Who says stock Yank motors don't make power...
Discussion
Troubleatmill said:
Just to spell out the important bit...
"“I sit on several FIA engine councils and it always comes up from our competitors. Whether it’s Porsche, Ferrari, or Aston Martin, they’re always complaining about what they perceive of as the advantages the two-valve engine has [over] their [designs], and want the two-valve engine penalized, said Fehan. “To that I say, ‘go back to the road car—if the two-valve engine is that much better for racing you ought to put it in your car.’ To which they have no answer.”
Read more: http://gmauthority.com/blog/2014/02/corvette-racin...
And that^^ is precisely the problem with "internet experts""“I sit on several FIA engine councils and it always comes up from our competitors. Whether it’s Porsche, Ferrari, or Aston Martin, they’re always complaining about what they perceive of as the advantages the two-valve engine has [over] their [designs], and want the two-valve engine penalized, said Fehan. “To that I say, ‘go back to the road car—if the two-valve engine is that much better for racing you ought to put it in your car.’ To which they have no answer.”
Read more: http://gmauthority.com/blog/2014/02/corvette-racin...
Firstly, that is an article on a GM website about "How good" a GM engine is. Do you think they would publish an article that says anything else?
Secondly, world sports car racing regulation imposes intake air restrictors and a rev limit on the engines used. These measures are used to bring close racing through "power equity" to the racing series. As such, the potentially much more powerful direct acting architecture engines in the european cars is "hobbled" (to ensure power parity), and as such, having to use a production engine with it's high CofG and high mass, yet being unable to utilise it's full power capability is a disadvantage in that race series.
In an un-regulated situation, you'd just design a bespoke, high power race engine, which would make the same power as the massive LS engine in 'vette, but be half the size and 1/3 of the weight. Something say like this 2.5 KF engine:
Which is tiny, weighs just 90kg, revs to 16k, and makes 600 bhp easily
DonkeyApple said:
Max, try and swerve the insults. You're not a child.
Stop deliberately ignoring what is written and stop being deliberately obtuse.
Not a GM fanboy as both you well know and as I wrote in my first post on this thread. This showing you've not read but just decided to have an argument at any cost.
Go back and read properly and start again. Night.
OK, back to the beginning:Stop deliberately ignoring what is written and stop being deliberately obtuse.
Not a GM fanboy as both you well know and as I wrote in my first post on this thread. This showing you've not read but just decided to have an argument at any cost.
Go back and read properly and start again. Night.
An LS engine without any boundary losses, as shown in the original "tuner" article linked made 85bhp/litre (which is sh*t)
Any 4v, direct acting european engine will make well over 100bhp/litre in the same condition.
You then gave the AMG 6.2 V8 as an example saying "the GM LS 6.2 has power parity with this engine".
But it doesn't, in fact, in OEM tune, it's the best part of 85bhp down
The simple FACT is that any engine with a direct acting valve train will have a significantly higher ultimate power potential than a pushrod engine of the same capacity. This is because the lack of valve system stiffness and increased inertia as a result of being indirect, limits maximum valve acceleration (and hence power!)
buggalugs said:
Anyone who wants to argue for pushrod engines from a bhp/litre angle is on to a looser. The question should be more, which ~500bhp engine would you buy with your own money to take to 100k miles - the ones that cost two/three times more with worse reliability, or this one?
I'm struggling to think of a modern 500bhp engine that won't do 100k miles?(the days of TVRs going bang every 10kmiles are long gone!)
Max_Torque said:
OK, back to the beginning:
An LS engine without any boundary losses, as shown in the original "tuner" article linked made 85bhp/litre (which is sh*t)
Any 4v, direct acting european engine will make well over 100bhp/litre in the same condition.
You then gave the AMG 6.2 V8 as an example saying "the GM LS 6.2 has power parity with this engine".
But it doesn't, in fact, in OEM tune, it's the best part of 85bhp down
The simple FACT is that any engine with a direct acting valve train will have a significantly higher ultimate power potential than a pushrod engine of the same capacity. This is because the lack of valve system stiffness and increased inertia as a result of being indirect, limits maximum valve acceleration (and hence power!)
