C7 engine?
Pro
Joined: Jun 2007
Posts: 525
Likes: 0
From: Sometimes Miami Sometimes Orlando Florida
So were DOHCs
DOHC sounds much more advanced, especially since they have so many more moving parts! and take up so much more volume per cubic inch of displacement. And weigh more. Yeah they are a lot more advanced.
The Wankel is much more advanced than both! They make tremendous power per cubic inch, they must be the best! Unfortunately their fuel mileage and emissions suck by comparison, and the long term reliabilty is still lacking. And I am a big fan of the rotary engine and its design simplicity.
DOHC sounds much more advanced, especially since they have so many more moving parts! and take up so much more volume per cubic inch of displacement. And weigh more. Yeah they are a lot more advanced.
The Wankel is much more advanced than both! They make tremendous power per cubic inch, they must be the best! Unfortunately their fuel mileage and emissions suck by comparison, and the long term reliabilty is still lacking. And I am a big fan of the rotary engine and its design simplicity.
Le Mans Master
Joined: Jul 2000
Posts: 6,559
Likes: 4,501
From: North Dallas 40 TX
SOHC engines are not "advanced". They are old news and therefore suck just like the OHV engine. Don't you know we must have DOHCs, 4 valves, and multiple turbos to be "advanced" and "cool" or is it "bad" or "off the hook". I am an old guy and can't keep up with the language of the whippersnappers.
Compare the 505hp OHV LS7 V8 with the similarly configured and powerful Ferrari DOHC V8. Start counting the parts. You will find that the Ferrari has more parts, gets less fuel mileage, has more engine friction, weighs more, takes up more space. There is a difference between can and do. I could take you back to a simpler time and show you one that has the potential with some redesigning of the head. The Ford 7 liter SOHC. Of course that is not "advanced" like a Ferrari DOHC V8. You could make a SOHC 4 valve per cylinder engine, or a 4 valve OHV engine too. Don't you see engineering reality has nothing to do with it. It is the perception of advanced, not the reality of what is advanced.
Once you go to a V design and 4 valves per cylinder to get the performance out of a small displacement engine, the moving parts of the OHC design multiples like rabbits. The advantage comes when you are designing to a restricted displacement due to arbitrary rules that the US does not have. We do not tax on displacement. We do not have the restriction of racing rules for road cars. It is an unecessary complication to have DOHC and meet the design and performance criteria of the Corvette.
Pro
Joined: Jun 2007
Posts: 525
Likes: 0
From: Sometimes Miami Sometimes Orlando Florida
SOHC engines are not "advanced". They are old news and therefore suck just like the OHV engine. Don't you know we must have DOHCs, 4 valves, and multiple turbos to be "advanced" and "cool" or is it "bad" or "off the hook". I am an old guy and can't keep up with the language of the whippersnappers.
Compare the 505hp OHV LS7 V8 with the similarly configured and powerful Ferrari DOHC V8. Start counting the parts. You will find that the Ferrari has more parts, gets less fuel mileage, has more engine friction, weighs more, takes up more space. There is a difference between can and do. I could take you back to a simpler time and show you one that has the potential with some redesigning of the head. The Ford 7 liter SOHC. Of course that is not "advanced" like a Ferrari DOHC V8. You could make a SOHC 4 valve per cylinder engine, or a 4 valve OHV engine too. Don't you see engineering reality has nothing to do with it. It is the perception of advanced, not the reality of what is advanced.
Once you go to a V design and 4 valves per cylinder to get the performance out of a small displacement engine, the moving parts of the OHC design multiples like rabbits. The advantage comes when you are designing to a restricted displacement due to arbitrary rules that the US does not have. We do not tax on displacement. We do not have the restriction of racing rules for road cars. It is an unecessary complication to have DOHC and meet the design and performance criteria of the Corvette.
Compare the 505hp OHV LS7 V8 with the similarly configured and powerful Ferrari DOHC V8. Start counting the parts. You will find that the Ferrari has more parts, gets less fuel mileage, has more engine friction, weighs more, takes up more space. There is a difference between can and do. I could take you back to a simpler time and show you one that has the potential with some redesigning of the head. The Ford 7 liter SOHC. Of course that is not "advanced" like a Ferrari DOHC V8. You could make a SOHC 4 valve per cylinder engine, or a 4 valve OHV engine too. Don't you see engineering reality has nothing to do with it. It is the perception of advanced, not the reality of what is advanced.
