big engine and nothing else

[henk4]

What Auto Moto and Sport takes as their test consumption is the overall consumption during the whole test period, including top speed measurements, where the pedal really goes to the metal accelaration tests etc. Although you are right in that it might not fully reflect normal driving practice, I think they are still comparable to other cars, having been tested under the same conditions.
What they also give is a sort of minimum and maximum consuption. Just looking at the Merc CLK 500, SOHC, 4966 CC, for which a test mileage of 13.5 litres is recorded. Minimal consumption is 9.5 litres, maximum 15.8 (probably long motorway trips doing over 200 kph and more) This is illustrative of where the ranges are. Mileage is to a very large extent dependent on the way of driving. Similar figures for the Focus ST170 (also mentioned in this thread are: Test 10,5, minimal 5.9, maximum 12.4 (You note there is a factor 2 involved here)

[Jay 02 TA ws6]

Well, overall consumption for a whole test period makes a little more sense, but I think it still understates the Vette engine a bit. It sorta makes you wonder why the Europeans don't go to the gas saving OHV design doesn't it? Another example is even the Viper engine. It is 500 HP. Try to find a 500 HP engine that can achieve 20 mpg. Other 500 HP engines, like Lamborghinis and Ferraris achieve about 11 mpg on the highway. The OHV also saves quite a bit of engine weight when you start talking about V8, V10, V12, or even V16 (I can't even imagine how much fuel the Bugatti Veyron is going to guzzle once it comes out). The Corvette engine could probably still produce 300 HP if it were 5.0 liters or so (very rough approximations, so don't chastise me if I'm off by a bit)... and then it's gas mileage would go even higher. I am a big fan of the pushrod when it comes to economic practicality. Now for performance reasons, it would be nice if it would rev a little higher... but 6500 RPM in the LS6 is nothing to scoff at.

[PimpmobileCaddy]

Originally posted by Tahoeman
actually, the engine in the upcomming C6, i supposed to have VVT, and it will be pushrod

Amazing. That's ****ing amazing. I wonder how they'll pull it off? This could be a modern first. First OHV to have VVT. That sounds awesome!

[PimpmobileCaddy]

Originally posted by Jay 02 TA ws6
Well if he's using "silly goose" as a cut-down towards Americans, he simply makes himself look like a complete idiot. Since to his target audience - that being Americans - it is at a 1st grade name calling level that sounds more like a book of fairy tails.

You gotta admit, it's really gay when says silly goose.

[Jay 02 TA ws6]

Could someone elaborate as to why OHV have never had VVT before? What is so difficult about it? Why can't OHV also be OHC?

And once and for all so I can get this straight... where in the hell does the camshaft go in a pushrod engine like the one I drive?

[henk4]

[QUOTE]Originally posted by Jay 02 TA ws6
[B]Well, overall consumption for a whole test period makes a little more sense, but I think it still understates the Vette engine a bit. It sorta makes you wonder why the Europeans don't go to the gas saving OHV design doesn't it?
Another example is even the Viper engine. It is 500 HP. Try to find a 500 HP engine that can achieve 20 mpg. Other 500 HP engines, like Lamborghinis and Ferraris achieve about 11 mpg on the highway. [QUOTE]

Again according to AMS test criteria the consumption of the Viper GTS was 18.8 litre per 100 km, which I have worked out as 12.6 mpg. Not far off the Ferrari marque, in AMS I could only find the 456 GTA, taking 20,2 litre per 100 km or 12.2 mpg. I have no idea where you got this 11 mpg figure from. The Modena does slightly better, 13.4 mpg. If these figures are the all round consumption than they must surely be doing much better on the highway. By the way what highway speed do you take 65 or 70 miles? Even at 70 miles some cars may have difficulty in using top gear.

I am glad your asking the same question now that I have been trying to answer. Why do the US manufacturers what they do, and why do other countries (Europe and Japan) things in a different way.

