Got a 4.3L V6? Use E85 !

SouthernSilveradoGuy85 · December 19, 2014

"for the V6: 285hp@5300; 305ft-lb@3900; "

Those numbers increase to 297hp @ 5300, 330ft-lb @ 3900 with the V6 on E85, makes it drive a lot like last year's 5.3l on E10.

(which had 315hp @ 5200,335ft-lb @ 4000RPM)

Ya but you put E85 in a 5.3 then the HP goes from 355 to 380 @5,600 and the TQ from 383 to 416 @4,100.

arkenzo · December 19, 2014

The reason I use 91 over 87 is better quality gasoline, there are better detergents in 91 and it's only a few cents more a gallon so WHY NOT use it over the standard 87 which could possibly cause issues like KR, which could rob you of performance and not allow your engine to run safely and at it's full potential.

It's only a few cents more, so use it

KARNUT · December 19, 2014

I'm not talking about E85. I'm talking about regular 87-91 octane. My 5.3 is designed for 87 and E85, so if I filled up with 89 or 91 octane then there won't be any difference in performance. On the other hand, if an engine is designed (or after tune) for 89 or 91 and you put in 87 I believe it will lower the performance from what I've read. So all in all, just put in what the engine is designed run on. It's that simple.

If you read the tuning section you will fine that the 5.3 doesn't like 87 gas. Its a high compression engine, it gets knock retard and pulls timing. So your truck runs better on 93,E85 much better than 87.

arkenzo · December 19, 2014

If you read the tuning section you will fine that the 5.3 doesn't like 87 gas. Its a high compression engine, it gets knock retard and pulls timing. So your truck runs better on 93,E85 much better than 87.

Makes a lot of sense, just because a car can run on 87 safely, doesn't mean it's going to run at it's full potential and safely. Gasoline is one thing I don't mess around with, use the good stuff and call it a day.

SouthernSilveradoGuy85 · December 19, 2014

If you read the tuning section you will fine that the 5.3 doesn't like 87 gas. Its a high compression engine, it gets knock retard and pulls timing. So your truck runs better on 93,E85 much better than 87.

I must have read my manual wrong, I guess I was speed reading. It said 87 or higher though. It said if you run lower than 87 then you may hear knocking. All I've run so far in almost 9,000 miles was 87 and haven't had any issues or heard anything weird. So I was right about not running a lower octane that the engine is designed for. I guess engine tech has gotten to where you can run higher octane and will make some difference, but really just mileage. But, being that 89 and 91 cost more I'm not sure if it would cost more or less to run a higher octane. I know it used to be where you shouldn't run a higher octane because it won't effect anything so you're just wasting money. At this point higher octane seems to get better mileage, but costing more per mile it's hard to say if you really save or not. I'll also add I've never gotten gas from a mom and pop type store, only the bigger chains or at least where it has a sign with a bigger distributor like Shell or BP.

KARNUT · December 19, 2014

I must have read my manual wrong, I guess I was speed reading. It said 87 or higher though. It said if you run lower than 87 then you may hear knocking. All I've run so far in almost 9,000 miles was 87 and haven't had any issues or heard anything weird. So I was right about not running a lower octane that the engine is designed for. I guess engine tech has gotten to where you can run higher octane and will make some difference, but really just mileage. But, being that 89 and 91 cost more I'm not sure if it would cost more or less to run a higher octane. I know it used to be where you shouldn't run a higher octane because it won't effect anything so you're just wasting money. At this point higher octane seems to get better mileage, but costing more per mile it's hard to say if you really save or not. I'll also add I've never gotten gas from a mom and pop type store, only the bigger chains or at least where it has a sign with a bigger distributor like Shell or BP.

I cant say if it will hurt anything but performance some. I notice before I started using E85 I seemed to get better mileage on 93 gas. But that's speculative too. All the tuners said there is quiet a bit of KR with 87 and 89 gas.

arkenzo · December 19, 2014

I know E85 has robbed me of some MPG's compared to 91, but my heavy foot contributed to that. I'm going through this first tank of E85 pretty quickly, when I fill up again on E85 I'll drive it regularly and report back.

