Extra fuel filter necessary w/ E-blends? (Aka not full E85)

[TouringM3]

Hey Buds -

Now that the wagon is built and the crank hub has been upgraded I’m excited to dabble with tunes, fueling, all the things. Of course I want to be smart and not ruin a good thing, so here’s my question:

I know that Bend Calibration sells an inline filter, flex fuel sensor, and others have hooked up radium filters when running e85. They also have a pretty meticulous recommended process when starting to run E85 and a few filter replacements. Better safe than sorry when it comes to clogged fuel systems, I def. get that.

I haven’t heard of - or found posts - referring to the need or safe benefit of adding a filter when running E30 / E50 ish blends. I would naively assume that any significant amount of Ethanol would necessitate adding a filter? What do you all think?


~David

[Commanderwiggin]

When in doubt, run a proper filter imo.

[slaughter.mode]

• I ran 50K of total mileage of mostly E85 and alternating pump gas on my 2015 F80.
  
• I'm just passing the 10K mark of miles now running a custom flex tune on my F82 (Ethanol content is usually 75% and above).

Both builds I've never touched the fuel filters and never had any problems.

People have 'told' me that running full E85 will chew away at the deposits left behind by pump fuel and clog my injectors but I haven't ever seen that happen.

For every full E85 tank I pour a few ounces of PowerPlus top lube.

I was thinking of running the STP Ethanol Fuel System Cleaner every 4K (works with DI) because of all these threads about filtration but we'll see.

[c4ss]

I ended up doing the recommended Bend protocol. Problem is, you don't know what kind of crap is in your gas tank until it's stuck in your injectors. If you've got poor quality fuel by you it's a no brainer IMO.

[slaughter.mode]

Originally Posted by c4ss

I ended up doing the recommended Bend protocol. Problem is, you don't know what kind of crap is in your gas tank until it's stuck in your injectors. If you've got poor quality fuel by you it's a no brainer IMO.

I feel you but also, that's just it. The factory fuel filter is absolutely equal to or superior to the Bend's offering and it sits in the gas tank and in the fuel. I've never seen a dirty one, ever. I've seen them because of pump upgrades. They're lifetime service items for a reason.

Bend is one of the pioneer developers of a 'bolt on' ethanol content analyzer product and 'took it a step further' in service of reliability by adding the filter but I know dozens of S55 owners who never bothered with these units and have been just fine. If I was Bend and the market didn't have much else to offer and I knew I was one of the best tuners out there (which they definitely are) I'd have done the same exact thing for the revenue boost. Anything that's for 'reliability' is a easy and justified sell, even if there's no data to prove it's worth.

MHD and PTF now have simple 15 minute DIY iterations that produce the same results and also work directly with the CANBUS. I'm very happy with mine and my Flex Tune. I would say honestly as these platforms begin to pick up in sales, don't be surprised if you see a Bend iteration come right after.

Maybe I'm just lucky but these Ms are everywhere in California and we have crappy ass ACN91 gas and I can't think of a single instance of where a injector failed due to the fuel filter not doing it's job.

[theweebabySeamus]

I thought the OE filter went down to 100 microns and the Bend one went to down to 10?

[slaughter.mode]

Originally Posted by theweebabySeamus

I thought the OE filter went down to 100 microns and the Bend one went to down to 10?

OEM is 10 but been tested as low as 4.4 from what I just googled.

[TopJimmy]

Many vendors use scare tactics.

"Don't believe da hype!"
-Public Enemy

Ethanol only causes gunk when it absorbs moisture from the air, which takes months. If you buy Pump E85 from a gas station then it's probably fresh. Ethanol in Pails are sealed with a pull-tab top, so it can't absorb moisture when unopened.

The only way you will create problems is letting a partial tank of E-mix sit in your tank for months. Buying old open pails is also a bad idea.

If you plan to leave a car sit for <60 days just leave it mostly empty and fill up with fresh E for use. For >60 days run the E down to — — and add 4 gallons of gas. The E25 presents less alcohol surface area to the air, and it'll run fine on a gas tune. To use the car go drive down to — — and fill with E again.

[Commanderwiggin]

So if a filter is meant to last a lifetime there is no way it's a low (<10) micron filter element. Secondly if you look at all BMW Diesels and factory equipped E85 compatible cars (Ex: Brazil) you'll see they're equipped with serviceable fuel filters exactly where the bend kits are. To add to this there are many cases where injectors are failing due to both wear on the pintles and media plugging causing imbalanced flows.

[Commanderwiggin]

Originally Posted by f82.959

OEM is 10 but been tested as low as 4.4 from what I just googled.

Link?

[slaughter.mode]

Originally Posted by Commanderwiggin

Link?

I'll try to dig it up, it wasn't an official BMW document so I didn't bother but it was one of those nerdy sites like Bob is the Oil Guy so I felt it had some validity to it.

A while back I had a issue with my F80, it was just dying. It turned out being the pump itself but I asked my SA about fuel filter replacement since I couldn't find any BMW published information about it and he said that they are 10 micron for fuel burning BMWs and 30 micron for diesel burning BMWs. He coulda pulled numbers out his ass but the fact he had the answer as I asked it gave me some assurance that it's legit. He also told me there's nothing in the CBS or timed maintenance that indicates fuel filter replacement. Take that FWIW.

[c4ss]

Originally Posted by f82.959

I feel you but also, that's just it. The factory fuel filter is absolutely equal to or superior to the Bend's offering and it sits in the gas tank and in the fuel. I've never seen a dirty one, ever. I've seen them because of pump upgrades. They're lifetime service items for a reason.

Bend is one of the pioneer developers of a 'bolt on' ethanol content analyzer product and 'took it a step further' in service of reliability by adding the filter but I know dozens of S55 owners who never bothered with these units and have been just fine. If I was Bend and the market didn't have much else to offer and I knew I was one of the best tuners out there (which they definitely are) I'd have done the same exact thing for the revenue boost. Anything that's for 'reliability' is a easy and justified sell, even if there's no data to prove it's worth.

MHD and PTF now have simple 15 minute DIY iterations that produce the same results and also work directly with the CANBUS. I'm very happy with mine and my Flex Tune. I would say honestly as these platforms begin to pick up in sales, don't be surprised if you see a Bend iteration come right after.

Maybe I'm just lucky but these Ms are everywhere in California and we have crappy ass ACN91 gas and I can't think of a single instance of where a injector failed due to the fuel filter not doing it's job.

I see both sides of the argument, but it's such an easy part to swap out. It's peace of mind for me.