V8, V10, V12

[nejcdolinsek]

I have a question:

Which engine, either a V8, V10 or V12, would produce more power/torque, if all had the same displacement (for instance 5.5l), all had the same amount of valves per cylinder, all were naturally aspired, etc., etc.,...???

[mindgam3]

hmmm, im not totally sure but if they were all exactly the same except for the number of cylinders i think the V12 would produce the most power as it dosen't produce any (or very little) vibrations. I think the difference between the 3 would be very small though

[Ford Capri 2.8i]

I totally agree with mindgam3 about the fact that a V12 engine would get the most final power if the three of them have the same total volume of cilinders, although the V12 would get the slower to rev an engine once it has to push the largest number of cilinders, and the friction of the V12 is the higest of them as well, in addition, the fuel comsuption of the V12 will be the higest, once it has the engine has to push 12 cilinders itself.....for instance during the ninetees, ferrari was the only formula 1 top team which had the 12 cilinders engine, the ferrari was the best in racetrack which had long straight lines, such as Hockenheim, Monza, whereas in other racetracks where the straigh lines were shorter such as Silverstone, Imola,....ferrari was seriously struggling to keep up the mclaren, the williams.....

[RC45]

I am just guessing here - but I think a 346ci push rod V6/V8/V10/V12 (based on the GM LS6) that maintains the same stroke, cam profiles and fuel system would produce the following numbers:

346ci V6 - 315hp @ 5000rpm & 367lb/ft @ 3500rpm
346ci V8 - 408hp @ 6000rpm & 396lb/ft @ 6000rpm
346ci V10 - 476hp @ 6500rpm & 416lb/ft @ 5500rpm
346ci V12 - 517hp @ 7500rpm & 428lb/ft @ 5500rpm

But of course, these are just random guesses... :)

[edit]

What? No takers for this debate? ;)

[mindgam3]

They aren't all the same displacement though are they?

[RC45]

They aren't all the same displacement though are they?

The same displacement - that is what " I think a 346ci push rod V6/V8/V10/V12" means... ;)

[T-Bird]

They aren't all the same displacement though are they?

If they are all 346ci then they all have the same displacement :roll:

[RC45]

Here they are then (since no-one wants to join the frey.. ;))

Imagine an LS6 small block chevy that is able to have 6, 8, 10 or 12 cylinders - maintaining the same stroke and cam profile and fuel delivery.

The astute amongs you will notice that the intake and exhaust valves of the V12 are the same as the V8 - of course these would not be able fit in the cylinder bore.. but this is to keep all things equal aart from number of cylinders.

I will go back and adjust details to be closer to reality at some later time.

V6 LS6
http://img52.exs.cx/img52/6157/V6_LS6.jpg
=
http://img22.exs.cx/img22/7357/V6__Table_LS6.jpg
=========
=========
V8 LS6
http://img22.exs.cx/img22/6443/V8_LS6.jpg
=
http://img22.exs.cx/img22/5495/V8__Table_LS6.jpg
=========
=========
V10 LS6
http://img22.exs.cx/img22/6486/V10_LS6.jpg
=
http://img22.exs.cx/img22/8014/V10__Table_LS6.jpg
=========
=========
V12 LS6
http://img22.exs.cx/img22/3466/V12_LS6.jpg
=
http://img22.exs.cx/img22/7375/V12__Table_LS6.jpg

:D

[T-Bird]

nice little program you got there RC45 that is one hell of a V6 :wink:

[BADMIHAI]

RC: is that Chris' program you're using? What happened to that guy anyway?

When it comes to the engine producing most power, I think it would be the V12.

[RC45]

RC: is that Chris' program you're using? What happened to that guy anyway?

Uhm no.

Let's just say that his program was so far from reality it wasn't real.. :P

This a commercial dyno-simulator.


When it comes to the engine producing most power, I think it would be the V12.

Well - considering that's what the math shows... ;) I am guessing that's a good call.. :P

[BADMIHAI]

Well - considering that's what the math shows...


"Go with the flow." I can't believe I said that. :shock:

[RC45]

Well - considering that's what the math shows...


