4.3 tune/gas octane

MD Chevy · May 24, 2014

I see all these topics about the 5.3 and 6.2, has anyone messed with the 4.3?

How about the gas? Anyone notice power or mpg gains with different gas, 87 vs 93 vs ethanol?

MD Chevy · May 27, 2014

Well I guess I will be the first to try a different octane? Put in 93 today. I will report back any power gains I notice and mpg in comparison to 87 octane.

fondupot · May 27, 2014

You probably wont notice too much of a difference to be honest. Maybe in hotter weather, you would notice the 93 octane more.

But if you are serious about wanting to increase power, get a custom tune. I'm sure Blackbear or the like can tune that 4.3 motor to get a few more good ponies out of it.

PickUPS · May 28, 2014

I tried 93 octane in my 2014 4.3. What prompted me to try was lower-than-expected mileage on a long expressway trip. It is much more efficient at 51-55mph than on the Eway.

I burned 4 tanks, over 2000 miles, of 93 octane. On the expressway it seemed to improve the mileage enough to offset the increased cost of fuel. For non-expressway driving it didn't offer much improvement. However, I really didn't look for better acceleration on 93. I've been satisfied with the power of my 4.3 but I am certain that fuel octane level alone won't produce near the power of my 2004 4.8 V8.

txab · May 28, 2014

If your 93 is non-ethanol, that would explain your mpg increase

MD Chevy · May 31, 2014

Well I am only 1/4 of the way through my tank. Gas mileage seems to be up at this point (at least more accurate with the DIC) and performance seems to be the same. I will say it idles smoother but that's it. Don't know if its worth it yet.

Brian S. · June 8, 2014

I tried 93 octane in my 2014 4.3. What prompted me to try was lower-than-expected mileage on a long expressway trip. It is much more efficient at 51-55mph than on the Eway.

I burned 4 tanks, over 2000 miles, of 93 octane. On the expressway it seemed to improve the mileage enough to offset the increased cost of fuel. For non-expressway driving it didn't offer much improvement. However, I really didn't look for better acceleration on 93. I've been satisfied with the power of my 4.3 but I am certain that fuel octane level alone won't produce near the power of my 2004 4.8 V8.

I've got good news for you.

Your 2014 4.3l has the same horsepower and more torque than your 2004 4.8l V8, and only 10% less than the 2010 5.3l I replaced with the 4.3l.

GM did this engine right, it replaces the old 4.8l and 5.3l very nicely, and kicks the minivan V6s in the Ram and Ford to the curb. Max torque at far lower RPMs on the new GM 4.3l.

MD Chevy · June 8, 2014

Went back to 87. My mileage was the same so no use spending the extra money. I will try E85 when I can get my hands on it.

I will say I love the power of this truck. I don't need more as all my towing will be 6000 and under. It has more power than my 2004 extended cab 5.3, much more power than 2009 crew cab 4.8 and close to the power of my brothers 2013 crew cab 5.3.

patriot · June 8, 2014

E85 will kill your MPG, but you'll gain power.

MD Chevy · June 8, 2014

As long as it is cost effective I'm fine. The 93 was not. E85 might be, time will tell.

stealthhtm · June 21, 2016

You probably wont notice too much of a difference to be honest. Maybe in hotter weather, you would notice the 93 octane more.

But if you are serious about wanting to increase power, get a custom tune. I'm sure Blackbear or the like can tune that 4.3 motor to get a few more good ponies out of it.

who is this Blackbear you speak of?