I went out to play on a long relatively flat stretch of road this afternoon.

Interested in making the highway mode work efficiently and effectively.

So if you use higway mode(spark and fuel) succesfully and documented your results, please feel free to chime in.

Basically what I was finding running highway spark from 1-3 degrees additional and highway fuel from 15.5 to 17AFR, did not result in the expected decrease in inj pulse width. Basically ran 5 different bins being the only diff the amount of spark and fuel AFR.

This is on a near stock 91 TPI 350. Mods are SLP catback and 24#SVO injectors.

BLM's were 126-130 at all times.

It was turned on via TC and temp enables, rpm enable were engaged and it was adding spark and lowering fuel.

Just the pulsewidth did not lower or in some cases was higher than the equivelant datalog not using highway mode.

How or what did u do to better reap the benefits of highway modes?

I more than likley wouldnt be asking this question, but at $2+ a gallon it would be nice if I could up cruising and highway mileage.

Also have poured thru searching here and have anything on highway mode printed out. I was running the modified code per Glenn on my old Formula setup, but the results were basically the same as now.

later and thanks
Jeremy

 

Why not just run Open Loop, and set things via the WB to the way you want.

Might just use the TPS opening as a guage of how happy the engine actually is. And it takes 10-15 in a given cruise condition for things to stabilize enough to know if you've actually done any good.

This is an ideal time for using a Prominator, since you can switch .bins on the fly and do real back to back comparisions.

BTW, with Black Car, with an idle TPS of .4v, cruisin at 70 is .84v.
Obviously, the engine is happy....

 

I need this one to pass emissions and is equipped with cats as well :-)

Trying to best utilize the factory setup.
(the other ones will be fun)

No $$$ to spend for new toys currently either :-)

later
Jeremy

 

That just means 14.7, and no excessive richness.

So closed loop, is best?

Oops, forgot.

 

Hi Jeremy,

maybe I am geting you wrong, but I wouln't look for a decrease in injector pusle width. What should this be good for?

Look for TPS, Map and knock under cruise conditions and be careful with additional SA.. I tested my engine on several long distance trips with highway mode invoked and logged every trip as far as my laptop batteries would carry me. All trips and logs were done on the same route and at the same speed (cruise at 75 mp/h).
With my engine I am currently running up to 6 deg. less timing in the peak torque area than in the stock chip and it made my engine happy.
Before, with more timing, I experienced 23 mpg on the autobahn at a steady cruise speed of 75 mp/h. This was due to lots of knock retard which did show up in a "sawtooth" SA curve when putting my SA data into a diagramm.

Now, with less timing, I am getting 27 mpg and I think there is still something to improve. My logs show that SA is between 20 - 32 deg. depending on load conditions when cruising in Highway mode.

The attached samples were taken on the same road.
The first graph shows, how much SA and MAP will vary when you have knock retard under cruise conditions.
The second one is with SA retarded.

(The red line represents MAP, the blue line SA, the grey line mph/10, the green line kmh/10 and the purple line knock counts/10.)

HTH,

Andreas

 

The second graph:

 

Jeremy,
are you sure, for whatever {part throttle}
test you are doing, that you have spark advance
adjusted for max engine output?

Try to 'over advance', to get an idea of what is best,
however, listed for knock while doing this.

I would not assume, that either a factory or
'whateve'r tune, would have best spark advance
at part throttle.

 

I too have found trying to use the PW isn't that productive. One problem is that while in closed loop the PW is oscillating to swing the AFR rich/lean. So a baseline PW is difficult to discover.

What does work is using the cumulative PW and distance terms from the ALDL stream (there goes another secret ). With these fuel consumption can be directly calculated. Both short term and trip average are handy indicators.

RBob.

 

Are you referring to the data at $3130 and 31 for the cumulative fuel and 3134 for the distance?
I don't have those identified enough to be sure.
I figured to use the running time at different loads to see where the fuel consumption gains are made at each load/rpm level on a per minute basis. That would give solid consumtion numbers to view as starting points for improvements.

 

All very interesting replies and making my brain think.

Sometimes you just need stimulation.

Last nite I was out having the lady drive as I played with several modified bins and making some small changes concerning cruise timing, both with and without highway mode..

I did see a small decrease in TPS necessary to maintain spped after I had pulled 1-2 degrees out of the majority of my cruising spark table.

This also coincided with myself verifying an IC of 23.8 works beautifully at stock fuel pressure for the 24# SVO inj.

At this point I was actually slighly richer blm wise 124-128 than I had been a day earlier when I originally made this post..

Looks like I will be investigating slightly rich and lower timing(has been suggested here before, but I have not had a chance to verify until now)... Weather is cold and raining so I will try and run some more tests when possible. Have a nice flat section about 20 miles each way that has 2 decent hills.

Looks like alot more testing will be in order.

Cumulative PW's and distance terms from the aldl? This anything that can be added thru say tunerpro ecu/xdf files. Have to teach myself that now as well. Want a complete know virgin bin ecu/xdf.

later and thanks for the input
Jeremy