Corvette C6 Topgear Track time.

[SFDMALEX]

I really dont give a fuck. But if they bashed a Ferrari the Corvette boys would agree. And dont tell me you wouldnt. Dont. Dont. I know you want to say no but dont.

Lastly. You either take the show seriously and agree with everything they have to say, or no and take it as pure entertainment.


Ohh and this whole argument is not going anywere...dont waiste your time people.


Just my take on this. I never liked the C5, never liked the C6, I never considered them to be great performers, I only like and respect the Z06. Not the POS C5 or the even worse C6. So I expected the TOP GEAR bashing.

I hope I wont get attacked for stating my opinion I got other forums to reply in.

[graywolf624]

But if they bashed a Ferrari the Corvette boys would agree. And dont tell me you wouldnt. Dont. Dont. I know you want to say no but dont.

I'm a tifosi.. so your barking up the wrong tree lol.. Granted Im not a corvette boy either.

Lastly. You either take the show seriously and agree with everything they have to say, or no and take it as pure entertainment.

I take it as pure entertainment but I find it sketchy to fake a drag race.

[SFDMALEX]

Ohh yes I forgot you are


Yep I have to agree the drag race looked fishy but you never know...

[Guibo]

Originally Posted by LotusGT1 @Guibo. Laptimes between a Z06 and the GT3 are compared. The comparison between the laptimes of the C6 and the GT3 were purely based on misinformation by some guys here.

Fair enough. I do find it interesting that lap times to the exact second are being debated on cars driven on different days by different drivers...on a 13-mile track.

Originally Posted by LotusGT1 Nevertheless, calling a Porsche 911 GT3 a limited-edition, hand-made, premiere, no-holds-barred, no-expense-sparred, trimmed-down, light-weight, racer-wannabe uber-sportscar is comical, and couldn't be farther from the truth. Childish might be a better word.

It is indeed limited (only 750 samples will make their way to the States this year). Even if the GT3 RS more accurately fits the description, it doesn't mean the GT3 is not a narrowly focused track-oriented car as well. There are numerous, substantial changes to the GT3 over the standard 996 that make it considerably more track-worthy.

[Guibo]

Originally Posted by mindgam3 The bigger the displacement, the more air you can physically get into the engine and the more likely you are to have a higher power output...

But the power doesn't come free. Nor does efficiency necessarily rise at a rate commensurate with displacement. In fact, the larger the engine becomes, the harder it is to maintain high levels of specific output, all things considered equal. If your displacement physically increases via larger pistons, larger valves, valvesprings, cams, connecting rods, etc, you're looking at increased reciprocating mass. Also, as your bore diameter increases, it's harder to maintain high compression ratios. That is why you'll very rarely see any automobile engines the size of the Corvette's approaching the specific output of engines the size of Honda's S2000. Not even the best of BMW's engineer's could get 120 hp/l out of their ultimate roadcar engine, the F1's S70/2. A decade later, and with advancements in variable valve timing, Ferrari's megabuck Enzo can't match the S2000's specific output. And these exotic engines are easily 10-15 times more expensive than the Honda lump. Honda's S2000 can't match the specific output of their '90s CBR600 sportbike. And that thing breathed through carburetors and had only a relatively rudimentary ignition system and certainly no variable valve trickery.
This is why it's ridiculous to compare hp/l in and of itself.

[Guibo]

Originally Posted by mindgam3 Engine reliability is the one thing that has let TVR down, but they've worked alot on this, and their newer cars (tuscan onwards) have much better reliability.

You would think. But Tamora engines and even later Tuscan rebuilds are still going pop.

[DanielW]

Originally Posted by SFDMALEX Just my take on this. I never liked the C5, never liked the C6, I never considered them to be great performers, I only like and respect the Z06. Not the POS C5 or the even worse C6. So I expected the TOP GEAR bashing.

have you ever driven one?

[SFDMALEX]

Originally Posted by DanielW Originally Posted by SFDMALEX Just my take on this. I never liked the C5, never liked the C6, I never considered them to be great performers, I only like and respect the Z06. Not the POS C5 or the even worse C6. So I expected the TOP GEAR bashing. have you ever driven one?

Are you trying to say that you need to drive a car in order to make a judgment on it?

