• Got the Contributing Memberships stuff finally worked out and made up a thread as a sort of "How-To" to help people figure out how to participate. So if you need help figuring it out, here's the thread you need to take a look at -> http://www.corvetteflorida.com/forums/showthread.php?t=3581 Thank you, everyone! Rich Z.

Tuning log for the C5Z

10-13-2013 - Tune #0024_CL

Reverted back to tune #0022_CL

Logged on 10-14

{B4522} Stall Saver RPM
Made values 100 less than target RPM

{B0101} Main VE Table
Seems to be running a bit lean. Adjusted from MAP E

{B5943} Spark IAT vs RPM Multiplier
1200 thru 2000 RPM changed to 1.00

{B5932} Base Spark In Gear
0 thru 800 RPM +2 degrees

{B5933} Base Spark in P/N
Copied from {B5932}

{B5920} Spark Smoothing Enabled

{B5929} Max TPS to Enable Spark Smoothing
Changed from 80.00 to 1.8


Log notes:

Frame 9624 - High
Frame 22520 - Low
 
10-14-2013 - Tune #0025_CL

Logged on 10-16

{B3613} PE Map Threshold
Changed from 90 to 15

{B3415} Wall wetting Min RPM
Changed from 0 to 300

{B3416} Wall Wetting Min TPS
Changed from 0.00 to 3.01

{B3314} DFCO Vehicle Speed Enable
Changed from 28 to 30

{B3318} DFCO RPM
Copied from stock Z06 tune

{B3606} Maximum Enrichment
Changed from 0.780 to 0.885

{B0101} Main VE Table
Adjusted from MAP E
 
10-17-2014 - Tune #0026_CL

Logged 10-17

{B0101} Main VE Table
Adjusted from MAP E and smoothed

{B4315} Throttle Follower Airflow
Copied from stock Z06 tune

{B4316} Throttle Follower Airflow RPM Multiplier
Copied from stock Z06 tune

{B4317} Throttle Follower Decay Rate In Gear
Copied from stock Z06 tune

**Idle too low when coming to a stop with clutch pedal pushed in

**Reloaded tune #0025_CL
 
10-26-2013 - Tune #0027_CL

Reverted back to tune #0025_CL

Logged on 11-09 and 11-21

{B4108} STFT Idle Enable
Enabled

{B1201} Abuse Management
7000
6900

{B3303} Fuel Cut Off Limiter In Gear
Changed from 6600 to 7000
Changed from 6599 to 6999

{B4603} Desired Idle Speeds
Raised values in higher temp range
Copied values from "In Gear" table into "In Park/Neutral" table.

{B4308} Airflow Parked
68 thru 284 raised values 20%

{B4307} Desired Airflow
Copied "In Gear" table to "Park/Neutral" table
 
10-26-2013 - Tune Valet_Mode_01

Preliminary - not tested

{B2201} ETC Rev Limit Enable
Enabled

{B3330} Fuel Cut Off In Park/Neutral
Changed from 6900 to 3500

{B3331} Fuel Re-enable in Park Neutral
Changed from 6899 to 3499

{B3303} Fuel Cut-off Limiter In Gear
Cutoff = 3500
Re-enable = 3499

{H0108} ETC Speed Govern Threshold
Changed 255.0 to 35.0

{H0109} Maximum Vehicle Speed (Non ETC)
Changed from 255.0 to 35.0

{H0111} Maximum Vehicle Speed (with ETC)
Changed from 256.0 to 35.0

{H0114} Maximum Vehicle Speed with RTD Fault
Changed from 256.0 to 35.0

{B1201} Abuse Management
Changed from 6600 to 3500

{B1207} Abuse Management Vehicle Speed Threshold
Changed from 0 to 255

{B1205} Abuse Management TPS Lower Threshold
Changed from 99 to 1
 
12-04-2013 - Tune #0028_CL

**Getting reduced engine power intermittently

{C6101} ETC Predicted Airflow
Added 30% to all cells

{C6102} ETC Predicted Airflow
Added 30% to all cells

**Note: At the time I thought the reduced engine power failure was being caused by something I had done in the tuning. Long story short, it turned out to be a defective TAC module.
 
