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Lagonda
09-11-2004, 06:01 AM
Hello,

I have a small question. I know that when you have more cylinder the engine will run smoother. So a 6-cyl is much smoother than a 4-cyl etc. So I was thinking, I would like to build a really really smooth engine with high torque from low to high revs and a decent amount of power (±250bhp). I was thinking about something like a 2 or 2.2 liter V8. Would this have any advantages over a 2 or 2.2 liter V6 ? Other question: is it possible to take an existing engine block and lower the displacement ? I don't know a lot about this stuff but I'm just exploring possibilities for a potential project.

Misho
09-11-2004, 06:23 AM
those cylinders r gonna be the size of a small coffee mug !!

good question though, hopefully our technical advisor (Matra) will provide helpful info as always expected from him.
why is it that most current car manufacturers seem to build cylinders of about 400-600cc volume. what would be the pros/cons of bigger/smaller cylinders ?

Lagonda
09-11-2004, 06:51 AM
Well how did I come to this idea ? Simple I saw that in the beginning a lot of racecars like the early straight 8 engines and a lot of Ferrari engines uses small displacements (1.5 liter V12 etc). And I think they did that because that was the only way to achieve smoothness back then. Now combine that initial smoothness with modern engine technology and I think you could create an engine that is soo smooth that it would even make the Lexus V8 blush. ;). Seriously tough, wouldn't it be possible with such a small displacement per cylinder to achieve really high rpm's ?

Matra et Alpine
09-11-2004, 07:07 AM
Well how did I come to this idea ? Simple I saw that in the beginning a lot of racecars like the early straight 8 engines and a lot of Ferrari engines uses small displacements (1.5 liter V12 etc).
You shoudl read back a little earlier in racing history.

The late teens and 20s saw the grwoth of engine CAPACITY to get power.

Culimination being the Fiat 27 litre racer.

So racing has played with the all parts fo the size spectrum

Long answer needed and no time, but yes you can to all of the questions raised so far. The why and why nots are little more involved :)

Lagonda
09-11-2004, 07:15 AM
Thanks, could you (or anybody else), if you have some time of course, explain the why and why nots ? ;) There is no rush to it, at all.

paul
09-11-2004, 07:51 AM
that bugatie is a w 16 that must run smooth as and with 1010 brake 4 turbos its a monster!

drakkie
09-11-2004, 10:04 AM
that bugatie is a w 16 that must run smooth as and with 1010 brake 4 turbos its a monster!

also not going into production, because of trouble with the engine,getting it to fit.

paul
09-11-2004, 11:10 AM
is it not????? explain ? gettin it to fit thats a load of rubbish they can make it fit they have to make it im goign to cry!

Lagonda
09-11-2004, 12:29 PM
is it not????? explain ? gettin it to fit thats a load of rubbish they can make it fit they have to make it im goign to cry!

That car will probably suck completely on the track. It's just a typical example of VAG megalomania.

KnifeEdge_2K1
09-11-2004, 02:02 PM
more cylinders doesnt always mean better smoothness, it's the camshaft geometry and the bore/stroke ratio that does that, if you have a 1 cylinder engine its not gonna be smooth at all even with counterweights because it fires once ever 2 revolutions of the crankshaft which is extremely uneven. a v6 doesnt nesscecarily run better then a 4 cylinder since a v6 is just two 3 cylinders mounted side by side, the v6 actually doulbes the vibration caused by a single 3 cylinder, while a strait 6 has nearly no vibration since it cancels the vibrations out from end to end. a v12 is even better since its two 6 cylinders mounted side by side, its even more smooth because of more firing cycles per crankshaft revolution. and 4 cylinders when you think about it at first seem like a good setup since everything is perfectly ballanced but infact it isnt, when a piston is at the bottom of it's cycle it actually moves slower then when its at the top which creates a different rate of the change in displacement causing more vibration which is why it needs twin ballancer shafts

boxer engines or horizontally opposed or flat engines are completely ballanced no matter the number of cylinders as long as they're even number of them on both sides

if your primary concern is smoothness make or purchase a boxer engine, the only companies currently mass producing them are subaru and porsche i think
but if you plan to make one then ur gonna have trouble since it needs duplicate blocks and cams and intake/exhaust is gonna be a problem if you're putting it in the chassis of another car bla bla bal

Egg Nog
09-11-2004, 02:06 PM
Bugatti didn't have any problems "making the engine fit"... that's a load of rubbish. They've been having problems adequately cooling the engine. They've been trying out different radiators and mounting locations without having to modify the body itself for new ducting.

paul
09-12-2004, 03:52 AM
i i see suppose so i large w16 block like that with 4 turbos snuggled all round it must create some heat!

KnifeEdge_2K1
09-12-2004, 01:39 PM
Bugatti didn't have any problems "making the engine fit"... that's a load of rubbish. They've been having problems adequately cooling the engine. They've been trying out different radiators and mounting locations without having to modify the body itself for new ducting.

yeah i they have huge air scoops like lambourgini murcielargo now i think, the intake needs to be fed air by the ton, cooling is a bitch, and even the brakes dont get adequet cooling using traditional methods

paul
09-12-2004, 02:53 PM
bad design then

megotmea7
09-12-2004, 09:31 PM
thats what you get when you design a car ass backwards... form over function strikes again...

fpv_gtho
09-12-2004, 09:40 PM
boxer engines or horizontally opposed or flat engines are completely ballanced no matter the number of cylinders as long as they're even number of them on both sides

if your primary concern is smoothness make or purchase a boxer engine, the only companies currently mass producing them are subaru and porsche i think
but if you plan to make one then ur gonna have trouble since it needs duplicate blocks and cams and intake/exhaust is gonna be a problem if you're putting it in the chassis of another car bla bla bal


i think i read something a while ago saying that because of the different firing pattern between Subaru's and Porsches engines, theyre both technically not boxers, only one of them is