[PimpmobileCaddy]

Not only is weight a factor, but the major factor in fuel economy is the engine designs in a car. I mentioned European supercars and American supercars fuel mileage as just an example of why low-end torque OHV's are more fuel efficient than high revving OHC cars with VVT, which usually the type of engines the European supercars carry.

OHC's are better for performance, but OHV's are usually just as good too.

[henk4]

Originally posted by Jay 02 TA ws6


And once and for all so I can get this straight... where in the hell does the camshaft go in a pushrod engine like the one I drive?

You mean you don't know where it is?

[Jay 02 TA ws6]

Originally posted by PimpmobileCaddy

OHC's are better for performance, but OHV's are usually just as good too.

From now on, I am going to call you "Mister I contradict myself." Seriously, look at that sentence.

So back to my previous question... why can't OHV's and VVT's go together? and where does a camshaft go in a non-OHC engine?

By the way, I apologize. The 11 mpg highway that I saw was for the Enzo. However, the Murcielago was not far off from there.

[Jay 02 TA ws6]

Originally posted by henk4
You mean you don't know where it is?

Yes... physically, where is it?

[henk4]

Originally posted by Jay 02 TA ws6
Yes... physically, where is it?

It is sitting in the V, just above the crankshaft, in a separate housing. Somewhere earlier in this thread there is drawing of the design of the four valve OHV engine that GM is preparing, it has two camshifts in the V, sititng above each other.

(just noticed that you are from Minneapolis drove through there 2 years ago en route from Road America to Calgary in a hired Pontiac Grand Prix, I think I got about 26.5 mpg on average out of that one, 3,7 litre V6, OHV or OHC I don't know.)

[Jay 02 TA ws6]

Okay, thanks, that is kind of where I thought it was. So why then can't pushrod engines have VVT? Is it possible to have OHV and OHC together?

The Grand Prix: 3.8 L V6, pushrod... if it was supercharged it made around 240 HP. The new Grand Prix GTP makes 260 HP, and 280 ft-lbs of torque!!!!

[henk4]

Originally posted by Jay 02 TA ws6
Okay, thanks, that is kind of where I thought it was. So why then can't pushrod engines have VVT? Is it possible to have OHV and OHC together?

The Grand Prix: 3.8 L V6, pushrod... if it was supercharged it made around 240 HP. The new Grand Prix GTP makes 260 HP, and 280 ft-lbs of torque!!!!

To combine OHV and OHC would be a waste. I think one of the reason why OHV engine have no VVT is that the rev range is much smaller, and the cams can deal with that, while in OHC engine that can rev much higher it makes sense to change the cams to make optimal use of this possibility. I am developing this idea while writing so I would not be surprised if it is absolute nonsense, but that at least would trigger a reaction from those who do know.

My Grand Prix definitely was not turbo charged, I think it had about 170 BHP or so. It surely felt less powerful than the Citroen.

[Jay 02 TA ws6]

Originally posted by henk4
To combine OHV and OHC would be a waste. I think one of the reason why OHV engine have no VVT is that the rev range is much smaller, and the cams can deal with that, while in OHC engine that can rev much higher it makes sense to change the cams to make optimal use of this possibility. I am developing this idea while writing so I would not be surprised if it is absolute nonsense, but that at least would trigger a reaction from those who do know.

My Grand Prix definitely was not turbo charged, I think it had about 170 BHP or so. It surely felt less powerful than the Citroen.

I strongly believe you had 200 HP in that Grand Prix. You do realize the difference between supercharging and turbo-charging right? Because that is the second time you have said "turbo" after I said "super".

I couldn't quite follow your explanation on the OHV, OHC, VVT thing... If the valves aren't overhead when you have OHC, where the heck are they?

[Kahless]

they did kill the camaro because of the money. that 22,500 wasnt paying the bills and they couldnt afford to keep pumping them out at a loss.