Honda Insight w/Acura TSX engine - Ecomodding

[tekcajwolley]

I admire your perseverance.
Curious about how your scangage calculates mpg and how that compares to the info available from the hondata app.
Best I’ve been able to do so far is 47 on a tank in the mountains of sw Colorado in winter.
I’m not wired for hypermiling but want reasonable mpg. I drive 65 on highways. For me driving 55 in a 65 creates just too much hate.
I’d like to get 65 mpg at 65 mph. Beginning to think that may be a bit wishful thinking.

02 insight with k20a3 with accord 5sp with 3.4fd also using kpro to access fuel tables.

[Ecky]

Originally Posted by tekcajwolley

I admire your perseverance.
Curious about how your scangage calculates mpg and how that compares to the info available from the hondata app.
Best I’ve been able to do so far is 47 on a tank in the mountains of sw Colorado in winter.
I’m not wired for hypermiling but want reasonable mpg. I drive 65 on highways. For me driving 55 in a 65 creates just too much hate.
I’d like to get 65 mpg at 65 mph. Beginning to think that may be a bit wishful thinking.

02 insight with k20a3 with accord 5sp with 3.4fd also using kpro to access fuel tables.

To my knowledge, the Hondata app calculates it based on MAP and RPM, and makes the assumption of stoichiometric AFR. Things like rich and lean areas of the fuel map, tip-in and (I think) declaration fuel cutoff simply are not part of the equation. So, you can think of it as an educated guess based on very few factors, none of which are the actual fuel used.

47 is pretty darn impressive for a K swap average tank. I think 65@65 may be out of reach for steady state driving - the stock engine is only 70-75mpg @ 65mph - but I may be wrong.

You might try oversizing your tires, LRR compounds, higher pressure, some aero mods. For the drivetrain, lean burn with modifications to the timing table could help. There's also the 2008+ Accord 5th gear, which is taller than the 03-07 5th.

Which K20A3 is it? Si or base RSX?

[tekcajwolley]

Thanks
I did a 3-stage d15 in a 93 civic sedan and easily got 52@70. As long as it was in 3-valve mode it did well. It would go into lean burn.

This is the base K20a econo 3-valve-4-valve engine. I picked it because I felt at the time it had the best chance of high mpg.
Don’t remember the size right now but put 15” oversized wheels/tires on it. Diameter is about 1” bigger. Pressured to 40
Right now it does 70 at about 2200. I upped the vtec threshold to 3000.

Been in the shop since January for little things like minor vibration, sound deadening, rsx cruise, and climate control ac.
Hoping to get it out real soon as I miss driving it.

A diesel dodge tried to smoke me out one day....

[Ecky]

Tires start to become critical with really high mpg numbers. I'm unsure if you were a part of the Insight community prior to your k swap, but the "wrong" tires have been known to reduce economy in our cars by 10+ mpg. I think your numbers are doubly impressive given they were in winter and with who knows what tires.

I haven't yet been able to get my Rostra cruise working with the VSS converter. Have any pictures you can share on the RSX cruise install? Or maybe a part list?

Reason I ask about whether it's an RSX or Si motor, the RSX lacks oil pump balance shafts and the pump is more under-driven, which could be worth a couple of mpg. It also has the variable length intake runners.

[tekcajwolley]

Be happy to share whatever I have.
Gotta prove it works first. Honda schematics (via all data) had connector c710 (under airbag) wired wrong. Had to go in and correct that. It’s up on jackstands now maybe try it out today. Of all Honda’s I’ve played with this has been the most difficult. (But with adhd and advanced age, maybe I’m the problem!)
Variable intake runners are good for a bit more torque down low. It’s the long runners I was after. I don’t really care about it shifting-don’t wind it out that much.
Absence of balance shafts may be contributing to vibration at 1800 which is 65mph. I tried to balance out the motor mounts but haven’t tested it yet on the road. The rear and left mounts are stock. The right is innovative (just the mount). I drilled holes in it to soften it up.
Yeah the tires are craigslist Firestone’s. After install got left hand torque steer. Even swapped left/right. Stock tires did not. Go figure! The wheels are 99civic si.
Thanks

Ps
I’m using Dakota digital vss converter.

[neptronix]

Just wanted to say this is an amazing build. Perfect intersection between gas sipper and race car.

It proves that fuel economy is moreso in the aerodynamic design of a car rather than the engine itself - at least in the hands of a skilled hypermiler

[tekcajwolley]

Originally Posted by Ecky

I haven't yet been able to get my Rostra cruise working with the VSS converter. Have any pictures you can share on the RSX cruise install? Or maybe a part list?
.

Question:
Did you connect your rostra unit to the raw vss signal or to the converted signal? Upstream or downstream of the converter?

[Ecky]

Originally Posted by tekcajwolley

Question:
Did you connect your rostra unit to the raw vss signal or to the converted signal? Upstream or downstream of the converter?

I previously had the Rostra unit working before my engine swap. The new transmission has a different type of speed signal (much higher frequency) which I believe is out of range of the Rostra unit, so it's connected downstream of the converter.

The converter's signal seems to work fine for the cluster and ABS, but I think it's what's not working with the Rostra unit. Rostra sells a separate VSS converter I might buy, but it seems silly to have two different converters if I could avoid it.

[Piotrsko]

How about a simple flip flop for the Rostra input for a divide by 2 or even a divide by ten chip? They are common on all the parts places I inhabit and just a couple of $

[Ecky]

Originally Posted by Piotrsko

How about a simple flip flop for the Rostra input for a divide by 2 or even a divide by ten chip? They are common on all the parts places I inhabit and just a couple of $

I was considering one of the divide by 4 or 10 chips, actually! Just a matter of priorities, haven't gotten to it yet.