Ignoring the fact that as you say push rod isn't the best for out right power but good for packing, you can get an LS3 from the OEM with 525bhp, for just over £6K. How much is a M156?An LS engine without any boundary losses, as shown in the original "tuner" article linked made 85bhp/litre (which is sh*t)
Any 4v, direct acting european engine will make well over 100bhp/litre in the same condition.
You then gave the AMG 6.2 V8 as an example saying "the GM LS 6.2 has power parity with this engine".
But it doesn't, in fact, in OEM tune, it's the best part of 85bhp down
The simple FACT is that any engine with a direct acting valve train will have a significantly higher ultimate power potential than a pushrod engine of the same capacity. This is because the lack of valve system stiffness and increased inertia as a result of being indirect, limits maximum valve acceleration (and hence power!)
DonkeyApple said:
Very many people for many years have screamed that DOHC is superior and GM have shown that it is not superior just different.
Your first post^^^^You claim GM have shown that Direct Acting Valvetrains (ie OHC) are not "Superior" (<< your words) to their push rod engines.
Unfortunately all the evidence, and basic maths, (F=MA) tells us that in terms of specific power, Push rod engines ARE inferior.
Max_Torque said:
Troubleatmill said:
Just to spell out the important bit...
"“I sit on several FIA engine councils and it always comes up from our competitors. Whether it’s Porsche, Ferrari, or Aston Martin, they’re always complaining about what they perceive of as the advantages the two-valve engine has [over] their [designs], and want the two-valve engine penalized, said Fehan. “To that I say, ‘go back to the road car—if the two-valve engine is that much better for racing you ought to put it in your car.’ To which they have no answer.”
Read more: http://gmauthority.com/blog/2014/02/corvette-racin...
And that^^ is precisely the problem with "internet experts""“I sit on several FIA engine councils and it always comes up from our competitors. Whether it’s Porsche, Ferrari, or Aston Martin, they’re always complaining about what they perceive of as the advantages the two-valve engine has [over] their [designs], and want the two-valve engine penalized, said Fehan. “To that I say, ‘go back to the road car—if the two-valve engine is that much better for racing you ought to put it in your car.’ To which they have no answer.”
Read more: http://gmauthority.com/blog/2014/02/corvette-racin...
Firstly, that is an article on a GM website about "How good" a GM engine is. Do you think they would publish an article that says anything else?
Secondly, world sports car racing regulation imposes intake air restrictors and a rev limit on the engines used. These measures are used to bring close racing through "power equity" to the racing series. As such, the potentially much more powerful direct acting architecture engines in the european cars is "hobbled" (to ensure power parity), and as such, having to use a production engine with it's high CofG and high mass, yet being unable to utilise it's full power capability is a disadvantage in that race series.
In an un-regulated situation, you'd just design a bespoke, high power race engine, which would make the same power as the massive LS engine in 'vette, but be half the size and 1/3 of the weight. Something say like this 2.5 KF engine:
Which is tiny, weighs just 90kg, revs to 16k, and makes 600 bhp easily
I'll admit to spending a week talking to a Prodrive engineers (Aston Martin Racing ) - a good few years ago - and we had a long chat about the bartering process that the teams go through. Of particular note were the discussions around air intake ( and what the Aston was really capable of - but the ACO had placed restrictions on what it wanted the lap times to be [ For s
ts and giggles..... he said the Astons were capable of a 1:39 time without ACO interference ] ) and what Aston believed to be the strengths of the Corvette team - and how they wanted to persuade the ACO to place restrictions on that piece of technology.It was quite an illuminating week in company with the guy. He liked champagne. A lot.
I've even spent some time with the Corvette Z06 chassis designer - and discussed the brief for what they had to do in the car - as there were limitations that the race team could do to modify the car/ engine.
So it was designed from the get-go - despite the fact that the general public buying the cars wouldn't really need/use the technology.
