Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec oversquare blocks

i read that the 3.0L is an "over-square" block because it's bore x stroke is 89mm x 79.5mm, and that this is deterimental to performance.

how, exactly, is this detrimental, since displacement is increased? i presume stroking would fix the problem, if it's significant. anybody look into this recently?

An engine with a large bore and short stroke will produce less overall torque, but has the ability to reach much higher rpms, and make more horsepower.
Also the ability to install larger than average valves.
Much better Volumetric Efficiency.
Less piston travel = faster revving.

Throw some DOHC heads on top of that and you have an engine with a broad, linear, near flat powerband.

I do think the 3L folks should really up their redline to 7500 atleast. Especially the Hybrid ones (higher CR)

Oh & I don't see a detriment at all...

think F1 and youll find the most screwed over bore to stroke dimensions you could ever want.

but also 800+ HP @ 18,000 RPM from 3L V10 DOHC 4valves per cylinder and depending on the design one or two plugs per cylinder

Speaking of plugs...It's interesting that the engines in the planes I fly have two plugs per cylinder for better performance. It's obvious too when you go through the magneto checks and watch the rpm drops as you shut one of them off. I'm curious as to why cars don't use the same system for increased performance. My assumption would be cost.

or sometimes packageing- sometimes there just isnt room in the combustion chamber design

To bad mine peaks at 6,400 RPM with SE UIM on it. I'll be singing a different tune though once the ported 3 liter UIM gets on there though... Then perhaps some larger valves too... hummmm, then I need a Ti crank and rods to hit 9-10K RPM, then new cams... Hum, this trip down day dream lane is getting expensive. I'd better quit before my credit card bursts into flame...