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      12-21-2024, 01:26 AM   #1
turnsignalslol
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Running tunes with higher octane levels

Sorry for the confusing title. My question is:

If you are running a 91 tune but only have ACN91 available, can you mix the ACN91 with E85 (E20-E30) and safely run the tune? I know that ethanol has a higher octane rating but it also requires more fuel so a concern would be running lean.

Would an ACN91/E85 E30 blend be good enough for an OTS E30 map or no? I’m assuming the tuners assumed you were mixing 93 and E85.

On the fence about tuning the M2 but only have ACN91 available and want to be able to run regular 91 or 93 maps.
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      12-22-2024, 11:09 AM   #2
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I run E20 with the stock tune. Should be fine.
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      12-22-2024, 11:19 AM   #3
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Quote:
Originally Posted by turnsignalslol View Post
Sorry for the confusing title. My question is:

If you are running a 91 tune but only have ACN91 available, can you mix the ACN91 with E85 (E20-E30) and safely run the tune? I know that ethanol has a higher octane rating but it also requires more fuel so a concern would be running lean.

Would an ACN91/E85 E30 blend be good enough for an OTS E30 map or no? I’m assuming the tuners assumed you were mixing 93 and E85.

On the fence about tuning the M2 but only have ACN91 available and want to be able to run regular 91 or 93 maps.
Funny you posted this, I went through this about a month ago.

TLDR; yes.

After experimenting on BM3 stage 2 OTS map1 (ACN91) and map 2 (91) I can confirm that with flex fuel and at least e30, you should be good to run a more aggressive map.

I haven’t dabbled in map3 (93 octane) but I have been running map2 (91) with e40 after calculating my mix. So far so good, runs great and strong still on stock fuel pump.

Technically you can run full e85 but I would not recommend that on stock fuel pumps. A reputable source told me to not go above e60 without PI’s so I tend to dabble in the e30/40 range.

I’ve noticed the car runs night and day better with ethanol vs without. Highly reccomend using your 91 map with some added ethanol if you have a flex fuel sensor.

PS- if you can, use a flex fuel multimap tune instead of the e30 tune. It’s essentially the same thing but Bootmod3 heavily works on and updates their multimaps over anything else and they are all flex fuel capable, meaning the map can detect your ethanol content with the flex fuel and alter your firing on the fly. If you used a 91 multimap tune with ethanol, you’d run better than an e30 since the multimap can alter with slight variations of ethanol content vs the e30 only utilizing e30.

Last edited by Geighty7; 12-22-2024 at 11:22 AM..
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      12-22-2024, 11:46 AM   #4
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Quote:
Originally Posted by Geighty7 View Post
Funny you posted this, I went through this about a month ago.

TLDR; yes.

After experimenting on BM3 stage 2 OTS map1 (ACN91) and map 2 (91) I can confirm that with flex fuel and at least e30, you should be good to run a more aggressive map.

I haven’t dabbled in map3 (93 octane) but I have been running map2 (91) with e40 after calculating my mix. So far so good, runs great and strong still on stock fuel pump.

Technically you can run full e85 but I would not recommend that on stock fuel pumps. A reputable source told me to not go above e60 without PI’s so I tend to dabble in the e30/40 range.

I’ve noticed the car runs night and day better with ethanol vs without. Highly reccomend using your 91 map with some added ethanol if you have a flex fuel sensor.

PS- if you can, use a flex fuel multimap tune instead of the e30 tune. It’s essentially the same thing but Bootmod3 heavily works on and updates their multimaps over anything else and they are all flex fuel capable, meaning the map can detect your ethanol content with the flex fuel and alter your firing on the fly. If you used a 91 multimap tune with ethanol, you’d run better than an e30 since the multimap can alter with slight variations of ethanol content vs the e30 only utilizing e30.

I personally would not go over e50 (keeping in mind, a good tuner would factor in their tune plus or minus "10" based on the percentage of e in the e85 and in the regular gas you are using) without upgrading pumps, lines and going PI (and at that point, should also go to single big turbo). I guess I would add if going full on out like that, would want to upgrade transmission.

Wanna play, gotta pay...
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      12-22-2024, 12:27 PM   #5
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Quote:
Originally Posted by M_Power Rob View Post
I personally would not go over e50 (keeping in mind, a good tuner would factor in their tune plus or minus "10" based on the percentage of e in the e85 and in the regular gas you are using) without upgrading pumps, lines and going PI (and at that point, should also go to single big turbo). I guess I would add if going full on out like that, would want to upgrade transmission.

Wanna play, gotta pay...
Ya that’s why I play in the e30/e40 range for that variable in percentage of e. The good thing is, with BM3 flex fuel sensor, it allows the user to see the level of octane from inside cabin.

Transmission will need to be upgraded after 650- I’m currently doing that with the manual now (new clutch, SSK, rear carrier, new front bearings, etc).

Personally I’m running hybrids if I ever decide to up the ante and go all out.
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      12-22-2024, 12:32 PM   #6
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I can’t imagine driving one of these cars ^^^^.
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      12-25-2024, 08:17 PM   #7
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I can’t imagine driving one of these cars ^^^^.
It’s fun/terrifying
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      12-25-2024, 09:04 PM   #8
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It’s fun/terrifying
I skydived in Kauai earlier this month.
That’s plenty of terrifying for a while.
Thank you.
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      12-26-2024, 05:46 PM   #9
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Why though? If you have OTS tunes why not just flash the ethanol one?
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      12-30-2024, 04:06 AM   #10
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Quote:
Originally Posted by curtdragon View Post
Why though? If you have OTS tunes why not just flash the ethanol one?
Because ACN 91 is the worst in the country and the OTS E tunes most likely were made for an E85 and 93 octane mix.
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      01-01-2025, 01:46 AM   #11
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I’ve run up to e40 numerous times without issue….It’s just gonna up the fuel to compensate and obviously lower your mpg…If you even care about that.
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