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WeldingRod

E85 Content in Colorado? - really 80% or worse?

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I'm moving to the burb's of Denver (nice neighborhood in Aurora, CO);

 

I have a car that requires 93 Octane fuel (or better);

 

Here in Michigan you can buy 93 or 94 Octane, and even higher at some stations (more expensive fuel of course);

 

I have a high-performanced super-charged engine, and after I move to Denver, fuel selection is going to be of great importance (to avoid detonation);

 

From what I've seen it is likely not feasible to find 93 or 94 octane fuel in Colorado.

 

What seems much more likely is finding E85, which is actually better for my engine setup. (burns cooler, and mitigates detonation better);

 

With that introduction being made.

 

The question is the real content seen at pumps in Denver/Aurora, CO;

 

I've seen mixed reports of the actual fuel being sold at the pump.

 

E75, E7X, E85????

 

What kind of fuel, or octane are you really able to get in that area?

 

E98 is actually pure, but this is bad for starting in cold weather;

 

E85 has some gasoline content for cold starting;

 

Winter blends have more gasoline, and less ethanol for better cold starting.

 

Each step of dilution with gasoline, is a step closer to detonation for me;

 

With the high altitude of denver, I have no doubts that E85 is not really E85, as most do not need the high octane capability.

 

I do however need every bit of the Ethanol...

(9.4 to 1 compression with 16 lbs of supercharged-boost!!!)

 

Thanks in advance for any information on fuel quality or content.

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E85 0r winter blend which is e85 105 octane or e70 (winter blend ) with some where around 95 octane ( just off the top of my head ) could be more octane. It should do your octane need and do the trick for starting. If I'm in error someone will post and refine this suggestion. Later.

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Weldingrod- E98 has 113 octane and very high resistance to detonation. E70 (winter) will typically run no less than 100 and no greater than 105 octane equiv,depending on the hydrocarbon used for gasoline portion. Summer E85 will be no less than 105 and no greater than 109. Spring/Fall E78 of course falls in between. Naturally aspirated engines are not able to take in as much air at the elevation such as Denver so octane requirements are reduced about two points. For turbo and supercharged applications I am not sure how this will apply since this may be on a 16# wastegate that will have more constant octane requirements.

 

Are your thoughts to change to larger injectors and/or custom tune your ECU for a full E85 program as would be typical in the performance world or are you thinking more of buying premium NL and blending in enough E85 to stave off detonation?

 

BTW- in Denver E85 would be E85 just like anywhere else (85% of E98) during the summer months because the E98 put in is cheaper than gas so the blender will use as much as possible for the season irregardless of what happens to octane. If you need a link to see the federal handbook of blend % and seasonal blend months let me know. When you see variability of E% in E85 within a local it is typically due to product turnover since the new season began. It can also appear to vary because the tests for alcohol content that are affordable and easily accessible to most of us are not super accurate (ie phase test) or subject to test errors (GM type conductivity/frequency).

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Thanks guys, it sounds like you are familiar with the fuel provided from these pumps, and feel comfortable that it matches the octane stipulated at the pump (E70 or E85);

 

Now just to avoid any confusion, you mention that fuel in Denver (due to altitude) is typically 2 points lower.

 

Do you mean then that considering the octane rating of E70 = 95; Then E70 in denver would be equivalent to 93 octan, or 94.8 octane?

 

Typically a point is 0.1;  That may not be what you were inferring, just trying to clarify.

 

I'm building an oversized fuel system, and can run the additional flow needed for 30% more fuel;

 

I will custom tune the A/F ratio, and spark on E85 here in MI, and I'll also test it with E70 to see if I need to back off the timing with Winter fuel.  If it's 95 octane I should be fine.  E85 would actually alow me to go nuts with the timing and A/F with that high of octane, but I'll keep it conservative and keep the head-room of the octane rating as extra insurance.

 

Thanks,

 

Don

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Seems like there are a couple terms getting thrown around which need some clarification.

 

The octane of any EXX blend in Colorado will be the same octane in Michigan.  Octane of the actual fuel doesn't change with altitude. The octane requirement of your engine will be less due to the altitude, though.  It could be reduced two 'points' or more.  On here, 'points' are generally whole octane points.  ie if you need 94 now, you would probably get away with 92 at altitude in Colorado - that is unless you change the boost level to compensate for altitude.  This also seems to work out fairly well in winter...you do loose a couple octane points to the winter blend, but cooler intake air offsets some of the octane requirement, too.