"Go with the flow." I can't believe I said that. :shock:

Dude - you must had your fibre this morning - you seem to be in a chipper mood... ;)

[mindgam3]

They aren't all the same displacement though are they?

The same displacement - that is what " I think a 346ci push rod V6/V8/V10/V12" means... ;)

lol, im asuming ci stands for cubic inches then?

We never use cubic inches over here so i just thought it was part of the engine name....

To be honest i wouldn't have thought the difference between them would be that great - not saying your estimates are wrong, but still

[T-Bird]

yes cubic inches

[RC45]

They aren't all the same displacement though are they?

The same displacement - that is what " I think a 346ci push rod V6/V8/V10/V12" means... ;)

lol, im asuming ci stands for cubic inches then?

We never use cubic inches over here so i just thought it was part of the engine name....

To be honest i wouldn't have thought the difference between them would be that great - not saying your estimates are wrong, but still

Well - as I posted graphs and tables of power from a dyno simulation program - it is a little more than an estimation.

Let's see you counter offer - with backup proof.

:)

BTW, as I posted, EVERYTHING is the same for all 4 engines - including valve size... and since the valves in a V8 would not even fit in the bore of a V12, the valve area part of the calculation is overly optimistic.

Which just go show, as with all things - there is no such things as a "all things being equal" comparison, when you are comparing apples and oranges.

Redoing the excersize with appropriately sized valves - and leaving as many as possible factors the same, the results may vary a little.

However - until someone posts something with some backing I am going to take these numbers over anything else provided. :)

BTW, 346ci is 5.7 litres.. a quick Google search would have retruned 5.7l as the capacity for the LS6... :P

[sentra_dude]

Well, this is what I know from Formula One in the early 1990s before they went to all V10s, and of course this isn't scientific or anything, just an observation...

The V12's (Ferrari) produced the most power while being the heaviest (more parts), lowest revving (more moving parts in the value train and more friction), and highest center of gravity; which gave the Ferrari's good speed on the straights but contributed to their less than ideal handling (among other factors).

The V8's (Benetton) produced the least amount of power but were lighter and could rev higher, which gave the Benetton's better handling because of lighter engine weight (they could put more ballast down very low in the chassis which equals lower CG).

The V10 is a nice compromise between the two, with good horsepower and good revs, while still being light, hence most manufactures drifting in that direction even before it was put into the rules.

I think it would be interesting to see F1 deregulated so that manufactures could choose what engine configuration they like. I'd like to hear what a V12 sounds like at 17,000...or even 18,000rpm (don't know if they could get a V12 that high, but you never know ;)) :D 8)

btw, nice graphs and such RC :D

[yg60m]

Mate, i think you're wrong for the revs, the power comes (partly) from revs and the most powerfull V12 revs more than a V8 because every piston only have 1/12 (i.e. 250 cc for a 3 liters engine ) of the total capacity to carry when a V8 has 1/8 (i.e. 375 cc for a 3 liters ) . The number of pieces gives a biggest fuel consumption but not a lower rev from what i know.

[IgotWRXed]

Mate, i think you're wrong for the revs, the power comes (partly) from revs and the most powerfull V12 revs more than a V8 because every piston only have 1/12 (i.e. 250 cc for a 3 liters engine ) of the total capacity to carry when a V8 has 1/8 (i.e. 375 cc for a 3 liters ) . The number of pieces gives a biggest fuel consumption but not a lower rev from what i know.

revs are a tricky problem as not all engines are created the same.

look at bigblock V8s, they have extremely low revs. but then look at a ferrari V8.

there are too many factors, hence why i gave a 3 line answer. :lol:

[Paco]

My money is also on the V12, simply because each individual cilinder is under less strain than with the other configurations (all having bigger cilinders).
This gives more balance, less strain on the material (total power is divided over 12 cil.) which in turn allows for higher revving and less miss-firing/detonation.

Drawbacks are a higher weight, bigger dimensions and a more fragile (since longer) crankshaft (at high revs). Best would then be a boxer 12-cil (as Ferrari used to have) for a low centre of gravity.

Just off-hand :)

[T-Bird]

honestly I would take a V8 over any of them though just because they are generally alot stronger of an engine and they make more than enough power if you want them to. Also alot cheaper to build and maintain

[RC45]

How about a little contest.

