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
