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No. Not true. Simply because the engine would have to built with stratospheric static compression and lots of boost to have a hope of needing all the knock resistance of normal E85 anyway. Not more than 0.01% of engines running around on E85 would be built even half that hard.

Marketing and profit margin. There is so little hydrocarbon in E85 that the marginal cost difference to the supplier is only about 15% of the marginal cost difference between 91 and P98. Yet they can probably charge ALL of the retail price difference between 91 and P98 when applying the marketing spin to E85 and 107octane E85. 6 times the extra profit makes it worth refining a little extra P98 to go into it.

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  • 2 weeks later...
  • 2 weeks later...

Maybe the theory of "under octane" ULP in the E85 is not a theory and they prefer to use a more highly refined dino like 98ULP .

I think ultimately E85 or similar is only ever going to get mainstream acceptance when you can prove to people that it works consumption wise , and to achieve that you need engines with high compression ratios . How you get around NOx emissions I don't know but I have read that direct injection engines gain more from evaporative in cylinder cooling so the higher a fuels octane the better assuming it doesn't get harder to light off like high octane petrol does .

A .

so just a bit of an up date on using the green 107 octane.

tested it and has the same ethanol content, so in the tank it goes.

Went for a 10 minute drive and parked up.

Started it up and it now runs like crap.....

Maybe, probably a coincidence..... but yeh..... my car didnt like it very much....

Also ive eliminated most other possible causes of my car running like crap, dosnt mean it is the fuel though.

It's not an issueswapping between tge two fuels. If the car is tuned right it should be able to go from 70 to 90% ethanol without any damage even at a track on either 105 or 107 . It comes down to knowing what you are running % wise whilst tuning and factoring in possible changes.

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I have found 107 needs a different coldstart map to the normal stuff. Aside from that havnt found much difference at all (will do back to back testing on a dyno in afew weeks). Was the same starting problem on 3 different cars when tuned on normal e85 then run on 107 (107 only recently became available at my local).

Yep I was having starting issues and got sick of the increased consumption .

My local EFlex servo is getting cheap ATM so that's what I'll stock up on . Starts are much better but need to get finger out and retune the cold and hot starts because they've gotten really rich .

$1.16.9/L acceptable , cheers A .

  • 7 months later...

Current brew is a 50/50 mix of E85 Lime and 98ULP . My engine was getting rough on E70 and I was beginning to wonder about the gum gunge some people get on their injector tips when using high eth fuels . I did use that ethanol fuel conditioner for a time but ultimately it didn't change the rough running much .

I started blending more ULP into the Eflex to get acceptable consumption and picked up 30L of green E85 for a 50/50 mix - as easy as splash blending gets .

Results look pretty good so far with power and general consumption . I suppose the octane would be around 102-103 which isn't far short of the old E85 but 57% of the fuel is now PULP which gives better consumption than 85% ethyl alcohol .

The down side is that Uniteds Green gut rot is a bit exy .

A .

Interesting discussion. I find it interesting that people are getting higher consumption from the 107 as well. My car was tuned on the 107 and I get very slightly better economy when I use it vs EFlex, granted I'm talking maybe 20-30ks per tank more, certainly not enough to offset the higher costs of united.

The car also feels the tiniest bit more responsive on the extremely low rpm as well with the united, like before around 2000rpm it seems smoother to take off from the lights or whatever. No idea if there is a reason for that or if its in my head.

Either way I just fill up with whatever I'm closest to when I need fuel, doesn't make much difference except price

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