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bg305 · 04-28-2023, 01:31 PM

I am not advocating anyone do this, nor have I ever tried it myself.. I am just curious to see what others who know more on the subject then I do think..

This video:
https://www.youtube.com/watch?v=sKygJFnDrlc

Claims if I am understanding correctly that they run E85 in a 987.1 Cayman (without cats but claim it would not matter) with no issues relating to running lean.

Everything else I have encountered regarding E85 in general says usually stock tunes will not alter the air fuel mixture to compensate for ethanol's lower power density which ideally should be something like 9.8 to 1 where E10 / regular gasoline is 14.7 / 1. To make it more complicated E85 can actually vary quite widely on Ethanol content anywhere from ~50% to ~%85 which will alter the optimum A/F ratio which is why flex fuel vehicles have a sensor to alter the A/F ration on the fly.

So, can this guy be accurate? is there something here I am missing? Do Porsche ECUs compensate? He mentions that the car ran rich to begin with.. but ~10 or 11 to 1? seems unlikely. I will admit my 986 (with Fabspeed 200 cell cats) has its own unique rich smell to it.. But just pumping E85 in and all is well???

04-28-2023, 01:31 PM	#1
bg305 01 Seal Gray 986 S Join Date: Sep 2019 Posts: 167	E85 stock / no flex sensor / tune.. ?? I am not advocating anyone do this, nor have I ever tried it myself.. I am just curious to see what others who know more on the subject then I do think.. This video: https://www.youtube.com/watch?v=sKygJFnDrlc Claims if I am understanding correctly that they run E85 in a 987.1 Cayman (without cats but claim it would not matter) with no issues relating to running lean. Everything else I have encountered regarding E85 in general says usually stock tunes will not alter the air fuel mixture to compensate for ethanol's lower power density which ideally should be something like 9.8 to 1 where E10 / regular gasoline is 14.7 / 1. To make it more complicated E85 can actually vary quite widely on Ethanol content anywhere from ~50% to ~%85 which will alter the optimum A/F ratio which is why flex fuel vehicles have a sensor to alter the A/F ration on the fly. So, can this guy be accurate? is there something here I am missing? Do Porsche ECUs compensate? He mentions that the car ran rich to begin with.. but ~10 or 11 to 1? seems unlikely. I will admit my 986 (with Fabspeed 200 cell cats) has its own unique rich smell to it.. But just pumping E85 in and all is well???