Damn, if thats so, we all should STFU and go play hide.

[fedezyl]

well I usually just enjoy reading these discussions but well, I figured why not bring in my 2 cents.
As far as the Corvette engine goes, the pushrod design is old and frankly outdated, the main advantage is that is a proven design, cheap to build since it's been used in most of the american V-8's and reliability, the problem really comes once you start raising the red line, when is the case when you are looking to get the most out of an engine, hence the hp/l argument, mainly the reason for as high as an hp/l ratio you want is because of engine size, bigger the engine, higher the weight, that can be somewhat contained by using Aluminium, as in the Corvette's engine, but still, a big engine as in the Corvette made it have some design compromises, as the leaf spring suspension on the back, even though it is high tech and has double wishbones in the back, it is still a leaf spring and therefore subject to it's design limitations.
As far as the car being made of plastic, I don't have a problem with the choice of materials at all. The interior is cheap, but well costs are saved a lot in that departement by making it cheap.
Going back to the subject of the engine, the easiest, cheapest way to get more power out of an engine is by increasing it's size, that's what they did in the early days of formula one, until they ran into the problem of weight and space, and therefore they needed to make the engine as efficient as they could, how? by extracting as much bhp per volume of the engine as they could, that way they could keep the engine small. When they started going for that "efficiency" they ran into some design limitations, pushrods for example, seen as the way for the engine to breathe more air, and therefore make more power, was to raise the RPM'S, the fact of having a long bar going up and down in the cylinder block created not only vibrations but induced some valve floating, as the valve springs needed to be bigger to counteract this, due to well, the spring moving a higher weight than just the valve, thus increasing again the weight of the engine as well as the size. also the 2 valve per cylinder design, bigger valves are needed when you increase the engine breathing capacity, the 4 valve per cylinder design allowed for better engine breathing without increasing the size of the head, thus keeping again size and weight under control. Then came overhead camshafts, and double overhead camshafts, again a compact light design that allowed for an easy an simple change on valve phasing thus again helping the engine breathe, try doing that on a pushrod design....., also the DOHC design allows for variable valve timing and lift, thus again keeping size, and weight under control while again improving engine breathing making it even more efficient.

So in the end, is the Corvette a good design, well yes and no, yes, it does ok on what it wants to do, but it definetely makes several compromises, is the engine efficient? compared to modern engines no, it's fairly outdated and limited on it's potential without any serious upgrade, and if we get into the tuning part, well...any DOHC design has a far greater advantage as far as tuning goes than a pushrod design.
Does it make american's happy? yes, they think having a big V-8 is fast and powerful, when in the end a 3.6 liter engine can get almost as much power as the V-8, I think the Corvette is never going to be as good as a sports car, because of the many design compromises, the thing is, what is cheap is cheap for a reason....
To me anyone saying that any of the american V-8's is efficient is someone that is blind and lacks total logic....

[RC45]

