That aside, mucking with the engine computer on-the-fly sounds very risky to me.
Something like accessport?
Thread Starter
Heel & Toe
Joined: Jun 2021
Posts: 17
Likes: 0
Something like accessport?
Hello - I'm curious - if there is an accessport available where you can keep it plugged and change tunes on the fly? I think I saw something like that but it didn't really explain much about being able to hotswap tunes. I only ask because I'm thinking of doing the E85 flexfuel thing and would like to be able to flip and flip back and forth depending on what's available. Thoughts?
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,475
From: South Florida
There is no such device for the GM ECU's. IT is more the ECU itself rather than the technology to do so. The Cobb AP's can do on the fly tunes with Subaru's and a few others because the factory ECU's allow this sort of communication. The GM ECU's do not, or at least it has not been figured out yet.
If you're going to do E85 Flex fuel, why do you want to swap tunes? Flex fuel means the ECU automatically adjusts to the Ethanol content and adjusts the tune on the fly. I really don't see any reason on a non turbo car to have adjustable tunes on the fly. The only reason to adjust on the fly in a turbo car is because its easy to turn down the wastegate and drop timing so that you can vary power levels at WOT. That is not the case with the LT1 or LT4.
If you're going to do E85 Flex fuel, why do you want to swap tunes? Flex fuel means the ECU automatically adjusts to the Ethanol content and adjusts the tune on the fly. I really don't see any reason on a non turbo car to have adjustable tunes on the fly. The only reason to adjust on the fly in a turbo car is because its easy to turn down the wastegate and drop timing so that you can vary power levels at WOT. That is not the case with the LT1 or LT4.
Burning Brakes
Joined: Feb 2018
Posts: 906
Likes: 196
From: Northeast, PA
There is no such device for the GM ECU's. IT is more the ECU itself rather than the technology to do so. The Cobb AP's can do on the fly tunes with Subaru's and a few others because the factory ECU's allow this sort of communication. The GM ECU's do not, or at least it has not been figured out yet.
If you're going to do E85 Flex fuel, why do you want to swap tunes? Flex fuel means the ECU automatically adjusts to the Ethanol content and adjusts the tune on the fly. I really don't see any reason on a non turbo car to have adjustable tunes on the fly. The only reason to adjust on the fly in a turbo car is because its easy to turn down the wastegate and drop timing so that you can vary power levels at WOT. That is not the case with the LT1 or LT4.
If you're going to do E85 Flex fuel, why do you want to swap tunes? Flex fuel means the ECU automatically adjusts to the Ethanol content and adjusts the tune on the fly. I really don't see any reason on a non turbo car to have adjustable tunes on the fly. The only reason to adjust on the fly in a turbo car is because its easy to turn down the wastegate and drop timing so that you can vary power levels at WOT. That is not the case with the LT1 or LT4.
OP, what he means by "turning down the wastegate" is the ECU can control boost by opening the wastegate sooner to limit PSI, it can also keep the wastegate closed longer to run a higher PSI.
Thread Starter
Heel & Toe
Joined: Jun 2021
Posts: 17
Likes: 0
There is no such device for the GM ECU's. IT is more the ECU itself rather than the technology to do so. The Cobb AP's can do on the fly tunes with Subaru's and a few others because the factory ECU's allow this sort of communication. The GM ECU's do not, or at least it has not been figured out yet.
If you're going to do E85 Flex fuel, why do you want to swap tunes? Flex fuel means the ECU automatically adjusts to the Ethanol content and adjusts the tune on the fly. I really don't see any reason on a non turbo car to have adjustable tunes on the fly. The only reason to adjust on the fly in a turbo car is because its easy to turn down the wastegate and drop timing so that you can vary power levels at WOT. That is not the case with the LT1 or LT4.
If you're going to do E85 Flex fuel, why do you want to swap tunes? Flex fuel means the ECU automatically adjusts to the Ethanol content and adjusts the tune on the fly. I really don't see any reason on a non turbo car to have adjustable tunes on the fly. The only reason to adjust on the fly in a turbo car is because its easy to turn down the wastegate and drop timing so that you can vary power levels at WOT. That is not the case with the LT1 or LT4.
Burning Brakes
Joined: Feb 2018
Posts: 906
Likes: 196
From: Northeast, PA
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,475
From: South Florida
The important part here is the Flex Fuel sensor.
Last edited by Internets_Ninja; Jun 26, 2021 at 11:27 AM.
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Thread Starter
Heel & Toe
Joined: Jun 2021
Posts: 17
Likes: 0
Who does this magical tune? I haven't been able to find it anywhere's (probably because my search parameters are crap hahaha
Safety Car
Joined: Mar 2004
Posts: 4,048
Likes: 1,475
From: South Florida
I am one of many remote tuners that use HPTuners to tune cars for flex fuel and other mods. It requires the owner to have their own HPTuners software and cable and to license their ECU. You can find a few tuners on here and a few more on HPTuners forum.
Last edited by Internets_Ninja; Jun 26, 2021 at 05:05 PM.
Burning Brakes
Joined: Feb 2018
Posts: 906
Likes: 196
From: Northeast, PA
You will need a flex sensor installed to run E-85.
Where are you located? People might be able to chime in and tell you where to take it that's reputable.