Needing answers about running B2-B20 in the 6.2L or 6.5L

[GM Guy]

I just found out that there is a b20 source at the next town over, and I was wondering if it is safe to use in a 6.2L/6.5L?

do I need to raise or lower lubricity additive concentration?
do i need to refrain from using it in either of the pump systems? (DB2 or DS4)
does anything special need to be done, besides packing extra filters?

I am curious about running biodiesel in the ol 6.x IDIs, and any input to this thread is greatly appreciated!

 

[guybb3]

Those concentrations are fine. No lubricity additives needed with any BIO in the fuel.

 

[jrsavoie]

I ran some about B20 in all of my vehicles for at least 500 gallons worth.
No problems.
I buy B11 when ever I buy. As that is what they have available off the truck. AT least once I bought another 50 gallons of straight soy and added to the tank before I had it filled.
But occasionally here they get a bad batch of soy oil. It's happened twice. Once in the winter making it especially bad. They run 3-4% in the winter around here.
I got one tank full in my 94. First time I ever thought I gelled up. The combination of the bad soy and the crap in my tank plugged my sock.
I like getting 500 gal at a time then if you have a problem there is no question that it was the fuel.

If you haven't been running soy you might want to start slow - I started at 3% and worked my way up to B-11. A couplf of friends filled out of my tank with B-11 and had plugged filters within a 1/3 of a tank consumption.
They said "your fuels is bad."
It was working fine in all of my vehicles.

 

[btfarm]

You'll likely go through at least 2 filters pretty quick due to the solvent effect cleaning your fuel system but once clean you should be good to go. Bio is a good pump lube but I usually run PS (silver bottle) every other tank to make sure and in winter every tank gets PS (white bottle). I don't have a sock to worry about like you do though.

 

[GM Guy]

so as far lubricity additives go, with B2 or greater, I dont need to use any, but if i want to, make sure that it is biodiesel compatable (IIRC, about every mainstream additive is biofuel compatable, Lucas, PS, Howes, etc)

but other than that pack extra filters and i am good to go?

 

[jrsavoie]

That's it.

 

[Pruittx2]

Hell I make my own,, and have run it at B90,, the truck loves it! Nice and quite,,
The thermal output of bio is about 10% less that diesel. So you will see a slight decline in MPG if you use B100, but some test have shown that at B20 the mileage is the same if not a tick better. Just keep an Eye on outside temp.

 

[GM Guy]

sounds like i have nothing to worry about, Ill try it out as soon as i get back from harvest.

thanks guys!

 

[Bernie]

For awhile I was running B10 in mine and it loved it. Ran smoother, cleaned a lot of junk out of the system and gave me about 2 MPG better mileage. The price was reasonable too, only a dime a gallon more than regular diesel (which I attribute to the station being right alongside an I-95 exit vs. the station I usually buy diesel from being a few miles away) so, with the 2 MPG increase, still made it cheaper to run. Then the station carrying it started playing games... I'd go in one week and it was marked as B10, the next week it was B5, the following week back to B10, then down to B2, but the price stayed about the same. Then, a week or two after they went to the B2 I noticed they did away with the bio completely, and bumped the price 15 cents per gallon, so I stopped buying there. Unfortunate, because that was the only station within 30 miles that carried bio.

 

[Acesneights1]

I can buy the stuff wholesale. I wouldn't run it. It eats the crap out of the fuel system overtime. You should really run Viton lines and o rings. The db2 is a pretty tough IP.

 

[Bernie]

I can buy the stuff wholesale. I wouldn't run it. It eats the crap out of the fuel system overtime. You should really run Viton lines and o rings. The db2 is a pretty tough IP.

I'm not sure just what you're saying you can buy wholesale. Can you clarify that a bit?

 

[WarWagon]

Running B99 in mine from time to time from AZBiodiesel a local refiner.

MPG goes down 10% due to less BTU content.

The lift pump is the first thing to commit suicide with it. Get a Walbro FB5 fuel pump rated for biodiesel or a less rated Carter rotary vane pump. The AC Delco pumps live longer than the Autozone ones. But something in the Bio eats the valves out of the stock lift pumps.

Next thing to change is the supply and return lines on the back of the engine. The factory ones are so old now that they will leak with bio.

DB2's tend to drop idle RPM with bio and may stall. Nothing wrong, just adjust the idle and TPS.

 

[Acesneights1]

I'm not sure just what you're saying you can buy wholesale. Can you clarify that a bit?

I am a fuel dealer and can get it at cost and still wouldn't run it.

 

[JeffMD]

I have been running B100 almost exclusively in my truck for the last three and a half years. As I understand it GM went to Viton lines during the 1993 model year. I have had no fuel related mechanical issues. The only problem I had was I didn't cut it with enough dino Diesel one time last winter. Used the power service red bottle and problem solved.

 

[Bernie]

I generally use the PS additives year round, regardless of what fuel blend I'm running. Silver in the summer and the white bottle during the colder months. As I said above, I've run B10 and B5 in the truck with no issues at all (other than a really dirty filter after the first couple of tanks full - which I watched for and changed) and even saw a 2 MPG increase with the B10 blend. Whether that was due to the cleaning action of the bio or not, I can't say, I just know what the numbers show when using it in my particular truck.

 

[redshift96]

I've now had three different 6.2's that I've taken from dino to B99 (B100 really, but labeled B99 for gummint purposes), with nothing but an extra fuel filter change or two along the way. No failed IPs, no failed mech fuel pumps, no injector probs, no rotted or softened lines. Some of the lines were still the originals (from '85; 86; and 90). So yeah, I wouldn't worry about it.

Can't remember where I read it, but I definitely recall someone mentioning that GM's fuel line materials changed at some point in the 80's. So if you had an '82 - '84, it might be worth proactively upgrading the lines, but otw, unless they're looking dry or cracked or swollen already, I wouldn't worry about it til you've gone through a couple tanks or so... then inspect for leaks or softening/swelling. Then again after a dozen or more fillups.

Buy an extra filter, fill 'er up, and go!

The oil source for most of the bio I buy comes from the waste cooking oil from the Nevada casinos. Sometimes I'll still start it up after work and think... damn, who's cooking dinner?.. before remembering that's what my exhaust smells like now. Makes me happy every time I realize I'm not breathing dino.