The K20a3 Discussion thread.
 

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.

But oil squirters are not bad, since the oil takes some heat from the pistons and allows to run leaner.

squirting happens at a much higher rpm than lean burn happens at.

Anyway, I still don't see the presence of oil squirters as a problem. I'd still feel more comfortable having this feature on the engine.

Hahahaha!

Cool thread idea. There is a guy on ecomodder named pgfpro who does some awesome modding for fuel economy and power. I hope he notices your thread.

So, you plan to try for some lean burn tuning, yes? A relatively easy combination would be some lean AFR and some tall gearing so you can cruise on a freeway leaned-out and low rpm.

pgfpro did something like that with an old civic some years ago (IIRC).

Ktuner is MUCH cheaper and just as versatile. I am using the K24A4 from the accord in my 5speed 1St Gen Insight build (the same economy 12-16 valve activation)

Really? K24 into an early Insight? That sounds cool.

Transmission started having issues, needs a new batery... to much$ to keep it going. Cheaper to just swap it.
Yeah whenever it gets moving along I will update it's old a** thread ....The goal is 50 mpg and 350-400WHP... gt35 turbo...

Not to hijack your thread lol sorry ...

But seriously on a look into Ktuner it is substantially cheaper

Anyway, maybe a K24 could actually be better to work on an efficiency-oriented project since it's undersquare, which usually leads to a better low-end torque.

If I'm not mistaken in the 2200 to 3400 rpm range I believe the K24 has a lower BSFC But I could-be mistaken... I would have to find the graphs again ,At very least they dirt cheap and more readily available engines