Originally Posted by fedezyl well I usually just enjoy reading these discussions but well, I figured why not bring in my 2 cents. As far as the Corvette engine goes, the pushrod design is old and frankly outdated, the main advantage is that is a proven design, cheap to build since it's been used in most of the american V-8's and reliability, the problem really comes once you start raising the red line, when is the case when you are looking to get the most out of an engine, hence the hp/l argument, mainly the reason for as high as an hp/l ratio you want is because of engine size, bigger the engine, higher the weight, that can be somewhat contained by using Aluminium, as in the Corvette's engine, but still, a big engine as in the Corvette made it have some design compromises, as the leaf spring suspension on the back, even though it is high tech and has double wishbones in the back, it is still a leaf spring and therefore subject to it's design limitations. As far as the car being made of plastic, I don't have a problem with the choice of materials at all. The interior is cheap, but well costs are saved a lot in that departement by making it cheap. Going back to the subject of the engine, the easiest, cheapest way to get more power out of an engine is by increasing it's size, that's what they did in the early days of formula one, until they ran into the problem of weight and space, and therefore they needed to make the engine as efficient as they could, how? by extracting as much bhp per volume of the engine as they could, that way they could keep the engine small. When they started going for that "efficiency" they ran into some design limitations, pushrods for example, seen as the way for the engine to breathe more air, and therefore make more power, was to raise the RPM'S, the fact of having a long bar going up and down in the cylinder block created not only vibrations but induced some valve floating, as the valve springs needed to be bigger to counteract this, due to well, the spring moving a higher weight than just the valve, thus increasing again the weight of the engine as well as the size. also the 2 valve per cylinder design, bigger valves are needed when you increase the engine breathing capacity, the 4 valve per cylinder design allowed for better engine breathing without increasing the size of the head, thus keeping again size and weight under control. Then came overhead camshafts, and double overhead camshafts, again a compact light design that allowed for an easy an simple change on valve phasing thus again helping the engine breathe, try doing that on a pushrod design....., also the DOHC design allows for variable valve timing and lift, thus again keeping size, and weight under control while again improving engine breathing making it even more efficient. So in the end, is the Corvette a good design, well yes and no, yes, it does ok on what it wants to do, but it definetely makes several compromises, is the engine efficient? compared to modern engines no, it's fairly outdated and limited on it's potential without any serious upgrade, and if we get into the tuning part, well...any DOHC design has a far greater advantage as far as tuning goes than a pushrod design. Does it make american's happy? yes, they think having a big V-8 is fast and powerful, when in the end a 3.6 liter engine can get almost as much power as the V-8, I think the Corvette is never going to be as good as a sports car, because of the many design compromises, the thing is, what is cheap is cheap for a reason.... To me anyone saying that any of the american V-8's is efficient is someone that is blind and lacks total logic....

I just read this tripe and feel dumber for it.

The Z06 5.7l V8 already revs to 6600rpm in street trim.

Take that same engine and grab an after market catalogue, spend $5,000 or so (I am paraphasing - but I can tell you the amount will be 10,000's less than any German, Japanese, British or Italian engine) on competition grade internals (as THOUSANDS of modified racing enthusiasts do EVERY WEEKEND at dirts oval all across the USA) and you can have a reliable 5.7l small block reliably spinning to 7500 to 8000rpm and producing 500hp on pump gas - or as much as 600hp on race octane.

Formula 1 changed over the years just as much because the RULES CHANGES - as well as technology progressing.

But this still does not make the push-rod V8 any weaker or less powerful.

You can not argue that the cost and complexity involved in gaining similar percentage increases in power is less for a DOHC than a push rod design.

[Guibo]

Originally Posted by fedezyl ...that's what they did in the early days of formula one, until they ran into the problem of weight and space..

Are you quite sure? Going by this theory, modern Formula One teams, even though they're allowed 3.0 liters, should be making 2-2.5 liter engines...because that would make them smaller and lighter. And a reduction in stroke would make revs easier.

Originally Posted by fedezyl Then came overhead camshafts, and double overhead camshafts, again a compact light design...

Compact and light? Take a look at this picture. The one on the right is actually marginally larger in displacement than the one on the left.



Take a look at the size of the heads:


Here's a popular conversion for the Datsun 240Z. On the left, a small-block Chevy. On the right, the DOHC from the "smaller" (in displacement) Infiniti 4.5 liter V8. Which one looks more compact to you?

Originally Posted by fedezyl Then came overhead camshafts, and double overhead camshafts, again a compact light design that allowed for an easy an simple change on valve phasing thus again helping the engine breathe, try doing that on a pushrod design....., also the DOHC design allows for variable valve timing and lift, thus again keeping size, and weight under control while again improving engine breathing making it even more efficient.

Hmm...Ok.
"The LZ8 3900 will be the first GM overhead valve engine to use variable valve timing, and it will be GM’s first V-6 to use DOD."
http://www.auto-report.net/index.html?gmpt05.html
This is partially correct. It will be the first GM OHV production engine to use variable valve timing. The XV16 had it too.

Originally Posted by fedezyl yes, they think having a big V-8 is fast and powerful, when in the end a 3.6 liter engine can get almost as much power as the V-8, I think the Corvette is never going to be as good as a sports car, because of the many design compromises, the thing is, what is cheap is cheap for a reason....