People submit the specs they want to see int he engine - I will build it... run the simulaiton and post the results.

Let's see who can design the best engine.

:)

I need capacity, cylinders, valve count, size and some cam specs, intake choice type etc.

What other realism rules should we have? (to prvent someone coming up with 12 cylinders 1000ci, FI, nitrous etc etc.. ;))



:)

[IgotWRXed]

hahaha i was about to suggest a 1000ci V-12 DAMMIT!!!

well, how about a W-16 :P ;)

[T-Bird]

maybe it should be based on an available engine

You know like nothing over a 572 or something

[RC45]

The simulation is limited to conventional round cyliner bores with reciprocating pistons in the counts og 4, 5, 6, 8 , 10 & 12.

Inline, V and flat layout.

Forced induction via centrifigal & roots type blowers as well as turbos & Nitrous are supported - as are 2 and 4 valve head layouts. (sorry 5 valve Ferrai guys ;))

Gasoline, Methanol, Ethanol, Propane and LNG are available.

Either way, take a look at the graph I posted on the first page to see the other detailed information you are free to manipulate.

[RC45]

maybe it should be based on an available engine

You know like nothing over a 572 or something

Good idea - there are numerous stock blocks in the application.

Y'all choose what you want to base it on and we will see if it is there.

Here is a sample:

Buick 4 - 112, 121 & 151ci
Buick 6 - 173, 181, 231, 252
Buick 8SB - 305, 350, 350 (4inch bore)
Buick 8BB - 400, 430, 455

Toyota 4 - 1.3, 1.6, 2.2, 3.0, 3.4
Toyota 6 - 2.5, 2.8, 3.0
Toyota 8 - 4.7

A bunch of Hondas, VW's, Porsches, Nissans, Volvos, Lamborghini's etc... (no Ferrari's)

[fedezyl]

hehe, that's a nice little programe you have RC, i'd say conventional gasoline and n/a engines...so we can make it more interesting, and having the engine have as wide as possible for a power band....just some thoughts

[fedezyl]

any alfa blocks?? heh

[RC45]

Sorry - no Alfas - but VW's, Audis, BMW.s and Saab 4's.

Maybe an Alfa "clone" is possible.. ;) One can change bore, stroke, valve size and number.

[sentra_dude]

Yes, this sounds like fun fun fun! :D

Although with all those variables it will be tough...but where's the fun if its not hard right? :P

I do think maybe set a few more guidelines, like only gas, and turbo...hmm isn't that cheating? ;)


Anyone want to comment on the ability of V8s vs V12s to rev?

[T-Bird]

OK just for basics to try this thing out Ford 427, 4 valve V8 Methane Turbo at 30psi
and a 36 degree overlap, intake 2.0 and exhaust 1.6 compression ratio 11.5:1
hydraulic lifters, racing cam (if available) you can do the little stuff if anything doesn't quite mesh well
WTF throw in a 200 shot of nitrous just for kicks :wink:

[fedezyl]

MMmm interesting! so if I gave you some info you could see wich modifications make more power....cause i'm looking to modificate my alfa's engine, it's a 1.3 4 pot 8 Valve twin cam, it makes 82 bhp stock, and 105bhp I think with twin webber carbs...

[T-Bird]

your car is carburated? what year is it?

[RC45]

T-bird - what brand and model turbo? Fuelie or carb? And what sort of CFM you thinking about? Intercooled?

And you want a drag race cam profile or a streetable/road course bump stick?

[T-Bird]

ok Garrett GTP38R turbo with dual 800CFM Holley 4 barrel carbs

[fedezyl]

the 1.3 liter engine in the Giulia Ti comes with a single double opening (don't know the name in english) Solex carburator, on the Giulia Super it comes with a twin double opening webber carbs

[T-Bird]

I think you mean a 2 barrel(the openings) Carb

[fedezyl]

hehe yeah, barrel that's the word! english improves everyday hehe
now...there's something I never really quite got straight, how does the size of the carb changes the powerband, as well as size of the jets? I remember reading something about it but never got it quite clear in my head....

