Minor adjustments and temperature trends Cadillac STS-V

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Making more room for fast revving at gear changes:

  • Raised Cutoff by 200 rpm: Engine Fuel Cutoff DFCO Cutoff vs RPM
  • Raised cam disable by 300 rpm: Engine Airflow Variable Camshaft Hi RPM Disable
  • Lowered Transmission torque management by 50% at WOT — Transmission Torque Management — Adder Modifier -0.50 at RPM 4500

1-2 Shift max rpm 6529 (target 30 mph / 6500 rpm)

Resulting shift 1-2 took 0.3sec then 0.4s on 2nd test. Need to retest cold due to the engine making more power cold.

Temperature trends hot / heatsoaked versus cold:

Corsa Cold Baseline Mar 25 2012 2nd Run



Down Delta MPH (Temps in Deg Fahrenheit)
Item 0 30 45 60 Across Run Heat Add
Ambient 55 55 55 55 0
6 IAT1 61 63 63 63 2 8
32 IAT2 93 93 100 106 13 43
0 MAT 93 93 107 129 36 23
Corsa Hot Run 1 3/26



Down Delta MPH (Temps in Deg Fahrenheit)
Item 0 30 45 60 Across Run Heat Add
Ambient 82 82 82 82 0
8 IAT1 90 95 95 93 3 11
30 IAT2 120 120 127 135 15 42
1 MAT 121 120 126 159 38 24
Corsa Hot Run 2 3/26



Down Delta MPH (Temps in Deg Fahrenheit)
Item 0 30 45 60 Across Run Heat Add
Ambient 82 82 82 82 0
9 IAT1 91 93 91 90 -1 8
27 IAT2 118 118 126 131 13 41
1 MAT 119 118 125 152 33 21

Interesting consistency that IAT2 uniformly starts ~30F and ends ~40F hotter than IAT1 regardless of ambient.  This suggests a way to check effectiveness of changes to the intercooler cooling system.  Other runs show a end range of 40-47F.

Update: 2008 Cadillac STS-V Corsa cold run day 2

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I did a fresh morning baseline with the Spectre intake + Corsa exhaust.


 0.4

Speed W/o Rollout W/Rollout Dist
0 0 0 0.0
10 1.03 0.63 6.9
20 1.75 1.35 22.7
30 2.48 2.08 49.5
40 3.33 2.93 93.1
50 4.26 3.86 154.3
60 5.24 4.84 233.9

60′ time was 2.3 sec, so still not good.  Unfortunately my pre-corsa cold air pre-run earlier in the week — also a 4.8s but 4.8s/5.12s — there was no usable Performancebox data file to compare the details from (tech glitch).

Accel results
Speed(mph)     Time(s)
0-60                   04.8
Distance()     Time(s)     @Speed(mph)
0-60′                  02.3                 32.8
PkAccelG     0.67G
I did disconnect the battery yesterday to speed up relearn, but the transmission is still hitting the rev limiter before shifting on some runs. Over time I suspect it will adjust, although it may need to be tuned to shift sooner.

My prediction is that the Corsa frees up 12-20 hp but I’ll have to get a better test run to prove that.  Today’s raw data is no improvement over the 4.8/4.9s posted prior to the new exhaust.

Compared to running hot in August pre-Corsa:

Today 0.4

August 90F
w/rollout
Speed W/o Rollout W/Rollout Dist Speed(mph) Time 0.44 Dist(f)
10 1.03 0.63 6.9 10 1.01 0.57 6
20 1.75 1.35 22.7 20 1.75 1.31 23
30 2.48 2.08 49.5 30 2.46 2.02 49
40 3.33 2.93 93.1 40 3.31 2.87 93
50 4.26 3.86 154.3 50 4.30 3.86 159
60 5.24 4.84 233.9 60 5.42 4.98 248

The difference appears to be from 50-60 mph.

Max calculated power on this 0-60 run was at 6105 rpm

Max calculated power based on torque delivered for the morning caused traction control to come on at the shift — an unusable run because I had not switched it off —

Here are my IATs for trending:

Corsa Cold Baseline Mar 25 2012 2nd Run



Down Delta MPH (Temps in Deg Fahrenheit)
Item 0 30 45 60 Across Run Heat Add
Ambient 55 55 55 55 0
6 IAT1 61 63 63 63 2 8
32 IAT2 93 93 100 106 13 43
0 MAT 93 93 107 129 36 23

I plan to start recording Richard’s correction calculator for runs so I have that info.  Today was about perfect for a correction factor near ‘1’.  I am using the air temp from IAT1 for the adjustment; Richard suggests use the actual air into the engine, which is IAT1.

Conditions:  Cold run, 3/4 fuel; Weather for this run:

Note: The relative horsepower calculations are made in accordance with  SAE J1349. The standard reference conditions for SAE J1349 are:  Air temp 77 deg F (25 deg C),   29.235 Inches- Hg (990 mb) actual pressure and 0% relative humidity.

2008 Cadillac STS-V Corsa 14157 install

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I went over to Pronto Muffler & Brake Center in Plano, Texas to have my Corsa 14157 axle-back (mufflers) system installed.

Corsa's media shot of the 14157 exhaust system

 

Here is the stock exhaust in place:

The Corsa 14157 system is specified for the 2005-2007 Cadillac STS, but is often used also — with modification — by STS-V owners.

Change in piping angle, 2.5 to 2.5 " join

The Corsa 14157 has 2.5″ piping, like the STS-V exhaust pipes.  In order to get them to fit together Pronto expanded the mouth of the Corsa pipe.  Also, because the angle of the piping was not exact a short section of new pipe was welded in to mate the two.  Finally, all the hangers were removed from the Corsa muffler and new hangers welded in place to fit.

Work in progress -- the shop aligned the exhaust properly then welded in place.

Here is an after shot:

The install took 1 hour of time for the Pronto Exhaust Specialist.  The resulting system sounds great and so far is drone free.

New Corsa Exhaust in place - street view

More info to follow with performance testing. Please let me know if you have any questions about the install.  Pronto is a joy to work with for exhaust installs, and always does a great job on fitment, centering the exhaust correctly etc.  I am happy to recommend them for any exhaust work.