E85 in the 4.3 Ecotec3, Yes or No?

[Black02Silverado]

Run E85.  It is set up for it. You can also contact BlackBear Performance and see if they can tune it.  I know they do V8's, not sure of V6's.  If they can then you will get even more power out of it.  Well worth the cost of the tune. You also have the advantage of E85 being local and like here it is a $1.00 cheaper than gas. 

 

[lordathey]

I ran E85 for two tanks and noticed a big difference in power and the transmission shifting. I switched back to 87 and I can really tell the difference now. I don't think there is any problems with running E85 because these vehicles were designed to run it.  I have seen vehicles that were converted to run e85 and they have had problems with the fuel system. As far as a tune is concerned I'm waiting for my warranty to expire, so I can run a blackbear tune. 

[bgbdwlf2500]

4 hours ago, tim5779 said:

So you've ran E85 for 8 years and haven't seen any negative affects on the fuel system?  Or did you just begin to run it recently?

 

I have run it the last 2 winters and haven't had any negative effects. I have seen a few posts about this topic where other members have posted and it sounds like they run more than 10% ethanol all the time

[bgbdwlf2500]

4 hours ago, sdeeter19555 said:

Read, but dont get hung up on the procedure.

With the varied alcohol to gasoline content of most flex fuel, you will likely find that you rarely get a true e-85, as "Flex Fuel" can be anywhere from 51% to 85%...it should be marked on the pump.

I'm completely converted to "Flex Fuel" now, and I'm only at 66% alcohol. It should go back up during the summer if things hold...these modern Flex Fuel vehicles don't care what percentage you run, they adjust on the fly. These trucks do report alcohol content, you need just need a way to reading it...I can see it through my Edge Insight. That's why I say not to worry about following the manual, you don't need to run the tank low to switch over.

The ECM doesn't make a determination to alcohol content for about seven to eight miles. And contrary to Internet lore, the system routinely samples the alcohol content in fuel anytime the truck is running, and adjusts as necessary; not just after you fill up. Mine will change everyday...

When they do finally make a determination to the content, they immediately run/feel different. If you have a catch can, watch it closely as they tend to fill up with water fast.

Steve
2012 2500hd 6.0l
 

I did what I was supposed to do, filled up with 87 after running E85 for months. Started it back up and took the truck on a long trip and the computer didn't adjust for the alcohol content which lead to a hard start condition. After reading a few posts on here about it I decided to just fill up with E85 when I got back. It fixed the issue so why my truck got stuck on the wrong percent I don't know. I now have the cheap OBD 2 scanner and its reading 80%, lowest ive seen is 76% in the last month. While I don't think a brand new truck will get stuck on the wrong percentage I would follow the procedure as there are consequences if it doesn't adjust correctly. From what I understand its only supposed to calculate after adding 3? gallons or something like that, which is why they call it a refueling event

[swathdiver]

Right, as Ted mentioned earlier, after a fueling event of 2 or more gallons, it takes about seven miles of driving for the alcohol content percentage to be recalculated.  It also checks and adjusts later on.  With the proper scan tool, you can reset this to zero and your fuel trims and let the computer start over.  Get yourself the GM MDI/GDS2 system.  The old GMT800/900 can use the Tech2.

 

Alcohol content varies and they don't have to tell us here in Florida.  Some stations are 51% another in the 60s and the newest one I've been using is 71% which causes the engine to stall on a remote start once on a cold morning in the 50s or below.  The motor loves FlexFuel, like using race gas but at 1/4 the cost!

[sdeeter19555]

Really, 60%? It was 10f here the other morning and mine didn't miss a beat starting with 66%...mine doesn't start or run any different in cold weather than any other day...but that's a 6.0l also.

Steve
2012 2500hd 6.0l

[amxguy1970]

7 hours ago, bgbdwlf2500 said:

If its a flex fuel then I would run it. these engines really aren't designed to run on 87 octane and you will notice the difference running E85 as they run so much better. I run it in my 2010 all the time unless I have a road trip planned. The mpg is horrible though, I think I'm down to 290 or so miles to a tank but I do let my truck warm up pretty much every morning, been colder than normal here in sc 

What? You have that backwards, they are designed to run on 87. Don't go around telling people they aren't designed to run on 87 when they specifically are. Even the 6.2 runs just fine on 87 and was designed to though it runs much better with 93 as they say in the manual. Think of the 4.3/5.3 with 87 to e85 as the 6.2 is with 87 to 93, they both run just fine as designed but run better with more power with their designated alternative fuel.

 

Tyler

[Grumpy Bear]

1 hour ago, sdeeter19555 said:

Really, 60%? It was 10f here the other morning and mine didn't miss a beat starting with 66%...mine doesn't start or run any different in cold weather than any other day...but that's a 6.0l also.

Steve
2012 2500hd 6.0l
 

I wondered about that. Good info Steve! 

[bgbdwlf2500]

1 hour ago, swathdiver said:

Right, as Ted mentioned earlier, after a fueling event of 2 or more gallons, it takes about seven miles of driving for the alcohol content percentage to be recalculated.  It also checks and adjusts later on.  With the proper scan tool, you can reset this to zero and your fuel trims and let the computer start over.  Get yourself the GM MDI/GDS2 system.  The old GMT800/900 can use the Tech2.

