K20A3 - Tuning for Economy

[I-S]

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

I have a UK honda accord wagon:



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:



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.

[CTD-Fab]

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!!!

[bartine]

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

[greasemonkee]

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.

[locomonkeyboricua]

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.

[BongoBennie]

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

[redpoint5]

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.

[redpoint5]

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.

[Stacygifford]

Originally Posted by dann_04

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.

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

Originally Posted by 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

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.

[Stacygifford]

Originally Posted by redpoint5

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

.

woops..... NVM lol