801535

I've got a jb4 installed, and running 4gal of e70 in the tank at the moment.

ucsbwsr

I would recommend calculating the ethanol percentage in your tank, it is less confusing for non-ethanol users and common practice for people running corn. You are running an ~E22 blend assuming your tank is full.

Do you have the JB4 usb cable?

Evan

801535

In my area the gas is "Winter blend" , and it contains up to 10% ethanol in it. The ethonal station that I go to has been tested to have above e70 rating. I don't really do any of the calculating because I assume running 4gallons or less of e70 is playing it safe for jb4 (map5) setting.

No I don't have a jb4 cable hooked up.

ucsbwsr

I understand why you would assume you are safe running that amount of ethanol. The JB4 E-Series guide on N54Tech.com says you can add 5 gallons in Map 5 and just go.

Understandably so most N54 tuning discussion is focused on E9X cars, unfortunately us E6X guys have more hurdles to clear. Our fuel tanks are a dual-saddle setup as opposed to a traditional single tank found in the 3 series and our low-pressure fuel pumps (LPFP) are not as efficient as our smaller brethren. Even with a brand new HPFP I was only able to run an E25 blend before my sock pumps were struggling to keep up with demand. In contrast some E9X guys can run E40/E45.

I am not saying your oem pumps will mirror the performance of mine but rather it is important to know definitively how your car is working behind the scenes, especially when increasing power, boost, and stress. The JB4 usb will allow you to datalog and record tons of information which really is invaluable for diagnostics and peace of mind. In addition, the usb cable will allow you to customize more user settings and update the JB4 firmware which can really help both driveability and performance (depending on how out-of-date your firmware is). Not to mention to can read and clear DME codes.

I highly recommend the usb cable, it really unlocks the potential of the JB4.
Evan

801535

Thanks for the insight of the Ethanol setup on our e61. I always put E first into the tank, and then fill rest up with Premium gas... The jb4 cables next on my list, and also Fuel it stage 2 pump is also on the list for beginning of next year.

ucsbwsr

Happy to help. The JB4 is a powerful tool and the usb cable helps unlock it's full potential.

Since you plan to further upgrade your fuel system (which I 100% support), take a good look at the Throttle Body Injection kit Fuel it offers. It will allow you to run 100% e85 on your stock turbos with the Stg2 LPFP. It's a well thought out system and if you purchase in conjunction with your LPFP Steve will knock off $100. The added octane of full E85 is nice for performance reasons but since the fuel is injected upstream of the valves it will also help keep them clean, and it may be trivial for some people but I really enjoy not worrying about blending; pull up to the ethanol pump, fill, and go rip.

Evan

801535

Nice...
In my area there's only 1 gas station within 40 mile radius, and It sucks because I eventually want to go 100% e85/e70 in near future. So right now, I grab all 6) 5gallon jugs whenever I'm in the area, and fill them up. So with the inconvenience at times. I was thinking about running water/methonal injections in conjunction with the 91octane and ethanol mix I'm running. My modified 135/335 charge intake charge pipes already have 2) 1/4" meth/psi bung welded into it. So it'll be an easier installation. What do you think about Meth injection?

Thank you.

ucsbwsr

Bummer to hear about the E85 access.

I have no personal experience running meth but if properly setup and controlled it is very beneficial. Guys who are pushing 550+whp are ditching the meth in favor for port injection and more fuel. There have been a few instances of guys cracking pistons and damaging engines in other ways and although meth wasn't the sole culprit, it seemed to play a role. The distribution can be inconsistent since meth is usually injected so far upstream

I would say go ahead and run it and if you are looking to upgrade the turbos or are getting into really high HP, be extra cautious and consider alternative fueling options. Just my opinion.

Evan