Does anyone have any info on this C6 Z06 for sale? EY55 CEX

Roscobbc

Moderator
I agree with you and can prove your viewpoint

Owner of a 2013 C6 Z06 came to me for custom tuning
First I did a testrun and with OBD-II scanner recorded many of the engine PIDs (parameters) and then analyzed that data and
from that custom tuned the stock GM tune into changes I made and flashed into the PCM

On the same day I then did a testrun on the same road and here we see the results and performance gains of the LS7 engine with just the tune
This shows how much GM had detuned what the engine really could do

Stock GM calibration ...................... My Tune
Max timing during PE (Power Enrichment going to WOT)
16 Deg ..................................... 22 Deg
Testrun Distance
37 Miles ............................................ 26 Miles
Fuel Injector Duty cycle (how hard the injectors were working)
91% ...................................................... 74%
Reported Engine Knock
524 Times ........................................... 9 Times
Maximum Speed I drove in MPH
128 MPH ............................................... 136 MPH
Reported flywheel Torque generated
425 ft/lbs .............................................. 522 ft/lbs
Reported flywheel HP generated
508 HP ................................................. 615 HP

All my manual shifts were done at 6,900 RPMs (Redline is 7,200 RPMs)

So this shows that the GM design of the 427 CI LS7 could handle a lot more than they allowed in the tuning
which is to reduce changes of engine failures to limit warranty claims and better gas mileage

I did this tuning back in 2015 and the owner to this day has raced the C6 Z06 many times and has had no engine problems
He sends me a OBD-II scanner recording about once a year to see if all is well or if tune needs to be tweaked as
parts age.


So before throwing on expensive mods, have a good custom tune done and then decide if more is needed
So comparing the 'stock' 508 hp / 425 ft/lbs against your custom tune 615 hp / 522 ft/lbs the only differences are in 'the tune'? - no mechanical changes?
What is the downside of your custom tune - will the engine be more likely to 'grenade' itself? - or higher wear rate - what effect will this have on fuel efficiency when engine use in a normal way? - could one expect the above results from a 'good' stock C6Z06 engine?

 

Roscobbc

Moderator
I think you'll find that the seller is an Anglia Region member........met him and the car at a Suffolk event a few months ago.
 

teamzr1

Supporting vendor
So comparing the 'stock' 508 hp / 425 ft/lbs against your custom tune 615 hp / 522 ft/lbs the only differences are in 'the tune'? - no mechanical changes?
What is the downside of your custom tune - will the engine be more likely to 'grenade' itself? - or higher wear rate - what effect will this have on fuel efficiency when engine use in a normal way? - could one expect the above results from a 'good' stock C6Z06 engine?

Hi Roscobbc
As having worked for GM in the Tech center it was common for engineering to adhere to the 80% rule
That meant to allow the engine's setup for production to maximum of only 80% of it's ability
So there is a lot more on the table and is limited by GM's calibration within the PCM

I tuned this 2013 Z06 4 years ago and as mentioned the owner has had zero issues with the LS7 with the custom tune in it
He did decide as I suggest to him was installing a bit larger fuel injectors (only mod for engine) as you really do not want to have them function over
an 80% duty cycle.
I then tweaked the tune for those and what the final results were.
GM limited the performance mostly by having the PCM command lower timing and shorter fuel injector ON times so
the AFR was leaner (for fuel mileage) and loss of torque by the lower timing.

Also, the PCM is an engine dyno and because of that there is torque management functions where the PCM can limit
the amount of torque output so adjust those torque tables to allow higher torque output
GM also due to forced to allow Ethanol in gas simply uses the engine knock tables to yank way too much timing out when even
minor knock occurs.

Custom tuning all of these then wakes the LS7 up and hence the good performance gains
In just cruising around then fuel mileage is not effected but uses more fuel of course when getting hard on engine such as racing he does and why
I had him go with the bit larger fuel injectors for the top end.