Heck.....I've been in one of the Le Mans 24 hours garages ( in 2011) courtesy of one of the teams., and been given a guided tour of the ACO race control building.... but that it just me having a moist moment.
But..... I'm no expert.
If you have a blank sheet of paper ..... the engine you design has absolutely no bearing whatsoever to the road car derivative.
But... in the real world of racing... where the race car has to have a fair chunk of it's DNA in the road car - it is a valid example.
Having owned a Z06, which accelerates pretty much quicker than anything else I have been in. The technology is way good enough for me.
It does 199mph
It got me from 0 - 100 in 7.6 seconds.
The ring times are silly fast ( not with me driving )
It did 0-60 in first gear.
It got 30 mpg on long motorway runs.
And it has a 100,000 mile warranty.
If you want a real world car - with a real world reliable performance engine - at a sensible cost. The LS engines are a pretty good bet.
BTW - I'm not married to big V8's - I loved the F20C engines too.
But then we would be comparing apples with oranges.
Edited for typos and predictive text errors
Edited by Troubleatmill on Sunday 26th April 21:06
Max_Torque said:
DonkeyApple said:
Very many people for many years have screamed that DOHC is superior and GM have shown that it is not superior just different.
Your first post^^^^You claim GM have shown that Direct Acting Valvetrains (ie OHC) are not "Superior" (<< your words) to their push rod engines.
Unfortunately all the evidence, and basic maths, (F=MA) tells us that in terms of specific power, Push rod engines ARE inferior.
The stupid thing is that you know darn well what I was talking about but are being deliberately offensive and obtuse.
The fact remains that GM have shown us DOHC fans that an old pushrod design can easily hold its own as shown in the basic numbers for a selection of large displacement V8 engines.
And then if you apply the cost factor then it becomes even more clear that the options are just different and clearly not either inferior or superior. You can even look at MPG figures for these corresponding applications and see that the pushrods are not exactly losing out.
The OP is correct in his observation. While big displacement is still allowed this type of engine design is still holding its own against far more complicated DOHC equivalents.
RoverP6B said:
85bhp/litre from pushrods without any forced induction, and GM sandbagging on true output by 70bhp... take that, those of you who insist all great engines are DOHC!
http://www.lsxtv.com/news/danzio-performance-basel...
Sandbagging?http://www.lsxtv.com/news/danzio-performance-basel...
I suspect if you add in the OEM intake, exhaust, ancills, and with the OEM ECU calibration on 95RON it would be about, umm, err 70hp down on that figure.
The LS engines are cheap, easy to package so I can see why people use them in kit cars and the like. But, they are nowhere near the same level as the European and Japanese 4valve engines in terms of specific output whilst still hitting Euro 6 emission targets.
As an example Porsche 991 which is fitted to cars which are sold in a similar market sector.
3.4-345bhp 288lb/ft 100bhp/lt and 84.7lb/ft/lt 211 g/km in a manual
3.8-400bhp/325lb/ft 105bhp/lt and 85.5lb/ft/lt 223 g/km in a manual
I suppose we should just look to the drag racing guys.
Imagine this........... You are driving a new Lingenfelter twin-turbo powered Corvette Z-06. Over a mile up the road, a Top Fuel dragster is staged & ready to 'launch' down a quarter-mile s trip as you pass. You have the advantage of a flying start. You run the 'Vette hard, on up through the gears and blast across the starting line & pass the dragster at an honest 200 MPH.... The 'tree' goes green for both of you at that exact moment.
The dragster departs & starts after you. You keep your foot buried hard to the floor and suddenly you hear an incredibly brutally screaming whine that sears and pummels your eardrums & within a mere 3 seconds the dragster effortlessly catches & passes you. He beats you to the finish line, a quarter-mile away from where you just passed him. Think about it – from a standing start, the dragster had spotted you 200 MPH..... and it not only caught, but nearly blasted you off the planet when he passed you within a mere 1320 foot-long race !!!!
That, my friends.....is acceleration.