Once you go to a V design and 4 valves per cylinder to get the performance out of a small displacement engine, the moving parts of the OHC design multiples like rabbits. The advantage comes when you are designing to a restricted displacement due to arbitrary rules that the US does not have. We do not tax on displacement. We do not have the restriction of racing rules for road cars. It is an unecessary complication to have DOHC and meet the design and performance criteria of the Corvette.
Last edited by PaintballaXX; Apr 20, 2010 at 06:05 PM.
Melting Slicks
Joined: Jul 2006
Posts: 3,167
Likes: 5
From: Holly Ridge North Carolina
I want more displacement! maybe 7.0L for standard and 8.0L in Z 
I want more HP naturally aspirated! 550 in standard 650 in Z to beat out the viper
GRRRR
Unfortunately what I want never happens....
I want more HP naturally aspirated! 550 in standard 650 in Z to beat out the viper
GRRRR
Unfortunately what I want never happens....
Le Mans Master
Joined: Jul 2000
Posts: 6,559
Likes: 4,501
From: North Dallas 40 TX
Wow you sure said a mouthful. I happen to like ohv engines but a dohc or ohc engine REQUIRES less parts to make. Whether or not a manufacture decides to take the simplistic way out with the typical ohc engine is irrelevant as far my point is concerned. I was simply correcting the one thing you said that is simply not true. Yes the ls engines are cheap, light, powerful and fuel efficient. I never said otherwise, take a chill pill.
Please give 3 current high performance examples that fit the Corvette, and its performance parameters that have fewer moving parts.
There must be some reason they don't build them that way.
I am sorry I just get sick and tired of people saying DOHC is so much newer and advanced, and OHV is old tech. (That is not directed to your response which was correcting my error.
1st Gear
Joined: May 2010
Posts: 1
Likes: 0
2000 to 2002 model years:
7.3L DIT V8 Navistar
7.2L (3126B) Caterpillar inline 6
5.9L Cummins inline 6
2003 to current model years:
6.0L DIT V8 Navistar
7.2L (3126B) Caterpillar inline 6
5.9L Cummins inline 6
ALL of the above are diesel engines. A V10 or V12 engine does not exist as an option for the truck in question. Hope this helps.
=============
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7.3L DIT V8 Navistar
7.2L (3126B) Caterpillar inline 6
5.9L Cummins inline 6
2003 to current model years:
6.0L DIT V8 Navistar
7.2L (3126B) Caterpillar inline 6
5.9L Cummins inline 6
ALL of the above are diesel engines. A V10 or V12 engine does not exist as an option for the truck in question. Hope this helps.
=============
Cheap SEO
Burning Brakes
Joined: Feb 2006
Posts: 926
Likes: 0
Direct Injection is the best thing to do. In fact, if that's the only thing changed, then that would possibly be just perfect.
The current engine is bullet proof and already has pretty high mpg's the keep the CAFE folks quiet. Chevrolet has already shown what great things they can do with DI. Just look at the Equinox, it's 4 cylinder can get up to 32mpg, with owners reporting even more than that. And it's an SUV, with absolutely no hybrid technology. The Corvette needs this kind of improvement.
As for the sound, yea they are kind of quiet. But, if you add the optional exhaust system to the current lineup of base C6 cars, then they turn out great. The engine isn't the problem, they should just add that exhaust as a standard option across the base C6 lineup.
The current engine is bullet proof and already has pretty high mpg's the keep the CAFE folks quiet. Chevrolet has already shown what great things they can do with DI. Just look at the Equinox, it's 4 cylinder can get up to 32mpg, with owners reporting even more than that. And it's an SUV, with absolutely no hybrid technology. The Corvette needs this kind of improvement.
As for the sound, yea they are kind of quiet. But, if you add the optional exhaust system to the current lineup of base C6 cars, then they turn out great. The engine isn't the problem, they should just add that exhaust as a standard option across the base C6 lineup.
