Topic: L4 v. V4 engines and torque

[GroovieGhoulie]

I was reading about the various V4 motorcycles Honda was putting out in the '80s and the articles kept commenting that the V4 engines, for a given displacement, put out more torque than an inline four could ever dream of.

How is that possible?  Same displacement, same number of cylinders, so how does altering the cylinder arrangement give more or less torque?

[SteveD CB500F]

I think the torque thing is more about design and tune than layout.

All I know is that my VFR800 (110bhp @ 12k rpm) will not ride below 3k revs whereas my 500/4 will.

[Pinhead]

I always heard it was the other way around. At least on cars/trucks, an inline-6 usually was torquier than a v-6, while a v-6 would be snappier. I've never driven an I-8, though, so those don't count.

My dad has an Allis Chalmers tractor that was sold in I-6 and V-8 models, both diesel, both 426 CI and the I-6 had a lot more torque.

[mlinder]

i6's are naturally balanced. Thus their smooth torque delivery.

[nickjtc]

i6's are naturally balanced. Thus their smooth torque delivery.

As are 90 degree 'V' motors.

Isn't this an issue of the way the power pulses are put to the ground, too? A V4 acts like two V-twins side by side....

[dusterdude]

torque is a product of engine stroke,if the v4 has a longer stroke it will make more low end torque than a shorter stroke engine.

[mlinder]

i6's are naturally balanced. Thus their smooth torque delivery.

As are 90 degree 'V' motors.

Isn't this an issue of the way the power pulses are put to the ground, too? A V4 acts like two V-twins side by side....

Inline 6's have no primary or secondary vibrations. No balance shaft..
http://en.wikipedia.org/wiki/Straight-6
I believe 90 degree V' have some secondary balance issues.
I could be wrong.

[SteveD CB500F]

Isn't this an issue of the way the power pulses are put to the ground, too? A V4 acts like two V-twins side by side....

The VFR is a 90 degree V with a 180 degree crankshaft and a firing sequence of 180/270/180/90, hence the odd sound it makes - I think it's more like half a V8 than 2 V-twins.

If you recorded it, it would go "BANG space BANG space space BANG space BANG BANG space BANG space space BANG space BANG"

Whatever, with my Micron Race Can at 8k revs it HOWLS...

[Terry in Australia]

torque is a product of engine stroke,if the v4 has a longer stroke it will make more low end torque than a shorter stroke engine.

I think you nailed it Dusty, long stroke "V"s are the gods of torque, hence most Harleys will kick a jap 4 for the first hundred yards or so in a stoplight drag, and all the top fuel drag bikes are big V twins.

Steve's VFR would probably be a lot torquier if it had a longer stroke and milder cam profiles like a hog, but it would lose the upper limits of it's RPM range. An inline 6 out-torqueing a V8? Pffft!

[SteveD CB500F]

The later VTEC VFRs switch from 2 valve to 4 valve operation at about 6k revs - ostensibly giving the best of both worlds...

At the same time, they switched back to chain-driven cams (it took the 1986-2001 to get over the VF debacle)

[mlinder]

torque is a product of engine stroke,if the v4 has a longer stroke it will make more low end torque than a shorter stroke engine.

I think you nailed it Dusty, long stroke "V"s are the gods of torque, hence most Harleys will kick a jap 4 for the first hundred yards or so in a stoplight drag, and all the top fuel drag bikes are big V twins.

Steve's VFR would probably be a lot torquier if it had a longer stroke and milder cam profiles like a hog, but it would lose the upper limits of it's RPM range. An inline 6 out-torqueing a V8? Pffft!

Thats not engine configuration, thats displacement and bore/stroke ratio giving that torque.

Most diesel tractor trucks are I6's, not V anythings... if that gives you an indication of good torquey engines..