Steady State cruise - surge / throttle oscillation?

[slick3]

Attached are my log and file.

2017 Camaro SS M6

Ported TB/IM, Cylinder heads, e85, ARH LTH's with cats.

Under steady state driving, with the throttle position steady, I am getting a weird rhythmic surge. I am pulling my hair out on this one. I have turned torque shapping on/off, raised and lower driver demand tables. Raised torque limits to the moon and back. Turned off spark smoothing, turned it back on etc. Messed with Trq mgmt max spark The throttle position moves up and down 2-4% during this operation and I cant seem to figure out why. When it does not surge, the throttle position is steady.

I have not been able to correlate this to a specific speed although it almost always occurs in any gear from 1800-2600 if I hold it steady for long enough. Tipping in slightly and leveling off seems to induce the problem almost on command especially in 4th or 5th gear.

Car runs absolutely perfect when its NOT doing this. Throttle is smooth, acceleration is smooth, pulls like a frieght train everywhere and LTFTs Are between -2% - -4%. Any suggestions?

[meatbag]

put a stock throttle body on it and see if its still doing it

[slick3]

put a stock throttle body on it and see if its still doing it

Are the ported units known to cause this kind of problem? I figured it was the torque model screwing with it... Thanks for replying...

[meatbag]

It's a common problem I see a lot. I usually try switching back to a stock unit just to verify

[veee8]

Agreed, ported TB's are a waste anyways on this platform. I've A-B comparison tested them a half dozen times on different cars, all show zero gain. Smoke and mirrors.

[slick3]

Regardless if they make power or not. The throttle response is a significant improvement over stock and I would like to keep the unit. I also do not have a stock unit on hand right now. Does anyone have any tuning changes that I can utilize to attempt to diagnose the issue. I am trying to use this as a learning opportunity.. Appreciate everyones input.

[Ben Charles]

During the surge what is TQ management SPark doing!??

My guess is it's coming in and out

[slick3]

During the surge what is TQ management SPark doing!??

My guess is it's coming in and out

In this example log, no its not coming in and out. But other times when its doing this, 1 out of every 3 or 4 times.... I will look at trq mgmt spark and yes its coming in and out in perfect rhythm b

[TriPinTaZ]

In this example log, no its not coming in and out. But other times when its doing this, 1 out of every 3 or 4 times.... I will look at trq mgmt spark and yes its coming in and out in perfect rhythm b

I have a ported TB and Intake manifold on my 2017 SS and trq management advance is pulling timing out in the middle of WOT pulls. No surging but I also don't have as many mods as you. When I removed the Ported TB but left everything else, the issue went away. Now I have to put it back on, datalog the right parameters to chase down where and what is causing the trq mgmt to kick in in the middle of a pull. Essentially, I think we have the same issue just mine is less severe than yours.

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[TriPinTaZ]

Since no one ever updates with solutions...... The solution above was two fold. #1) the TB I had was ported poorly. #2) After a different TB, and other mods, I just had to adjust Virtual Torque and Driver Demand to get Torque Management to behave properly.

[pjs]

Thanks!

[Sneakyws6]

I had the same issues on my 2017 Camaro SS with a ported OEM TB/IM, ARH catless headers. I swapped my throttle body back over and the issue went away. I then went and checked out the OEM stock TB to the OEM ported unit and here is what I found out.

There are 5-10 rwhp gains to me made with a properly ported TB and another 5-10 rwhp gains with the IM. The stock TB doesnt have a idle air port, the idle airflow comes from air that bleeds around the throttle plate from when the ECM cracks the plate open slightly. The problem I found on my bad TB was the porter had opened up the bleed by area just ever so slightly. I figured it out while measuring the opening on the stock TB and on the ported TB. I sent that TB back and they ported another TB and left the area the butterfly rests in alone and only ported the main throat of the TB. Issue was resolved.

I saw the same thing on the Katech ported OEM throttle body, they did theirs via CNC and made certain to leave the area the throttle blade rests in alone as they found the same thing I did, if that area was opened up it messed up the idle airflow and would show up as surging while under light throttle steady state driving.