K20A3 - Tuning for Economy
 

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 :thumbup::thumbup:

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:eek:

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.

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, :p

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

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.

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.

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.

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.

the K20A3 is an i-VTEC

look closer:thumbup:

"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

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

Yeah I miss my 01 GSR :(

Well bro I have one sitting under the hood of my car. It says right on top of the engine i-VTEC 2.0 DOHC. Your telling me my engine is lying to me?

Vtec kick
 

and if your saying that VTEC doesnt give you an extra boost then I must disagree with you there too. there are plenty of videos on youtube where you can clearly hear and see the results of vtec kicking in

If your block says k20a3 it uses vtec-e and VTC. True v-tec has high and low cam profiles for the intake and exhaust. If you dont believe me take your valve cover off and see for yourself. Also notice the difference in HP and TQ from lets say a k20a2 and your engine.

From a tuner standpoint people hate the k20a3, it seen as the worst K series mainly because it doesn't uses true vtec. But, for economy I think this engine has great potential.

You do get a "boost" @ about 2300 when the engine goes from 12 valve mode to 16 valve mode.

Great job on your FE by the way:thumbup:

I know what you are saying. The engine does say I Vtec. EP3 and Rsx are basiclly the the same.. same engine as rsx but not the rsx s. Yeah unfornatly the K20A3 in my mind has made a shame out of the civic si breed. I would have rather had the coupe si of older years. I remeber my Integra GSR with a B18, the B-series were my favorite. When the Vtech cams switched, you would have to hold on to the wheel. That was my favorite car. I am intreasted to test the new Si though. But I will not take myself to the dealer to test it out, in fear that I am not ready to buy. I will love it to much. But that being said the ep3 is a good midrange car faster than some but not fast. Handles good and You can get a Xmas tree in the back with the hatch shut, if you fold down the seats. Ok mpg and looks are ok. I bought the car used b/c of the price and wanting a slighty sporty car.... And no matter what it is a HONDA, the best company. For the price/quality you can not beat a Honda.

Let me know when you start working on an R18. :)

That is one cool engine, the way it works to eliminate most pumping losses is very interesting. A turbo manifold would be insanely easy but the drive by wire system is kinda sketchy for tuning I would think.

For anyone that cares here is a great writeup on that engine.

Technical Overview of Honda's new R18 i-VTEC Implementation

Oh, i know you guys love hardcore numbers and A-B-A testing but the guys driving didn't really come through, sorry:(

The engine was leaned out to 17-18:1 without any noticeable changes in how it ran, misfiring, ect. The speeds were very ecomodder unfriendly @ 80-90 mph but the newly tuned engine burped out 41 mpg:thumbup: The total trip mileage was approx 850 miles.

They had made this same trip before and stated that approximately half the gas was used for this trip compared to any previous ones. I believe the driver does not have any hypermiling knowledge either so i dont think DWL or anything like that was used. I do want to say that the previous tune was pretty bad and his car didnt run very well, worse then a bone stock car. So the better tune probably accounted for some of the 50% fuel reduction.


Hopefully I can get the local tuner, Locash, to do a real economy tune on his dynapacks for a small fee. I'm really interested in how far this engine can be pushed:turtle: I wanna see 25:1


Ep3's and Rsx's getting 50mpg may be in the future


Before any of you guys ask the tuning software is $1000 for a K series so unless your car already has it installed this may not be a $$$ friendly mod.

Kpro is too damn expensive. I much prefer running crome on my obd1 ecu, :)

Nice results though!

Yeah KPRO is alot. Greddy has a newer engine management system out for around 300 you may want to check it out. I think it is called Greddy E Manage.

Leaning it out would be mpg friendly, but not necessarily 'eco' friendly. NOx emissions sky-rocket until you start getting into ultra-lean burn capabilities.

I can idle my 17 year old Swift under 21:1 a/f and lean it out fairly far while cruising, but it will never approach the ultra-lean burn zone

I'm thinking you could adapt a Insight Cat and program Hondata to richen up after a certain amount of time spent in lean burn to do a NoX burn.

So there you go:thumbup:


And speaking of ultra lean burn, direct injection is the way to go. I remember reading something about mixtures of 40:1 and higher are possible.

What you need is that magical 200mpg carburetor!

Do able but you'd have to fork for a new one. I pretty sure junk yards aren't allowed to sell cats.....

This is true. Alternatively, you could get buddy buddy with someone who works at honda and wait to see if something passes through.

Raising the Vtec engagement to 2700 will be nice. I try shifing my civic at 2200-2500 but the lack of torque is just painful. I feel that an accord 5spd is more suited for hypermiling due to its higher low end torque. A 94 accord auto can do 50-55mph staying at 2k rpm. I am getting better mpg out of a 94 accord than my ep3.

I have though about getting kpro and tuning for mpgs, but it is fairly expensive. you would bebetter off first dropping your tranny and adding a 6th gear from the acura tsx. It takes your rpms from 3500 at 65mph to 3000.
search on ephatch.com and you should find the howto. If not, pm me i have the url on my work computer.

Also for those of you questioning the k20a3 as an i-vtec engine, it is. Vtec is simply valve timeing(and lash) electronically controlled. The intake side has a high and low cam profile. The exhaust does not. Honda did this to tune it for economy and emissions. At 2200 rpms the vtec solenoid locks and both valves operate on the higher cam lobe. as for the i it simply stands for with inteligence which is what honda calls it when they ad the variable camshaft angle. So a k20a3 is an i-vtec engine. It is designed for economy and lower smog emissions. Plus it says ivtec right on the side of the ep3 in vinyl decals lol.

