Clipse or tephra. Are you either of you logging the Mivec Load vs the Fuel load?

 

nah i just log load raw.

 

Its because you are getting less EGR, which means more O2 is getting in the cylinder.

1)
The more you retard the Exhaust the more Exhaust remains in the cylinder. Because Exhaust remains, you have less total O2 in the cylinder. Swapping that exhaust for fresh air, means more O2 all with the same amount of gas, therefore making it lean.

2)
Also the more you retard the Exhaust, the more overlap you get. When both the intake and exhaust valves are open, if there is more pressure on the exhaust side than there is on the intake side, exhaust gases flow out the intake side. The exhaust gas collects in the intake manifold and as soon as the exhaust valve closes and the piston descends, the exhaust is sucked back into the cylinder.

Make sense?

Now I numbered the 2 situations, because the 1st one is due to retarding the opening of the valve. And the 2nd one is due to retarding closing of the valve. Granted we are forced to retard or advance both at the same time, but all the literature I've been reading about cam shafts always separates the 2 events.

 

UPDATE: I am fairly satisfied my current tune is good. no knocking and good power (same as prior to Christmas):




I truly believe that the issue was the HFC allowed a bit sooner spool, and because I hadn't tuned my AFR properly in that range (2500rpm) I was running just too lean.

I will attempt the HFC again this weekend and go from there

Can anyone give me some tips on what I can do about the slight loss of torque on low rpms (like 1000 -> 1500, ie take off rpms)?

 

I actually had a interesting result happen to me...

I changed Ecu Option set 3, bit 0 (lean on/off). I changed 0 to 1.

My AFR's richened up during spool up from 12's to 11's...

I will try to do some back to back testing and see...

 

So I was looking through the rom....

Is it possible we are hitting so internal fuel cut below 3000 rpm...

I know the BOOST limit table starts at 3000 and goes 7000rpm... then what are the limits set to below 3000 and after 7000rpm?

Is it possible there is another boost limit in those outlying areas?

 

it should use the value of 3000rpm for less than 3k and 7000rpm for greater than 7k...

if you think its fuel cut, just look at your IPW. that will definitely tell you whats going on

 

I was just brain storming can't figure out for the life of me why the car will lean out while spooling up at the 260-280 load mark in the 2500-3000 area... only thing I can conclude it is affected by the MIVEC... There is no knocking. Just lean...

I seen it on a few EVO's can't put my finger on the reason... adding fuel doesnt do anything nor does taking away timing.

 

I am a complete neophite at this, you guys are WAY ahead of me plus I have only made it through 1/2 of this thread thus far this a.m.! But just in case:

Here is a tibit I gleaned off of the Cobb AP help file concerning the Open Loop Load Tables "Tuning Tips – Reduce these values to allow the vehicle to enter open loop fueling earlier and thus avoid a lean condition while under boost."

? Paul

 

interesting

 

yeh I already reduced my OL tables a bit to sotp being so lean in higher loads..

but you have to becareful and actually TUNE those bit of the fuel map...

 

Here are the values that I've set mine to. I have them just high enough to stay in Closed Loop while driving on the highway / 80 mph, but low enough to enter open loop as soon as you gun it. Hitting the gas on the highway can put you briefly in open loop, but it doesn't hurt anything.

Cobb's Stage 2 maps have you in Open Loop while at highway speeds greater than ~55 mph. They also don't disable LTFT from affecting Open Loop, so I was all confused one trip when my AFR was stuck at 15.3 for a couple of hours. Then a month later I added new injectors and realized I couldn't scale them on the highway if I wasn't in Close Loop. It was at this moment that I realized what was happening on that previous road trip.

70
73.75
85
85
80
76.25
70
60
51.25
43.125
31.25
20
10
0
0
0
0
0
0
0

 

so did you make the open loop high load table 1 and 2 the same ?

 

What specific table is this please? I have graduated from neophite to novice but I still find many of the Cobb table titles confusing.

 

Those are the Open Loop tables. Cobb calls one set of them Open Loop Throttle Table, but they are labeled wrong. I made all 4 the same because they are all lower than stock numbers.