Downside of tuning ?
You cannot make more HP/Tq without using more fuel, but again that is only when making use of higher RPMs and bouncing the rev limiter, Often
Being owner has had zero problems in the 4 years of tune shows if the tune is done with quality and touching all functions to work together well

The big downside is many fools buy a tuning tool and then think they are a pro when they know crap about how the engine functions and end up with a very bad tune that has caused engine failures.
This is where these chassis dyno shops out of the blue call themselves "tuners", spend a few minutes doing WOT only and then ignore all the tuning required before engine gets into the WOT mode, so their tunes stink overall, and you cannot tune every vehicle the same way.
That is where custom tuning comes in and the only way I will do a tune

Where I have been tuning since mod 1990s and spend all my experience since then in each tune I do, not one of the vehicles I have tuned has failed SMOG testing and not once has GM voided a warranty due to the tune installed because I assure the engine is not pushed beyond its design ability

My 1999 Corvette with 500 HP when N/A and also when using 200 shot of NOS I tuned in 2000 and to this day engine has been solid except once
at drag strip to prevent breaking out of the dial in E.T I was running I downshifted when RPMs were too high and bent 1 valve

I find in most cases any GM vehicle with gas engine that is stock will have a gain of 30 HP, the fuel mileage will be better and also tuning (if having auto tranny), then overall of tune engine/tranny the vehicle wakes up and that includes, SUV, Pickups, etc
 

Roscobbc

Moderator
Hi Roscobbc
As having worked for GM in the Tech center it was common for engineering to adhere to the 80% rule
That meant to allow the engine's setup for production to maximum of only 80% of it's ability
So there is a lot more on the table and is limited by GM's calibration within the PCM

I tuned this 2013 Z06 4 years ago and as mentioned the owner has had zero issues with the LS7 with the custom tune in it
He did decide as I suggest to him was installing a bit larger fuel injectors (only mod for engine) as you really do not want to have them function over
an 80% duty cycle.
I then tweaked the tune for those and what the final results were.
GM limited the performance mostly by having the PCM command lower timing and shorter fuel injector ON times so
the AFR was leaner (for fuel mileage) and loss of torque by the lower timing.

Also, the PCM is an engine dyno and because of that there is torque management functions where the PCM can limit
the amount of torque output so adjust those torque tables to allow higher torque output
GM also due to forced to allow Ethanol in gas simply uses the engine knock tables to yank way too much timing out when even
minor knock occurs.

Custom tuning all of these then wakes the LS7 up and hence the good performance gains
In just cruising around then fuel mileage is not effected but uses more fuel of course when getting hard on engine such as racing he does and why
I had him go with the bit larger fuel injectors for the top end.

Downside of tuning ?
You cannot make more HP/Tq without using more fuel, but again that is only when making use of higher RPMs and bouncing the rev limiter, Often
Being owner has had zero problems in the 4 years of tune shows if the tune is done with quality and touching all functions to work together well

The big downside is many fools buy a tuning tool and then think they are a pro when they know crap about how the engine functions and end up with a very bad tune that has caused engine failures.
This is where these chassis dyno shops out of the blue call themselves "tuners", spend a few minutes doing WOT only and then ignore all the tuning required before engine gets into the WOT mode, so their tunes stink overall, and you cannot tune every vehicle the same way.
That is where custom tuning comes in and the only way I will do a tune

Where I have been tuning since mod 1990s and spend all my experience since then in each tune I do, not one of the vehicles I have tuned has failed SMOG testing and not once has GM voided a warranty due to the tune installed because I assure the engine is not pushed beyond its design ability

My 1999 Corvette with 500 HP when N/A and also when using 200 shot of NOS I tuned in 2000 and to this day engine has been solid except once
at drag strip to prevent breaking out of the dial in E.T I was running I downshifted when RPMs were too high and bent 1 valve

I find in most cases any GM vehicle with gas engine that is stock will have a gain of 30 HP, the fuel mileage will be better and also tuning (if having auto tranny), then overall of tune engine/tranny the vehicle wakes up and that includes, SUV, Pickups, etc
Can we comfortrably say that up to an additional 20% more power is available with a 'tune' (such as you can do) with no adverse affects and no additional components required?
Can this be done just by sending PCM to you for re-programming and you can extract the various information about the current state of the engine from the PCM - do your 'tune' and post back to us? - or do you need to physically access the engine and run it?
 

