[BongoBennie]

I have been searching for a good research thread on the K20a3, Honda's "Fake VTEC" "******* K" engine. While it's not the most efficient 4cyl it is the most efficient of the VERY popular K series. K-Pro is a very flexible ECU and many options are available. With such a vast aftermarket support in products and services I think it's a good candidate for an ECO performer.

A3 advantages for eco over A2 (that I know of):

Crank is lighter as well as only semi counterweighted

Rods are lighter and bottom width is slightly smaller for less friction. Stock rods are known to handle 300+ HP and 8K rpm, ARP bolts are an easy upgrade.

No oil squirters and less aggressive oil pump for less drag (bad for rev monsters)

Less moving parts in the head and less aggressive valve spring rates with titanium retainers on the shelf.

RSX version has a dual length intake system.

Smaller exhaust ports.




Another difference is combustion chamber has quench pads and has +.7 more compression over the A2

You can swap any piston into an A3 made for an A2, Type R yields 12.2:1 I'm assuming due to oil squirters the Type S/R pistons would be very light weight.



What makes the K so good though in my opinion is Kpro, Not only is it wideband but you can use aftermarket super sensitive and accurate O2 sensors.

It will also utilize an E85 content sensor, you can also use staged injectors for a legit bi fuel system (87 for cruising, E85 for Full power)

I'm on a slow path of putting my own engine together and posing a few questions on HT and K20.org but the conversation always getting into full throttle mentally and despite all the knowledge I get from them, when you call my engine stupid.... well, you end up here on ecomodder. Other than the engine and the car, I'm still pretty open to which way to take this build and not sure how much I want so spend, I hope to get some feedback and start a discussion about the motor.