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I'm still a bit taken aback by not knowing that cold-air intakes are needed on the V-series. As best I can tell, my FSM shows my air cleaner on the fender well above and behind the left headlight, and I assumed that there is a cold-air intake from behind the headlight like my old car. But if you and otther CTS-V guys are seeing gains from a cold-air intake, well, bye-bye 3.7 second 0-60 mph time, hello 3.5 second 0-60 time!

I'm recalling the videos that you posted this week of the first two tuning runs of a 2013 CTS-V coupe. These first two runs were of a stock car, and I noticed that he seemed to have trouble hooking up in the first run. In the second run, all they did is lower the pressure on the rear tires to 28 psi and increase the air in the front tires to 50 psi, and, viola, they got commonly-published times of 3.7 seconds 0-60 mph and 12.0 seconds ET in the quarter mile, both apparently including reaction time of about 0.25 seconds.

But, back to your DynoJet runs, they are based on what the car reads in its sensors. Could the low speed torque peaks actually be tire slippage? You might find out by dropping the pressure a bit in the rear tires and doing a second run.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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More to follow on this topic but reading through the data I see where the data file has some confusing data

Time Engine RPM (SAE) rpm

13:00.203 3564

13:00.219 3635

13:00.250 3676

13:00.265 3676

13:00.297 3668

13:00.328 3677

13:00.344 3677

13:00.375 3683

13:00.390 3728

13:00.422 3728

13:00.453 3778

13:00.469 3828

so at the beginning of the file the RPM goes up then down then up again -- once I snip those few records off the huge torque peak at the beginning of the run in the virtual dyno disappears.

Next I am back to studying the Boost PSI over time. I am surprised how spikey it is.

Bruce

2016 Cadillac ATS-V gray/black

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I studied boost vs RPM for the 2008 Cadillac STS-V LC3 engine in this post but I am back on this topic again.

2013-05-25-Boost-vs-RPM-1024x558.png

This graphic shows the Boost from the Supercharger in pounds per square inch (PSI) of pressure in blue, and the incoming air volume through the mass air flow sensor feeding the supercharger in LB/Min in red.

Read More: http://caddyinfo.com/wordpress/cadillac-supercharger-boost-vs-rpm/

Bruce

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Now, that's a performance curve that makes me smile.

The MAF and boost curves tell things about the breathing. Apparently there is a natural dead spot around 4500 RPM that the boost partially overcomes. It's probably due to a resonance that helps somewhere else, say, 5200 RPM.

It looks like the boost is trying to maintain nearly constant torque over the operating RPM range and thus overcome all the usual swoops of a high-performance engine torque curve. GM has designed engines to have flat torque curves since 1937, when the 3.5 liter bowtie six had a constant torque from 1200 RPM through almost redline, giving it a remarkable driveability. They continued this for that engine design through its end of life in the 1962 model year in its 3.8 and 4.3 liter versions. The horsepower race force a trade for constant torque for increased horsepower but driveability has remained a driving design concept all along.

The fact that the boost actually decreases with RPM while the torque actually increases tells me that the natural breathing of the Northstar works better at higher RPM. I doubt that my LSA maintains its flat torque curve by decreasing boost at high RPM.

The spikiness of the boost pressure looks like something you would expect from a stepping motor in a feedback loop driven by an 8-bit register or some such. It may well be exactly that. But it isn't enough to feel, much less enough to affect driveability. I don't know where DynoJet is getting the data for that curve so I don't know if the curve represents actual pressure in the intake plenum or a computed value from RPM, MAP, TPS, MAF, and the control signal for the by-pass valve actuator, but I suspect that a short digital word is in the computation of that data somewhere and the actual pressure in the intake plenum is smoother. I would call the rough appearance of the curve an artifact of the instrumentation.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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This is kind of one of those "science works" graphs, but shows boost vs IAT2:

kn-2013-05-25-boost-vs-iat2.png

as the boost goes up, the supercharger presses more air into the manifold, which compresses the air, raising the temperature. The rise in temperature makes the air less dense, which acts to reduce the air density, causing the blower to work harder.

I sent a note to Active InterChiller, which makes a system that runs an A/C cooling line through the intercooler coolant flow as a way to bring the intercooler coolant way down. We'll see how that sorts out.

Bruce

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highbaro_ExhaustCamPosition.png

another variable -- the engine reduces the exhaust cam base angle from 5 degrees at lower rpm to 2 degrees at mid and back to 4 degrees at high rpm.

This mirrors the lower air flow in that range?

Bruce

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First, your curve of boost and IAT2 in post #31 shows the boost increasing with RPM, which I didn't see in post #28 when I should have, so what I should have said in response to post #28 is that MAF seems to increase more with RPM than boost. This is of course partly due to the excellent breathing of the Northstar but your low-restriction intake is part of the increase of MAF with less boost, too, because it all starts with higher air pressure out of the air cleaner.

