It only happened ONCE !!!!! (and it meant nothing...)

[pete roper]

Wow. I mean, wow.  Read what you just typed and think about it. There will be a quiz.

Really, Peter. Think about that. It’s one of the stupidest things I’ve read for a while. You know better than that.

[jacksonracingcomau]

Really, Peter. Think about that. It�s one of the stupidest things I�ve read for a while. You know better than that.

Frgive him Pete, Woolyback maybe ?
But what he wants to know is why same faired bike uses more fuel with more modern engine ?
Kind of reverse of everyone else

Tell him it’s weight, he is light as air
Or parasitic losses lose more fuel than cylinder head gains ?

[Huzo]

Frgive him Pete, Woolyback maybe ?
But what he wants to know is why same faired bike uses more fuel with more modern engine ?
Kind of reverse of everyone else

Tell him it�s weight, he is light as air
Or parasitic losses lose more fuel than cylinder head gains ?

Both our names are Peter.
Who's forgiving whom..?

[Huzo]

Now here I go again..
If that's the stupidest thing you've read I need a while, you should get out more, but back to the (unanswered) question.
It's a big risk to play in your pool and try to ask a sensible question, but I meant it in good faith.
Can I ask it this way. Why does my Norge burn it's fuel more efficiently @ 90-110 k's, than a "well mapped"' "well tuned 8"?
To try to understand, is it because you can't have an 8V with such an allegedly superior torque and power curve above 4,000 rpm, and still be more efficient when piddling around @ 90 k's with one finger up your fundament..?
Please read this and understand where I'm struggling.
If mine (4V) and Ian's (8V) are doing EXACTLY the same work side by side @ 100 k's, all I thought was that both rear wheels are transmitting the same torque to the road regardless of which donk is turning it.
Am I wrong to that point. (You better not say no.)
I'm not talking about maximum balls out 100% throttle setting screaming it's wog guts out on some bastard dynamometer.
Now IF (and that's a big one), I'm correct to there, how can mine do that same work on less fuel in that performance regime, regardless of how comparatively feeble it is up the scale.
And just to digress..
I'm willing to bet my flat tappets that I could take either Pete or Beetle out this afternoon into another pool and make them seem like bumbling fools and fend off a myriad of "stupid comments" but that's not the pool I'm drowning in.
And also..
The late great Albert Einstein was once heard to say..
"If you can't explain something simply, you don't really understand it"...
Ok, 5 point harness secure, I'm ready..

[jacksonracingcomau]

Both our names are Peter.
Who's forgiving whom..?

Prob both
 you �pr for calling you stupid
Pr-you for wording your question in a way he thought stupid

But, on topic, there was a recent test of all heavy cruisers on mcnews. com.au
Cali 1400 won the economy part, wasn�t a 2vpc Guzzi in it but all fair comparisons
Is relevant in modern world, always was to me, range , even if money irrelevant
Efficiency measured in BSFC, simply explained as power obtained for each pint of fuel

[Huzo]

Prob both
 you �pr for calling you stupid
Pr-you for wording your question in a way he thought stupid

But, on topic, there was a recent test of all heavy cruisers on mcnews. com.au
Cali 1400 won the economy part, wasn�t a 2vpc Guzzi in it but all fair comparisons
Is relevant in modern world, always was to me, range , even if money irrelevant
Efficiency measured in BSFC, simply explained as power obtained for each pint of fuel

See mate, that's where my knowledge base really starts to crumble and I have to improve.
Oh and..
Pete never said I was stupid, (he knows I'm not)..
He said my question was.

[jacksonracingcomau]

See mate, that's where my knowledge base really starts to crumble and I have to improve.
Oh and..
Pete never said I was stupid, (he knows I'm not)..
He said my question was.

Google will get you there quickly
BSFC

[Huzo]

Google will get you there quickly
BSFC

I'll only learn enough to get myself into deep water..(too old)
And what's BSFC mean ?
I can think of a killer acronym, but it doesn't fully apply here.

[Litre1000]

.....then why am I trying so hard to get an 8V Guzzi? I do prefer the performance of GM’s 5.3 V8 over Ford’s 5.4 multi -valve V8. And, the Stelvio looks fun, the Griso looks tough, but the Norge is kinda sexy....


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[jacksonracingcomau]

I'll only learn enough to get myself into deep water..(too old)
And what's BSFC mean ?
I can think of a killer acronym, but it doesn't fully apply here.

