And why does the corvette not come from the dealer with a Tune?

 

It comes with a factory tune which is geared more towards longevity, emissions and fuel economy. A custom tune plays with air/fuel/timing tables to "wake it up" so it will perform better.

 

With all new vehicles, the factory has to develop a tune that is easy on the drivetrain, since it warranties the same and they have certain noise and comfort criteria that they apply to make sure they don't get complaints from folks who buy them.
Therefore, the tune has what we call Torque Management ("TM") built into it. TM generally uses three things to reduce power on a WOT takeoff and during gear changes to limit the shock on the drivetrain. It uses the Electronic Throttle Control ("ETC"), ignition timing retard and reduction in fuel delivery (it also uses these things to limit the vehicles top speed) to reduce power during those events.
Also, the factory has to tune each vehicle to operate within a wide range of atmospheric and driving conditions (Death Valley vs. Alaska and weekend warrior vs. granny's grocery-getter). This means that some significant compromises need to be made to the tune to ensure the vehicle functions properly and doesn't destroy it's engine, no matter what environment it's operating in. Basically, they err on the safe side by a decent margin to make sure they don't have problems with warranty claims, etc.
Therefore, GM tunes the Corvette to meet a bunch of criteria that most of us "performance freaks" don't really care much about, and so we can always find some extra performance from reducing (or eliminating) TM and tightening up the shift speeds on automatic transmissions and leaning out the Air/Fuel mixture and advancing ignition timing to suit our own atmospheric conditions and driving styles, so to speak.
So even factory-stock cars will benefit from a retune to suit pernsonal needs and conditions.
Of course, once we start changing parts, a tune becomes essential for optimum performance and in some instances it's absolutely necessary to make the vehicle function properly again.
That's my grossly oversimplified explanation, anyway. Hope it helps...

 

Awesome guys, Thanks a lot for the info.

 

You hit it on the head. GM leaves hp on the table for longevity, emissions and mileage. The AFM runs quite rich. Leaning the engine and adding timing picks up a good amount of what was left from the stock tune. And killing TM and firming the shifts in the A-6 really gives a sop boost irrespective of the actual hp increase. When my '13 goes past 4500 in WOT it actually feels like a turbo is kicking in. That is not an exaggeration. And that is at 7000' altitude with the Intune 91 octane tune, Bullets and Superbee. One of these days, I'll take it to low altitude, fill it with 93 octane and see how it runs.

 

And would only add that the EPA specs are a big challenge also.

 

Thanks for this explanation! I suspected much of what you go into here (balancing performance to meet a broad spectrum of requirements), but wanted to learn more detail and your post really helped me better understand.

Question: What recommendation do you have for changing the factory tuning (pay someone to update via mail order, find someone local with a shop, purchase a tuner...).

 

Lots of opinions on this. And I guess it all depends on what you want out of tuning. For me and my Z06, I went the route of emailed tunes. My 2007 Z06 is basically stock with the exception of a true CAI solution that I have built for it. I'm using a full K&N 63-3060-1 intake covered by a custom cut Halltech Bee Hive. In addition, I CAD designed and built on a 3D printer an air scoop that pulls in fresh air (because I had to patch/cover the hole I cut in the radiator shroud for a Vararam that just would not fit no matter how hard I tried) Anyway, after my custom CAI solution, I was getting P0171 and P0174 codes (Bank 1 & 2 Too Lean) over and over because apparently my CAI actually did what I intended it to do. So in order to fix the fuel mapping, I needed a tune. Every local shop I called gave me the standard $500 for a dyno/drive-ability tune.

I found a great deal on a used DiabloSport Predator u7194. An InTune or Trinity would have also worked for me too. I chose to go with a DiabLEW tune from Lew at diablewtune.com. All I had to do was run a data log while driving (which takes into account my specific environmental conditions better than just a standard canned tune in my opinion). Then I sent him the data log, and the OEM stock tune files. Then he built a tune specific to my Vette from there. It is an iterative process with Lew. I ran the first tune from him for a couple hundred miles to let it settle in and allow the computer to adjust and then data logged again. No codes at all and it ran great, by the way - really woke up my Z. He then tweaked the tune for me and sent me round 2 of the tune. I'll continue this until it is right where I want it, and the follow-up data logs look good to him too. Hard to beat that service for less than $150.