[T-Bird]

do you mean the like the overall power curve or just the top HP number?
It all has to do with the CFM flowing through the Carbs and into the engine the ironic thing is that I have seen people install new carbs and install the largest jets and they make less power than with th enext size down that I never understood myself.
Jets are basically fuel injectors so the bigger the more fuel in essence. and larger Barrels means more air it's that simple but sometimes like in your case you may have to change out the intake manifold to fit the larger carbs but that's a case by case thing but I would recommend replacing an Intake manifold and carbs at the same time. and remember if you are messing with Carbs and your not 100% sure becareful even the pros have lit them on fire before priming them for the first time.

[fedezyl]

heheh, nah, i'm not actually doing the fitting, i'm installing the Super's .40 DCOE webber carbs, it has it's own different intake manifold though so it shouldn't be a problem, it's more like i'm interested in how it works though....and well trying some stuff out, specially like cam settings and compression ratios...also fiddling a little bit with exhaust and intake manifold lenghts too..
oh about the power curve, I meant overall, I came to realizing a while ago that peak power isn't everything and it's best to have a large power band than a typical honda engine that has to be really thrashed....

[T-Bird]

yeah it's nice to have low end torque (as in the bigging of the curve) and HP more towards the top with a nice overlay not like some Turbo cars that are flat till about half way.

[fedezyl]

Thing is I remember having read somewhere on a web site, well actually the web page is from an ex Fiat engineer that worked for Fiat Argentina and he was explaining how different venturi sizes on the carbs gave more low end power than higher and viceversa

[RC45]

How is this for a "simulated" 1.3l Alfa ;)

http://img52.exs.cx/img52/4125/fedezyl1.jpg

http://img52.exs.cx/img52/9858/fedezyl1_table.jpg

[ahmedgiyab]

I think that the most HP comes from the V12, but a V8 has more torque...... :wink:

[sergei_dekker85]

I have a question:

Which engine, either a V8, V10 or V12, would produce more power/torque, if all had the same displacement (for instance 5.5l), all had the same amount of valves per cylinder, all were naturally aspired, etc., etc.,...???

I'd take the V12....more cylinders make quite a bit of diff....tts y the FIA decided 2 use V8s instead of the current V10s for F1 in the future....and I've driven a E240(Inline 4) and a 328I(Inline 6) and theres a noticable difference esp in power

[caugb]

V12s must have more internal friction than V10s and V8s. They will have less cilinder speed (linear), so capable of achieving more revs in the rod. So, expect more power but less torque. That's basically what the numbers are saying and what I expected.

[sergei_dekker85]

well it seems 2 be that the torque is coming at out at a lower RPM than those V8s and V6es....only thign si that the BHP is at a higher RPM and For v12s their powerband is wider compared 2 the rest

[astonmartinandy]

Sorry can someone please explain to me how an engine with the same capacity can have such different power outputs? I appreciate the difference in each piston size and the strain placed upon the engine, but I still can't understand the difference with a constant capacity..

Anybody help?! :?

[caugb]

There is no easy answer, but this can help.
More cilinders means more valves or valve area, so the engine can breath better.
Obviously that depends in the bore x stroke ratio, but it is not reasonable to expect that you can maintain the valve area in a V8 the same as a V12. It would require a extremely flat cilinder and vibration problems could arise.
Then you have a physical limitation, piston linear speed. Even with the new lucricants, you can not exceed a certain number (sorry, I don't remember), because the friction will likely cause extreme heat and your engine is over.
I will try to find a technical article on that, with pictures, to make this easier to understand.

[T-Bird]

but in a V12 with the same CI as a V8 the V8 will have larger valves to compensate for valve area so that doesn't really matter. see the Valves in a V8 of let's say 6.0 liters from say a Chevy :wink: and the V12 6.0 from a certain Ferrari, the valves in the Chevy will be much larger than of those in the Ferrari correct. and they have pretty much mastered making Flat Piston surfaces already along with one for high compression with contours for Valve clearance so that wouldn't be that much of a problem. You can't say that a Flat Piston wouldn't work.

[caugb]

I was trying to simplify the discussion, but it is not helping.
Let's get back to basics. Using the same materials, the smaller pistons of the V12 engine will have less mass (weight).
So they have less resistance to speed up and to stop, a movement the pistons do thousands of times per minute.
So they can achieve more RPMs.
So they can breathe more air and fuel (more RPMs, more times the 4-stroke cycle is repeated per time).
So they can deliver more. More power (work/time).

