Silly Idea #2

[matsondawson]

High compression makes engines more efficient.
When cruising at 100km/h your burning sod all fuel in a low compression environment. If you disconnected 3 injectors whilst cruising you'd have to open up the throttle more, creating more compression in the cylinders and increasing efficiency.

What am I missing here?

[michaeli]

I think one of the American cars 'acutually' does this electronically with a V8 which runs on 4 cylinders until you floor it...

The principal is there but you'd need a hell of alot of technology to make it work....

[SGHOM]

some big V8 'yank tanks' can run with no oil or water !! /yes
they just shut down 6 of the 8 cylinders, & carry on going !! when they get hot, it just shuts down 6 others !! :rolleyes4 :rolleyes4

[I-S]

Yes, cadillac and chrysler have "Displacement on demand" systems.

The Chrysler 300C 5.7 HEMI V8 (soon to be sold here) gets 25mpg combined, which isn't bad for a huge american car (based on the merc E-class platform) with a 340bhp hemi...

[bernmc]

Big mercs do it too.

[matsondawson]

I think one of the American cars 'acutually' does this electronically with a V8 which runs on 4 cylinders until you floor it...

The principal is there but you'd need a hell of alot of technology to make it work....

What technology would you need? Have a switch, if your cruising disconnect 3 injector outputs on your ecu.

[Kenneth]

What technology would you need? Have a switch, if your cruising disconnect 3 injector outputs on your ecu.

I think it would be a good idea to disconnect your igniters also... which shouldnt be too hard with the individial igniters that seem to be used on modern cars.

You wouldn't want a little waft of unburnt gas to enter the cylinder and be cause a lean combustion when you switch off the injectors.


What might also be nice is to turn off the cylinders in a pattern. ie: make pistons alternate by firing once, missing once so you dont have the same cylinders firing all the time.

[Kieran]

What might also be nice is to turn off the cylinders in a pattern. ie: make pistons alternate by firing once, missing once so you dont have the same cylinders firing all the time.

Yeah, that's what the big, bad Northstar V8s in Caddilacs do. These are also the engines that Derek's on about - When the Caddy STS arrived in the UK, Jeremy Clarkson commented that they can go for up to 50 miles with no oil or water. Handy in the Uk, that - I mean, that 50 mile stretch of arid desert in the middle of brum is a nightmare to cross........................ :rolleyes4

[I-S]

You mean longbridge?

[Kieran]

You mean longbridge?

/lol /lol