 

That is an excellent follow up, thank you. I have a 2013 427 (essentially the Z06 engine on a Grand Sport body). If I understand you correctly, purchasing a tuning device allowed you to interact with diablewtune and with the tuner you're price from them was +\- $150?

 

Currently, diabLew Custom Tune is priced at $145. That is assuming that you already have a Predator, InTune, or Trinity. I bought my Predator locally from craigslist second hand. He also sells the InTune and Trinity as part of a package deal, or you can buy one yourself somewhere else like I did.

So yes, once you have the tool, you can backup your stock tune to PC, install the DiabloSport standard canned tunes, data log and export to PC, and install custom tunes created by DiabLew Tune. The Predator also allows you to make some parameter adjustments yourself with the tool. But I left all of that up to Lew.

 

I want to thank "myself" for having something to do with your GS purchase. Hang around awhile, guys like you are always in need!

After that converter you may want to do a supercharger and I think you will be where you want to be i.e. in ZR1 killer territory in a comfortable, power is always on tap ride.

If "I" did a quiet supercharger which I may (I have an A.C. 9 second street turbo V6 Buick too) I would run it on 93 octane and leave the alky injection alone, I would just get what I could from the gas; sure alky will let you run more boost, etc. but the more stuff/systems the more something may/could go wrong down the road. I have seen a lot of fast Buick's running strong with alky/pump gas (Hell, I got an alky system on mine but stop using it) but than for some reason the cars take a crap down the road, guys have said I don't understand it, I had zero detonation when the engine blew. There maybe something about mixing two different fuels in the combustion chamber because the cars that seem to last year after year are the ones that run on either race or pump gas or have different tunes for (pump gas, race gas, e85). Just wanted to give you my thoughts. Oh, and your post is top shelf material.

 

If you're not going to install a big aftermarket cam, the easiest, simplest way is to do what I did (I'm kinda lazy, so I like easy and simple) and buy an Intune with a custom tune from Diablew. If I remember correctly, he will even give you a discount on the Intune if you buy one from him with his custom tune as a package.
He will then get you to install a base tune, and do some data logging (which is very easy on the Intune) and send it back to him. He will instruct you what to do and will use your data to tweak your tune until he gets it right. If you check out the various threads about Lew and the Intune on the Tune/scan forum you will see what I'm talking about.

 

GSM, you kill me man! I'm just telling it like it is and trying to share what I've learned so I can be useful at the same time.

So, to sum up: what you're saying is that, like with humans, cars can be unpredictable and sometimes react violently when engaging in the consumption of alcohol!

I get your thinking though. The idea of me having to keep a separate small tank full of some other type of fuel, just to run a supercharger, wouldn't make much sense to me, since, if that would be the case, I would just stick with nitrous, as I'm am much more intimately familiar with that, as I have installed that on every car and almost every boat I've ever owned ( I even nitroused a lawnmower once)

However, if I did go the blower route and if it was possible to run it at a lower boost level with pump gas on the street, and then at the track be able to easily change a pulley get more boost to run like a 9 second ET with methanol, that would be okay. Of course, in that case I would probably throw the highest octane unleaded race fuel I could find too.

But, alas, now we have digressed from the original topic of this thread, and have taken a tangential turn into supercharged territory!
More on that on another thread soon...

 

I just want to know how many acres per hour you could mow?

 

I never found out, on account of the little Briggs and Stratton motor giving up the ghost on the first hit!

 

I hope your c6 doesn't do the same

 

Makes two of us!
That was like 25 years ago though, so I've learned a little bit about nitrous since then...

 

I'm able to run my H&C NA tune with the nitrous up to a 150 shot with the 1 gallon fuel cell and C16 with bre7 plugs