 

Alcohol content varies and they don't have to tell us here in Florida.  Some stations are 51% another in the 60s and the newest one I've been using is 71% which causes the engine to stall on a remote start once on a cold morning in the 50s or below.  The motor loves FlexFuel, like using race gas but at 1/4 the cost!

I'm going to try to ease back into 87 and see if it adjusts for it. You're right though, engine guys are building to run on flex fuel now since the octane is 95 to 110 from what I've read and is way cheaper than race fuel.

1 hour ago, sdeeter19555 said:

Really, 60%? It was 10f here the other morning and mine didn't miss a beat starting with 66%...mine doesn't start or run any different in cold weather than any other day...but that's a 6.0l also.

Steve
2012 2500hd 6.0l
 

I haven't had any issues so far on cold mornings either. Only hard start was when the perce rage was wrong as I said before.

53 minutes ago, amxguy1970 said:

What? You have that backwards, they are designed to run on 87. Don't go around telling people they aren't designed to run on 87 when they specifically are. Even the 6.2 runs just fine on 87 and was designed to though it runs much better with 93 as they say in the manual. Think of the 4.3/5.3 with 87 to e85 as the 6.2 is with 87 to 93, they both run just fine as designed but run better with more power with their designated alternative fuel.

 

Tyler

I see your point, however in my head if you have to pull timing to run on 87 it wasn't DESIGNED to run on it, it WILL run on it. If it was designed to run on 87 they wouldn't have added the timing tables for more octane, it would run the same on whatever fuel was in it. GM knows they can't sell a truck that has a mandatory 93 octane requirement. I stick with E85 except for long trips because the octane is much higher than 93 and it's around 1.00 cheaper than 93. 

[swathdiver]

87 octane is crap, the engines idle and run poorly on it and always get better mileage and run better with 91/93 or FlexFuel.  It costs more to run the lower octane fuels anyway, not just in the reduced mpgs but in the faster wear on the fuel system.  

[tim5779]

1 hour ago, amxguy1970 said:

What? You have that backwards, they are designed to run on 87. Don't go around telling people they aren't designed to run on 87 when they specifically are. Even the 6.2 runs just fine on 87 and was designed to though it runs much better with 93 as they say in the manual. Think of the 4.3/5.3 with 87 to e85 as the 6.2 is with 87 to 93, they both run just fine as designed but run better with more power with their designated alternative fuel.

 

Tyler

Actually, my manual (2017) DOES state that you can run as low as 87 octane, but E85 is preferred.   These motors are 11:1 compression so they are in fact designed to run better on higher Octane fuels...E85 being preferred.  I get that, but my initial question was to see if anyone has run it long enough to notice any long term negative side effects?

[tim5779]

...BUT, it doesn't really matter cause you guys have made up my mind.  There's alot of real world data here, and some damn good experienced opinions as well.  As soon as she hits "E" I'm gonna fill her up with E85 and see what she does.  I'm thinking 15+ horse and 25+ ft/lbs will definitely be blatantly obvious.

[sdeeter19555]

87 octane is crap, the engines idle and run poorly on it and always get better mileage and run better with 91/93 or FlexFuel.  It costs more to run the lower octane fuels anyway, not just in the reduced mpgs but in the faster wear on the fuel system.  

For this very reason I run premium or Flex Fuel...I could care less if it gives more power or better mileage (or not), the truck just runs/feels so much better on the higher octane fuels.

Steve
2012 2500hd 6.0l

[Grumpy Bear]

21 minutes ago, tim5779 said:

Actually, my manual (2017) DOES state that you can run as low as 87 octane, but E85 is preferred.   These motors are 11:1 compression so they are in fact designed to run better on higher Octane fuels...E85 being preferred.  I get that, but my initial question was to see if anyone has run it long enough to notice any long term negative side effects?

Stop the buss. Detonation has little to do with mechanical compression ratio all by itself. It has everything to do with BMEP. That's determined by a combination of mechanical compression ratio AND inlet valve closing angle AND MAP. Knock resistance is even influenced by combustion chamber and piston crown shapes. Operating temperature and fuel strength. Tail gas composition which is influenced greatly by lobe separation angle. Not just a fuels octane resistance. That last one alone can account of 20* at full power. 

 

These motors no only retard spark via a knock sensor they also are equipped with VVT and a bunch of it. It's, in part, why they can run such high static ratios and not detonate at idle. You can run 14:1 on 84 octane if you close the inlet late enough. 

[Fire2968]

From the manual of a 2017 GMC Sierra 5.3

 

If the vehicle has a yellow sticker on the fuel door, E85 or FlexFuel can be used. (See E85 or FlexFuel section)

 

Except the 6.2L engine, use regular unleaded gasoline meeting ASTM specification D4841 with a posted octane rating of 87 or higher. Do not use gasoline with a posted octane rating of less than 87, as this may cause engine knock and will lower fuel economy.

 

For the 6.2L engine, premium unleaded gasoline meting ASTM specification D4841 with a posted octane rating of 93 is highly recommended for best performance and fuel economy. Unleaded gasoline with an octane rrated as low as 87 can be used. Using unleaded gasoline rated below 93 octane, however, will lead to reduced acceleration and fuel economy.  

 

CAUTION:

 

Do not use fuels with any of the following conditions; doing so may damage the vehicle and void its warranty:

 

 - For vehicles which are not FlexFuel, fuel labeled greater than 15% ethanol by volume, such as mid-level ethanol blends (16-50% ethanol), E85, or FlexFuel.