I don't think you understand how cheap it really is. A Chevy LS6 is about $6-7K. And makes 405 hp and about an equal amount of torque. A standard, normally aspirated Porsche flat-6 is $20K. We're not even talking about GT3 engines here. And makes nowhere near that kind of power or torque. Porsche's 996 Turbo is right on the mark for power and torque. But oh, dear. It's $40K...And sure as hell isn't as cheap to service.
You have to ask yourself: Why is Porsche's engines continuing to increase in displacement? How large was the original Porsche flat-6? How large is the 997 C4S engine? By the same token, recall that the original BMW M3 had a 2.3-liter inline-4. It's gone from an I-4 to an I-6. Next up is a V8. Same with with the M5, except it's a level up from the M3.
What all of you guys are forgetting about is that peak hp doesn't matter as much as the way that power is delivered, its effective powerband, the shape of its torque curve, and the area under the curves. Take a look at these two modified engines:

One is a turbocharged I-6. The other a naturally aspirated V10. They both put out about 640-650 RWHP. But does hp=hp? Not necessarily. Look at the area under the curves. Which do you think would have better throttle response? Which do you think would make a better street engine, ie. which is more driveable?
These are ALL considerations into why GM chooses to use pushrods (which it says saves them $2.7B a year). In the case of the Corvette, not only is it cheap to build, it's cheap to service, it's durable, less complex (compared to a DOHC design), and it offers the instant throttle response owners look for. On top of that, they can afford to use a lazy overdrive 6th gear: the Z06/C6 basically does with 5 forward gears what many of its competitors do with 6. And that lazy 6th gear means better fuel economy. The Z06 is about as fuel efficient as a standard 996.

[RC45]

What he just said

[Guibo]

BTW, the crated shipping weight on an LS6 is 497 lbs. Crated shipping weight for the identical-displacement, Lotus-designed all-aluminum LT5 found in the ZR-1...741 lbs. So much for the theory that DOHC design is lighter. (The LS6 is also noticeably narrower at its widest point than the LT5.) I'll grant you that DOHC has better outright breathing capabilities (there are 1000+ rwhp ZR-1's, and there are 1000+ rwhp pushrod Corvettes), but the claim that DOHC is lighter for a given application is pretty much false. And considering NONE of the manufacturers will give you an engine stressed to its absolute max (they have warranties to consider after all), outright breathing potential is substantially outweighed by other factors.

[mindgam3]

Originally Posted by fedezyl well I usually just enjoy reading these discussions but well, I figured why not bring in my 2 cents. As far as the Corvette engine goes, the pushrod design is old and frankly outdated, the main advantage is that is a proven design, cheap to build since it's been used in most of the american V-8's and reliability, the problem really comes once you start raising the red line, when is the case when you are looking to get the most out of an engine, hence the hp/l argument, mainly the reason for as high as an hp/l ratio you want is because of engine size, bigger the engine, higher the weight, that can be somewhat contained by using Aluminium, as in the Corvette's engine, but still, a big engine as in the Corvette made it have some design compromises, as the leaf spring suspension on the back, even though it is high tech and has double wishbones in the back, it is still a leaf spring and therefore subject to it's design limitations. As far as the car being made of plastic, I don't have a problem with the choice of materials at all. The interior is cheap, but well costs are saved a lot in that departement by making it cheap. Going back to the subject of the engine, the easiest, cheapest way to get more power out of an engine is by increasing it's size, that's what they did in the early days of formula one, until they ran into the problem of weight and space, and therefore they needed to make the engine as efficient as they could, how? by extracting as much bhp per volume of the engine as they could, that way they could keep the engine small. When they started going for that "efficiency" they ran into some design limitations, pushrods for example, seen as the way for the engine to breathe more air, and therefore make more power, was to raise the RPM'S, the fact of having a long bar going up and down in the cylinder block created not only vibrations but induced some valve floating, as the valve springs needed to be bigger to counteract this, due to well, the spring moving a higher weight than just the valve, thus increasing again the weight of the engine as well as the size. also the 2 valve per cylinder design, bigger valves are needed when you increase the engine breathing capacity, the 4 valve per cylinder design allowed for better engine breathing without increasing the size of the head, thus keeping again size and weight under control. Then came overhead camshafts, and double overhead camshafts, again a compact light design that allowed for an easy an simple change on valve phasing thus again helping the engine breathe, try doing that on a pushrod design....., also the DOHC design allows for variable valve timing and lift, thus again keeping size, and weight under control while again improving engine breathing making it even more efficient. So in the end, is the Corvette a good design, well yes and no, yes, it does ok on what it wants to do, but it definetely makes several compromises, is the engine efficient? compared to modern engines no, it's fairly outdated and limited on it's potential without any serious upgrade, and if we get into the tuning part, well...any DOHC design has a far greater advantage as far as tuning goes than a pushrod design. Does it make american's happy? yes, they think having a big V-8 is fast and powerful, when in the end a 3.6 liter engine can get almost as much power as the V-8, I think the Corvette is never going to be as good as a sports car, because of the many design compromises, the thing is, what is cheap is cheap for a reason.... To me anyone saying that any of the american V-8's is efficient is someone that is blind and lacks total logic....

