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Any tips for a noob trying out tuning?


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Well I figured since I have HPTuners I'd give tuning a shot on the 03 SSS I just picked up. The truck is bone stock other than a Vararam CAI and a Magnaflow muffler. Starting off I just wanted to adjust tire size, remove the speed limiter and reduce the amount of both engine and transmission torque management. I went out and logged the truck on the stock tune before messing with anything and at WOT I was seeing upwards of 8* of KR which I thought was kind of crazy for a pretty much completely stock truck.


Went back to the house and saved the log and pulled the stock tune, saved a copy of it and started working on the torque management and speed limiter. I followed some simple instructions I found on the HPT forum to remove all torque management, but used my own values to reduce it by 75%. Then uploaded the new tune file and went out for another log. This time I saw no KR at all at WOT, the shift from 1-2 felt a bit sluggish but I know I'm going to have to either add a vette servo or some more tuning work to fix that issue. But overall, the truck felt like it pulled much stronger than before. I also noticed though that with the stock tune, the commanded AFR was 14.68, but with my modified tune the value for commanded AFR was gone in the scanner.


Now, I don't know if something that I modified in the engine torque management is the culprit for the missing AFR value or not, because other than clearing codes, shutting off rear O2s or loading in a custom tune, this is the first time I have ever messed with HPT on my own. For peace of mind until I got some insight from someone more knowledgeable, I loaded the factory tune back in the truck before going to bed last night and kept my foot out of it on the way to work this morning. I did have a few instances passing other cars on the highway at about 1/2-3/4 throttle that I saw about 2* of KR this morning however so Id like to try and figure that issue out along with making sure my values for torque management are acceptable for a stock trans.


Thanks in advance!

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  • 2 weeks later...

Stock trans will die. There arent very good behind these big ole 6.0s. Would probably pump Tranny line pressure to get the shifts you want. Adding a vette servo aswell as a Transgo HD2 Shift kit to mine made it 100% better! (Just dont add any gold rings or flip the servo)

As far as AFR thats weird. I would see if you can call a rep. tuner who can answer it 100% for you. Never ran into that issue but when it was my truck with just longtubes and intake i was a 12.5AFR

or close to that.

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With the parameters you changed in the file, your scanner should still log commanded AFR unless you changed the default configuration in the scanner. Make sure you are using the standard default configuration (unless you intentionally changed it).


My recommendation is to master the scanner function of the program first. Learn how to add and delete individual parameters, understand the stock histograms, create custom configurations and custom displays. Then you can move into a bit more involved scanning by setting up custom histograms and adding in a wideband o2 input. Logging commanded AFR against real time AFR from your calibrated wideband is just about the most important histogram you can run.


For actual tuning, assuming you are using your stock O2 sensors as reference, start with dialing in your Ve table. There are TONS of tutorials on this and I think I even wrote one a while back. Once your Ve is close to perfect +/- 2-3%, go to your MAF calibration and dial in your same cruising range. In order to dial in your upper ranges (PE range) on both the Ve and the MAF tables, you will REQUIRE a wideband with data acquisition outputs. Pretty sure I wrote a "How-2" for calibrating your MAF somewhere on this forum...its bee a while.


Once your fueling is dialed in, move into adding timing for some extra HP. Shift points, TM, speed limiter, code deletion etc. can be done anytime. Unless you are doing some rather big mods (Cam, Heads, blower etc.). you will not have to touch the tricky parts of the tune file (idle balance etc.). Once you become comfortable with the tuning package, you will find yourself tuning your Ve and MAF constantly to get to that perfect (and elusive) 0% error (AFR commanded vs actual).


Also, once you are dialed in with fueling, you can tackle the KR you are seeing. My experience is that the knock sensors are very sensitive to false knock and should be desensitized in the tune file a little bit. Others say not to mess with it. Your choice. There are many types of true KR so read up on it and how to adjust.


Tuning software can be very intimidating and dangerous if you do not know what you are doing. Start small and build on your knowledge base. Pretty soon you will be dialing in a massive head cam package with a some type of power adder!

Oh, and find a local tuner and ask if you can watch over their shoulder. EVERYONE does it differently to achieve the same results.

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