IMO none of the gas engine "tuners" are worth the price. No real gains to be had, even though everyone that bought one claims they "feel" a difference. I guess sure, you'll feel different shifting (firmer or softer, or whatever you choose) or a more sensitive throttle, but to gain a half second in the 1/4 or anything like that, it just won't happen. Now if you're boosted or running a diesel then yes, gains you can actually feel. But for N/A gas engines, smiles per miles will be very little. Again this is just me and my thoughts
I beg to differ. My Titan ran 7 tenths of a second quicker with a Hypertech in the 1/8 mile. The first tune that went on my 97 van was also a Hypertech and it was 4 tenths quicker in the 1/8. I then gained another 3 tenths tuning the L31 myself. The L31 has a ton of power locked up in the tuning. The stock timing tables are laughable.
I ran the Hypertech WOT spark mapping for years in my L31. On the older Vortecs, Hypertech only changed the 95-105 KPA range and I smoothed the table out a bit from there for my own tune. When I went to the 0411 I used the 4.3L Hypertech spark map. The 4.3L timing works because the 4.3L is 3/4 of a 350. My L31 loved their spark tables. People that dyno tested them always saw similar results to what they advertised in their power charts.
Stock 0411 350/4L80E van tune
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0411 with Hypertech 4.3L spark advance, torque management revised and shift points tweaked.
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This was after an LS truck E-Fan and homebrew 4" CAI setup using a GM 85mm LS truck MAF. I ended up removing both because I had to put the clutch fan back on. But it did run very nicely when it was not overheating in summer.
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