12-04-2013 - Tune #0029_CL

{B4349} ETC Throttle area conversion
Changed from 0.0330 to 0.0192

**Car will not idle after blipping the accelerator pedal

** Rolled back to tune #0028_CL
 
12-07-2013 - Tune #0030_CL
Reverted back to tune #0028_CL

Logged on 12-08

{B4403} IAC Effective Area
Shifted cells down 6 steps

{B3618} PE Modifier Based on RPM
Flattened cells above 4000 that were sloping upwards (lean)

Disabled P1516 in Engine DTC Processing Enablers and Engine DTC MIL Enablers

**As of today (08-03-2014) this is the tune that I have been running in the car since 12-07-2013.

**There is still a slight surging when driving down my dirt road below 10 mph, but I believe there is nothing that can be done about it via tuning. Perhaps the car just doesn't like being driven that slow.... :D

And to be perfectly honest, often my stock C6 Z06 will do the same thing.
 
Tune# 2014_10_06_0001

Not logged

I had a couple of things I wanted to try to straighten out, so decided to work on a new tune.
  1. Faint gasoline smell at idle so I suspected that maybe the AFR was a bit rich in the low rpm/low kPa range of the VE table.

    B0101 - Main VE Table - leaned and smoothed cells in 15-30 kPa & 400-2400 rpm range.

    B3647 - Commanded Fuel vs RPM - Leaned out idle cells 5%

    B0107 - Max Speed for Idle Mode - changed from 5 to 0

    Just for grins I also replaced the filter on the rocker arm covers breather.

  2. I noticed that sometimes when shifting the AC on and off, the engine would buck a bit during the transition, so I wanted to try to smooth that out a bit.

    B4367 - A/C Clutch On Spark Torque Ramp In - Changed from 6 to 4

    B4368 - A/C Clutch On Spark Torque Ramp Out - Changed from 6 to 4

    B4370 - A/C Torque ETC Max Compensation - Changed from 10 to 5

  3. Throttle response is just a bit spongy feeling at low-mid RPM levels, so I wanted to try to sharpen that up a bit.

    B3616 - Normal PE Mode Enable (TPS%) - Adjusted 1600 to 4400 rpm -20% and smoothed manually.

Took it out for a test drive today and there seemed to be improvements in all three areas I addressed. I also noticed that the low speed (under 10 mph) seemed to be improved in that the car didn't surge as much as it used to. So I may work on #1 above a little bit more.

Wish I had kept notes like this all through the tuning effort. I recall that a LOT of the later work I did was simple chasing a ghost since I thought the REDUCED ENGINE POWER problem I was getting intermittently at startup have been caused by my own tuning fumbling. Obviously it was the TAC module all along, since replacing that cured the problem. I know I had been playing around quite a bit with the engine startup parameters chasing this problem, and initially I had the engine startup up REAL sharp and firm. So I softened it a bit thinking this was causing that error. Maybe I'll look into that as well sometime soon.
 
Drive ability tuning is a fine art that takes many hours to learn. Most tuning shops don't get that involved when tuning. They get it close enough for their liking and leave it. I've read a few shop tunes over the years and with logging, seen where they didn't focus on and fixed it for people. Perseverance.
 
Yeah, and it's going to mostly be trial and error using lots of baby steps. It's not quite so tough if you have a mostly stock engine with a few bolt-ons to work on , but as Mike Carnahan told me, I'm probably using the worst case scenario to try to learn tuning on.
 
Tune #2014_10_09_0002

Not logged.

B0101 - Main VE table - Lowered and smoothed low kPa and low RPM cells about 5 percent.

B3647 - Commanded Fuel vs RPM - 20-35 kPa & 0-1600 cells made leaner and smoothed.

