Category Archives: Virtual Dyno

TUTD shift speed test 1 — Too high

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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 hptuners

Unfortunately, it never shifted and just hit the rev limiter in 2nd.  I will have to recheck the calibration for commanded shift speed and rethink why it didn’t shift.

TUTD shift speed miss 2013-06-20

Max boost of 9.5-10 psi, and a nice max delivered torque of 468 lb -ft at 3530 RPM, max calc hp of 548.8 hp at 6580 RPM.

TUTD shift speed miss 2013-06-20 VD

The Virtual Dyno shows a steady 377 WHP from 5500 on — looking a lot like the car needs more something to keep raising torque/hp after 5500 RPM.  I would like to see the car get to 440 WHP in 2nd gear tests like this one (!)

Conclusion:

Today’s test was not successful in changing TUTD shift behavior.  The car put up good numbers, although the Virtual Dyno WHP continues to stay below goal.  Restoring the additional timing at high RPM seem successful.  I have recalibrated the TUTD for the next test.

Update:

TUTD timing vs retard b

Pulled 0.5 of timing at the two points where KR is coming up, and added some timing at 6800 RPM to push up the last bit of the curve.

 

Retest2 Cold for Comparison and more RPM reversion oddity

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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

and here is a comparison with the previous test results:

Comparison test to retest

Different days, so equivalent given the test method.

amsoil retest2 another odd run

Another odd result reflected in Virtual Dyno on the 1st (red) run.  I see the issue in the data file but I am uncertain if this reflects a data capture glitch, or an actual phenomena.  You can see the same issue in the Hp/Torque graphs above around 5500 rpm.  These are x-y graphs, so that divot near 5500 rpm means that the RPM built to 5600, then went back down to 5500, then up through to the shift point — all during wide open throttle.  I am unclear what is causing this.  The 2nd run at the same day same site is shown in blue; although it also shows a lower RPM hp peak it is much closer to the expected values.

amsoil retest hptuners 2013-06-16

I added a boost solenoid check to see if the boost solenoid was involved in the variance for the boost psi, but the solenoid remains at 100% duty throughout the scan.

Even on this ‘cold’ run, we are running into IAT2 retard of 1.3 degrees at redline, reducing total timing to 22 degrees.

Conclusion:

  • Continue to see occasional odd data around 5500.
  • Analysis of the delivered torque / hp appears to give a consistent method of determining progress in tuning.
  • Run to run variances appear to tie to the boost variances, which suggests that these may be actual changes and not sensor variances.
  • Max observed boost 9.7-10 PSI above 6300 RPM
  • Max MAF lb/min 60.5-61.5 lb/min
  • Injector Duty cycle 90-92%

Amsoil eaau6065 filter Cold Retest log

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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]

Torque vs Boost and SC Inlet Vacuum

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.

Here was the HPtuner data at peak in 2nd gear:

HPtuners screen capture

HPtuners screen capture

The V was cool and almost out of fuel.

The Virtual Dyno run reads high Torque, Low HP:

Virtual Dyno suggests good Torque but low high RPM HP

Virtual Dyno suggests good Torque but low high RPM HP

I am uncertain how to interpret this relative to the other readings.

Conclusion:

I include these dataruns to study repeatability and build info on my current setup.  The key to tuning is to have a solid reference set to compare to.