Like I said, I am not as familiar with this software, as I can now see, you're actually changing code and it doesn't look like a real interface in all areas(?)..

What I noticed on other cars with other software is that if you are trying to change the switch point while using narrow band feed back, the car just adds or removes fuel to attain the desired average switch point. Completely opposite a wide band o2 sensor using closed loop feedback control, where the measurement is actually air/fuel and using lambda calculations it can add or take away the exact amount of fuel needed to get to where ever you set... and very quickly. The only software I know of that you can dial it in perfectly is with a Motec.... hehe... I learned many things using a Motec.

I once saw first hand a 1,000 hp car with a Motec keep the engine from blowing up by using a closed loop style feedback. The extra boost a pump didn't turn on... 30% fuel added instantly...in the log the air fuel never deviated from the desired lambda table.... blew me away.

I'd like to see what's up with the evo X's; don't they have a wideband factory?

back to the switch point; trying that theory on a couple of cars (not evo's) with the narrow band switch point, it had a real hard time staying around the my settings. I also noticed some tip in bucking, but that car was exaggerated due to the large cam. It just got worse with the switch point. It just got worse mileage with a cam period.

I'll keep reading. I can't believe how much stuff there is on this subject. I'm on page four of my second LONG post. I got kiddo's so I can only read a page or two at a time. Been out of the Mitsu scene for a while.

wp

 

I recently setup the simulated NB O2 by wiring the LC-1 output into my ECU. Thanks to Jack_of_Trades for the info here

I set the switch point in LM programmer to this (as posted earlier):

.80v @ 15.55
.10 @ 16.3

So far so good. AFR's are hovering around mid 15's now at cruise and idle with no changes to the ROM or map. Open loop is unaffected and driveability seems fine. Will see how the economy goes over a couple of tanks of fuel

Attached is a log of a hwy cruise @ around 110km/h (about 70mph). As you can see, the AFR's do swing around a little bit. There's some 14s and some 16s mixed in there.

Just wondering about fuel trims though? My trims were almost spot on prior to making this change, now they seem out a fair bit. Do I need to make any changes to bring trims back into line?

110Cruise.zip

 

Eisen7 what kind of mileage did you end up getting with the updated LC-1 AFR? I've been thinking about which route to take for economy modding.

Sorry to bring this back from the dead....

 

I haven't been able to do any decent MPG tests as I've been playing with the tune lots over the last couple of months, so have usually done a few WOT logging runs each tank I'm also yet to do any freeway cruising since changing to simulated NB.

The best I've got in city driving is 13.1L/100km or 17.95MPG. That's with 4 or 5 WOT pulls in 3rd gear though...

Will post updates when I do some freeway kms.

 

Any numbers yet? I figure you've had some time to figure out your mileage?

 

I tried changing my timing in the lower load cells and got a 20% improvement in fuel economy. All I could get was 280km per tank, now I get 340km a tank before the fuel light goes on. This is an Airtrek, so probably a different size tank and its auto.

 

Nothing better than what I posted last sorry mate But I'm still working on the power/tq tune, so there are lots of road pulls in amongst regular driving.

Hopefully in a few weeks I'll have something solid to report. Am still yet to do any freeway cruising too. It's all been around town driving.

 

Has anyone with ACD noticed different economy numbers for the various lockup settings?

I'd take a guess and say highway driving in Tarmac would get better mileage than Gravel since the turning resistance is less as the lock is decreased as soon as there's steering input.

But wouldn't Gravel have the potential for better straight line mileage because it locks less when going straight causing less lockup losses? But start turning even a little bit and Tarmac would be better?

That's the kind of thought process I'm thinking of. Since the ACD has been flashed successfully in the ACD flashing thread, I assume it's only a matter of time before we have the capability to do an economy flash on the ACD to achieve the best possible mileage.

Perhaps an aggressive unlock with even the slightest steering change or g-force. And it would have minimal lockup for accel/decel...

I really don't know what would work better or not but it has to be worth at least 1mpg right? I would think a center diff lockup change would have some effect on mileage since something like tire pressure seems simple but has major mileage results.

 

I've done a couple of tanks now since finishing my tune. Best highway figures are 10.24L/100km or about 23MPG. Best city figures are 13.5L/100km or 17.4MPG.

So overall OK, but nothing all that brilliant to argue that simulated NB is the way to go for everyone. I might change it back to use the front o2 and see if it's any better or worse.

 

Just a thought, if you do a COUNT in Evoscan Map Tracer, you will notice the 2 cells with the highest count are 500rpm Load 20 and 30.

In fact, the car spend a lot of time idling.

With this, I lean out the AF at these 2 cells, the car stutter a bit during idle at traffic light, but I assume, since there's no load on the engine, it should be fine?

Any opinion on this ?

 

Yes, lean idling works. Also lean cruise. For lean cruise go open loop and run it so lean it misfires the add a touch of fuel. Note that it is just in a few cells to do that in also.

 

Just wondering the stuttering at idle, does it do any harm to the car ?

My gut feel is, low load, no knock = no harm. However, it's like the car is dying off and trying to grasp air ... Uneasy feeling

 

IMHO, I wouldn't mess with idle. As Silverstream pointed out, your car does enter the idle cell frequently, but this is because your car is stationary there. i.e. if you are idling, your car is in the idle cell, but if you are cruising, your car can be in any of 100 different cells (there is not one or two cells devoted to cruise), so I don't think this is significant.

The problem is that your car is not making much power at idle. The horsepower (and as a direct result, fuel consumption) at idle is minimal --> the horsepower produced is simply the amount of power it takes to overcome any drag (alternator, AC, power steering, engine drag). Even if you were able to make your idle twice as efficient, I doubt it would be a noticeable difference in fuel economy.

What type of mass airflow rates are you guys logging at idle? I'm guessing around 5lb/min?

 

The point here is, if you do a count, you'll noticed the car spent a huge amount of time at idle cell of 500rpm, 20-30 load. Realistically it's more like 750rpm, 20-30load.
Especially so in city driving, with tons of traffic and lights.

My stock map has that cell assigned AFR of 13.6 !

Simplistic calculation, I am burning unnecessary fuel for doing nothing ! I don't mind burning lots of fuel when I'm gunning it though Just idling and burning tons of fuel don't feel right.

So instead of leaning cruise, I am looking at leaning idle.

On the other hand, the 13.6 overly rich idle could possible be there to cool the engine after a run ? More of a safe guarding protection ?

 

13.6:1??? I must be missing something here. Assuming you're in closed loop at idle and the stock car uses a narrow band oxygen sensor, shouldn't you be at 14.7:1???

Here is about how much gas you consume:
Fuel consumption = (time) x (mass airflow rate) / (air:fuel ratio)

For a fixed amount of time, lets say you lean out the air:fuel ration from 14.7:1 to 16:1, then your fuel consumption goes from 0.34 UNITS --> 0.3125 UNITS (assuming a very high 5lb/min air flow rate) You must do a lot of idling for this to every pay off....

At cruise, I'm guessing that you're consuming 10 times the amount of fuel as at idle. As I'm sure you're aware, lean AFR's can cause excessive EGT's, knock, and damage to the cat. (if you have one). It may be worth the risk during cruise conditions where fuel savings are large, but why do this at idle?