Second, your plot of boost and IAT2 shows a remarkable intercooler performance, again probably better than that of the factory setup. Part of the IAT2 performance is due to the cooler air that your intake provides. This curve will change with ambient temperature. I don't think that it will change with ECT unless the supercharger/intercooler are affected by ECT, which I doubt.

Third, it looks like what I was calling a natural dead spot around 4500 RPM coincides with reducing the exhaust cam base angle to 2 degrees.

You didn't say what the color-coded two-dimensional plot is but the axes tell me that it's air mass in grams per cylinder versus RPM, in counts, over a drive time. But the blue highlighted row seems no different from the other rows, so I take it that the whole map of counts is of cam base angles in degrees, and that you highlighted a row that is what you see if the throttle is opened enough. You see a different curve of cam base angle versus RPM at 0.48 g/cyl, for example.

My car apparently doesn't have VVT. I can't find it in the shop manual DVD. I would like to see the VVT control to understand what is happening with the map in your post.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I highlighted that row as I know the cyl airmass is 1.06-1.07 at high rpm. I think the retard on exhaust cam at high cyl airmass may be a nod to limiting dynamic compression vs absolute power but not sure. I need to setup a histogram and see where the engine actually ran among these cells.

Still unclear why low and high rpm would be this but I need to go study what the intake cam is doing. Might be interesting to see how the rwd 4.6 looks here also -- they may have not changed for forced induction altho blown engines like diff vvt settings than NA engines.

Bruce

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Does a positive base cam angle change of 5 degrees mean a retard of cam timing of 5 degrees? The graphic looks like that because you get a lot of base cam angle change at low RPM and low throttle, where you would want low-end torque to be better for driveability and economy.

If that's the case the base cam angle changes below 3500 RPM make sense. Retarding the base cam timing at high RPM may be a torque management thing like spark retard, but unlike spark retard it reduces the air charge and thus gives better efficiency than retarding spark, which means lower engine heat generation. If that's what it is doing, there is a complex algorithm involving a balance of boost, base cam angles, and spark advance to produce a desgned-in torque at a given RPM for ambient ECT and IAT2.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Added a page here: http://caddyinfo.com/wordpress/vvt-tuning-for-the-cadillac-sts-v-lc3-v8/

to think about VVT cam tuning

Bruce

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I'm having trouble assimilating why the intake cam angle advances with RPM but doesn't decline to zero at redline. I can understand why the exhaust cam would retard at low RPM to minimize valve overlap and again at higher RPM to improve breathing. But it seems that the most use of the exhaust cam angle retard is at low RPM and low throttle, probaby to keep valve overlap at a minimum at light load. But it seems that the highest peak horsepower would be with no intake cam angle advance and maximum exhaust angle retard at redline.

This is all armchair engineering. With a reasonably accurate model of what goes on in a cylinder as a function of RPM, vacuum/boost, cam angles, temperatures, mixtures, and spark timing, an examination of the trade space for each RPM range would reveal a strategy to meet any given set of requirements. GM would develop that model as a cornerstone of the engine development process but we don't have it. We also don't know all of their requirements or how they decided to apply them to the engine performance model. What we do see even with the HPTuners software and OBD interface is a thin slice of the result. That's better than just the end of the stick that you get with a dyno or a time receipt or a GTech.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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The conventional wisdom for Forced Induction is: Advance Both at Low RPM, Retard both at High RPM

Cam Phasers: [ref]
Intake: Initial timing 133 degrees ATDC with 40 degrees advance authority
Exhaust: Initial timing 117 degrees BTDC with 50 degrees retard authority

I wonder if cam position as shown in HP Tuners is degrees of advance for the intake, and degrees of retard for the exhaust?

So at high RPM the OEM tune is advancing the Intake 20 degrees to (153 degrees ATDC?), and retarding the exhaust by 5 degrees (to 122 degrees BTDC?)

What I think is needed is to Retard both at high RPM, so that would mean taking 5 degrees out of the intake cam from 20 to 15.

Bruce

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after a month Amazon has decided they can't buy a Spectre replacement filter for the CAI.

Due to a lack of availability, we will not be able to obtain the following item(s) from your order:
"Spectre Performance SPE-HPR9886K Air Filter"
We've canceled the item(s) and apologize for the inconvenience. We must also apologize for the length of time it has taken us to reach this conclusion.

I have seen stock somewhere along my travels, but I suppose I'll try the amsoil one for a comparison test.

Bruce

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Apparently Summit Racing has it in stock:

http://www.summitracing.com/parts/spe-hpr9886k

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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Good catch.

I am working on the theory of MAF lb/min and relationship to HP, as well as clear way to determine air intake effectiveness. Interesting rule of thumb: 1 lb/min of air flow ~= 10 hp.

Test baseline, log lb/min. Change filter, log lb/min. Delta lb/min converts to hp.

