Multi valves/Multi cylinders

[carmadaaron]

why do manufacturers tend to move to multi valves and multi cylinders nowadays? like BMW and Mercs....


Cheers

[david burton]

no idea, don't even know what it is!

[bstardchild]

why do manufacturers tend to move to multi valves and multi cylinders nowadays? like BMW and Mercs....


Cheers

Cos if they'd stayed with single cylinder lumps like dumper trucks thats the performance we would have now

More cylinders = smoother power pulses

BMUU and Merc are into top end market so smooth is expected

- 4 cyl OK
- 6 cyl Smoother
- 8 Cyl V-smooth
- 12 Cyl Ultra Smooth

Multi Valve

Basically down to combustion chamber filling and weight

- 2 small valves flow more than 1 of eqvilient size
- more valves = lighter valve train and so less stress on the chain/belt - engine can rev higher and produce more power

Does that help

[polopowah]

errm is that what my mpi engine is (multi-point injection?)
whats benefits are there to be had, especially in the 1.0, because i heard somewhere that my 1.0 is equivalent to most other 1.2 makes of car,of the same year, not sure though, does seem rather pokey!
-Ben-

[Tahrey1043]

nah mate that simply means one injector per cylinder, mounted closer to the actual intake (rather than waaaaay up for singlepoint) for better responsiveness and control of fuel delivery. sort of like multi carbing it but less wasteful on fuel. your engine is still very likely a 8v.

BTW engines with a multiple of 6 are generally the smoothest for some reason - an 8 or a V8 will be smoother than a 4 of any kind, but still needs a balancer shaft and doesn't run so smooth as even a straight 6

agreed though - V12 = teh schmoovness.

i think it's just a case of "bigger is better" in marketing terms, and if only some dumb corporate f****r would do that with MPG again we might avert the winter oil crisis that's screaming from the pages of the metro (quality broadsheet i know!)
mind you thats all down to bloody americans driving tanks on their roads and tanks (and fighter jets) in other peoples countries. thats what, 5 miles to the gallon out of a combat tank when cruising, 10000lbs of aviation fuel used on a 2 hour sortie even in a (fairly slow, built to be extra efficient) F117A?



edit - wtf did i write "still likely 16v" for? dumkopf!

[carmadaaron]

r multivalves expensive?

[bstardchild]

r multivalves expensive?

Exhaust valves on a 24V 6 cyl 3.0 Vauxhall are £60 each plus vat (sodium filled to lighten and help with heat dissapation)

Inlet valves on same are £8 each plus vat (not sodium filed)

- when the timing chain snaps (and it can after 150K) it does 12 x Exhaust and 12 x inlets

I've got plenty of bent ones spare

[carmadaaron]

so better engines have multivalves...... crappy manufacturers tend to have less valves....

[bstardchild]

so better engines have multivalves...... crappy manufacturers tend to have less valves....

Multi valve doesn't neccesarily make em better Nice Big block chevy only has 2 valves per cylinder (OK so it's got 8 cyl's) and can make seriously good bhp

Multivalves tend to make power at the top end of the rev range

2V or 3 V engines tend to be more torque in the mid range

Korean cars have multi valves

[carmadaaron]

ah i c.... so multivalves doesnt have to mean multi cylinders....

[bstardchild]

ah i c.... so multivalves doesnt have to mean multi cylinders....

Nope

I've got a 6 cyl 12V that has two per cyl and a 6 cyl 24V that has four per cyl

You can get 3 cyl (*spits) C*rsa's that have 12V but they haven't got 6 cyl - just 3!!!!

[SiDaBa]

[quote="bstardchild]You can get 3 cyl (*spits) C*rsa's that have 12V but they haven't got 6 cyl - just 3!!!![/quote]

That would be mine and Aaron's car and any other 1.2 9n (65) owner

[david burton]

i still don't get why they've suddenly started using the multi-valve phrase - surely it is more than just 4 valves per cylinder etc? that's been around for ages.

and a 6 cylinder engine is smoother than an 8 cylinder - the 6 cylinder is "perfectly balanced" in all modes, the 8 cyl is not

[bstardchild]

i still don't get why they've suddenly started using the multi-valve phrase - surely it is more than just 4 valves per cylinder etc? that's been around for ages.

and a 6 cylinder engine is smoother than an 8 cylinder - the 6 cylinder is "perfectly balanced" in all modes, the 8 cyl is not

Depends of the firing orientation "IMHO" you can make a lumpy 8 like big block V8 (corvette) or a mega smooth 8 like the Ferrari I've just been round the block in - not that quick tho!!!!

[Karl_CLCoupe]

Anyone remember when manufactuers made a big thing of having 16V engines in their cars? The one that springs to mind is Renault with their 'sporty' 19 16V and Clio 16V. Now it seems like common place to have 4 valves per cylinder.

Karl.