roddog30

I was wondering what the difference was in the two. Can the hand held programers tune your car? I want to do headers, exhaust and intake.

05_C6Z51

I've been wodering this myself. If the shop tuners, many of them appear to have real talent, can tune via mail order, then why can't some of the handheld tuner models accomplish somthing close to this?

BTW, this is nothing against the shop tuners. I would like to ability to revert back to stock when going to the dealer then reloading the program when I get it home.

Buffy

The handheld tuners provide one or more fixed program sets and some options for common parameters like speedometer calibration. They're probably the way to go if you want firmer shifts for your auto transmission, or have changed the wheel diameter. They may provide a little better general performance by tweaking up timing a bit, say optomizing it for 93 rather than 91 octane gas. I don't have much info on the LS2 tuners yet because they're just coming onto the market, we may learn of more capabilities.

The custom tune is more appropriate if you've changed cams or made other significant modifications.

Personally, I have reservations about mail-order tuning. To really get the car right takes some data collection. On the other hand, if they've done several C6s with headers they should have a pretty good idea of what to change for headers. Still, a couple of dyno runs to check it wouldn't be a bad idea.

As to what's being tuned, there are two sets of parameters used by the car: the heuristic (learned) set and the predictive set. The main need to change the predictive set is for WOT operation. Performance tuning is primarily concerned with air / fuel ratio and timing during WOT operation. The car will usually learn normal operation pretty well, during non-WOT operation the car will go closed-loop and learn the correct parameters to maintain a near stoichiometric air / fuel ratio. At any time the car will sense knock and retard the timing accordingly.

However, the learned offsets are applied in a block. If you alter the flow characteristics of the engine, especially with a new cam, you'll probably need to change some of the curves, which means editing the tables, and that's where you need the tuner's experience and tools.

There's always the issue of changes being overwritten by updates from the dealer or interfering with such updates. Once you've changed it, life gets more complicated!

05_C6Z51

On the C6, what folsk seem to be after is the TM mod, A/F, timing, etc. I guess the question is, will the Handheld programmers adjust this with similar setting as a dyno tuner?

davidfarmer

What is the TM mod?? What exactly are they changing.

Buffy

As I understand it, there is (or may be) a feature called Torque Management which reduces power under certain circumstances, probably to protect the drive train. It is of concern mainly to drag racers. There have been several threads about it; some tuners say that they can disable it.

roddog30

Thanks Buffy for the explanation. I have not made up my mind on saving my money or spending 2-4 hundred on a good custom tune. T/M is not a problem for me, I have a manual tranny.

Buffy

Some people claim that torque management affects manual transmissions too, but it seems a lot of this is based on the claim that the car seems to have almost as much "punch" in 2nd as in 1st. My major limitation in 1st gear is keeping the rear tires from spinning, so I don't think it's an issue for me either.

Oh, and the guys getting the best 1/4 mile times seem to be the ones launching pretty easy anyway.

davidfarmer

ls2edit can do all of that. I don't know what the units of the number are, but it looks easy enough to change them to higher values.

Buffy

Oooo! That looks like fun! Many hacking possibilities here.

We might be able to make some guesses at the values:
131068 = 0x1FFFC >> 2 = 0x7FFF, or the max value for a 16 bit signed integer. This probably means "unlimited".

If we assume the 4000 and 8000 are ft/lb x 10, that's right on the specs for a Z51 6-speed.

The 317 MPH is 511 KPH, or 0x1FF or 0x1FE >> 1 = 0xFF, or a probable max value.

So it looks like a lot of stuff is just set to the maximum value, which means it'll use the values that are there.

I will now repeat to myself 100 times: "You must not hack this car" "You must not hack this car" ...

boosted_z06

Your wasting your time for values at the top are not used in the Corvette as their is no reason to monitor torque of a front axle.

Buffy

What? You ordered your car without the AWD option?

Yes, obviously this is generic stuff. But if they're set to "unlimited" anyway, it doesn't matter. Sometimes the trick is figuring out what does and doesn't matter.

zo6vetteman2003

Most handheld tuners work best on a stock vehicle. Once you start modding, handhelds are limited. The best thing you can do is install the mods. and have it dyno tuned by an experienced tuner. Mail order tunes can get you in the ballpark of a good tune, but it is never optimized. There is nothing better than collecting data first hand and making the proper adjustments in conjunction with a few dyno runs to get it right.

jdwk

Ok, I was under the impression that the home user could not do much tuning with LS2Edit, and was mainly to load and unload the flash file that you would get from a tuner.
Halltech, for instance, offers this service.

From this it looks like I can do everything with LS2Edit, and a wideband. Now is there a way to read and log the torque measurements too? Then you basically have your own dyno shop.

Scooter70

LS1Tech's tuning forum
LS1Tuning.com

Start by reading the stickies at the top. They should help you out and give you more info about tuning then you ever wanted to know. (The second one isn't as active but it does contain some very good info.) Also, each of the above companies has their own forum to discuss specifics about their product.

LS2Edit is certainly not the only game in town. EFILive and HPTuners will have LS2 products available soon. Both can integrate a wideband to log O2 readings along with all of their PIDs.

Happy Reading.

midnite902

Good info.

Thanks

zo6vetteman2003

My car was tuned with EFIlive.

davidfarmer

Those trans torque numbers are direct ft-lb, as I understand it. Rememeber, you get torque multiplication from the clutch (or torque converter) as well as the 3x from the trans (roughly in 1st) and 3x from the diff (again, 3.42 or lower).

Ken tells me these numbers are already high enough. Modifying the "torque in gears" tabs is where you really tweak things.

I would have tried HPTuners had it been available sooner. I've already been tuning on my car for nearly 2 months with LS2edit. It is a very powerful tuning program, just doesn't have the scanning ability of the other programs.