B3616 - Normal PE Mode Enable (TPS%) - 1200-2000 sharpened the slope to enable PE at lower pedal position.

The first two tables were addressed to try to lean out low kPa (which is really HIGH vacuum, aka PSI) / low RPM cells. This resulted in smoother idle and low speed driving (surging reduced), but also raised engine idle speed while IN GEAR at bit as well. This causes a noticeable drop in rpm when the car comes to a dead stop. Not objectionable, and the higher rpm actually makes shifting easier at low speeds since the engine speed doesn't drop as much.

I think leaning out those low end cells is making the engine happier since it is running smoother and picking up RPMs as a result. So perhaps the AFT was too rich and the engine didn't like it much.

The B3616 table was to address throttle response, but there wasn't any noticeable change, pro or con, while driving. I may be barking up the wrong tree trying to work with Power Enrichment at those RPM levels.
 
Tune #2014_10_16_0003

Not logged.

B3306 - Cold Engine RPM Limiter (RPM) - 176 thru 284 coolant temperature changed from 5000 to 7000 rpm

B4315 - Throttle Follower Airflow - 0.51 thru 3.55 TPS% increased 20% and manually smoothed.

B4316 - Throttle Follower Airflow RPM Multiplier - increased from .17 to .18

Mostly played around with the throttle follower tables with the hopes of increasing throttle response. But the more I thought about it, the less I had hopes that this would do what I was hoping for. But I loaded the tune anyway, just to see what happens.

Actually it WAS an improvement, but not in the way I had expected.

From what I can gather, the throttle follower tables are the digital equivalent of the dashpot on a carburetor. For those of you who don't know what this does, it softens the release of the gas pedal to keep the plate from slamming shut abruptly and causing a sudden drop in engine rpm and subsequent power. Which would cause a possibly unexpected engine braking effect. So the dashpot acts as sort of a shock absorber in the way it works on engine rpm in relation to the gas pedal.

Anyway, what the changes I did to the tune seemed to slow down the engine rpm drop when I would take my foot off of the gas pedal. This seems to have made overall driving just a lot smoother. Since the engine doesn't drop RPM so quickly between shifts, shifting just seems overall smoother and not as jerky from the time I let of the gas pedal prior to engaging the clutch and then pressing the gas pedal again after releasing the clutch after the gear change. Coming to a dead stop seems smoother too as the engine RPM drops gradually and smoothly. I was also able to cruise on my dirt road at only 8 mph without any noticeable surging, so I guess the surging was caused by the PCM trying to use the throttle body plate (air flow) to hunt and peck for the desired RPM, and the swings were smoothed out when I slowed down the follower values.

And I think actually acceleration was improved a slight bit, since during shifting the RPMs didn't drop so much between shifts, so the subsequent pressure on the gas pedal wound up starting from a higher rpm level than before.

Perhaps looking at the throttle cracker tables might be worthwhile at this point.

So I've got the tune progressively better than before, in an unexpected manner, but apparently have to find a different tree to bark up for what I am really after. What I think I need to find is the digital equivalent of the accelerator pump. Seems to me I tried finding that before, with no success, but maybe I just need to keep on digging. I didn't think the throttle cracker tables would do that, but perhaps I'm mistaken and just need to try them. Or maybe there is no single table set for that function and it is a combination of two or more seemingly unrelated tables that will act in that manner. :shrug01: As can be seen, not much is glaringly obvious in this tuning stuff.
 
Yes sounds like they did not disable the "power enrichment delays" in your tune--There can be sometimes a 2 second delay in a stock tune
Also did they remove your TQ management ? your Abuse mgmt ? adjust your " ETC pedal TQ limit reduction " ??
All these things all reduce throttle response

Found this on corvetteforum from tblu92
 
I actually emailed Chuck at CoW about what he is offering, but so far haven't gotten a reply. I think he may be out of town.

But if this is a tune that requires the PCM to be locked by him, not interested. I'm not turning over ownership of my PCM to anyone.

Have you played with that table?
 
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