Now... of course it isn't a pushrod - and needs a rebuild after pretty much every run... but it is doable...
http://www.arizonacorvetteenthusiasts.net/topic/24...
Imagine this........... You are driving a new Lingenfelter twin-turbo powered Corvette Z-06. Over a mile up the road, a Top Fuel dragster is staged & ready to 'launch' down a quarter-mile s trip as you pass. You have the advantage of a flying start. You run the 'Vette hard, on up through the gears and blast across the starting line & pass the dragster at an honest 200 MPH.... The 'tree' goes green for both of you at that exact moment.
The dragster departs & starts after you. You keep your foot buried hard to the floor and suddenly you hear an incredibly brutally screaming whine that sears and pummels your eardrums & within a mere 3 seconds the dragster effortlessly catches & passes you. He beats you to the finish line, a quarter-mile away from where you just passed him. Think about it – from a standing start, the dragster had spotted you 200 MPH..... and it not only caught, but nearly blasted you off the planet when he passed you within a mere 1320 foot-long race !!!!
That, my friends.....is acceleration.
Now... of course it isn't a pushrod - and needs a rebuild after pretty much every run... but it is doable...
http://www.arizonacorvetteenthusiasts.net/topic/24...
I suppose we should just look to the drag racing guys.
Imagine this........... You are driving a new Lingenfelter twin-turbo powered Corvette Z-06. Over a mile up the road, a Top Fuel dragster is staged & ready to 'launch' down a quarter-mile s trip as you pass. You have the advantage of a flying start. You run the 'Vette hard, on up through the gears and blast across the starting line & pass the dragster at an honest 200 MPH.... The 'tree' goes green for both of you at that exact moment.
The dragster departs & starts after you. You keep your foot buried hard to the floor and suddenly you hear an incredibly brutally screaming whine that sears and pummels your eardrums & within a mere 3 seconds the dragster effortlessly catches & passes you. He beats you to the finish line, a quarter-mile away from where you just passed him. Think about it – from a standing start, the dragster had spotted you 200 MPH..... and it not only caught, but nearly blasted you off the planet when he passed you within a mere 1320 foot-long race !!!!
That, my friends.....is acceleration.
Now... of course it isn't a pushrod - and needs a rebuild after pretty much every run... but it is doable...
http://www.arizonacorvetteenthusiasts.net/topic/24...
Imagine this........... You are driving a new Lingenfelter twin-turbo powered Corvette Z-06. Over a mile up the road, a Top Fuel dragster is staged & ready to 'launch' down a quarter-mile s trip as you pass. You have the advantage of a flying start. You run the 'Vette hard, on up through the gears and blast across the starting line & pass the dragster at an honest 200 MPH.... The 'tree' goes green for both of you at that exact moment.
The dragster departs & starts after you. You keep your foot buried hard to the floor and suddenly you hear an incredibly brutally screaming whine that sears and pummels your eardrums & within a mere 3 seconds the dragster effortlessly catches & passes you. He beats you to the finish line, a quarter-mile away from where you just passed him. Think about it – from a standing start, the dragster had spotted you 200 MPH..... and it not only caught, but nearly blasted you off the planet when he passed you within a mere 1320 foot-long race !!!!
That, my friends.....is acceleration.
Now... of course it isn't a pushrod - and needs a rebuild after pretty much every run... but it is doable...
http://www.arizonacorvetteenthusiasts.net/topic/24...
LittleEnus said:
007 VXR said:
I have a LS2 6.0 making 681bhp 
Wow you must be really cool!
Max_Torque said:
DonkeyApple said:
It is definitely worth noting that an NA AMG 6.2 v a 6.2 LS built to the same standards don't differ in any meaningful terms in BHp, torgue or economy.
http://www.chevrolet.com/performance/crate-engines...
http://www.chevrolet.com/performance/crate-engines...
http://www.chevrolet.com/performance/crate-engines...
And... they are not expensive.
Edited by Troubleatmill on Sunday 26th April 22:16
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