Bruce

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They don't show stock when I went back to order; their est delivery was in 3 weeks and the note says:

  • This is a special order part. When you complete checkout, the part will be ordered for you from the supplier.

I think I'll stick with trying to get the paper and then test my cleaned Spectre vs kn vs Amsoil

EaAU6065.jpgAmsoil eaau6065 paper filter on order.

Bruce

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amsoil+eaau6065.JPG

Amsoil eaau6065 in the box at my house.

I want to get more baseline runs on the K&N cold with current timing setup then we'll throw this filter in and see how it compares for MAF readings.

Bruce

2016 Cadillac ATS-V gray/black

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Whichever wins the shootout, I would keep an extra one in the garage.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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K&N RU-3100 comparison to Amsoil eaau6065

I recently replaced the Spectre filter in my 2008 Cadillac STS-V (supercharged 4.4L V8) with Spectre CAI with a K&N RU-3100 due to delayed availability of the Spectre replacement. I also picked up an Amsoil eaau6065 filter. These are both the same form factor — 6″ mouth, 6″ long, 7.5″ to 5″ cone shaped. The K&N is oiled gauze, and the Amsoil is a microfiber dry filter.

The K&N was $39.86 ($43 delivered via Amazon) and the Amsoil $60.05 (just over $72 delivered).

The test runs were done using a similar method but on different days; 88F for the K&N, 91F for the Amsoil test. To test the two filters I used HPTuners to capture both lb/min output from the MAF during a wide open throttle acceleration run in 2nd gear, and vacuum pressure at the supercharger inlet in PSI.

kn-vs-amsoil-hot-runs-maf-and-sc-inlet-v

Read More: http://caddyinfo.com/wordpress/kn-ru-3100-comparison-to-amsoil-eaau6065/

Bruce

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Amsoil eaau6065 filter Cold Retest log

I ran a cold/empty test for my 2008 Cadillac STS-V with Spectre CAI and an Amsoil eaau6065 filter this morning to have for reference. Today’s run was with the normal 2-3 shift at peak. [Click on images for larger versions; hit back in browser to return]

amsoil-cold-retest-torque-vs-boost-1024x

Torque vs Boost and SC Inlet Vacuum

The comparison data is from “Rethink advance full cold 0531″.

Today’s run looks as expected. MAF peak at 60+ Lb/min and Delivered Torque look on target with previous cold runs in warmer weather. The SC inlet vacuum appears to run ~1.45 psi vs the ~1.3 psi we saw with the K&N filter.

Read more: http://caddyinfo.com/wordpress/amsoil-eaau6065-filter-cold-retest-log/

Bruce

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Retest2 Cold for Comparison and more RPM reversion oddity

Ran another cold test with the Amsoil eaau6065 filter. More odd results from Virtual Dyno — although I see the issue in the data file, I just don’t know what is causing it.

Backstory: I continue to test & tune my 2008 Cadillac STS-V with the 4.4L Supercharged VVT, DOHC V8. Rated from the factory at 469 hp (350 kW; 476 PS) at 6400 rpm, 439 lb·ft (595 N·m) at 3900 rpm. Goal: 440 whp or 550 hp.

Summary-torque-hp-boost-vacuum-1024x646.

Read More: http://caddyinfo.com/wordpress/continuing-to-build-data-for-comparison/

Bruce

2016 Cadillac ATS-V gray/black

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I think you may have hopped over a pavement seam or some such to cause the glitch at 5500 rpm.

CTS-V_LateralGs_6-2018_tiny.jpg
-- Click Here for CaddyInfo page on "How To" Read Your OBD Codes
-- Click Here for my personal page to download my OBD code list as an Excel file, plus other Cadillac data
-- See my CaddyInfo car blogs: 2011 CTS-V, 1997 ETC
Yes, I was Jims_97_ETC before I changed cars.

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I would like to note that this could be caused by suddenly shifting the transmission from touch-up/touch-down to normal and back to sport in the middle of the run.

I'll stop doing that for comparison tests.

Bruce

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TUTD shift speed test 1 — Too high

Tested my 2008 Cadillac STS-V with the LC3 Supercharged 4.4L DOHC VVT V8 this morning cold, low on fuel. Today’s experiment was to add an auto-shift at the top of the tap-up/tap-down shift for 2-3, so I can lock the transmission into 2nd gear for testing, but then have it auto-shift at redline and avoid either having to pop it out of sport mode and back in to get it to auto-shift, or just hitting the rev limiter in 2nd.

For this test I also restored the stock calibration higher advance at high RPMs. I recognized that what this higher advance does is offset the beginning of IAT2 retard, with the net effect of hitting closer to the ‘ideal’ timing.

TUTD-Shift-Speed-miss-2013-06-20-hptuner

Read More: http://caddyinfo.com/wordpress/tutd-shift-speed-test-1-too-high/

Bruce

2016 Cadillac ATS-V gray/black

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