Tag Archives: ATS-V

ATS-V LF4 HPTuners Tune 3c2

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Current Scan snapshot:

Prior scan snap shot at same rpm/speed showing throttle closing then:

First test for my ATS-V LF4 with tune 3c2. My intent is to change the least number of parameters in order to allow the engine to make as much power as it can. My goal is a stable 18 psi tune with no KR and no throttle closing.

Current conditions were 68F, 12 mph wind, 92% humidity, 29.81 in Hg pressure. SAE correction factor 0.9923039631981221, so 467 hp equates to 463 SAE 1349 HP.

There was some Knock Retard (KR) at cylinder pressures 1.16-1.32 during full throttle operation. I used a table to analyze where I was getting KR by RPM and pressure, then reduced the spark commanded in this region by 1 point in the effected areas. A rule of thumb is reduce the spark 1/2 of the KR observed. In my case this appears to have reduced the KR but not totally, so I will need more attention here.

Torque Management – General – max engine torque limit – I multiplied the 0% and 20% alcohol rows by 1.2, for a 20% increase.

Torque Management – General – TCS max torque set from 445 lb ft to 550 lb ft.

Torque Management – Driver demand – tables A and C I multiplied the bottom row by 1.1, then the bottom 2 rows by 1.1, then the bottom 3 rows by 1.1. This applied a stacking increase the the bottom 3 rows.

Torque Management – S/C Boost control – max limit I added 2 psi across from the left up through manifold temp 158, leaving higher temps unchanged. This added 2 psi to ceiling when the manifold temperatures are in check.

Good news: Holding throttle. the first image shows throttle is matching the pedal input. Also, boost (math) around 18.x psi total; here, 17.8 psi versus 14.9 psi prior, so 2.9 psi increase.

To do list: Still some KR to clean up with reduced spark. I also still see hints of desired falling in ranges I am unsure why it is not holding stable, so more study needed.

I am making progress toward my goals; I see 18.4 psi of boost, and no throttle closing. More tuning needed for KR.

Cadillac ATS-V HPTuners Stock Scan & Throttle closing

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I am starting to run driving scans on my 2016 ATS-V to get a feel for how the engine operates. The LF4 twin turbo 3.6L engines use a torque management based strategy. The control sorts out what torque is desired, then manages the powertrain to make that torque, independent of throttle input. The throttle input (gas pedal) is treated as a request — so you might have the pedal on the floor, but if the engine is making over 100% of the torque planned at that moment, the actual throttle may close to maintain the torque to the planned levels.

In the image above, the Cadillac is accelerating through 61 mph, at 5313 RPM. The pedal is at 100%. The actual throttle however, is at 67.8%. The ATS-V was making “too much” power at that moment. If you examine the 2nd row in chart vs time, the green line is throttle %, so where we see dips in the green vs yellow line is where the ATS-V is reducing engine power to desired or planned output.

In this case, at this point, the total boost pressure of 31.5 psi (without adjusting for baro) was higher than the Desired Boost pressure of 30.7 psi. So the engine controller is pulling back the throttle because too much power is being made.

I also note that the stock file is running a few points of KR, or knock retard. There is a ramp up of the planned advance in that range. The engine controller goes from a spark advance of 8 degrees up to 10.5 then down to 10 degrees. That appears to be too much since the KR (knock retard) is going to 2-3 degrees there. Although it is possible that a richer air fuel ratio (AFR) would be fine.

The ‘stock’ commanded AFR is 12.8, lamda 0.909 equivalence ratio commanded. This is within the range of what most tuners are doing with the LF4 direct injected V6. This ATS-V may prefer to be slightly richer, but needs more research.

Correction Factor: Ambient air: 72F, Intake air 75F. Baro 29.5223 inHg, 83.13% humidity so SAE J1349 correction of 1.01555. 453.6 hp corrects to 460.7 hp.

Cadillac ATS-V air filter replacement

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Since my 2016 Cadillac ATS-V is aging out of the Dealer Maintenance period I decided to refresh my OEM air filters.

LF4 Air filter box

The LF4 in the ATS-V has dual air filters feeding the twin turbos. The ‘left’ or driver’s side turbo is immediately in from the filter box. The right or passenger side turbo is across on the right side of the engine.

AC Delco A3202C x 2 needed

I ordered new filters from Rockauto; they run $28 each as I recall. I ordered a new oil filter at the same time to share in the shipping cost.

AC/Delco Filter A3202C Filter

The filters themselves are cannister type pleated paper filters, and were made by Mahle for AC/Delco. There is one filter for each turbo inlet tract.

6 screws and lift up the top, and Dirty Filters ready to come out. Push on the sides of the ‘rod’ to retract the tabs on the filter ‘rod’ to release each filter.
Dirty Filters after removal. Lots of leaves and debris demonstrate the intake has a pretty open access to the filter (!)
Clean new filters in place.
This is the view looking forward from the air box to the front of the engine — the opening that the filters breath through. Air can flow through the front grill more or less directly to the air box.

It took only a few minutes to change the filters, then put the 6 screws back snugly in place. My impression is the engineers did everything they could think of to mitigate the need or benefit of an aftermarket intake.

I note that K&N says their intake adds 34 hp, which suggests the stock setup is not ideal, or there are other factors in play. See K&N’s dyno here:

https://www.knfilters.com/dynocharts/63-3093_dyno.pdf