E85 Upgrade?

Badnewcastle · April 22, 2015

Thanks POS, makes sense. Also explains why changing fuel octanes on this 5.3 is so niticable compared to the one I had before.

WendysOrBust · April 22, 2015

I'm baffled on this whole E85 thing... I'm using right now, 1st tank. Definately getting less MPG's but more power which is where the confusion for me comes in. From what read, the MPG drop is due to the fact that a gallon of gasoline has more energy than a gallon of ethanol. If that's the case then where does the extra power come from? Is it just burning that much faster?

Energy does not equal power. Gasoline has more "energy" since less is needed per spark. Due to ethanol properties you have to use more e85 per spark compared to gasoline. This is why you get a decrease in mpg when you switch to e85. Our 5.3's produce more horsepower and torque on e85 because it has a much higher octane rating compared to gasoline, between 100-110 depending on alcohol content. Our ECM's have an alcohol sensor inside the fuel pump which allows the truck to switch to a different timing/fuel mixture which produces more power. About 20hp/20trq to the wheels!

http://gmauthority.com/blog/2013/07/lingenfelter-performance-puts-the-2014-silverado-on-the-dyno-with-video/

I really feel that there should be a sticky on e85. This gets asked about once a month.

Sierra2015 · April 23, 2015

We had e85 on last 2009 Silverado and it didn't seem to make much difference and I believe the engine runs hotter with this type of fuel. So this time around we didn't get it on truck, but if it had it would have been okay too. They also did not charge 100 extra then either for it. Noticed it's not as popular around here as it was in past in WI

WendysOrBust · April 23, 2015

We had e85 on last 2009 Silverado and it didn't seem to make much difference and I believe the engine runs hotter with this type of fuel. So this time around we didn't get it on truck, but if it had it would have been okay too. They also did not charge 100 extra then either for it. Noticed it's not as popular around here as it was in past in WI

The older gen trucks did not have an ECM capable of using different maps to make more power as the new ones do. And that's strange that the engine was running hotter. Traditionally engines run cooler while on e85 and this is what makes it so popular in high horsepower applications.

Sierra2015 · April 23, 2015

I checked it, engines do run cooler on e85, I said I believed which was wrong from a sales person at gmc dealer

Chevyman3308 · April 23, 2015

I just started using E85 and the only thing I have noticed it has a hard time cold starting. Anyone else have this problem? It probably takes a good 3 to 5 seconds to start.

POS VETT · April 23, 2015

That's normal.

SteveBBB · April 24, 2015

I just started using E85 and the only thing I have noticed it has a hard time cold starting. Anyone else have this problem? It probably takes a good 3 to 5 seconds to start.

I have noticed the slow starting with mine, I have used E85 for several tanks. It usually cost about 90 cents a gallon less here.