Some interesting reading on Direct Injection.
http://www.audiforums.com/forum/showthread.php?t=113568
http://www.audizine.com/forum/showth...-up-Megathread
http://www.clublexus.com/forums/is-f...injection.html
Le Mans Master
Joined: Feb 2000
Posts: 8,099
Likes: 398
From: Oakland, CA
Wasn't Audi first? Early adopters usually pay a higher price and have more issues than those who follow. Direct injection is fast becoming common technology. Porsche, Buick, Hyundai... by the time C7 hits the showroom, direct injection will be passe.
Early fuel injection had problems too, and yet it had compelling advantages; we don't have carburetors anymore.
Still, I might wait until the second model year this go-round. We might not see a repeat of Cross-Fire Injection, but C6 did give us the Pilsbury steering wheel and SHIFT TO REVERSE.
Early fuel injection had problems too, and yet it had compelling advantages; we don't have carburetors anymore.
Still, I might wait until the second model year this go-round. We might not see a repeat of Cross-Fire Injection, but C6 did give us the Pilsbury steering wheel and SHIFT TO REVERSE.
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Burning Brakes
Joined: Feb 2006
Posts: 926
Likes: 0
Wasn't Audi first? Early adopters usually pay a higher price and have more issues than those who follow. Direct injection is fast becoming common technology. Porsche, Buick, Hyundai... by the time C7 hits the showroom, direct injection will be passe.
Early fuel injection had problems too, and yet it had compelling advantages; we don't have carburetors anymore.
Still, I might wait until the second model year this go-round. We might not see a repeat of Cross-Fire Injection, but C6 did give us the Pilsbury steering wheel and SHIFT TO REVERSE.
Early fuel injection had problems too, and yet it had compelling advantages; we don't have carburetors anymore.
Still, I might wait until the second model year this go-round. We might not see a repeat of Cross-Fire Injection, but C6 did give us the Pilsbury steering wheel and SHIFT TO REVERSE.
Any idea what is being used in the Cadillac version?
Racer
Joined: Aug 2007
Posts: 305
Likes: 1
From: DRAYTON VALLEY ALBERTA
No it's not...
Everybody gets so caught up in new engine tech like DOHC, VVT, horsepower per liter, etc. Let's take the S65 mill from the new V8 M3... It's 4.0L motor putting out 414HP - so it hits that magic 100HP+ per liter mark everybody talks about. Now look at the LS7 in the Z06... It's a 7.0L motor putting out only 505HP - so way less than 100HP per liter. Obviously the LS7 is crap compared to the S65 - right? If you look beyond the HP per liter argument, you realize that pushrod engines are smaller and lighter than more modern OHC designs (of similar displacement). The S65 in the M3 weighs 445 LBS - the LS7 weighs 458 LBS... Now maybe it's me, but I'd imagine only a fool would complain about an extra 91HP for a measly 13 LBS. And if the extra 91HP isn't enough of an argument, then the extra 175 FT-LBS of torque should be.
There's more than one valid right way to get horsepower out of a motor. GM has done a great job with the LS series motors over the years... They're bulletproof and easy to work on. No they don't rev to 8,400rpm or have high HP per liter, but they put out a remarkable amount of HP/torque in a relatively small and lightweight package.
Everybody gets so caught up in new engine tech like DOHC, VVT, horsepower per liter, etc. Let's take the S65 mill from the new V8 M3... It's 4.0L motor putting out 414HP - so it hits that magic 100HP+ per liter mark everybody talks about. Now look at the LS7 in the Z06... It's a 7.0L motor putting out only 505HP - so way less than 100HP per liter. Obviously the LS7 is crap compared to the S65 - right? If you look beyond the HP per liter argument, you realize that pushrod engines are smaller and lighter than more modern OHC designs (of similar displacement). The S65 in the M3 weighs 445 LBS - the LS7 weighs 458 LBS... Now maybe it's me, but I'd imagine only a fool would complain about an extra 91HP for a measly 13 LBS. And if the extra 91HP isn't enough of an argument, then the extra 175 FT-LBS of torque should be.
There's more than one valid right way to get horsepower out of a motor. GM has done a great job with the LS series motors over the years... They're bulletproof and easy to work on. No they don't rev to 8,400rpm or have high HP per liter, but they put out a remarkable amount of HP/torque in a relatively small and lightweight package.
