SD Tuning - What to do after the table is complete - i.e. what do you turn back on

[Keep]

Good evening, its been a bit, but the weather is finally turning around so I can finish up my VE tuning. Just ran out of time before weather turned.

Anyway.

Once you have finished tuning your VE table, and are going to run SD only. What do you re-enable in the tune?

STFT
LTFT
DFCO
COT

Anything else that needs to be set back to on, or normal?

Thanks in advance for all the help.

B

[5FDP]

A lot of it is personal preference and what kind of build you have.

Certain engines/combo/exhaust will not like long term fuel trims, so people only use short term trims.

DFCO I always leave on.

COT I never keep on but it's because well those things aren't there.

[Keep]

Thanks. The cats were on the downpipes for the Camaro manifolds when I bought them, figured might as well leave em. One less thing for the folks up here to complain about.

As for build its mostly a cruiser, I wont be pounding on it to much with the stock 11 Spline axles still there.

Any other tables/buttons that need to be reedited?

[bk2life]

going to run SD only.

if this is the engine in your signature, its very mild, why only run in SD?
SD is usually for more 'wild' combos

[blindsquirrel]

Some run better in SD, even 100% stock. Dunno why. You won't know if it's better or not unless you do A-B-A testing. If it drives better and gets better mileage and makes more power in SD, why use the MAF?

[Keep]

if this is the engine in your signature, its very mild, why only run in SD?
SD is usually for more 'wild' combos

It is, I was told that SD would be my best bet for the use of the car, which is a cruiser. This is in a 57 Chevy Wagon, so summer only type work. I would happily turn it all back on if thats what it calls for.

With the placement of the MAF/IAT there in not a long straight enough section to not cause more issues then it solves. There is a 90 elbow connected directly to the MAF/IAT in the setup, my understanding is this will cause turbulence thus causing issues with the sensor readings. Again this is from my understanding of how they function. And I have been known to be wrong in the past!

[bk2life]

It is, I was told that SD would be my best bet for the use of the car, which is a cruiser.

can you post a picture of the intake/engine bay?

Some run better in SD

Being a cruiser, and sounds like he wants to be able tog o anywhere without any concern in fuel, elevation, any issues at all, i would use the MAF, closed loop, and tune it to make it work at sea level, or hihg up in the rockies. His engine combo is a mild one, propbbaly has cruise control as well. If it was a bit of a challenge, but, to me, id have the entire system working as GM would have had it.

And, i do agree some like SD only, but, for a cruiser like his, it deosnt make sense to be SD only.

[blindsquirrel]

Why doesn't SD work with altitude? It still updates the BARO PID like everything else. MAF is not magic.

[Keep]

Here are some pics.




You can see the MAF/IAT directly behind the filter there.

I am planning on building a box around that filter as it tends to pull air from under the hood at idle/stop. IAT's climb rather fast

(edit) and maybe wrap that intake pipe.

[blindsquirrel]

At low flow the majority of the air will hold tight to the short side of the bend, as flow increases it'll increasingly move to the middle, towards the long side of the bend. The MAF is only sampling air at one location and doesn't know the tube it's installed in acts weird like that. It will under-report sometimes and over-report others.

[kingtal0n]

You can see the MAF/IAT directly behind the filter there.

I am planning on building a box around that filter as it tends to pull air from under the hood at idle/stop. IAT's climb rather fast

(edit) and maybe wrap that intake pipe.

A (filter) box for the filter is ideal, that is a great idea and I always if there is room. I need to get around to doing this myself.
If you can fit a generic paper filter in the breathing side of the box it will prolong air filter lifespan inside the box.

If you wrap the intake pipe this added insulation will also trap heat inside the pipe. Insulation barrier does not totally prevent heating it slows down heating. The pipe itself can radiate heat and reflect heat being aluminum and reflective. Instead of wrapping I recommend cleaning the pipe and placing some thin lightweight aluminum shield around the pipe to reflect radiant heat and interfere with convective heating.

See the thin shield below the intake pipe? Directing hot radiator airflow below the pipe and reflecting heat from the exhaust below. This engine runs for hours in traffic daily Florida concrete sunlight bumper to bumper 188*F fan cycles on and off with a 88*F IAT.

IMG-8314.jpg


Finally, maf sensors, I avoid them if possible. There are, as blind is suggesting, inconveniences and particular tendency's where maf design, positioning, application, many variables to attend.
The best thing I can recommend is, Tune the engine without the maf. Then, try the maf also. Compare the two in terms of mileage or whatever you value. And see what works best for you.

[Keep]

At low flow the majority of the air will hold tight to the short side of the bend, as flow increases it'll increasingly move to the middle, towards the long side of the bend. The MAF is only sampling air at one location and doesn't know the tube it's installed in acts weird like that. It will under-report sometimes and over-report others.

I figured it was something like that. Everything I have read said the MAF ideally needs a 10-12 straight section for it to work correctly with out any turbulent goofiness.

[Keep]

Okay, the winter slumber has finally ended. Took it out for a little romp. I could use some help with the timing, its gets -8 in the upper sections, I think that whole area is high, but I am not sure how far to pull the timing up at that end. I cleaned up the VE, and the MAF (not used) table. But did not touch the timing table on the final tune.

Included - Tune of the log attached, tune adjusted after the run, that needs help with timing table.

16 Apr 2023-tune before enabling STFT.hpt
16 apr long run.hpl
13 Apr 2023.hpt

[Keep]

Quick bump for timing table help. (see above)

[SiriusC1024]

I figured it was something like that. Everything I have read said the MAF ideally needs a 10-12 straight section for it to work correctly with out any turbulent goofiness.

And a MAF screen.

[Keep]

And a MAF screen.

But removing that screen is good for 10 HP!!

[Alvin]

Okay, the winter slumber has finally ended. Took it out for a little romp. I could use some help with the timing, its gets -8 in the upper sections, I think that whole area is high, but I am not sure how far to pull the timing up at that end. I cleaned up the VE, and the MAF (not used) table. But did not touch the timing table on the final tune.

Included - Tune of the log attached, tune adjusted after the run, that needs help with timing table.

16 Apr 2023-tune before enabling STFT.hpt
16 apr long run.hpl
13 Apr 2023.hpt

This looks like a bad knock sensor. I'll bet it will throw a code if it hasn't already. But when they fail they go to max allowable retard while in PE.

[Keep]

Thanks, I will take a look and see if there are any codes.

[Keep]

Nope, no codes, nothing else to indicate an issue with a knock sensor. I remember seeing/reading something about needing to "desensitize" the sensors with any changes. I will dig into that a bit.

[blindsquirrel]

The thing about these knock sensors, they can output a valid, but wrong, signal when they are getting to end of life. Old O2 sensors can do the same thing. There are more failure modes than just shorted or open.