teamzr1

Supporting vendor
In short, Yes but also regains any loss that may happen as getting too much knock, misfires, or degraded sensors like O2s
and in most cases will better then fuel mileage along with the performance gains

Use this as example a 1999 C5 with the LS1 engine which in this case was stock but owner put shorty length headers on that do not give much improvement
As you know for 1999 LS1 the GM specs at flywheel was :
  • 345 @ 5,600 rpm Horsepower.
  • 350 @ 4,400 rpm Torque.
Here is after I did the tuning.
The owner then went to a load bearing dyno I knew would do a correct testing
They first calibrated the dyno
They set in the values for weather and elevation
They set the dyno brake load to match the weight of this C5 plus drivers weight
I had them do two back to back pulls and superimpose those to see that the results were about the same
Owner took photo of dyno monitor, so the results shown are exactly what the dyno end results were

The REARWHEEL results for the 2 pulls, torque is on left side and HP is on right graph
Now being these are at the rearwheels, use a factor of 10% drivetrain loss for a manual tranny to see what numbers are at flywheel

Notice the 2 pulls on left we held max RPMs to about 5,200 RPMs and then the set of pulls on right to about redline at 6,600 RPMs
and as shown was stock rear end gear of a 3.42 ratio

carl-dyno.jpg

Along with the gains, seen here are at peak, but there also is good gains at the lower engine loads as GM's PCM calibration due to the torgue management allows less torque from dead stop/idle to about mid-engine load/RPM, so torque curve is lower there
But I redo all the torque tables along with timing, so now more torque is allowed early on, so the curve goes up more quickly

In the end if you compare what the flywheel numbers were and now the rearwheel the gains were quite nice and the C5 lives in Ca where the smog testing is tougher yet the C5 has passed all smog testing since I did the tuning about 12 years ago and owner says it still runs as good as when I tuned it

So not to confuse folks, I will break this into a few more posts
 
Last edited:

teamzr1

Supporting vendor
As to tuning, I can care less about quantity, it is about quality
I do not do "cookie cutter" Canned tunes.
I tune each vehicle as if I owned it and I expect to quality
Each vehicle I tune to its own merits, as to is stock, if not what mods, type of gas used, what the elevation is
does the owner grassroots racing, spirited driving on streets, their drive style, what type of tranny it has

I can tune most GM vehicles from mid 1980s to about present, as long as they are gas engines.
Pre 1994 such as Corvettes C4 I call used ECM (Engine Control Module) and the GM calibration is burned into an E-prom
I have to tune them different from newer as older had less tuning functions and then new tune is burned into an E-prom
Auto tranny tuning is also done within same tune

1994 and newer is a PCM, (Powertrain Control Module) instead of a E-prom it has flash memory where tune is stored for engine and tranny
After about 2005 being the newer auto tranny had so much in functions GM gave the tranny its own controller (TCM) and I also tune them

Not all but here is some of what I am touching in tune

1. Idle Speed Tables (with and without A/C on)
RPM limit By Gear
RPM Limit by Temperature
RPM Limit Delay
Maxumum MPH allowed
Fuel Air Ratio Table
Volumetric Efficiency Table
MAF calibration Table
Fuel Pressure versus voltage
Fuel Injector flow rate Manifold vacuum
Fuel injector Offset Table
Power Enrichment vs. Temp Table
Power enrichment versus RPM Table
Wide Open Throttle Hot & Cold Tables
Closed Loop Enable vs. Temperature
High and Low Octane Spark Adv. vs. RPM vs. Load
Base Spark Advance in Gear, and In neutral Tables
Knock retard Tables
Misfire tables
Coolant fan(s) as to what coolant temp they come on and how fast they rotate

2. Misfire Tables
Torque Management tables
Knock Learn Parameters
Maximum Torque Parameter
Each Shift Speed
Normal Mode Shift Speed vs. Throttle position for each Up and Down Shift
Performance Mode Shift Speed vs. Throttle position for each Up and Down Shift
Wide Open Throttle Shift Parameters
Each Shift Firmness
Abuse mode

