411 PCM with 2 bar enhancement......blended MAF and SD operation......possible?

[Alvin]

Very true, but unless it is an all out race build, I have no idea why someone would put a cam big enough to cause that problem in a boosted application.

dude..

The amount of yukons and suburbans I tune with stock manifolds stock cats and a huge ass cam because some dudes wife's truck ate a lifter. People just don't know what they are doing building stuff.

[slarsen47]

I did not want to get into the specifics of this particular vehicle(s) and tune in this thread.............

Trying to keep this as a general Speed Density close loop or open loop discussion.

Because others have suggested the cam may play a significant role, my cam specs are as follows (very modest).

Comp 54-426-11
Valve lift at .566 and .568
Duration at 222 and 224
LSA 112
rpm range 1800-6800


The car runs and drives like stock except for more power..............not saying tune is perfect and cannot be improved......But no issues with the SD open loop only tune.

The question was whether there is any advantage to be gained by using the narrow band sensors and going closed loop.

Consensus seems to be get rid of the MAF sensor if it is not used.

Is there consensus among the expert tuners that it is preferable to run narrow band O2 and closed loop SD in mostly street application?

And to reserve the open loop ONLY SD for more radical cams and mostly track cars?

[Alvin]

Supercharged right?

IF so SD closed loop.

If NA you could use a MAF but at the very least it needs to be tuned in speed density first.

[slarsen47]

Thought I would throw in an update on this.

Nice sunny Saturday to do some testing on the 98 pre-turbo Camaro.

With the transient change my 100 lb injectors are now responding nicely.

Did some major VE updates and tweaked idle area.

Ran it almost up to full throttle (82%) and 4400 rpms with the Air Fuel right at 14.7 and 11.7 with power enrichment.

ARF error map is really good mostly under 1-2 percent without much work.

No narrow bands or fuel trims, just straight VE.

So I have convinced myself that straight SD no narrow bands works perfectly fine.

Turbo kit going in next.