Amen Brother
Drifting
Joined: Feb 2002
Posts: 1,260
Likes: 0
From: Chapel Hill NC
Like almost anything
Modern DOHC engines: "Fiat (1912), Peugeot Grand Prix (1913, 4 valve), Alfa Romeo Grand Prix (1914, 4 valve)"
Most ideas appear very early in a development cycle. They come into and out of favor as materials and knowledge develop and requirements change. The internal combustion engine is no different. DOHC engines in multiple valves are no different.
Most ideas appear very early in a development cycle. They come into and out of favor as materials and knowledge develop and requirements change. The internal combustion engine is no different. DOHC engines in multiple valves are no different.
Safety Car
Joined: Jul 2004
Posts: 4,806
Likes: 70
From: Rochester MN
Ok, the young, lurking noob is going to make his prediction. lol
5.5 liter, direct injection. Still 400+ hp
It's a win/win. GM gets to make a smaller, more fuel efficient engine, while at the same time maintaining the current power outputs of the LS2/3.
So that renders moot the old theories of GM creating a smaller, lighter, Solstice-sized C7 with a weaker engine. Screw that weight ricer logic. :P
Before anyone says, "Why not just add D/I to the 6.2? ZOMG! EVEN MOAR POWER!!!" I honestly think a lot of people, and probably GM management, feel that the base Vette already has enough horsepower. I mean c'mon, 400+. Why make it even more unnecessarily fast when they can simply maintain all the awesome performance you already have while reaping much better fuel economy. It's a no-brainer, imo.
5.5 liter, direct injection. Still 400+ hp
It's a win/win. GM gets to make a smaller, more fuel efficient engine, while at the same time maintaining the current power outputs of the LS2/3.
So that renders moot the old theories of GM creating a smaller, lighter, Solstice-sized C7 with a weaker engine. Screw that weight ricer logic. :P
Before anyone says, "Why not just add D/I to the 6.2? ZOMG! EVEN MOAR POWER!!!" I honestly think a lot of people, and probably GM management, feel that the base Vette already has enough horsepower. I mean c'mon, 400+. Why make it even more unnecessarily fast when they can simply maintain all the awesome performance you already have while reaping much better fuel economy. It's a no-brainer, imo.
I thnk we have a winner
440 HP
Drifting
Joined: Jul 2009
Posts: 1,358
Likes: 59
The poster that said ohc engines had less parts than ohv obviously has not taken them apart. My 03 cobra has 4 camshafts, about 16 feet of timing chain and heads that weigh 40lbs more(each) than my z06 heads. I will take the 16 little pushrods over all the extra crap on the 4 valve engine anyday...especially when the 4valve costs more, makes less hp, and gets poorer fuel economy. One camshaft is actually brilliant over the idea that you need a cam for each set of valves...that is monkey thinking...simpler is always more genius. Take a colt 1911 completely apart and do the same with a glock. You get the idea.
Cruising
Joined: Jul 2010
Posts: 10
Likes: 0
From: Luxemburg WI
What I find odd about this conversation is guys jabbering about smaller engines that are more fuel efficent... Honestly did anyone of us stand in the showroom looking at one of these rockets and ask the salesmen " what will I get for fuel milage " ?? Sure as hell wasn't me and besides for a 505 HP vehicle I think the mpg is great although I never checked it. GM should continue on its currant path giving us more HP with the C7 like they have with all the models before...
Pro
Joined: Jun 2007
Posts: 525
Likes: 0
From: Sometimes Miami Sometimes Orlando Florida
For a ohv engine you need 1 camshaft, 16 valves, 16 rockers, 16 springs, and 16 pushrods. That's 65 moving parts not counting the pistons and crank etc. With a sohc engine you only need 2 cams, 16 springs, and 16 valves. Thats 34 moving parts. If so desired, a ohc engine can directly actuate the valve. These days that's not usually how its done, but that wasn't what I was arguing, so no need to quote me just to point that out.
Racer
Joined: Jul 2010
Posts: 409
Likes: 87
From: Hutto, Texas
And an 8.0L V8 would be rediculous... not that i would complain, but that would push the cost of the Vette even higher than it is now, and make it that much harder for younger Vette enthusiasts (like myself being 22) to obtain.
As for power, 550 horse for a base model is almost too much for some people to handle... I think 450-475 would be bordering on too much power for a base model Vette.