OK so I was reviewing my 2010 HHR Owner’s Manual (pg. 6-8) and it references ASTM D 5798 and says that means 70-85% ethanol, and makes vague implications of possible problems with fuel not within that range.

(I understand the problems with hard starting in cold weather at high ethanol concentrations and I’m not talking about that.)

ASTM D 5798-11, 2011 update, presumably, seems to have changed the spec to 51-83%. The latest ASTM standard seems to be D5798-19b is the same percent 51-83%

An ASTM document say an Flexible Fuel Vehicle (FFV) can use anything between 0-85% ethanol.

I’m going to assume with the current low low price of crude, suppliers are going to use the minimum amount of ethanol in the blends or worse.

Apparently tuning for E30 is a thing now, and achieving it by blending at the pump. And tuners using E blends are talking about testing at the pump every time.

But do I have anything to worry about with a flex-fuel HHR?

 

Are you on a tune now ?
I really don't think a supplier is going to change the blend because of price.
There is more than likely more of the E85 jammed in pipes because they can't sell it now.
That's why price is low to sell it off and still make some sort of profit.
A flex fuel system will adjust to the blend you put in your car.
That's why going from regular E10 and E85 has no effect on your engine other than E85 will give you more pep and you burn through it fast than E10.

 

A 2010 LS/LT is FlexFuel, the computer calculates the alcohol content and compensates. It is a different story with SS.

What Cat Man said.

 

Thanks, good info! Here’s my perspective; no tune (yet) on the 2010 SS 5-sp, but thinking about it, so am edumacating myself on ethanol in fuel.

Not trying to school anyone here, questions coming, but here’s perspective, my reality, for context:

- It’s clear you can’t know what you’re getting at an E85 pump without actually testing each time. For one thing, it’s apparently an EPA recommended practice for individual gas stations to add 87 unleaded to a tank of left-over “summer” E85 to bring the ethanol down (to 70%? Can’t remember the number) to avoid hard starting in the Winter. And because as little as 51% ethanol is permitted, it WILL happen when gasoline is cheaper than ethanol.

- There is (or may be was) a push for E30 at the pumps, on the theory that it’s harmless to engines designed for E10. It’s illegal now, exceeds 10% limit for regular, too little to call it E85.

- E85 economics vary with engine design and depends on whether it was optimized for E10, E85, or something in between. Fuel consumption penalty seems to vary something like from 5% to over 20%, depending on the engine. VVT is a big plus for trying to flexfuel (to coin a verb) and engine. Right now E85 in my area actually cost more than regular but I’ve seen it over $1 less. 93 is indefensibly expensive and racing fuel is insane.

- E85 can be a big plus for performance turbos, and even my 2.2 flexfuel get a little HP bonus from it.

- All three of my HHR’s are VVT; the 2011LS is already FF of course. 2008 2.4L, 2010 SS 5-sp

SO The Questions are:

1) How does FF in an Ecotec work? There’s no fuel chemistry sensor, per se, right? Does it just just adapt spark and valve timing until preignition is sensed and then adjust, or something else?

2) Anyone know for sure if E85 can cause chemical damage to materials (seals, hoses, fuel-wet plastic parts, sensors, corrosion, etc.) to a non-flexfuel ecotec engine? Generally, and specifically my 2008 2.4 and 2010 SS 2.0?

3) I know tuners work with E85 and other specific ethanol percentages, but ever heard of tuning to adapt to various %’s? Seems plausible, doesn’t it? Anything in the way? Missing sensor?

4) 2008 2.4 already adapts to fuel quality and already has VVT. Any reason retrofitting a flexible fuel tune couldn’t be explored?

Tell it like it is! (Just don’t make stuff up)

 

The 2008 doesn’t have the Flexfuel programming in the ECM , VVT is to reduce engine knocking and improve fuel economy.
E85 does effect components of the fuel system in a negative way , many posts about it in the inter webs. Mostly older carburetor issues in rides that sit in the garage and probably do not have any ethanol compatible metals
The cost of tuning for it far outweighs the savings



A damaged Holley carb jet block

 

I asked ZZP about an e47 tune, would I be able to run e10 sometimes. They said I would have to run e47 at all times.

 

The computer uses "magic" (in the Arthur C. Clarke sense) to calculate the alcohol content based on input from various sensors including the O2 sensors, Crank sensor, knock sensor and more.

 

Thought that was a possibility. Wizardry. The computer shouldn’t care what the ethanol % is per se. but rather, should be imputing (such a cool word) combustion properties, with the aim of determining optimal fuel charge, and valve, injection and spark timing for the task of the moment. Serious development investment, my guess.

This ”E47” stuff seems to be an invention of the tuner world, based on the easy procedure of mixing 50/50 E10 & E85. But I think maybe that could result iin as little as 25.5% ethanol. I don’t know anything about tuning, but it seems that without some of that flex fuel wizardry, aftermarket performance tuning for ethanol blends pumped at gas stations could have some serious limitations.

Now even more curious, don’t know if I’ll get to delving further.