3. Injector Pulse Width and Offset Voltage
Force Motor Current vs. Temperature vs. Throttle Position
Desired Shift time vs. Torque for each Up and Down Shift
Torque Reduction vs. RPM
TCC lock tables
Normal Mode TCC lock speed for each gear by Throttle Position
Performance Mode TCC lock speed for each gear by Throttle Position
Cruise Mode TCC lock speed for each gear by Throttle Position
Normal Mode TCC release speed for each gear by Throttle Position
Performance Mode TCC release speed for each gear by Throttle Position
Cruise Mode TCC release speed for each gear by Throttle Position

4. Turn Error codes off or turn EPA Smog Tests off
M6 CAGS turned off
Fan Temperature low and high speeds
VATS disable
Speedometer
Gear and Tire size scaling
Speed Limiters


5. Mods, tune in if custom CAMs, heads, porting, supercharged, Turbo, NOS, stroked, etc
Change of rearend gears, tire and/or wheel size changes.
Larger fuel injectors installed, 3rd party air cleaners, cold air boxes, etc
 

teamzr1

Supporting vendor
Custom Tuning process

IF you intend to buy a tuning tool and do the tuning yourself having no experience I say walk softly and do not get cocky with your tune
or it could cost you in engine or tranny damage, or the least vehicle fails smog testing, this is where someone like me custom tuning since 1995 knows how to make all save but perform well and still pass smog testing

My Process

1. Since I only do quality custom "one off" tunes you guys would need a OBD-II scanner (maybe share it with other members)
I can point to a cheap one bought from like Amazon that works with a laptop that has MSwindows and has a Bluetooth interface
I tell you how to make up a PIDS group (Parameters) for scanner and then go for a good testrun and scanner keeps recording all those
PID values. That includes the torque PID, so we can see exactly what the torque is at any engine load and from that compute also what the HP is

That is then emailed to me to fully analyze, and now it would be like the vehicle is with me and the recording also gives me an idea what your
drivestyle is like. You also tell me what the weather and elevation was
From that I bias then base tune to email to you

You would need to buy a tuning flash tool, it could be used on unlimited GM vehicles, you own the tool, no per PCM charge as other tuning tools
charge. (again maybe share tool with others) or you buy tunes from me, you get your own customers and do the OBD recordings and the tune flashing, and you charge them what you want over my tune costs.
Using the flash tool you download the GM tune, it becomes a file on your laptop
The tunes I email to you, you flash into the controller, tool is very easy to use some only flashing, takes about 5 minutes

Once flashed in your go for another testrun with scanner recording, which you email to me to analyze, and I email you a tweaked tune from the data I saw in recording
This process then is you would have downloaded and saved stock tunes that later could flash back in or would also have saved any tunes from me and could flash different tune levels I sent to you

I save under your name a directory on my file server and save all recordings, the flashes you send me, the tunes I email to you and the results of all the analyzed scanner data so if needed later I have them and also later if doing other mods I can then tweak past tunes to include those changes
 

theseoldcars

CCCUK Member
The red Z06 in the first post – that's been owned by two (or more, perhaps) people on PistonHeads, and they all regret selling it. Reputedly, it's a well-sorted example.

It popped up recently here: RE: Chevrolet Corvette (Z06) | Spotted - Page 1 - General Gassing - PistonHeads UK

I owned this car back in 2012, and subsequently sold it to another PH'er.

I regretted selling it the moment he drove away. So much so that I bought another. Which I then sold a year or so ago. And have regretted since.

Now wait for the usual 'it's only a pushrod N/A; how pre-historic is that?', the 'but it's got leaf springs therefore must be crap' and 'the interior plastics feel cheap' comments.

I'd buy another like a shot, if my back and knees would let me get into i
This car has a long PH history as I was owner -2 and I bought it off a PHer.

Brilliant car and possibly the only one I really regret selling out of all the metal I have had.
I purchased it in 2012 from one of you and sold to the other in 2017. ( yes yes chris, I know...)

This one is actually 564bhp
 
Top