Splash Blending with E85

[Robb235]

Been reading about running E85 in a naturally aspirated vehicle that wasn't designed as a flex fuel. Some people say there's no benefit unless you're running forced induction. Others report a decent gain in power by doing nothing more than running E85 and supplying the additional fuel it demands. There was a thread somewhere on one of the LS1 forums where a naturally aspirated motor gained 5% or 7% power or something just from switching to E85.

I decided to give it a shot. I don't know if the ECM's Long Term Fuel Trims can adjust far enough to account for the 30% stoich difference between gas and E85. Some people say it can adjust +/-20%, others say it's more like +/-35%. So I decided to mix gas and E85 to make an E50 mix. I've gone through probably 8 tanks now running the E50 mixture.

First thing I noticed is that my LTFTs are now anywhere between 15-18%, depending on load and RPM. So the ECU is definitely adding fuel to compensate for the richer mixture that the E50 requires.

Next thing I noticed is that the engine is smoother and more responsive. It has a bit more power. It's not like adding a supercharger or anything, but the E50 mix does give it more of a kick in the pants. Nice when merging on the interstate.

It's hard to tell what the impact to my MPGs is, since I mainly use my 4Runner to drive to and from work. With regular gasoline my mileage varied so much depending on traffic, how long I let the engine warm up, how many times I'd make short trips, etc. I haven't noticed much difference in my mileage.

I did get to track one 255 mile road trip from Knoxville to Clarksville, TN. Even with sitting in a Nashville traffic jam, I returned 20mpg. I typically get 20-21ish on regular gas depending on how much I pay attention to my MPGs. So 20mpg wasn't the big mileage hit I was expecting.

I don't have any real reason for running E85, other than experimenting and playing around, and now to utilize the small bump in power I get.

Figured I'd share my results.

EDIT: Forgot to mention that it takes a little longer to start when cold now. Maybe an extra second at most to crank.


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[2016 4Runner SR5]

I don't see this ending well. Nothing to support that other than gut feeling. Keep us posted over the next 6 - 12 months and let us know what happens.

 

[Robb235]

I don't see this ending well. Nothing to support that other than gut feeling. Keep us posted over the next 6 - 12 months and let us know what happens.

I'm not too worried. There's lots of older cars that are running E85 with no ill effects. Go to the MR2 forums and you'll see those guys have been running E85 (turbos love E85) for years on cars older than ours. I don't anticipate running E50 to be a problem in the long term.


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[thecole1098]

Perhaps THAT is why you are dying when idling

Not saying that is why, but these engines are not designed to be running E85.

 

[Robb235]

Perhaps THAT is why you are dying when idling

Not saying that is why, but these engines are not designed to be running E85.

Ha, I knew someone would say that. That's a separate issue because it would happen all the time if it was due to fuel. I think my corroded battery terminals are more likely the culprit.

Btw, what makes an engine "designed" to run on E85? These engines weren't "designed" to run with superchargers either, but TRD decided to do it anyways.


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[thecole1098]

Ha, I knew someone would say that. That's a separate issue because it would happen all the time if it was due to fuel. I think my corroded battery terminals are more likely the culprit.


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Not necessarily. It could run great when the engine is getting more air as the E85 blend is richer than unleaded so if the engine is receiving more fuel at idle and doesn't have the extra air to compensate, it could be flooding the engine. This is also why your LTFT is higher now

I wouldn't think corroded battery terminals would only affect it during low speeds/idle like you are describing.

 

[Robb235]

Not necessarily. It could run great when the engine is getting more air as the E85 blend is richer than unleaded so if the engine is receiving more fuel at idle and doesn't have the extra air to compensate, it could be flooding the engine. This is also why your LTFT is higher now

I wouldn't think corroded battery terminals would only affect it during low speeds/idle like you are describing.

If engine was flooding out, my AFR would be pegged rich. That isn't happening. AFR is staying right around 14.7 everywhere in closed loop (WOT open loop it dips down into the 12's). Also, if it were running that rich, there would be a lot more drivability issues. Ran about 8 tanks with no issue. On a vehicle with 1/3 of a million miles on the clock, I'm more inclined to think the intermittent dying (it's only doing it occasionally, but when it happens, it's repeatable) is something else, like a sensor, dirty IACV, etc. I feel it would be more consistent if it were fuel.


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[kevincva]

Good luck with that, not sure how your feeling more power when E85 has less power than regular gas. What does you MPG look like?

 

[muellernautique]

not sure if this is something I would try in any of my vehicles, but what I have been using recently that definitely provides an obvious increase in fuel economy I've started trying to fill up with ethanol free gas whenever possible. the new buc-ees has it and it really makes a difference in mpg. can't really tell a difference on how my peppy my truck is though.

 

[phattyduck]

I'm mostly just amazed at those prices! (the expensive station near me is >$4 / gallon for regular right now. Most are in the mid $3 range)

I have a feeling most/all of the improvements you are seeing are placebo. If you are running an engine that can take advantage of the octane, it can help. I don't think the 5vz-fe is one of those engines (assuming no forced induction).

