K20A3 - Tuning for Economy

[Vince-HX]

So this engine has peaked my interest in the last few days after doing a fair amount of research and talking with engine builders and few tuners. It uses the same vtec-e cam lobe technology as the legendary Vx and Hx honda engines.

One thing that this engine doesnt come with is lean burn though. Maybe it was to reduce Nox emissions or something like that but the most important thing is that this engine is @ least as capable to opperate in a tuned leanburn mode as the d15z1 and d16y5 engine

So one of my coworkers went on a roadtrip in his roomates EP3 and since it already had Hondata KPRO installed he started messing with tuning it for a mild leanburn cruise. From what he said its running 18:1 @ light loads under cruise and on the freeway doing 80+ mph it was getting around 40 mpg

With a more capable wideband controller and NTK sensor he should in theory be able to run up to 25:1 ratios and my local professional tuner confirmed this also. He also could raise the stock vtec engagement point from 2200 to about 2700 for in city gas sipping.

From what ive gathered NOBODY has tuned a k20a3 engine yet for this kind of economy driving, kinda really exciting really

You guys know what this means? You could have a 400hp stock block turbo engine that pushed 40+ mpg in the right hypermiling hands. The ultimate sickness

***insert evil laugh here***

I'll keep you guys updated when I get some real numbers back.

[SVOboy]

Stick it in a CRX and I'd be real interested,

Actually, that's pretty cool, I thought all the K were i-vtec, learn something new everyday,

[Vince-HX]

I dont think k motors fit well in Ef's, ground clearance and hood issues. Ever see the Hasport Crx? Granted its stupid-charged but the hood is cut all to hell. Super quick car though.

and i guess you could call it i-vtec-e, lol

[SVOboy]

I don't know about the hasport krx, but I remember watching the rywire build and I thought they just had to chop the supports out of the hood, but then that was three years ago and I don't remember...

Still would be a fun ride.

[Vince-HX]

Oh, forgot the Hasport is a k24 block and k20 head, the k24 block is about an inch taller but the torque is worth it I hear.

If my lawsuit pans out and i get paid a decent amount I think a fully built Krx would be in the works for sure.

Speaking of fun ride, a new hire @ my work has a 320hp/260tq Crv-tec 90 Hf and I get to drive it tomorrow, i'm stoked. His turbo kit it all log-tastic right now but he plans to build a 600hp engine for it soon.

[EP3]

Yeah you can raise the vtec with a VAFC I use to have one. Never thought of raising the Vtec point...hmmm intreasting. EP3s and RSXs have a K20 I-Vtec engine I believe. K24 are in Crvs, Accord 4cyc and I think some other Acuras too. The K24 does offer better tq.

[EP3]

I remeber when I use to have a VAFC I could gain a few hp with just straighting out the fuel curve. I am assuming this would also increase the fuel mpg if this was done too.

[rsx2002]

the K20A3 is an i-VTEC

[Vince-HX]

Originally Posted by rsx2002

the K20A3 is an i-VTEC

look closer

"On the other hand, the K20A3 uses a completely different method, but is still called VTEC. At low rpm, the two intake valves operate with different cam lobes. One valve gets the primary lobe (the taller lobe) and the other gets the secondary lobe (shorter). The exhaust valves always get shoved open by a single lobe with no tricks at all. When VTEC kicks in at 2300 rpm, both valves start following the primary lobe. That's it. There's no 5500 rpm kick in the seat."

Hondata has a nice writeup on this

Tech - K Series Tech

[Vince-HX]

I love the variable intake and it looks to have made some nice gains in hp and torque. B18 gsr engines also came with a variable length intake but never were they made on a D series

However, my tuner has confirmed with me that if I can modify a Gsr intake to fit my d series he can program the ecu to control it.

Kinda off topic but this stuff is cool to play around with