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[07GTS]

Yup. The lean cruise on the earlier engines would lean out the AFR's by up to 3 ratio's so going from 14.7:1 out to 18:1 and added a couple of degrees of timing. What the boys on the PCM hacking forum found was that you got the most complete burn at 15.4:1 on lean cruise and my findings are much the same. On my most recent trip where lean cruise went from .75 to 1.35 as speed increased from 100 to 110km/h economy went out the window and the throttle felt crap. Unfortunately I didn't have any tuning gear with me so I couldn't adjust to suit on the return trip but have adjusted the rest of the lean cruise on the L67 to 15.4:1 and pegged back the timing a touch to suit. Need to go on another long cruise to test now....

damn thats a big shift .75 to 1.35 no wonder it went to crap, i always seemed to get something going on when i didnt have laptop in vehicle and wanted to adjust it, least your lean cruise is a separate adjustment, on the e38 ecu have to sneak a way to do it without affecting other areas

 

[Immortality]

Going from .75 to 1.35 is 15.45:1 to 16.05:1 Not a huge jump but I think that is what cost me the economy. Gotta test these things....

With our L67 I always had the best economy doing 120-130km/h which is getting into big ticket territory so I went from 3.07 to 3.73 gears to get the engine rpm and road speed to be more complementary (and legal). Now it's all about getting the tune to do what I want. On MAP based systems ignition timing is based on load (MAP) so as soon as you fit gears and see less load for any given RPM you get more appropriate timing. With MAF where ignition is based on airflow you need to adjust everything to suit. MAF is a PITA......

 

[07GTS]

Going from .75 to 1.35 is 15.45:1 to 16.05:1 Not a huge jump but I think that is what cost me the economy. Gotta test these things....

ok was thinking the .75 to 1.35 was some form of lambda/EQratio which is like 60% shift, yea i got fueling is map/rpm and timing is cyl airmass/rpm so i get a bit of room to play

 

[Immortality]

The later model ECU's have a lot more smarts than the earlier stuff. Having the option for both MAF and MAP is the ideal setup.

 

[Hq King]

The later model ECU's have a lot more smarts than the earlier stuff. Having the option for both MAF and MAP is the ideal setup.

Does the vf ls3 have both maf and map

 

[07GTS]

Does the vf ls3 have both maf and map

yes MAF mass airflow and the SD (mafless or volumetric efficiency) is MAP based, factory use a blended MAF/VVE (map) up till bout 4000rpm and after that its more reliant on the MAF

 

[Hq King]

So is there any advantage of getting rid of the maf as I see alot of people seem to do ?

 

[07GTS]

So is there any advantage of getting rid of the maf as I see alot of people seem to do ?

yes and no just depends an the engine combo some do better past a curtain point without the maf, on the VE-VF the maf can go pretty far if u keep it and if it were tune with or without it u shouldnt notice any difference, only issue with keeping the maf can be that alot of tuners think setting it to use primarily MAF from 3-400rpm and up then they dont have to tune the VVE but u always have to tune both if the maf is kept, the whole mafless started back when the maf was a restriction but the VE onwards is fine, maf is easiest to tune u dont even need a dyno its all just airflow, VVE or MAP is load based so u need a dyno to hit all the cells u can

 

[Hq King]

Hey thanks 07gts thats a good explanation I thought that was the case but was not really sure so I thought I would ask and be thought a dummy rather than state something and remove all doubts as I quite often do