kept right with the Z06 around the racetrack.  In fact, the GT3 was a little faster--but that half-second per lap may be the difference between the Z06's great tires and the Porsche's fantastic tires.  It's the whole car, after all, that's put to the test at the limits of performance.
And whomever quoted exchange rates as an indication of what a Z06 costs in Germany has obviously never purchased an imported car in Germany!  I have--OK, technically a motorcycle.  In 1971, I bought the first vehicle I ever owned (and still have it)--the European spec 1971 Honda CB-750 Four for 5,106 Deutchsmarks.  Since I was a GI, I could buy the cycle tax-free and import-duty-free provided I signed a contract that specified that I was (a) not a resident of West Germany, (b) that I would export the vehicle, and (c) that I would have to pay the Bundesrepublik both the original taxes and the original import duties if I ever sold the motorcycle within West Germany.  If I had been a West German citizen or a permanent non-citizen resident of West Germany, that motorcycle would have cost me over 8,000 Deutschmarks.  The Common Market (or European Union, if you prefer) may have changed that ratio of 5,106 to 8,000+ somewhat, but it may be even more lopsided today.  Even back then, taxes and import duties were over 3,000 DMarks on a 5,106 DMarks vehicle.  Apply that ratio to the currency-converted US price of a Z06, and expect your result to be somewhere short of what a German citizen would probably have to pay in 2007 to drive a Z06 away from a dealership. 

[mazda6er]

The Nethead here is on a roll. Oh baby. 

[southdiver1]

And whomever quoted exchange rates as an indication of what a Z06 costs in Germany has obviously never purchased an imported car in Germany!? I have--OK, technically a motorcycle.? In 1971, I bought the first vehicle I ever owned (and still have it)--the European spec 1971 Honda CB-750 Four for 5,106 Deutchsmarks.? Since I was a GI, I could buy the cycle tax-free and import-duty-free provided I signed a contract that specified that I was (a) not a resident of West Germany, (b) that I would export the vehicle, and (c) that I would have to pay the Bundesrepublik both the original taxes and the original import duties if I ever sold the motorcycle within West Germany.? If I had been a West German citizen or a permanent non-citizen resident of West Germany, that motorcycle would have cost me over 8,000 Deutschmarks.? The Common Market (or European Union, if you prefer) may have changed that ratio of 5,106 to 8,000+ somewhat, but it may be even more lopsided today.? Even back then, taxes and import duties were over 3,000 DMarks on a 5,106 DMarks vehicle.? Apply that ratio to the currency-converted US price of a Z06, and expect your result to be somewhere short of what a German citizen would probably have to pay in 2007 to drive a Z06 away from a dealership.?

The Southdiver here....
I lived in Germany for almost 4 years. I owned German cars and (drum roll) American cars purchased while over there.
Both prices that I quoted were pre tax prices. Also, this is not 1971, it is 2007 and the rules have changed quite a bit since the nethead was in germany.
Do you really expect me to believe that a 55K euro car will be 110K euro car simply because of taxes?
A good example...
in 1993, I bought a H-D Wide Glyde from PX sales. Picked it up in Mintz Kastel and rode it back to Augsburg. I sold it the next day for 35K American. The exchange rate was right aroung 1.63 to 1.65  I wrote that he gave me 12K American for the bike. He ended up paying less then 20K American once all was said and done. I can't remember exactly how many DM it was.
Things have changed.

[Nethead]

southdiver1: Yo, SouthDude!? Thank you for the prompt and informative reply!? It's good that import duties have changed in Germany--although American vehicles sold in Germany still constitute a small percentage of annual vehicle sales there.? Still, American vehicles need all the foreign sales they can get!? The exchange rate when I got there was 3 DeutschMarks, 62 pfennigs per dollar--but once that started dropping it seemed like we got fewer and fewer DMarks every payday.? It was still over 3-to-1 when I finished my twenty months...
Back then, 5,106 DMarks would buy a good used VW, or one of the six greatest bikes on Earth at the time.? For the Nethead here, there was never a question as to which one to do!

