[ZLE dude]

Originally Posted by 7LitreC5

Max ethanol content for you is going to be different than most of the others here because of your altitude. You make less power so you can run more E%. I would recommend that you get a gauge (Banks will do it) or buy HPT so that you can monitor the low side fuel pressure and ethanol content.

I am running a Magnuson 2300 with 80mm pulley, NW 103mm tb, and a Roto-Fab Big Gulp. At my altitude, I see 11.5 psi of boost. I am running E85 out of the pump from Kum and Go which actually 66% ethanol. My low side is dropping on a long pull. I will be fixing that with a JMS.

If I were near sea level there is no way that I could run E66 with my mods.

So here's where i got confused. I also assumed it would be my low side but the JMS voltage booster is doing it's job well. My low side pressure never waivers from 73psi, but as soon as I get over E60, like E65 for instance, my high side pressure will nose dive from 2900psi down to around 1200-1500. Keep it under 60% and it will maintain 2900psi no problem. Luckily I've got a Banks Data Monster and watch/log everything 24/7 so it was easy for me to see that it didn't like it. I also hooked up my HPtuners and logged pulse width and it showed similar poor results above 60%. BUT, every car is different, these are only my results.