Factory Turbocharged Engines and E85

My knowledge of turbos and E85 is mostly gleamed from the internet, so excuse any myths or general silly info. This is mostly a question about new or newer cars with fancy engine computers and factory wide band O2 sensors. (They do have those as standard now, right?)

From what I've read, turbos and E85 should be good match. You can run higher pressures (either from the turbocharger or from engine compression or combination of both) and can advance the ignition. Both can lead to more power. Right?

So why don't we see factory turbocharged engines with flex fuel badges? Case in point: the 2.3 EcoBoost Mustang. Is it because it's direct injection and the pump is already maxed out and the flow for E85 is that much higher?

I have a Grand Cherokee with the Pentastar 3.6 that can take E85. I did one tank just to see what it did and lost fuel economy. No big surprise. When engines are designed for two different fuels, it's hard to maximize the efficiency of one with out hurting the other. But with a fancy controlled turbo and computer you should be able to maximize it for both fuels, right? You hear about DIY turbo'ed engines using E85 as a poor man's street legal race fuel.

So what gives? Why no 2.3 EcoBoost that makes 400hp while on E85? What don't I understand?

It's still going to take ~30% more fuel for the same power.....

Ranger50 wrote: It's still going to take ~30% more fuel for the same power.....

But make more power. It's going to take 30% more fuel to make more power.

In reply to Ranger50:

Not when you get a higher efficiency due to higher compression. ECONOMICAL, HIGH-EFFICIENCY ENGINE. TECHNOLOGIES FOR ALCOHOL FUELS states they were getting a 20% increase in fuel economy over baseline gasoline engine.

That and one gallon of e85 has 73% to 83% the energy of one gallon of gasoline. Racers run it because they dont give a crap about mpg and e85 is WAY cheaper than a comparable octane gasoline

RossD wrote: In reply to Ranger50: Not when you get a higher efficiency due to higher compression. ECONOMICAL, HIGH-EFFICIENCY ENGINE. TECHNOLOGIES FOR ALCOHOL FUELS states they were getting a 20% increase in fuel economy over baseline gasoline engine.

If that were a practical solution, everyone would do it. It would be an easy increase of fuel economy, AND would have an astronomical effect on CAFE numbers.

But the answer is that the mechanical fuel pumps can't put out the flow for E85. I will say that DI and E85 are a great match- almost no particulates, emissions are really good, but the flow limit of the pumps really hold back the potential.

My 1993 Eagle Talon is tuned to run ONLY off of E85. E85 is the equivalent on 110 octane from a stability standpoint. I currently run 42 psi of boost. I'm not sure that sort of pressure would even be possible with pump grade gasoline. The car would pre-detonate constantly and probably go BOOM.

In regard to the E85 setup I did have to run a much larger fuel pump and injects. The fuel pump is a Walbro 455(not a typo). The injectors are ID 2000cc.

In reply to alfadriver:

We know we can get 300 hp from the the fuel pump on the 2.3 Ecoboost with gasoline. What could you get if you put that pump on the 1.0 EcoBoost? Or how about using two pumps on the 2.3? Twice as much horspower?

I'm less concerned with high horsepower numbers, like the DIY turbo guys are probably concerned about, but more along the lines of using turbochargers to get some more efficiency out of the E85 by compressing it higher.

I probably don't understand enough. I'd rather see the same fuel economy and power using E85 on turbo engine compared to the same engine running E0-E10.

RossD wrote: In reply to alfadriver: I probably don't understand enough. I'd rather see the same fuel economy and power using E85 on turbo engine compared to the same engine running E0-E10.

E85 will never generate the mpg of gasoline. As stated earlier e85 is not as energy dense as gasoline. E85 requires about 30% more fuel by volume to generate the same hp.

Theoretically you could run real lean with a ton of timing on e85 and get better mpg, buy depending on egt's that could be very dangerous. Even then I think you would have difficulty overcoming the 30% energy deficit.

You probably cant get the same economy...you need at least 30% extra fuel, also iirc stoich with e85 is richer by a bit than gas as well. Its good for making power, not good for economy.

Seems like A mix of DI and port injection (like Toyota's D4-S) would take care of the flow problem...I wonder why more manufacturers don't copy that setup. There are twice as many injectors to break but it has power and reliability advantages even for a NA car on gasoline.

NordicSaab wrote:

RossD wrote: In reply to alfadriver: I probably don't understand enough. I'd rather see the same fuel economy and power using E85 on turbo engine compared to the same engine running E0-E10.

E85 will never generate the mpg of gasoline. As stated earlier e85 is not as energy dense as gasoline. E85 requires about 30% more fuel by volume to generate the same hp. Theoretically you could run real lean with a ton of timing on e85 and get better mpg, buy depending on egt's that could be very dangerous. Even then I think you would have difficulty overcoming the 30% energy deficit.

I understand that it has less energy per given unit, but compressing it more should get you a higher efficiency therefore, hopefully, offsetting the greater volume required.

I think I must be barking up a tree that doesn't really exist. Otherwise, like Alfadriver said everyone would be doing it.

RossD wrote: In reply to alfadriver: We know we can get 300 hp from the the fuel pump on the 2.3 Ecoboost with gasoline. What could you get if you put that pump on the 1.0 EcoBoost? Or how about using two pumps on the 2.3? Twice as much horspower? I'm less concerned with high horsepower numbers, like the DIY turbo guys are probably concerned about, but more along the lines of using turbochargers to get some more efficiency out of the E85 by compressing it higher. I probably don't understand enough. I'd rather see the same fuel economy and power using E85 on turbo engine compared to the same engine running E0-E10.

