CP

I was wondering...how come automobile manufacturers don't utilize a "V" engine setup until 6 cylinders are used? They use straight 4s and Volvo uses a straight 5(Audi used to). Why not a V-4? Outboard motors use them. Don't small airplanes, snowmobiles and street bikes use these also(speculation)? I'd think that it would save space in the engine compartment. There obviously is a reason or we'd see them on the road today.

WJM

first V shapped engines besides being more compact are cheaper to make than inline engines.

Now onto why arent V-4's in existance for cars... Well there are some VW in europe has a VR-4 if memory serves.

second why put a motor cycle engine into an area that has to be wide enough for two people. That means more structual members you have to put in. Even though an engine is on mounts it still acts as a stiffener to the front chassis by linking the two sides of the car. Ease of access, vibration, and many more items contribute to why you would want an inline and slightly larger engine to having a compact v4

SAvant

This would "fill" the engine compartment even better and allow better weight distribution and a bigger crumple zone. Am I wrong on this?

mark

Audiboy

picture a 4 cylinder 4 stroke engine. The power comes in every 1 revolution for each piston. Hence the crank design is such that two cylinders are in phase with each other, two are opposite. Now put this on a V4 (90 degree). You will need to have each bank of pistons fire alternately to smoothen out vibrations. Picture a crank for this. They will have the crank designed such that the two lowest points are only 90 degrees away from each other. You will need heavy counter rotating mass to balance out the piston weight and more to counter the expansion stroke. Practical maybe for small engines, but for large displacement, I see a top load washing machine doing towels strolling all over the garage

Besides, I-4 engines need so much reinforcement to hold compression and the straight would be cheaper to mill and have less moving parts and less parts.

unA4dable

Two sets of heads rather than one? More complicated manifold plumbing? Twice the camshafts?

I'd think a V4 would be more expensive than an inline, all else being equal. Engine balance is a trickier issue with V4s, since they're not inherently balanced.

As far as their use in motorcycles, V-type engines have a form factor that falls more naturally into the motorcycle frame and drive configuration.

-dan

xr4tic

and 4 cylinder motors need as much as they can get.
Probably has something to do with the way the crank is made, rod lengths, and how the rods act on the crank.

ColoradoMark

Only one I can think of was in the Saab Sonnet

WJM

the reason V shaped engines came out is because of the simplicity in the blocks and many other factors.


I swear Im right on this though...

WJM

you have 2 or 3 engine mount points so the depth of the engine doesnt really do much for you.

If you have a longer, transversly mounted engine the shorter your offsets have to be.

WJM

this is also true on average....general rule of thumb