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There are big differences in a 305 and 350 tune. Most of them cannot be edited with HP Tuners either. Best to start with a 305 tune for a 305 and a 350 tune for the 350. The 305 uses 3 02 sensors before the single cat and 1 after. The 350 uses 1 02 in front and behind each of its dual cats. Closed loop fueling will be all kinds of wrong with the 350 tuning running a 305 with the 305s stock 02/exhaust configuration. HP Tuners has a utility on their website to convert a .bin to a .hpt file. I have a 305 .hpt file, but I am 100 miles from my tuning laptop it is on at the moment. There are a load of differences between the 305 and 350 tuning. Apples and Oranges in comparison. For my 99 Tahoe that had a L30 running the L31 exhaust setup in my Tahoe, I used a L30 file and edited the exhaust configuration and 02 sensor configuration to match the 350 using Tunercats OBD2. Those settings are not in HP Tuners software. The L31 350 tune barely ran the 305 in the Tahoe and it was all out of whack.Have you tried the repository on HP tuners website?
There are .bin files available at gearhead-efi.com, but you won't be able to use HP to load them.
You should be able to make a 5.7 file work fairly easy, IMHO all you would need to change is the displacement, as long as the 5.7 and 5.0use the same injectors.
On that note where would one acquire a z56 tahoe stock tune? Or is it not even different then a civilian tahoe?There are big differences in a 305 and 350 tune. Most of them cannot be edited with HP Tuners either. Best to start with a 305 tune for a 305 and a 350 tune for the 350. The 305 uses 3 02 sensors before the single cat and 1 after. The 350 uses 1 02 in front and behind each of its dual cats. Closed loop fueling will be all kinds of wrong with the 350 tuning running a 305 with the 305s stock 02/exhaust configuration. HP Tuners has a utility on their website to convert a .bin to a .hpt file. I have a 305 .hpt file, but I am 100 miles from my tuning laptop it is on at the moment. There are a load of differences between the 305 and 350 tuning. Apples and Oranges in comparison. For my 99 Tahoe that had a L30 running the L31 exhaust setup in my Tahoe, I used a L30 file and edited the exhaust configuration and 02 sensor configuration to match the 350 using Tunercats OBD2. Those settings are not in HP Tuners software. The L31 350 tune barely ran the 305 in the Tahoe and it was all out of whack.
Not much different. Shift points for the 3.08 rear gear, speed limiter and efan is enabled. Timing and fueling wise they are the same as any other L31 of the same year model. Some of the later L31s had less timing advance and more PE delay.On that note where would one acquire a z56 tahoe stock tune? Or is it not even different then a civilian tahoe?
When do you think you can get ahold of the 305 file?There are big differences in a 305 and 350 tune. Most of them cannot be edited with HP Tuners either. Best to start with a 305 tune for a 305 and a 350 tune for the 350. The 305 uses 3 02 sensors before the single cat and 1 after. The 350 uses 1 02 in front and behind each of its dual cats. Closed loop fueling will be all kinds of wrong with the 350 tuning running a 305 with the 305s stock 02/exhaust configuration. HP Tuners has a utility on their website to convert a .bin to a .hpt file. I have a 305 .hpt file, but I am 100 miles from my tuning laptop it is on at the moment. There are a load of differences between the 305 and 350 tuning. Apples and Oranges in comparison. For my 99 Tahoe that had a L30 running the L31 exhaust setup in my Tahoe, I used a L30 file and edited the exhaust configuration and 02 sensor configuration to match the 350 using Tunercats OBD2. Those settings are not in HP Tuners software. The L31 350 tune barely ran the 305 in the Tahoe and it was all out of whack.
Had no idea about the cat and o2 difference, almost sounds like a Cali vs Fed emissions deal. Never really looked at a 305, I always assumed it was setup the same as the 350.big differences in a 305 and 350 tune. Most of them cannot be edited with HP