I personally wouldn't worry too much about the ethanol content ruining engine parts though. The 3rd gen was designed at a time where E10 was a normally available fuel, so the fuel system can handle ethanol.

-Charlie

 

[Robb235]

Good luck with that, not sure how your feeling more power when E85 has less power than regular gas. What does you MPG look like?

All I know about my MPGs is in my original post. I have the one long trip where I got 20mpg on E50. Other than that, my mileage is so variable on gas or E50 due to varying traffic on my commute, how long I let my car warm up in the morning, varying number of short trips I make, etc.

As far as why the E50 produces more, I'm not entirely sure. Yes, it's true that ethanol has lower BTUs than gas, even when you factor in its richer stoich.

Ethanol has a higher octane, so theoretically you could advance timing to take advantage and run more efficiently. However I doubt our ECU is advancing timing, because the knock sensors aren't active below 3k RPMs.

Maybe the cooling effect that alcohol has on the intake charge? The burn characteristics of ethanol? Maybe the ethanol cleaned a bunch of sh!t out? Hell, I don't really know the answer why there's a bump in power. It's not a massive bump, but it's noticeable.

Here is the thread where a guy dyno'd his NA car on gas, then on E85, and picked up some power:

https://ls1tech.com/forums/fueling-injection/910348-some-hard-data-dyno-testing-e85.html


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[Robb235]

So I have a set of green top fuel injectors out of a 7MGE that I grabbed at a junkyard. I've read that they're rated at 315cc/minute, which is 29% larger than the stock 245cc/min injectors. Being that E85 requires about 30% more fuel, these would be perfect swap to run straight E85.

The temperature this weekend was finely decent, so I took the opportunity to swap injectors. I needed to clean my Idle Air Control Valve, so I figured I'd kill two birds with one stone. I disconnected the battery to clear out the fuel trims and reset the ECU (I hate losing my radio presets). I still have an E50 mix in the tank, so after swapping in the 315cc injectors, I expected to see my Long Term Fuel Trims somewhere around -10%. It started and idled fine, and when it got up to temp the LTFTs immediately went to +20% with the Short Term Fuel Trims bouncing around in the high teens.

Oddly, the reading from the front AFR sensor indicated that it was burning a stoich mixture. The idle seemed fine, although I never placed the engine under any load.

It was definitely not what I was expecting. I think something is up with these injectors, so I shut the engine down. I swapped the stock injectors back in. I'm going to send these green 315cc injectors to Witch Hunter to be cleaned and balanced, and will try again when they come back.

Picture of stock brown 245cc and green 315cc injectors:

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[JayRolla]

I've ran e85 on boosted applications for over 17 years. Just run gas and be done with it. The gas mileage lost is not worth the gains without boost.

 

[Robb235]

I've ran e85 on boosted applications for over 17 years. Just run gas and be done with it. The gas mileage lost is not worth the gains without boost.

I've always had an interest in alternative fuels, so I'm doing this for no other reason than curiosity and experimentation. I already have the larger injectors, so it isn't really costing me anything to do this.


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[Robb235]

So when I put the green 315cc injectors in, I thought something was wrong with them due to LTFTs being so high. Turns out I have a vacuum leak somewhere, so the injectors were fine. With stock injectors back in, my fuel trims are sky high at idle (+35) but go back to normal (~+19 due to higher ethanol content) when under load. I may have forgotten to reconnect a hose somewhere when putting everything back together.


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[phattyduck]

The 5VZ fuel injectors are 'air assisted' - you may have missed that hose and you are getting unmetered air getting let in at the injectors.

-Charlie

 

[Robb235]

The 5VZ fuel injectors are 'air assisted' - you may have missed that hose and you are getting unmetered air getting let in at the injectors.



-Charlie

Which hose is this? You have a picture or diagram or something?


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[phattyduck]

Which hose is this? You have a picture or diagram or something?

http://www.toyota-4runner.org/3rd-gen-t4rs/228872-how-disable-injector-air-assist.html

(includes my post before I found out about it!)

-Charlie

 

[KingPrat]

Have fun eating through your fuel lines and components. Ethanol burns differently, but that is truly where the damage comes into play.

Obviously a different setup, but my father had to have 3 carburetors replaced on his chainsaws because of the ethanol in the gas. Thankfully Stewarts carries non-E premium...

 

[muellernautique]

Have fun eating through your fuel lines and components. Ethanol burns differently, but that is truly where the damage comes into play.



Obviously a different setup, but my father had to have 3 carburetors replaced on his chainsaws because of the ethanol in the gas. Thankfully Stewarts carries non-E premium...

yep. same thing happens to marine engines when guys fill up at gas stations instead of the marina. like I said in my earlier post, if your vehicle can run on 87, ethanol-free gas is the bee’s knees. i just haven’t found it in 91/93 near me.


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