[RC45]

I was trying to simplify the discussion, but it is not helping.
Let's get back to basics. Using the same materials, the smaller pistons of the V12 engine will have less mass (weight).
So they have less resistance to speed up and to stop, a movement the pistons do thousands of times per minute.
So they can achieve more RPMs.
So they can breathe more air and fuel (more RPMs, more times the 4-stroke cycle is repeated per time).
So they can deliver more. More power (work/time).

The facts above account for higher HP by revving to higher RPM's - but what accounts for the higher HP at the same RPM levels?

Afterall, you move the same amount of mixture at 6000rpm in a N/A 5.7l engine (with all factor equalt), no matter how many cylinders you have.

[caugb]

The facts above account for higher HP by revving to higher RPM's - but what accounts for the higher HP at the same RPM levels?

RC45,
that's the point! We are not comparing HP/rpm, but max HP. If you can rev more in a V12 and get more HPs out of that, you are going to win!
If you have a engine that stops at 6.000 and the same one (imagine a 3000cc, like F1, V10s because V12s are forbidden) that revs to 19.000, which one will win? The answer is on TV almost every Sunday. The same can be seen in the Honda V5 MotoGP engine, more powerful than the V4s, L4s and I4s of the competitors.

[RC45]

The facts above account for higher HP by revving to higher RPM's - but what accounts for the higher HP at the same RPM levels?

RC45,
that's the point! We are not comparing HP/rpm, but max HP. If you can rev more in a V12 and get more HPs out of that, you are going to win!
If you have a engine that stops at 6.000 and the same one (imagine a 3000cc, like F1, V10s because V12s are forbidden) that revs to 19.000, which one will win? The answer is on TV almost every Sunday. The same can be seen in the Honda V5 MotoGP engine, more powerful than the V4s, L4s and I4s of the competitors.

I think you miss my point.

Peak HP at a higher RPM is not being debated or contested - never was.

But rather higher HP at the same RPM point.

Peruse the graphs the engine simulation produced.

[caugb]

Which engine, either a V8, V10 or V12, would produce more power/torque, if all had the same displacement (for instance 5.5l), all had the same amount of valves per cylinder, all were naturally aspired, etc., etc.,...???


Peak HP at a higher RPM is not being debated or contested - never was.

What point? This topic IS about peak HP. You brought valuable contribution with the simulations and charts, but we are talking peak power here!
When you compare a V8 with a V12 at some RPM other than the one that delivers the peak HP for each engine, you are just confirming that different architectures deliver power/torque differently. But you have to go to the bottom line, peak power. And even then, it is very difficult to say if this "winner" engine is better to drive in a car, because it can be too difficult to really use that part of the power hidden in so high RPMs.

[RC45]

Which engine, either a V8, V10 or V12, would produce more power/torque, if all had the same displacement (for instance 5.5l), all had the same amount of valves per cylinder, all were naturally aspired, etc., etc.,...???


Peak HP at a higher RPM is not being debated or contested - never was.

What point? This topic IS about peak HP. You brought valuable contribution with the simulations and charts, but we are talking peak power here!
When you compare a V8 with a V12 at some RPM other than the one that delivers the peak HP for each engine, you are just confirming that different architectures deliver power/torque differently. But you have to go to the bottom line, peak power. And even then, it is very difficult to say if this "winner" engine is better to drive in a car, because it can be too difficult to really use that part of the power hidden in so high RPMs.

Whoa there big fella. I have no idea what crawled up your ass... :roll:

I was simply posing a question - if you get down to it - the question of peak power is as stupid and as purely academic and pointless as HP/l.

By expanding the discussion to discuss other points on the power graph we prolong the life of the topic.

If "the bottom line is peak power" - then someone could have posted 4 peak HP numbers and locked the topic.