Brake specific fuel consumption
Racers use because tank size limited or weight considerations, but do read up

Doesn’t answer your question but gives you term to rephrase it, without being ridiculed

[luthier]

And the answer is:    If both bikes are geared the same then they will have to rev at the same rate to go at the same speed. Thus it doesn't matter how efficient the 8v is at making torque compared to the 4V as the 8v is wasting it's energy by comparison unless it's being used.
So the example of using it would be to compare the two at the same revs going up a very steep hill.  Then with heaps more torque the 8v would effortlessly cruise up while the 4v would have to change down a gear and rev more to reach the same amount of torque.
In that situation the 8v would use less fuel.
Same goes at higher speeds that require more torque to cut through the wind resistance. But at common speeds and requirements the 4v wins the economy stakes every time as it is getting less fuel and is lower tuned.
Am I even partly right Pete?

[jacksonracingcomau]

Because it obeys the laws of thermodynamics.



Wow. I mean, wow.  Read what you just typed and think about it. There will be a quiz.

speak further, apparently needed, thermodynamics the law, of course

[Rhodan]

Cars not motorcycles but I found it interesting.
https://medium.com/starts-with-a-bang/throwback-thursday-what-does-torque-in-a-car-do-a58a7ca5342a

[beetle]

Huzo, here is the quiz.

8V Norge & 2V Norge. Same bore & stroke. Same gearbox, same final drive. Each turn of the crank produces the equivalent rotation of the rear wheel.

For every power stroke, what is happening in the 8V combustion chamber to produce an energy conversion that is applying more force to the conrod for increased torque?

[Paul Brooking]

Huzo, here is the quiz.

8V Norge & 2V Norge. Same bore & stroke. Same gearbox, same final drive. Each turn of the crank produces the equivalent rotation of the rear wheel.

For every power stroke, what is happening in the 8V combustion chamber to produce an energy conversion that is applying more force to the conrod for increased torque?

Aha
The old swept volume thermal efficiency argument (?) [emoji89][emoji89][emoji89]


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[Huzo]

Huzo, here is the quiz.

8V Norge & 2V Norge. Same bore & stroke. Same gearbox, same final drive. Each turn of the crank produces the equivalent rotation of the rear wheel.

For every power stroke, what is happening in the 8V combustion chamber to produce an energy conversion that is applying more force to the conrod for increased torque?

I suggest Beetle.
That in your idealised but realistic scenario, that if both bikes are doing the same work since they are at the same speed and mass, then the 8V crank is experiencing the same thrust from the big ends as the 2V.
I would have expected then, that the 8V would have required a lower throttle setting (manifold pressure) since it is reputedly more efficient.
This I would have thought, would have translated into less gas gulping.
But seemingly not so.

Now to answer your question.
During the power stroke, I would have thought that the number of valves meant nothing since they've been closed and the expansion of gas is occurring.
If the swirl is better in the 8V, then the better mixing of the fuel/air mixture, should have produced either more thrust for equal mixture mass, or less required mixture mass for equal thrust.
Can you forensically pull that reasoning apart and constructively put me on the right track..?

[Paul Brooking]

 

[pete roper]

At certain engine speeds the 8V is definitely NOT more volumetrically efficient but that is due to the charge transition issue that is the real 'Elephant in the corner' that people are ignoring. Overall though the better breathing of the 8V will produce more torque for any given throttle angle than the older motor and the mechanical losses will be appreciably less.

[beetle]

I suggest Beetle.
That in your idealised but realistic scenario, that if both bikes are doing the same work since they are at the same speed and mass, then the 8V crank is experiencing the same thrust from the big ends as the 2V.
I would have expected then, that the 8V would have required a lower throttle setting (manifold pressure) since it is reputedly more efficient.
This I would have thought, would have translated into less gas gulping.
But seemingly not so.

You suggest incorrectly. They are NOT receiving the same "thrust". Forget efficiency. Who said the 8V was more efficient? Not I. For the sake of this argument, assume equal efficiency. And I by efficiency, I mean mechanical efficiency. At the same RPM, same gear, both engines are producing the same wheel travel per revolution. Do you get that?

Now to answer your question.
During the power stroke, I would have thought that the number of valves meant nothing since they've been closed and the expansion of gas is occurring.
If the swirl is better in the 8V, then the better mixing of the fuel/air mixture, should have produced either more thrust for equal mixture mass, or less required mixture mass for equal thrust.
Can you forensically pull that reasoning apart and constructively put me on the right track..?

Ye Cats! Ignoring combustion chamber shape, or piston crown design, or any other mechanical advantage for producing more efficient energy transfer to the rod (more thrust), the only way to get a more energy transfer is to produce a bigger bang. The 8V gets more air and fuel into the combustion chamber than the 2V. That means more torque. That means mechanical losses (friction, etc) through the clutch, gearbox, drive shaft, bevel box and wheel, are more easily overcome. Excess energy not used to turn the wheel is converted to heat. Oh, the laws of thermodynamics. Pesky things!

It does not mean you have to turn the throttle less, but it does mean that when you do turn the hurry handle, you accelerate faster, or go up a hill (as luthier said) with greater ease. The downside is you use more fuel. Oh, one could map the 8V to use the same amount of fuel and produce the same torque, but what's the point of that?