Thank you, someone who understands the term efficiency in this context

[quote="Guibo"]
But the power doesn't come free. Nor does efficiency necessarily rise at a rate commensurate with displacement. In fact, the larger the engine becomes, the harder it is to maintain high levels of specific output, all things considered equal. If your displacement physically increases via larger pistons, larger valves, valvesprings, cams, connecting rods, etc, you're looking at increased reciprocating mass.
[/Guibo]

If all things stay the same, increasing the displacement WILL increase the power. I never said that the relationship between Displacement and output power was linear, but its the general trend. Obviously theres limitations.

As for bigger engines being smaller? If you take modern engines, a smaller displacement engine is going to be smaller. Obviously this varies from manufacturer to manufacturer.

Originally Posted by T-bird So if a car has a 1.8T motor and another has 2.0 that 1.8 making more power is more efficient because it makes more power with less air? although it uses more air/fuel than the 2.0 because the Turbo compresses the air meaning it uses more and more fuel is put in the mixture because of it. So if you throw a Turbo on a Vette engine it makes more power yes but why does it do that? it uses more air, doesn't mean it's more efficient than the N/A version does it? This efficiency thing doesn't work in your arguement Efficiency has nothing to do with power! What you are saying is that an engine that brings in less air/fuel but has to have all these fancy things to make it burn better is more efficient than a bigger one that is a more basic design. The biggest reason that Porsche and Subaru make more power out of their engines is because of the layout the Boxer design has alot less parasitic loss through the connecting rods and crankshaft because of the lesser effort needed to move the pistons outward(in this case) than an engine that has to push them upward.

In your scenario, the 1.8T wouldnt make more power with less air - thats the whole idea of a turbo; to get more air into the combustion chamber per cycle. The 1.8T would make more power with more air. Comparing forced induction engines with NA engines with HP/litre dosent really work as you aren't getting roughly the same amount of air in the cylinder for each engine.

Of course efficiency has something to do with power. What makes a 3 litre V10 F1 engine produce more power than say a CGT's 5.8 V10? It's because its more efficient at combusting! All the technology and lighter parts in an F1 engine means it is more efficient.

The reason porsche make more power out of their engines is because they're more tecnologically advanced. The boxer engine has something to do with this, but its more to do with the they're better developed and designed engines.

Originally Posted by graywolf624 Hp/liter is very poorly(if at all) correlated to power per weight.. power per weight is what gives us handling and acceleration. hp/liter effects nothing.. hp/liter doesnt even give power /engine weight. Prime example.. the 5.0 liter in the 80s mustangs is over 100 pounds lighter then the modular 4.6 liter in the newer ones(without the turbo) The difference between arguing about something that directly effects acceleration... f=ma thus less mass means more acceleration versus.. something that effects nothing.

I never said that there was a correlation between hp/litre and power to weight. I gave that as an example of your so called "made up numbers". Arguarbly power to weight has more effect on the car than HP/litre, but they're still both important in their own right.

You're right though HP/litre doesen't effect anything when u consider it on your own - did i ever say it didnt? I said it was a good statistic to use when comparing engines.....

Less mass dosen't neccesarily mean more acceleration. It's alos how you put the power onto the road. Hence why 4WD cars are usually faster off the line.

[jon_s]

Originally Posted by RC45 I just read this tripe and feel dumber for it.

Some of your opening lines crack me up