:roll:

[caugb]

RC45,
sorry if I looked agressive in any manner. :oops: I am very happy to meet people like you to have a nice technical discussion.
I understood you point, but the engines will deliver power in such different ways that maybe it is not fair to choose a certain RPM and check the power delivered. BUT (there is always a but), if we compare % of power/torque versus max power/rpm, probably we could reach an agreement regarding efficiency of both engine architectures.
I have to collect the data, but if more power (% of max power) is delivered at certain RPM (let's say 30% of RPM of max power) in a V8 vs the V12, we can agree that this engine is better than the other.
Even if power is delivered at high RPMs, the gears can be changed to use it. So this percentage comparison may help reaching some interesting conclusions. :agrue:

[RC45]

No problem,.. :) really - that's why i wasn't sure if you were just low on fibre today - or the Net simply incorrectly portrayed the emotion.. ;)

Back to point t hand.

I was not championing any particular layout yet - but simply noting that when an engine simulator is setup to show a 5.7l pushrod engine with 6, 8, 10 and 12 cylinders - that the power increases as cylinders increase, and the power band gets wider and wider as as the cylinders increase.

So - not only does higher revs deliver higher RPM, but even the power at the same RPM point showed an increase as the cylinder count increased.

Bearing in mind that the graphs I posted maintained everything the same across the engines (everything - even cam grind and valve size and fuel flow - which is a situation that would no be true for real life) except bore size.

[caugb]

So - not only does higher revs deliver higher RPM, but even the power at the same RPM point showed an increase as the cylinder count increased.

I noticed that when I reviewed the graphs. Wouldn't you expect something different? I would expect longer power curves, but with less inclination, so power SHOULD be higher for V8s than V12s at lower RPMs, V12s keeping the increase further more in terms of RPMs, achieving more HPs at the end.
Even knowing that some conditions are physically impossible (eg valve size) as you mentioned, this is the only part of the simulation that does not seem correct/understandable for me (V12s more powerful than V8s even at lower RPMs).

[nejcdolinsek]

Sorry for the confusion, but I was wondering about peak power/torque... don't kill yourselves over this :wink:

[RC45]

Sorry for the confusion, but I was wondering about peak power/torque... don't kill yourselves over this :wink:

And this peak would need an RPM number... right? :) :lol: ;)

[nejcdolinsek]

^^ I really don't care :wink: Whatever you want.

[caugb]

And this peak would need an RPM number... right?

So let's choose 10.000rpm. Ops, Your V8s can't go that far! V12s rules!

Just kidding, RC45!

[mindgam3]

forgive me if i've got the wrong end of the stick because i haven't read the whole topic but....

Why should we be comparing HP produced at the same RPM for different engine layouts?

I thought that almost all V8's will produce more power or more of their power at lower revs than V12's mainly because their peak power is almost always lower.

I just don't see the point of comparing power produced at the same RPM number for different engine layouts

sorry if i've mis understoodd the discussion

[TT]

I admit I didn't follow the whole discussion, but this small scan should give a pretty quick answer to what is better between V8, 10 or 12 ;)

http://img66.exs.cx/img66/4878/m5engine.th.jpg (http://img66.exs.cx/my.php?loc=img66&image=m5engine.jpg)

[RC45]

forgive me if i've got the wrong end of the stick because i haven't read the whole topic but....

Why should we be comparing HP produced at the same RPM for different engine layouts?

I thought that almost all V8's will produce more power or more of their power at lower revs than V12's mainly because their peak power is almost always lower.

I just don't see the point of comparing power produced at the same RPM number for different engine layouts

sorry if i've mis understoodd the discussion

JUst like HP/l - it is simply a measurment at a point in time.

SImply an academic excercise to see what produces what power where.

:)

[RC45]

I admit I didn't follow the whole discussion, but this small scan should give a pretty quick answer to what is better between V8, 10 or 12 ;)

http://img66.exs.cx/img66/4878/m5engine.th.jpg (http://img66.exs.cx/my.php?loc=img66&image=m5engine.jpg)

What ???? ;)

You never read the topic? This is just a freepost then.. right.. ??? ;)

[TT]

No idea why, but I was fearing some Euro vs japanese vs american cars discussion :P

[RC45]

No idea why, but I was fearing some Euro vs japanese vs american cars discussion :P

Well - some folks have tried real hard to steer it that way - but all it is about is which number of cylinders does what and when... ;)