 

As for tuning in Michigan, I wouldn't worry about it too much - it will probably change substantially when you go to CO, you will just have to re-do it all over again anyway.

 

As for 'going nuts' with the timing.  There is an optimum advance for your specific engine set up.  Going beyond that will not generate any more power regardless of altitude or fuel.  Higher octane will allow you to reach that timing number, but going beyond it will start to cost power again.

 

FWIW, I have not noticed any issues with 11:1 CR +15psi boost @ 870 ft elevation here in KS - though different engines can have different octane tolerance.

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Thanks for the clarification.

I would like to believe that E85 is the same across the whole country.  Unfortunately that doesn't make it a reality. DOT3 brake fluid, and 91 octane fuel are also supposed to be the same from all suppliers, but there is plenty variation.

 

Yes, I'm compensating with more boost, and some added compression.

I know exactly where MBT spark is (max brake torque- most power achievable for a motor);

  In some instances your better off backing up a bit from MBT, depending the induction configuration you don't need the small power increase from a few more degrees of timing, vs. the risk of detonation and motor damage you may see from it.  Of course there are many implementations of knock retard that can be used, I just don't like relying on corrective action and running on the ragged edge.

 

You are correct, one can go too far with timing, even before maximum power is reached.

 

That's the great part of tuning your own engine, if 5000 ft requires some further tweaking it's all in the palm of my hand. It sounds like I'll be ok with the fuel out west. 

 

Thanks again guys.

 

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Thanks guys, it sounds like you are familiar with the fuel provided from these pumps, and feel comfortable that it matches the octane stipulated at the pump (E70 or E85);

 

Now just to avoid any confusion, you mention that fuel in Denver (due to altitude) is typically 2 points lower.

 

Do you mean then that considering the octane rating of E70 = 95; Then E70 in denver would be equivalent to 93 octan, or 94.8 octane?

 

Typically a point is 0.1;  That may not be what you were inferring, just trying to clarify.

 

I'm building an oversized fuel system, and can run the additional flow needed for 30% more fuel;

 

I will custom tune the A/F ratio, and spark on E85 here in MI, and I'll also test it with E70 to see if I need to back off the timing with Winter fuel.  If it's 95 octane I should be fine.  E85 would actually alow me to go nuts with the timing and A/F with that high of octane, but I'll keep it conservative and keep the head-room of the octane rating as extra insurance.

 

Thanks,

 

Don

 

Don- Corey said it well- elevation only reduces octane requirements and this is why you see lower octane gasolines offered in Colorado than the lowlands. E85 however remains just as it is anywhere- E70 (Winter) will have an octane equiv of 100 to 105 and E85 (Summer) will range from 105 to 109. You will not find a guarantee of octane on an E85 pump because most state regulators do not want the octane posted for E85 lest grandma decide she should put some high test in her '82 Regal. Like Corey- I think your tune will need some A/F adjustment moving from Mich to Aurora which is what- 5300'. You can advance timing to the point that you lose power because the gas expansion is not at the ideal crank angle. Remember- with E85 that 85% of the fuel has the identical burn characteristic and thus is consistent whereas pump gas has some 18 major components and up to 100 overall-- all variable in quanity and consistancy. Bracket and Drag racers will chose either a very expensive race gas (with highly controlled components), 100% methanol, E98, or E85 so they can obtain both power and consistancy that is hard to find with pump premium.

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Dont be a stranger Don- when you get to tuning let us know how it is going. There are a couple of guys here that are regulars and live around Denver. They both have Subies -- turbo and N/A.

 

I will be interested in what you use for tuning software, A/F (or Lambda) monitoring, and what you find you will need to adjust cold start enrichment vs gas.

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Thanks !  Yes, TinkerFreak already pm'd me about his Subie, and mentioned he lived close to Aurora.  He said there is a new Track east of town, and Bandimere will close in October.  It sounds like he has one fast 2.0 Subie!

    I'm still piecing together the motor and the fuel system, and I'll be running out of time fast.  I'll be a little scarce for a couple months, with my head buried in the motor/trans/fuel system build up, among other items. I'll be back tuning once I get the beast on the road. 

  I'm a little unfamiliar with Denver so it's good to here there are a few track-venues to go have some fun test'n tune action!

 

I may need a little education from you guys on what direction your going on cold enrichment adjustment, on my eec strategy it's all open loop cold-start settings.    I'd guess you guys are going further lean, with 60lbs injectors (x8) I have trim that up a bit already.

  Going to take some time, but I'm eager to get there. 

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