Lean => Hot

[Piledriver]

I'd still suspect a throttle balance issue given a 20% trim requirement, with a L/R head delta.
(unless the heads differ greatly)

The fuel and spark trims are powerful tools, but its all too easy to try and fix it in software and forget the basic mechanical effects.

Looks like you are compensating for something

Hmmm looked like it in the first graph, anyway, trim tables don't match suspicion.

[Corysvdub]

Here are the cylinders with EGO trim per cylinder



Here is the main trim table. I haven't spent to much time on it, just basic to get it close.

Glad to see you got most of those sensors hooked up on your 1600

[Max Welton]

Amazed how tight the EGTs are. Very nice.

Max

[MarioVelotta]

Pile, I have put my snail on all the throttles. # 2 pulls less than the other 3 but it leaks down only 2.5%. I believe that I am loosing compression in #2 mid stroke.

I also think that the 3/4 side has less compression overall. I didn't put the motor together so I don't know the CC's or total compression unfortunately.

[Piledriver]

Could be a slightly twisted shaft, that's not a huge delta.

[MarioVelotta]

That's what I though too. So I closed the throttle plates as much as possible and ran on the bypass circuit with the same differential leading me to an actual mechanical issue somewhere.

[Piledriver]

Gotcha, that sort of thing is worth beating to death simply to know, or at least eliminate as much as possible.

[Steve Arndt]

That's what I though too. So I closed the throttle plates as much as possible and ran on the bypass circuit with the same differential leading me to an actual mechanical issue somewhere.

I've thought about trying this, with a big balance tube and and an IAC on my 45 ITBs. Did it drive or behave any different running on the bypass vs throttle blade air?

[MarioVelotta]

That's what I though too. So I closed the throttle plates as much as possible and ran on the bypass circuit with the same differential leading me to an actual mechanical issue somewhere.

I've thought about trying this, with a big balance tube and and an IAC on my 45 ITBs. Did it drive or behave any different running on the bypass vs throttle blade air?

I can only do it at idle with the bypass in the throttle body's. I am not using an IAC currently. So I can't drive.

But That sounds fancy. Leave the throttle cable a little loose and driving the initial idle to say 10% via closed throttle plates and IAC solenoid driven from a spare PWM table using TP as the load.

[Piledriver]

The ignition idle stabilizer feature works well, I ran that and a CIS warm up air valve for years.

Proper name is idle advance, you can do a lot with it and the ignition idle correction curve.
The MS does not have to know you lack an IAC, enable closed loop and all sorts of features become available.

[Dive!Dive!]

Interesting stuff Mario
I also have EGT on all 4 runners , but only a single AFR at the collector. I also am fully sequential and have the ability to trim each injector (AEM EMS-4).
I currently have the following trims :
#1 : -7%
#2 : +10% (but is going up to +15% or more as its still hotter than the rest)
#3 : +2%
#4 : 0%
All four throttles flow the same with the snail. The heads are all hand ported and the intakes flow the same on the flow bench, Compression is the same.....
My take on this is that the injectors we all tend to use aren't that accurate. I know you can buy matched sets but they are a lot more $$
Plus there will invariably be variation across the four inlet tracks even if we think they are the same.
As mentioned above, scary to look at a single AFR. I can also add a fuel trim based on EGT feedback and will be implementing that as a safety measure....
It really is fascinating stuff!
Steve

[Steve Arndt]

Plus 1 for carbs, load based automatic sequential timed fuel delivery... LOL

One of my next upgrades is better spray pattern matched flow injectors.

[Piledriver]

#2 : +10% (but is going up to +15% or more as its still hotter than the rest)

egt is a funny beast, and almost borders on reading tea leaves without additional data.

Adding fuel is roughly equivalent to retarding the timing, so you might get better results leaning it out.
retard the timing and watch the egt...

Setting up an injection flow test rig is pretty simple.
The spray pattern is ~just as important as flow.

Unfortunately 4 WBO2s are the only way to be reasonably sure what the EGT is really telling you.
Then you can play with the ignition trim tables and expect pretty even results.
Perhaps move O2 sensor around and tune each bore if you have the bungs installed, and have the required trim tables.
(I'm considering that, as I have a spare WB, and welders)

Mario, are you running the extended bungs and/or heatsinks?
It's pretty easy to overcook a sensor when they are upstream of the collector.

[MarioVelotta]

The lc2 comes with long bungs ~1" so there is a good amount of material to dissipate the heat. The tips are about flush with the port wall.