Have any of you guys bumped up the timing in the 40-70 load range, 2k-4k rpms? That's pretty much the highway cruising part of the map. I'm currently running the stock values for timing in that range, but I'm a bit hesitent to increase the timing due to the crap 91 cali gas I'm stuck with. Eh, I guess I can be the first to try!

Just wanted to see what experiences anyone else has had.

 

just drive at 55-65 mph back int he day that is why the older cars had a red 55 mph as reference. and stay out of boost i know i know that can be very hard

 

Yeah, you can tune your car to get 25 mpg but end up drinking a half tank of fuel going through the gears a couple of times

 

Why would you be 'going through the gears' tuning for highway cruising? It's in the 40-70 load range, mostly 3k-4k rpms; i.e. light throttle, just cruising.

For those that were wondering, I just compared the stock high octane and low octane ignition maps for my 05. They have the same values for 40 and 50 load in the 3k-4k rpm range, 1 degree less timing at 3k rpms for 60-70 load (for the low octane vs. high), 2 degrees less timing for 3.5k-4k rpms.

I just bumped up the timing from stock in the 40-70 load range, 3k-6k rpm range by 2 degrees. Guess I'll find out tomorrow on the highway how it likes it (on my drive to visit family, so I'm not 'wasting' gas). Oh, and I was already getting 24-25mpg hwy with 70-80mph cruising, with a little bit of drafting

 

well your never "wasting gas" to visit family cant wait to hear baout it

 

I'd be more inclined to approach the problem by leaning the mixture out. (Force the car into open loop, and WATCH YOUR WIDEBAND. )

 

I think that carbon guy was saying you can save the gas at cruise but all it takes is a moments aggravation or hurry and your back where you started.

I'm doing the open loop cruise mod, there are a couple of threads in ecuflash forum about doing this option. Even one that is based on a wide band emulating the narrow band, with a gas saving attitude.

Whichever way you go I don't think you will find lots of money left over when you fill up. Its like percents of percent. Every bit helps though.

 

I just set up my LC-1's 1v output as the O2 source for my closed loop operation. I've got it leaned out to about 15.7:1 currently. The next time I take a trip I'll have something to report.

I had done the lean cruise mods before by forcing open loop and was running between 15.7 and 16.1 ... I got 320 miles on a tank at best. I can't remember the gallons on the next fill up, but that would likely be around 23-25 MPG. Not too shabby.

 

I use the LC-1 at 15.5 - have my closed/open loop crossover higher so I can go into part throttle boost and still stay in closed loop, helps get the car up and moving from a light. I also added timing to the part throttle areas and I get less knock than on the stock timing at part throttle.......Also the car drives so smooth, very impressed so far in my part throttle tuning adventure.

I recently went on a trip w/ my gf, trunk loaded with our crap - the trip was part highway/city/country roads and I traveled 326 miles on 12.1 gallons of fuel.

26.9 MPG - I also live in PA (Hills & Mountains out the ying yang)

I honestly don't think 30 mpg is out of the question or close to it with less weight in the car and all highway with minimal elevation changes.

- My next move is an 87 octane map for my m-f commute since i don't really rip on the car anyway.....thanks to map switching going from 87 during the week and 93 on the weekend is no problem at all.

- First though I must install my nisei front mount and injectors

 

i bumped up the timing a bit in that area and car runs much smoother and i get like 27mpg even with boosting a little.

 

With regards to changing timing at low load areas, I've tried it before. I can't tell any difference from feel. with data I can't see any difference either. I'm under the assumption that if you change the timing then a different throttle percentage will be required to maintain whatever speed+load you were at before the change. Maybe the change was but I never noticed it.

 

Interesting about the open loop mod and also the wideband mod. I'm not inclined to modify the basic ECU function/strategy as far as the open loop mod goes, and no wideband, so I'm just trying to optimize the timing maps a little

I ended up adding 2 degrees to the base timing from 2k-3k rpms also, 40-70 load range and didn't get any knock on the drive to work this morning (city streets so mostly 2k-3k rpms). Well, I did get some in the 100-120 load range... Hopping onto the highway tonight, so I'll see how it does in the 3k-4k rpm range.

Regardless, I also have the motorcycle for gas mileage, but figured I might as well optimize the car some

 

Would someone mind posting up some lean cruise maps that show what changes you made in these areas? I would assume you would change open loop load #2, open loop throttle low load, and the fuel map.

 

How do you force it out out closed loop? I assume if we change the 14.7 areas now it will not use them anyways?

 

There is a sometimes un-defined table that actually adds timing advance in those cruise areas already ... it's defined for the 94170015 ROM already and I know JB was playing with it on the IX ROM. I would think the best approach from your angle would be to define that table and make your advance adjustments there as I believe there are conditions in place for using or not using that map ... knock, etc.

For the post above ... you are correct. Just changing the open loop maps will not lean out cruise or idle conditions. You have to modify the "open loop load" or "open loop throttle" tables to change the crossover point and then you can tune the curise areas.