Has anyone built an engine for economy?

[BLSTIC]

I'm not talking a refresher type build. I'm talking about bringing compression up to (say) 13:1 to get more efficiency, and then using higher grade fuel (or water injection) to compensate for increased knock tendency.

Or making an atkinson cycle engine (higher geometric compression ratio, with cam timing altered to reduce cylinder filling and pumping losses, allowing the engine to work on lower octane fuel).

Personally, i think B16A Vtec engine with higher compression pistons, custom cams (to provide said atkinson cycle), turbo, and water injection (to restore lost torque from wierd cam timing) would be able to power most any FWD vehicle at a decent rate while providing higher efficiency.

I realise that a set of high compression pistons, water injection, and re-programming engine management may run to a high cost, but surely SOMEONE has done it while retaining a cam profile that at least considers economy.

[Frank Lee]

I know guys that built E85 engines with high CR but that's about it. Don't know of any successful home-brewed Atkinson or Miller or whatever cycle builds.

[cleanspeed1]

There was a guy here that put together a 3 phase VTEC Honda Civic with a turbo. Do a search on the site, see if it'll help.

[Joenavy85]

I remember seeing a thread about a (Briggs?) 10HP 1 Cylinder engine being used with a CVT (I think) to power a Metro, apparently it got great mileage but looked hideous.

Correction a Diesel Honda

http://www.teamswift.net/viewtopic.php?t=22429
http://utterpower.com/10hp_chevy.htm

I'm aware this is a swap, not a build, but still is impressive

[TheEnemy]

I have been planning a ballanced build but I am waiting on money and time.

My plan is 10:1 CR up from 8:1

Knock prevention includes
Ceramic thermal coatings particularly on the exhaust port and valve.
High flow water pump.
cleaning up the water jacket for better flow.
Combustion chamber smoothing
Oil jet piston cooling
Cold air intake
Custom program with an aftermarket ECM
long tube headers
High flow exhaust, mufler, CAT.

More perfomane minded mods
Cleaning up the ports for better flow velocity

Other efficiency mods depending on money
Roller rockers
Roller cam ($1600 for my engine)
Ceramic coated bearings (more for durability)

Aluminum heads will help (mine are Iron), but even then I wouldn't suggest going past 12:1 with a low RPM cam