You can make more power with multiple pumps. But the high pressure pump is the most expensive part of direct injection. So it's really expensive. Your suggestion of an E85 optimized car would be for a very tiny segment of the country, were E85 is super easy to get. So that's a lot of cost for a tiny volume. Be it for fuel economy or power, it's not really worth it.

The Ecoboost in the Ganassi DP car has multiple pumps, so that shows kind of what's possible.

Then your question:

RossD wrote: I understand that it has less energy per given unit, but compressing it more should get you a higher efficiency therefore, hopefully, offsetting the greater volume required. I think I must be barking up a tree that doesn't really exist. Otherwise, like Alfadriver said everyone would be doing it.

The benefits of higher compression diminishes as you get higher and higher. I'd have to look at my old texts, but the difference between say 12:1 and 15:1 isn't so much to be worth it- for sure not enough to make up for the lack of energy in the fuel.

Then there's the idea-

GameboyRMH wrote: Seems like A mix of DI and port injection (like Toyota's D4-S) would take care of the flow problem...I wonder why more manufacturers don't copy that setup. There are twice as many injectors to break but it has power and reliability advantages even for a NA car on gasoline.

You'll start seeing more of that. But Toyota's stated reason was for emissions, originally. But it's not an ideal solution- either. Workable, but not great.

My honest question to the DI world- now that we've all made major advancements in the modelling, and have some really trick injectors- both tip design and spray design- how about we use all of that to go to open valve injection? Most DI engine inject really early in the stroke anyway, and getting rid of the high pressure pump rids the system of a major drag. How much of the charge cooling/compression benefit can you get by doing a port injector really, really well- just like DI systems are designed.

i did some testing in this area with my 84 Regal T Type a few months after i got it back in '04... rolled into a gas station on an almost empty tank and saw that they had E85, so i pulled up and filled it up. it took a little bit for the computer to "learn" the new fuel, but it was fine once i was out of the parking lot. then i gave her hell pulling away from a stop light and it felt like i gained 50hp.. when i got home, i adjusted the wastegate for more boost- 20psi- and it felt like i gained another 20hp over that. it's amazing stuff..

regarding fuel economy: in my T Type, my fuel mileage would pretty consistently drop from 17 to 13 when i put the corn juice in- with the cost per mile generally being about the same due to E85's price advantage at the time. i've tried it in other cars blended at various levels thanks to the blender pump at the Cenex where i used to live, and in general fuel economy doesn't suffer at all until you get over 50% blend: in one weird trip in my T Type where i had a full tank of E85, i got 24mpg with 2 passengers, a trunk full of luggage, AC blowing ice cold, and cruising down the interstate at 80mph for an hour and a half. i have no idea how or why that happened, but that's what it calculated out to..

i had 97 and 98 Cavaliers with the pushrod 2.2 that loved the stuff, but my '04 Cavalier with the Ecotec 2.2 absolutely hated E85- it would barely run if you ran a mostly full tank, and driveability and fuel economy took a nose dive from 30ish to around 20 if you got more than 50% in it.. my '01 GTP loved the stuff and wouldn't lose fuel economy until about 70%- maybe the force fed 3.8 liter GM engines have something magical about them where they thrive on corn juice..

some day, i hope to get an actual E85 chip and the matching 60lb injectors for the T Type and really have some fun..

RossD wrote: I understand that it has less energy per given unit, but compressing it more should get you a higher efficiency therefore, hopefully, offsetting the greater volume required. I think I must be barking up a tree that doesn't really exist. Otherwise, like Alfadriver said everyone would be doing it.

Increasing timing beyond optimum just increases negative work done by the engine (compressing an expanding charge) even if it is not detonating.

What you'd need to do would be to increase compression to take advantage of the octane. The issue with that is, gains from increased compression taper off. The gains from 6:1 to 7:1 are huge, the gains from 12:1 to 14:1 are tiny.

In another context, E85 can create gains in economy over pump gasoline if you are comparing performance engines. A 7:1 engine turbocharged to the limits of pump gas will get better fuel economy if you raise the compression to 10:1 and run it on E85 to make the same level of power. In this case the gasoline engine was compromised for power vs. economy and running on alcohol allowed that compromise to be removed.

novaderrik wrote: some day, i hope to get an actual E85 chip and the matching 60lb injectors for the T Type and really have some fun..

What, you mean you don't have 60lb injectors for pump gas?

Lemme put it this way. Had one customer whose engine ended up at ~730whp on race fuel. He converted to E85 and he made 10% MORE power. This on a relatively high compression engine with a moderately big turbo (67 or 72mm, I forget). The high compression made the throttle and turbo response incredible.

So being able to adjust the boost depending on the fuel type doesn't have as much effect on economy as it does on power?

In reply to RossD:

No. Will have no effect on economy- as the car needs what it needs to go from point a to b- and all increasing boost does it increase the air flow, increasing the power. If the car does not need more power or energy to go from a to b, the boost will do nothing.

All the fuel can do is allow increased compression, which should increase thermal efficiency, but it's diminishing returns, as we've pointed out.

Most here would probably be surprised how little a car really needs to move at a reasonable pace.

Alfadriver: I think that's what I've been missing. Adding boost doesn't have the same effects as adding compression.

We had a lab in college where we calculated the required horsepower for a Ford Contour to travel 35 mph on a flat road. It was something like 12-13 horsepower.

In reply to RossD:

Which is over double what it actually takes. For a contour, 12-13 hp will give it something slightly over 50mph.

And my point more being that even at 1500 rpm, that's not a lot of torque to make that power, which would be no boost.