LT1 Throttle Oscillation Question

[GHuggins]

Horizontal vs vertical, whichever. I set it up the way it is by the OEM.

This table shouldn't change that much if the throttle area table is set, but none of the aftermarket throttle bodies have this data available. There is a missing throttle area table that is important.

Maybe a picture of the important missing table with it's axis?

I've had good luck changing that throttle area table to control both blips and help with idle even using some of GM's other tables. It usually goes hand and hand with the pedal progression table though. That's even with the etc max setting set according to manufacturer whether it be one of GM's or an AM.

[smokeshow]

Well if the map torque model is wrong, what's that table matter anyway

[GHuggins]

Because it'll help get things more right or rather more in line Cause without the throttle and corresponding manifold tables being set right then all you do is skew things more and more to work around them.

[smokeshow]

Touching that table is exactly what I'd consider skewing things to work around issues.

[GHuggins]

Your talking about the throttle area table that I mentioned. OK, why does GM change it for the same TB on different applications?

[smokeshow]

They're better equipped to make those changes.

[GHuggins]

Well, OK, Not denying that for a second BUT those are some pretty big changes from GM going from NA to NA and then to boost using the same TB and the values always go down for more airflow so even though I might not have it correct, it does seem to be moving it correctly

[DSteck]

What example do you have of those being different for the same throttle body?

FYI, your starting memory location was wrong.

[GHuggins]

LT1's, L86's and LT4's all use the same tb. L86's in the trucks are set up to open more aggressively, even more so with the smaller tb's of the L83's. I've always assumed due to the heavier vehicle weight and the towing factor of the trucks. LT1's are more linear and then the LT4's go a lot lower. This is of course comparing with the old axis scaling.

No info on the other throttle table then

[smokeshow]

TPS vs area has nothing to do with the position command to the throttle. Not the place to tweak things if you're trying to change throttle response.

[GHuggins]

Not to change throttle response. To Fix flares....

You can literally take an LT1's area table and put it into an L86, just for example, and fix just about ALL of the factory throttle flares that the trucks have (there are actually several occasions on here where people complain about them with shifting) without changing one other table. Plus if you add boost, you can lower that table and get all throttle control back all the way to holding an 80% throttle position if you so wish to do so. It doesn't matter if the air models are fully dialed in, SCIAP's are in place and the torque is dialed in as good as you can roughly from a dyno. These bigger blowers people are running today cause problems with throttle control.

[smokeshow]

Ah. I've never seen that on any truck. Lucky I guess.

[will_974]

GHuggins the only other potential throttle control table i have is this one attached.
i wasnt able to quite figure out what the axis were, or what the content was.
However, it is vastly different on LT1 vs LT4.
And it is in the correct section of the calibration to be a throttle controlling table.

Maybe DSteck can confirm or deny for us.
Attached is located for a 2016 Cadillac ATS

Thanks DSteck for fixing and confirming the origins of the throttle rate, now known as the Throttle position vs throttle Area chart!!
I appreciate this!

unknown_throttle_tables_12670753.xdf

[DSteck]

It is commanded engine power as a function of vehicle speed and axle torque request.

And now, like Homer Simpson, I'm going to slowly back into the bushes and disappear.

[96GS007]

Well....I had to disappear for a bit due to some family matters, but Amateur Hour has now returned

Quite the conversation going on and other than philosophically speaking.....all way over my head. Conceptually I sort of follow but geez...amazing how far engine controls have advanced. Nonetheless I guess I'll stick to running a factory that builds advanced radars.

I did get the car out before the cold spell hit us today in Dallas. I made the adjustments Greg alluded to on the Airmass side of the VTT and it didn't die once....until I got home. Of course we have a driveway with a slope (enough that "Hill Assist" will activate), the car gets squeezed into the narrow side of the garage that has a door with only a couple inches of clearance for each side mirror, and there's a couple inch "step" up to enter the garage which all means I can't just zip right in. Long way of saying it may have been more about me than the car. I'm sure some of this is also trying to have near stock driveability with something that's not remotely close to stock. It is however 99% there. It's surprising how well this drives.

Attached is a log and the tune that's in the car currently. More testing to come in a week or so after some travel and the weather warming back up.