SouthernSilveradoGuy85 · December 19, 2014

I haven't really done the math. Right now 89 octane cost 20¢ more than 87 and 91 cost 40¢ per gallon more than 87. Times that by 20 gallons (gauge is at 1/4 full with a 26 gallon tank which mine is) then that's $8 more for 91. Can someone chime in on which would be cheaper for the full run of the tank, more mileage but cost 40¢ more per gallon.

KARNUT · December 19, 2014

I know E85 has robbed me of some MPG's compared to 91, but my heavy foot contributed to that. I'm going through this first tank of E85 pretty quickly, when I fill up again on E85 I'll drive it regularly and report back.

I lost 2MPG in town, 3 on the HWY.

redwngr · December 19, 2014

I cant say if it will hurt anything but performance some. I notice before I started using E85 I seemed to get better mileage on 93 gas. But that's speculative too. All the tuners said there is quiet a bit of KR with 87 and 89 gas.

Which engine?

(you could add it to your avatar info)

My dealer has told me he has customers with 5.3L that are finding better mileage, on 14/15 5.3L with 93 vs 87. (he didn't have/offer info about E85 vs 87, and since I can't run it I didn't ask)

redwngr · December 20, 2014

I must have read my manual wrong, I guess I was speed reading. It said 87 or higher though. It said if you run lower than 87 then you may hear knocking. All I've run so far in almost 9,000 miles was 87 and haven't had any issues or heard anything weird. So I was right about not running a lower octane that the engine is designed for. I guess engine tech has gotten to where you can run higher octane and will make some difference, but really just mileage. But, being that 89 and 91 cost more I'm not sure if it would cost more or less to run a higher octane. I know it used to be where you shouldn't run a higher octane because it won't effect anything so you're just wasting money. At this point higher octane seems to get better mileage, but costing more per mile it's hard to say if you really save or not. I'll also add I've never gotten gas from a mom and pop type store, only the bigger chains or at least where it has a sign with a bigger distributor like Shell or BP.

You didn't read it wrong.

From 2015 manual:

For all vehicles except those with

the 6.2L V8 engine, use regular

unleaded gasoline meeting ASTM

specification D4814 with a posted

octane rating of 87 or higher. Do not

use gasoline with an octane rating

below 87, as it may cause engine

damage and will lower fuel

economy.

If the vehicle has the 6.2L V8 engine

(VIN Code J), use premium

unleaded gasoline meeting ASTM

specification D4814 with a posted

octane rating of 91 or higher.

Regular unleaded gasoline rated at

87 octane or higher can be used,

but acceleration and fuel economy

will be reduced, and an audible

knocking noise may be heard. If this

occurs, use a gasoline rated at 91

octane or higher as soon as

possible. Otherwise, the engine

could be damaged. If heavy

knocking is heard when using

gasoline with a 91 octane rating or

higher, the engine needs service.

KARNUT · December 20, 2014

Which engine?

(you could add it to your avatar info)

My dealer has told me he has customers with 5.3L that are finding better mileage, on 14/15 5.3L with 93 vs 87. (he didn't have/offer info about E85 vs 87, and since I can't run it I didn't ask)

5.3

Sent from my iPhone using Tapatalk

Brian S. · December 20, 2014

Ya but you put E85 in a 5.3 then the HP goes from 355 to 380 @5,600 and the TQ from 383 to 416 @4,100.

Ya but this thread is about the 4.3l and E85, so I didn't bother posting anything off topic like what the Chevy 5.3 gets for hp. That would be off topic.

SouthernSilveradoGuy85 · December 20, 2014

Ya but this thread is about the 4.3l and E85, so I didn't bother posting anything off topic like what the Chevy 5.3 gets for hp. That would be off topic.

For some reason I was thinking that I was in the other thread about the 4.3 and 5.3.

Fire2968 · December 20, 2014

The reason I use 91 over 87 is better quality gasoline, there are better detergents in 91 and it's only a few cents more a gallon so WHY NOT use it over the standard 87 which could possibly cause issues like KR, which could rob you of performance and not allow your engine to run safely and at it's full potential.

It's only a few cents more, so use it

99% of the time is this incorrect. It is the same fuel with the boosters added in at the pump level as it comes into the nozzle.

If you go to almost any gas station they will have 2 tanks. One for Gasoline and one for Diesel. The 87,98,91 change is just additive.