30% mix - fueling experts chime in

[50BMG]

I'm mixing mine with C85, the fuel is Tier 1 91+ E10.
So based on what your saying it's 89 + 10% ethanol.
In my area, 87,89, & 91 all contain 10% ethanol, according
to the pump. So obviously 91 here isn't 89 + 10%.
Looking at my logs I have yet to see any knock.

Wildhorse,
Sorry if I'm preaching to the choir here.
In my opinion, those statements you eluded to should be taken with a grain of salt.
It's a case of too much information for what we are discussing.

From what I remember, the octane number posted on the pump is the "end result" octane number no matter how it was derived (adding alcohol/octane/cetane, etc... to gasoline). That octane number is also a product of a simple averaging calculation between 2 different ways to test for the octane of the fuel; the "research" method and "motor" method.
This is why the octane on the pump is usually shown as (for example) "Minimum Octane Rating 93 (R+M)/2 Method".
So, the listed octane number on the pump is "supposed to be" the lowest octane the fuel should end up being if tested, whether it's also a targeted 10% ethanol, OR a 0% ethanol "rec gas" type of product.
93 octane is 93 octane either way.

I've read in the past that "Neat" (pure) ethanol is @ 109 octane, so most places I've seen an octane listed for E85 show that fuel mix to be @105 octane out of the pump (ironically, the math actually works out to 105.4 octane IF pure E=109 ethanol is indeed mixed with 85 octane gasoline to get the E85 blend).

There's a couple good calculators I use online when I test both fuels that will tell you the actual mix ratio of E85 to E10 gas to get whatever final mix % you want, as well as a resultant octane number for that mix that account for the actual E% numbers you can test for at the pump too.
I used them both to get my final E30 mix as being @ 96.4 Octane.

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[engineermike]

@50BMG another point is that the knock suppression of ethanol is actually much greater than the octane rating would suggest.

 

[GregO]

I'm an old school carburetor guy. I can just about tune a Holley with my eyes closed.

 

[50BMG]

What @K4fxd said. PCMTec gets you full access to tune whatever you want for $200-300. It's a software package and you have to get a dongle as well (part of the cost mentioned). It's really a bargain. But tuning isn't so straight forward and is definitely a learning process. I did a flex tune on a nearly-stock 2019 for a local guy and it works pretty good, but it takes some doing to get it done.

The PCMTec out of Australia?
https://www.pcmtec.com/pcmtec-editor-protuner-edition-usvp1

But Flex Tune software is separate from that, correct?

 

[K4fxd]

But Flex Tune software is separate from that, correct?

No. Ford has flex software built into the factory ECM all we as tuners do is turn it on and set parameters that are not populated. Most people copy the F150 tune.

 

[engineermike]

The PCMTec out of Australia?
https://www.pcmtec.com/pcmtec-editor-protuner-edition-usvp1

yep that’s the one. It’s like $180 us and you need the j2534 dongle too.

But Flex Tune software is separate from that, correct?

Like k4fxd said, you can activate the stock flex logic properly using PCMtec, which is what I did. It’s confusing because PCMtec also offers can-bus flex where you can install an actual fuel ethanol sensor and tune accordingly. @mejohn50 has done this himself.

 

[Joshinator99]

yep that’s the one. It’s like $180 us and you need the j2534 dongle too.



Like k4fxd said, you can activate the stock flex logic properly using PCMtec, which is what I did. It’s confusing because PCMtec also offers can-bus flex where you can install an actual fuel ethanol sensor and tune accordingly. @mejohn50 has done this himself.

Hard to believe HP Tuners hasn’t put this together for Mustangs yet… so easy to do on the GM side with HPT…. Have you started a support ticket with them on this?

 

[WildHorse]

Most people copy the F150 tune.

I would do it from scratch.

 

[engineermike]

Hard to believe HP Tuners hasn’t put this together for Mustangs yet… so easy to do on the GM side with HPT…. Have you started a support ticket with them on this?

canbus flex or just access to all the oem flex parameters?

 

[Joshinator99]

canbus flex or just access to all the oem flex parameters?

With GM you add in a one wire GM sensor into the fuel line and plug into an open molex connection on the ECM. Couple of tweaks in the tune and full automatic timing and fueling based on E content is automatically done by the ECM on the fly. It’s already all in the OEM programming, you just alter a couple of values to “activate” it.

 

[engineermike]

@Joshinator99 in hpt you can activate the factory flex logic, no sensor needed. But they’re lacking some critical parameters to make it work right. PCMtec has access to all the parameters, and also options to add an ethanol sensor but the tuning is a little more complicated. Ford never installed a fuel sensor so the logic doesn’t exist to accommodate it.

 

[K4fxd]

Ford never installed a fuel sensor so the logic doesn’t exist to accommodate it.

And Ford's logic is a lot better than I ever thought. I had a massive vacuum leak and the car still correctly sensed the e content of the fuel I was using.

 

[engineermike]

And Ford's logic is a lot better than I ever thought. I had a massive vacuum leak and the car still correctly sensed the e content of the fuel I was using.

I agree. I’m completely happy with it. Lots of misinformation and inadequate tuning is out there making people think it’s not good.

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