Hey guys my monte is heavily modded. Gen 3 ported in and out matching lim 3.0 pulley xp cam stage 3 zzp heads 2 short stack intercoolers wiz air intake currently on 42.5 green giant injectors aem in tank high flow fuel pump, Zzp transmission 3.29s few more mods on my page. Should I go to e85? I know I'll need the e85 fuel pump and 60# injectors. Any input guys? Thanks

 

Seems the people I talk to using E85, they don't like the average 30% decrease in fuel economy

 

Yea that's true but I want more power
From my setup. Is the power gain worth it?

 

I have used this several times once in the SUV by mistake someone else filled the tank and It actually robbed power from the vehicle.
Then I usually get a new rental that is flex fuel and Have tried it in those as well to see once how they do. No improvement and a loss off acceleration and fuel economy has been the result.
So the only thing you can do is try it and see what happens?

 

Yea will do, plus remember your SUV wasn't tuned for it so in sure it threw it off but according to my tuner I will get a decent gain

 

Which pump do you have now? I wouldn't think you would 'need' the E85 pump. Most gas pumps seem to work just fine with E85. Pump life can be shortened, but I'd sure hate to go through all the work of another pump swap until it was absolutely needed.

I've got the monte on E85 now, it's been working well so far. I've also had a lot of buddies over the years make the switch, and the majority love it.

There are a few cons:
-gas mileage (obviously)
-availability (depending where you live it can be better than other places, but its not like you're just going to hop in the car and aimlessly take a road trip).
-cold starting (the colder it gets, the harder it is to start - especially if you keep with straight E85 like from VP or something; the colder states will automatically change their blend in colder months to add more gas)
-variable mix ratio (continuing on the thread above - the mix ratio is not always 15/85. The stations automatically switch over in certain months to different mixes, so you have to be ready for this in your fueling. The solution is obviously to buy a drum from a place like VP, but that stuff is far more expensive than pump E85)

The one main pro is obvious - higher octane. You can run a lot more boost and timing without KR. It's cheap race gas.


Keep in mind, you're not going to magically pick up huge power just from the fuel switch. The big power gains come from adding in more timing and boost. I'm not sure how much you're pushing timing, but it doesn't look like you've got a ton of boost to add still by starting off with a 3.0". You could definitely drop to a 2.8" with the swap and have full timing, but it's sort of a diminishing return from there down to a 2.55"- you're just getting so far out of the efficient range of the M90 at that point.

Since you'll already have heads/cam/IC and E85, the next real step is going to be a turbo setup if the E85 and smaller pulley isn't enough.


If the SUV that was accidentally filled with E85 was not a flex fuel vehicle, then it should be expected to lose power. The fuel mix ratio is much different between 'straight' gas (the usual 10% ethanol blend) and E85, so if the pcm is expecting one fuel, and you give it something different- it can have a hard time trying to compensate.

Also, it should be expected to lose fuel economy switching to E85. The stoich air/fuel mix ratio takes a lot more fuel, so you will always lose MPG. To offset this, E85 is typically cheaper to make it closer to a wash. However, if you're concerned about MPG at all, E85 is not the way to go. Being that the OP has already done heads/cam/taller gears, etc- he's obviously more concerned about power anyways.

As for the rental not picking up power / acceleration - that is completely normal. It would be no different that taking a regular gas vehicle and filling it up with 100 octane unleaded race gas when it's designed to run on 87- there are no gains to be had. Most of the flex fuel cars run on E85 or 87 octane E10, so they typically don't run a ton of timing and don't usually have crazy high compression to take advantage of the octane. As a result, you don't typically gain power by switching.

The people who rave about big power gains are almost always people changing to it on a boosted car. With a boosted car, you can take advantage of the higher octane by cranking the boost (smaller pulley / adjusted WG setttings). Sure there are some people who have a crazy high compression NA setup that run it- but since compression isn't adjustable, they were probably planning on race gas or E85 when they built the engine with that much compression.

 

I second everything bumpin said! Good post sir!

 

Nice write up!! Thanks for taking the time to explain all that in a way that was easy to understand.

 

yea bumping great post back thanks. exactly the 2.8 i feel is too low on the gen 3 yet it is ported to match a gen 5. the 3.0 from a 3.1 I'm currently on will definitely help a bit though. also i have the in tank aem high flow fuel pump from zzp. rewire kit and I'm also getting the 60# dekas and new fuel filter as we speak for the e85 swap

 

I also agree with everything that bumpin said. e85 is the way to go and once I get my Monte back together, that's exactly what I'll be using too.