Discuss all things tuning in this section. News, products, problems and results.
so my old boss (one who said it would be years for me to learn everything I need to know to tune a car), called me up and said I’ve got an 07 Silverado that I just did a dod delete kit on it and put an LS9 cam in. Can you tune it? I said sure! So after work I dropped by hooked it up to the HP tuners (the person that had lended us the computer and HP tuners module already performed the DOD delete and anything else that needed deleted) and it was pulling -15 to -19 on ltft and about -7 to -10 on stft. Had him drive around to collect as much data as possible. Came back and started thinking of what I should do. I didn’t have a wide band to hook to the computer, HP tuners was the basic one and not a PRO so I couldn’t wire a wide band to it. So I said what ever I do I need to make small adjustments.
The truck initially had a severe bog on the low end and was very sluggish accelerating. So I said well, there’s already an error in the narrowband O2s from what Andre has said so it’s probably not accurate that it’s pulling an actual 15-19% of fuel. So I went to the MAF low and took out 4%. Went to MAF high and took out 1%; all done across the board to keep its shape. I figured worse that can happen is, it acts funny and I just either add 1% at a time back or it won’t be enough that I pulled. Then I went to the virtual VE table. I added 3% of fuel up top from about 92.5kpa to 100 from 2400 to 4000. At 4000 in the histograms it should the kpa dropped off back to around 94.7kpa. So I changed 92.5-95kpa the same additional amount of 3% on up to redline. Then I went into ignition high map. Added a degree of timing down low, added a degree of timing up top. Change target idle speed to be 50-80 rpm higher. Flashed it, started it up. My old boss walks over. “Dude the idle already sounds better!” I look at the fuel trims, it’s now only pulling maximum -6 LTFT and -0.8 stft. He gets in, I start the scanner. We go for a drive. The second he goes into reverse he’s like ahh yea I already notice the difference. The bog on the low end was instantly gone. Even initially just ever so slightly touching the go pedal, it was instant responsiveness, no hesitation.
Drove it around, felt as though it had the same throttle response as stock. Maybe even a little more UMPH or pep in its step! I had him drive around in closed loop going up to 3800rpm and then returning to normal cruise. Had him do a pull and she really came alive up top and she hadn’t before. He goes if you’re happy I’m extremely happy with it. And I said with it feeling as it should, me not having an LM2 to connect to the computer to make it precise, I’m not going to touch another thing! So we drove back and he was more than happy with the tune.
I was actually pretty shocked because because I was able to feel the results of my own tune where as before with tuning my buddies drag car at the track, I’m not the one driving so I have to rely on how he says the car feels.
Nice work. It's always rewarding when you can turn an absolute dog into something that drives nicely and produce an increase in power too!
Little worrisome when i didn't have any sort of AFR reading though but seemed to like it didn't do anything out of the ordinary and the customer is extremely happy with it