[r0tor]

so would everyone also like for the magazine to retune the Z06's suspension after putting on the stickier tires to get rid of the increased body roll from stickier tires?

[SVT666]

so would everyone also like for the magazine to retune the Z06's suspension after putting on the stickier tires to get rid of the increased body roll from stickier tires?

The magazine should probably replace that archaic leaf spring too.

[southdiver1]

so would everyone also like for the magazine to retune the Z06's suspension after putting on the stickier tires to get rid of the increased body roll from stickier tires?

No..
I would like for a magazine to go ahead and put the SAME tires on BOTH cars. Nothing more or less.

[SVT666]

Actually, no coils anywhere. The leafs (mono actually) run left to right under the car (much like a sway bar) connecting the two lower A-frames. The spring is bolted to the chassis in its center. That's it for "springs" as far as the Corvette is concerned. See the inherent issue?

Thanks a lot for that Cougs.  I'm not a huge Vette fan so I don't pay a lot of attention to the suspension setup like I would on say a Mustang.  Frankly I don't see the inherent issue if the car handles and performs as well as it does.  I would like to see GM try coilovers on a test mule to see how the handling changes though.

[r0tor]

No..
I would like for a magazine to go ahead and put the SAME tires on BOTH cars. Nothing more or less.

chassis tuning is done with specific tires in mind... you can't change the tires without hampering the suspension setup which is why they always test with OEM tires.  So suddenly they stick on grippier tires and now the vette has a noticeable increase in body roll and a lack of responsiveness - which would bring up even more complaining.

[565]

Thanks a lot for that Cougs.? I'm not a huge Vette fan so I don't pay a lot of attention to the suspension setup like I would on say a Mustang.? Frankly I don't see the inherent issue if the car handles and performs as well as it does.? I would like to see GM try coilovers on a test mule to see how the handling changes though.

I'm sure GM has, and decided to keep the Composite transverse springs.  I went to Wikipedia  and pulled some info on these transverse leaf springs.  The Pros and Cons may surprise you.

"Advantages of transverse leaf springs
Less unsprung weight. Coil springs contribute to unsprung weight; the less there is, the more quickly the wheel can respond at a given spring rate.
Less weight. The C4 Corvette's composite front leaf weighed 1/3 as much as the pair of conventional coil springs it would replace.
Weight is positioned lower. Coil springs and the associated chassis hard mounts raise the center of gravity of the car.
Superior wear characteristics. The Corvette's composite leaf springs last longer than coils, though in a car as light as the Corvette, the difference is not especially significant. No composite Corvette leaf has ever been replaced due to fatigue failure, though steel leafs from 1963 to 1980 have been.
As used on the Corvette, ride height can be adjusted by changing the length of the end links connecting the leaf to the suspension arms. This allows small changes in ride height with minimal effects on the spring rate.
Also as used on the Corvette, the leaf spring acts as an anti-roll bar, allowing for smaller and lighter bars than if the car were equipped with coil springs.


Disadvantages of transverse leaf springs
Packaging can be problematic; the leaf must span from one side of the car to the other. This can limit applications where the drivetrain, or another part, is in the way.
Materials expense. Steel coils are commodity items; a single composite leaf spring costs more than two of them.
Design complexity. Composite monoleafs allow for considerable variety in shape, thickness, and materials. They are inherently more expensive to design, particularly in performance applications.
Susceptibility to damage. Engine fluids and exhaust modifications like cat-back removal might weaken or destroy composite springs over time. The spring is more susceptible to heat related damage than conventional steel springs.
Perception. Like pushrod engines, the leaf spring has a stigma that overshadows its advantages. "


As you can see, the composite leaf is actually a more expensive setup than simple steel coils.  I mean a simple Chevy Aveo comes with steel coils, but only the Corvette uses these composite leaf springs.