I agree that direct injection is great and much more efficient, but you run into the problem of cylinder wash which causes a decent amount of wear and tear over the traditional style injection. I'm just waiting to see how long these new cars are going to last with direct injection from the factory.

IMO, HCCI plus direct injection plus variable compression (using delayed intake valve closing) is the way to go.

Yeah I hear ya. I hit 29mpg mark. I was going for 30mpg, but I am pretty impressed for my first time. I know I can get better though. This is mostly city driving. When I move I will be mostly on highways. So we will see. My wifes 05 Honda civic 4-door lx auto gets sometimes in the 40s without really going crazy. But at highway speeds it is around 2k ish.

So, I thought I'd begin posting here with an old thread revival.

I have a UK honda accord wagon:

http://www.askisaac.com/images/car/9237.jpg

As you can see, what we are sold as the Accord is the Acura TSX in the USA (what you are sold as Accord is the Honda Inspire in Japan, not sold in europe). This has a K20A6, which is basically the same as the A3, but with the aluminium rather than plastic inlet manifold. 5-speed manual.

So, this thread concerning the A3 is of great interest as I think it likely any improvements made to the A3 should be directly portable to the A6.

So far, my fuel economy is as follows:

http://www.askisaac.com/images/hondampg1.gif

Note that the mpg numbers are in miles per imperial gallon. The 33.2mpg(imp) average = 27.7mpg(US).

Is there anything further to report on the tuning of the A3?

Also interesting discussion here on direct injection. Since there is no legislation in europe regarding NOX (or at least nothing like as stringent as the USA) such engines are fairly commonplace here. VAG have their FSI, renault with IDE, etc.

My previous car was a mitsubishi Galant GDI wagon. 4G64 2.4 litre, but with direct injection and high compression, huge EGR, etc. It was a nightmare to run. It produced huge amounts of carbon (decoking was a common requirement), was never smooth, went out of learn burn mode at the slightest provocation. Overall in 11000 miles I averaged 33.6mpg(imp), which as you see is barely better than the accord, despite a lighter car with fewer toys. The accord has significantly more power and much more enjoyable to drive. There are issues with many direct injection engines requiring the use of premium fuel (98/99 RON in europe) to avoid knocking, but it doesn't bring any economy benefit (I ran 4000 miles on 99RON, the rest on 95RON with that car... the 95RON was 0.2mpg better, which is within the statistical variation of the measurement). In the end, mitsubishi decided that direct injection didn't work their way with european fuel (apparently it works great in japan with ULS 100+RON), and gave up on it - all of their current lineup in europe are again port-injected. My experience with it didn't exactly warm me to it.

I'm back!!!!, different username though

This Is Vince and I know I have been absent from the forums for quite some time but projects have kept me pretty busy.

I do want to report that I know OWN a 2003 Civic Si with a K20A3 and i will be tuning it to the max pretty soon. My Mpgs are about 28-32 with 215-45-17 tire combo and mild to slightly aggressive driving. With Kpro I my goals are 50+

let the fun begin!!!

:)

Vince

What kind of results did you get on modding your Civic Si?

I have a 2005 Si and am considering a K-series ECU reflash at $295 - quite a bit cheaper than a full K-Pro kit.

Fill us in!

Ben

I completed a build/tune on a fellow's gsr a couple months ago. Combustion chambers were reworked/valves unshrouded and prelude injectors were used to retain decent atomization. The engine handled an impressive (for a tumble chamber) 19.5 afr before it began to misfire at a 3000 rpm cruise. I locked in closed loop at 17.5 with a .5 afr swing. As expected, less rpm required more fuel. Unfortunately, the driver pulled the vehicle from my possession before I had a chance to do further testing.

Any new info on your 50mpg goal? I also have a Co worker that has civic si 2004 and told him to buy the kpro so we could tune his car af ratio to 19/1 to get him better mpg he drives over 100 miles a day to work so the kpro would pay for its self the first year.

So I'm doing a swap, K20a3 eco-ish build. Subscribed!

This thread is almost a decade old and has no updates, so I wouldn't hold your breath.

Instead, you should start your own thread and keep everyone updated.

This thread is almost a decade old and has no updates, so I wouldn't hold your breath.

Instead, you should start your own thread and keep everyone updated. I have an Acura TSX, and I bet the thing killing MPG more than anything is the short gearing. Most cars will do about 36 RPM per MPH in top gear, but my 6-speed does 43 RPM per MPH in 6th.

That said, it would be fun to play with tune. My VTEC has the opposite problem where it comes on way too high in the RPM band. After VTEC kicks in, I only get 1000 RPM to enjoy the power before having to shift, which drops RPM below the 6,000 RPM engagement point. VTEC should kick in around 4,500 RPM in my opinion. At this engine speed, you're not going to accidentally engage it, and it leaves plenty of room to accelerate without dropping out of VTEC when upshifting.

yep
https://www.kseriesparts.com/cr/HON-5SP-2-6SP.html



Just use the intake from a CRV, they bolt up, and have variable runners.

I have been building a K swap first gen Insight for 2 years now.... Lean burn vtec-E and all. No k pro for me though.. Ktuner is way cheaper.

woops..... NVM lol