So yeah, the 8V is thirstier. Who knew? Oh, only every 8V owner who has also owned a 2V.

[pete roper]

Paul? Have you ever examined the Guzzi 8V top end? If you’re interested drop over some time. I can show you stuff, explain why I think things work like they do, and then you can make your own decisions about how the engine works.

Pete

[molly]

All things being equal the 1200 2V motor would do the job for most people. Trouble is progress and emission legislation wait for no man. I personally could not think of a better bike to travel the world on than a 1200 2V Norge but inevitably the great unwashed want more and that's what Guzzi tried to do with the 8V engine. The fact they scored a own goal and ruined the reputation of the initial 2V  CARC series is now history and a cause for debate here.

[Paul Brooking]

Paul? Have you ever examined the Guzzi 8V top end? If you’re interested drop over some time. I can show you stuff, explain why I think things work like they do, and then you can make your own decisions about how the engine works.

Pete

Thanks Pete
I've adjusted valves and am about to balance the TBs
I will book a time with you to visit later in the year.

For my sins I am a lapsed Mechanical Engineer, so I am watching this conversation with interest whilst frantically recalling long forgotten thermofluid dynamics lectures.

VTEC motors and variants attempt to handle this quandary by switching between 2&4 valve operation as revs increase .
As I recall, the consensus was that a 2v motor achieved its torque during the bottom end of its rev range, a 4v motor during the top end.
There is a point in the increased rev range in a 2v motor where the incoming "slug" of air fuel mixture over extends  the inlet track and interferes with the efficient combustion of the mixture. In a 4v motor low revs results in the "slug" of mixture not entering the combustion chamber as efficiently as required.
In Huzo's case I suspect that the 4v motor is operating in its inefficient zone compared to the 2v motor.  At, say, 150kmh, this arrangement would be reversed with the 4v being more efficient than the 2v.

[beetle]

No. A stock 2V never makes more torque than an 8V. The 'consensus' wasn't.









You lot can wax lyrical all you want. I don't care whether you prefer a 2V or 8V. I don't care If you quote a world renowned Guzzi guru. I don't care whether you get 4.5 L/100 or 6.5 L/100. You either accept it or don't.  I'm done here.

Carry on.

[Paul Brooking]

No. A stock 2V never makes more torque than an 8V. The 'consensus' wasn't.









You lot can wax lyrical all you want. I don't care whether you prefer a 2V or 8V. I don't care If you quote a world renowned Guzzi gurus. I don't care whether you get 4.5 L/100 or 6.5 L/100. You either accept it or don't.  I'm done here.

Carry on.

Wasn't comparing the torque of a specific 2v MG motor vs a 4v MG motor I was speaking about 2v motors in general having their torque available at lower in their rev range than a 4v having its torque available higher in the rev range
The VTEC concept is aimed at combining those traits to achieve a flat torque curve over a wide rev range


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[lazlokovacs]

I really enjoy threads like these, a lot of really interesting information

thanks to all for sharing knowledge and for asking good questions

[TimmyTheHog]

You lots are funny and just as lazlokovacs says, quite informative!

[jacksonracingcomau]

At, say, 150kmh, this arrangement would be reversed with the 4v being more efficient than the 2v.

And that should , of course, been part of Huzo’s experiment having the identical bikes with different motors together, esp in the nt.

For the game that was played out, it would appear bringing the 8v was not just bringing a knife to a gunfight but having the hand that holds the knife strapped behind your back.
Then something about elephants doing a charge transition.

All good , I’m hoping the v85 comes to fruition, no elephants in room, light weight, seriously good bsfc and enough mumbo to win both experiments.
I, for one , ike both grunt and range, less is more

[pete roper]

 

Yup. And when they 8V it in a few years time? You’ll once again retreat into your superstitious hatred of technological advance. Don’t worry, I get it Martin. You’re just missing out on so much.

(I expect a response saying that all the Nuovo hi cams have been a disaster and that the old 2V is superior in every way. Don’t bother. We’ll never agree.)

[jacksonracingcomau]

Yup. And when they 8V it in a few years time? You�ll once again retreat into your superstitious hatred of technological advance. Don�t worry, I get it Martin. You�re just missing out on so much.

(I expect a response saying that all the Nuovo hi cams have been a disaster and that the old 2V is superior in every way. Don�t bother. We�ll never agree.)

No Pete, I love and want techno advance
Just not going backwards
Cake and eat it
Options from other manufacturers of course but Guzzi in my blood
When (if) better than I have, off the floor I’m in
Wil keep the lario too, posibly a centauro and a griso, not a hater of valves
I just want to see better from Mandello, thin chance this is it.
No more lemons, please Luigi

[kingoffleece]

I feel guilty for not having purchased a ticket.