Quickvr4

Does anyone run E85 in their C55? What modifications are required?

Thanks,
Derek

Frederic944

Why would you like to run E85?

///AchMeinGott

Very generally speaking, you'll need to run a fuel system set up to pump at least 25% more fuel then stock, and tune for it immedietly. It helps make power, but it makes any car stupidly thirsty.

That being said, it's not exactly the best idea $$$-wise for a stockish N/A engine. The M113's compression ratio is 11:1, up there, but nothing sky high, and as far ar I can tell, premium is recommended not just 93. I've never heard about any M113 knock sensor being overly protective, so the motor isn't retarding timing. Since high octane E85 aids in preventing detonation, well, there isn't anything to prevent. With stock compression/cams, you can only ramp up timing so much to use the available airflow, even on E85. Run something extreme like custom pistons/heads for 12.2 or 13:1 compression, or slap on a supercharger making 10psi and 100+ octane(or E85) is nearly required.

Of course, if you already knew all this, I'm in for results lolg

swedepat

and coldstarts will be harder if you don´t tune it correctly.
it need about 100% more coldstart enrichment than on petrol.
But just when cranking.
When started you need to ramp it down really really fast otherwise you´ll flood the engine.

an other thing to bear in mind, m112 and m113 engines have this coating in cylinderliners called 'alusil'.
I dunno the compability with alcohol fuels.
As i´ve seen a lot of corrosion in fuelsystems with E85 fuel(aluminium that corroded)
Alusil is a marriage between aluminium and silicone, exactly how i dunno.
But name 'alu' makes me banging the big drum.

Rgds.

insame1

I have also read that there are issues with the rubber bits in the engine that can be degraded by e85.

swedepat

There aren´t any rubber thingys that could cause any problem except o-rings at the injectors.
But i never had any problem with those.
More with uncoated aluminium that´s corroding and 'plugs' everything in fuel system.
No problems inside engine thou, but i´m unsecure about this Alusil stuff.

When having an seasonbased hobbycar and there are long periods of non using you must run engine clean with petrol.
This because ethanol is bonding moisture.
I´ve seen problems in cast iron blocks, it corrodes in cylinders just where the top piston ring is resting against the wall.
To overcome this problem you can run additive like esteroil in fuel.
but,, be warned!!
You catalytics might not like it.

Very good fuel for everday use, but for longer parking? nope!
And as stated, to get some economy out of it you need about 13-1 in compressionratio.

Rgds

insame1

Interesting read

http://www.snopes.com/politics/gasoline/e15.asp

PelicanParts.com

Cold starts are inevitable with E85, but just require a few more cranks when the car has been sitting. If you live in a colder climate that drops below freezing, I'd suggest investing in a block heater. Your gas mileage will decrease drastically as well. Yes, E85 is more harsh on components, but it shouldn't be much of an issue. (Speak with whomever will be helping you with the conversion as I would assume they will know what components are at risk). E85 burns cooler and cleaner. Your temps will be happy and your HP output will increase drastically. Typically, an E85 conversion requires a fuel pump, fuel injectors, and a tune. Definitely do your research and make sure you're modifying correctly before putting E85 in the tank.

-Luccia

///AchMeinGott

True
Also true
That's being optimistic. Like I said, I've never seen anything about aggressive knock sensors on the 5.4, so there's little to no detonation. Stock cams/compression will always create a hp ceiling, no matter how aggressive timing could be with E85.
True. The entire system, tank to injectors, needs upgraded for at least 25% more fueling. I don't know if stock injectors can handle that, but bigger injector piece of mind is nice.

Frederic944

It's not because the Knock sensor is not active that you are running at MBT, MB would have calibrated the engine to be a few degrees in the knock zone but far from MBT, so yes, running E85 will increase your torque/HP by allowing you to run closer to MBT, but the ECM will require to be recalibrated to take advantage of the higher RON of the E85.

C3Duece

If making more power is your goal E85 would be a bad move for any N/A car unless the CR is 13:1 or more. The extra octane would quench the spark and you make less HP/TQ. Even if you're doing it to save $$$ on gas the savings would be marginal because E85 doesn't burn as efficiently as petroleum gas. E85 is GREAT for high boost cars though.

swedepat

Adding E85 to an otherwise unmodded engine will give you about 2-3% more power max.
But!
There are so many other drawbacks so i can never recomend it for everyday use unless you know what you´re doing.
Way shorter oilchangeintervals are eating economy you might get if you´re raising compression.
I´d say you´re just fooling yourself.

I have quite a lot of experiance when tuning boosted 'euroengines' on E85.
Excessive wear on cylinders and bearings are also a thing to calculate with.

But yes!
It runs colder, and having a bigger 'window' on running wrong air/fuel ratio and still makes good power.
And with that said you can run as fat at 0.76 in lambda and get really high 'virtual octane' as int runs so cold it becomes really knockresistant.
I boosted 2.1bar on an engine with 11.1 in compressionratio= no problems!
really nice responce, almost instant boost with an GT3582r and 2.3 litre engine.
(if in boosted register)

But for our mercedes´s,,, no!
Just go for premium fuel and drive carefully if wanting to get economy.
The far cheapest way there is.

Rgds

Frederic944

Few rectifications:

- E85 runs cooler because you run less oxygen, E85, at stoechiometric, runs a AFR of 9.8 where gasoline runs at 14.7, works a bit like with normal gasoline, you run lower AFR to cool off your combustion.
- E85 doesn't have a "virtual" high octane but a real RON close to 101/102, thus allowing more spark to be added to reach MBT, where you are knock limited with gasoline
- So, yes you will get high power/torque on a stock engine, but only if you re-tune the ECU.
- And no, you don't pick E85 for FE, as it need, as seen above, at least 20% more E85 than gasoline to run stoechiometric, so your FE will decrease by at least 20-25%

swedepat

Yes,, it DOES have a high 'virtual' octane.
You can boost way more than it would be allowed with the same temps and ignition on racefuel with the same octane.
This due to larger window of stoich, you can let it run a bit more rich and get the temps down a bit more, allowing more boost.

Here in Sweden were running about 0.76 lambda as richest, allowing us to get about 1250-1300hp in an 2.1litre fourbanger with 11-1 i compressionratio.

///AchMeinGott

Multiple stock(even stockish) N/A engines disprove "high power/torque" increases, but not multiple enough to say tons, because... well... people know there are only minor gains to be had with E85 on stock motors and don't do it, given the fueling mods/scarcity drawback. 12. compression or 20psi on 11:1, go for it

Taking a complete wild guess, I would say 15whp TOPS over a custom 93 octane on the later 5.4's.