Ethanol fuel

[Beach civic si]

Hi I have a 2019 civic si with a Ktuner and stage 1 tsp tune. Runs amazing but notice the knock control little high at.79
Live in Cali so the highest octane is 91
You think it’s a gas issue?
Would adding 1 gallon of e85 to the tank be of any benefit as far as knocking or performance gains
Thanks for the info

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[Jonmd89]

Might want to try a different station with a full new tank, I barely hit that high off of 89 octane and never above .49 on 93 octane

 

[Beach civic si]

Might want to try a different station with a full new tank, I barely hit that high off of 89 octane and never above .49 on 93 octane

Sounds good I’ll give it a try wish we had 93 out here lol

 

[Beach civic si]

Sounds good I’ll give it a try wish we had 93 out here lol

A tuner recommended adding 1 gallon of e85 to the tank but wasn’t sure if that was ok for the engine

 

[360glitch]

California 91 is known to not be the greatest, even by 91 standards. You can safely blend in a small amount of E85 to help up the octane a bit but I would not start off with more than a gallon.

 

[Beach civic si]

I know ethanol can retain moisture and cause some corrosion so just wanted to see if anyone has done the e85 addition to 91 octane

 

[360glitch]

I know ethanol can retain moisture and cause some corrosion so just wanted to see if anyone has done the e85 addition to 91 octane

Yes you can actually buy a flex fuel kit and safely run up to 40% ethanol in these cars. Some even run straight E85 but that is typically recommended against. Not due to corrosion, but because it over works the fuel system and leads to misfires.

Even without a flex fuel kit, the ECU can handle having 1 gallon blended in without issue.

 

[Beach civic si]

Yes you can actually buy a flex fuel kit and safely run up to 40% ethanol in these cars. Some even run straight E85 but that is typically recommended against. Not due to corrosion, but because it over works the fuel system and leads to misfires.

Even without a flex fuel kit, the ECU can handle having 1 gallon blended in without issue.

Sounds good but is there any benefit in doing so?
Like decrease knock or increased performance?

 

[Beach civic si]

Sounds good but is there any benefit in doing so?
Like decrease knock or increased performance?

I meant not the flex fuel kit but just running one gallon of e85
I know the flex fuel kit adds performance but does adding one gallon have any benefit?

 

[amirza786]

I live in Northern Cal, but travel to SoCal frequently and I ran my 2018 Si with Ktuner TSP's Stage 1 for 15K on California 91 from Costco and I usually fill with Arco 91 when I hit near the Santa Clarita area, and never had an issue with knock. K control mainly stayed on .49 most of the time an occasionally hit .51 at WOT max but mainly stayed on .49. Now I drive a 2010 IS350 where 93 is recommended but of course you can't get that here so I use 91, again no issues with knock at all. Maybe it's the gas station you are using? Instead of adding Ethanol, maybe figure out what is causing the issue. Do you have an aftermarket intake or any other bolt-on?

 

[Beach civic si]

I live in Northern Cal, but travel to SoCal frequently and I ran my 2018 Si with Ktuner TSP's Stage 1 for 15K on California 91 from Costco and I usually fill with Arco 91 when I hit near the Santa Clarita area, and never had an issue with knock. K control mainly stayed on .49 most of the time an occasionally hit .51 at WOT max but mainly stayed on .49. Now I drive a 2010 IS350 where 93 is recommended but of course you can't get that here so I use 91, again no issues with knock at all. Maybe it's the gas station you are using? Instead of adding Ethanol, maybe figure out what is causing the issue. Do you have an aftermarket intake or any other bolt-on?

 

[amirza786]

Yes you can actually buy a flex fuel kit and safely run up to 40% ethanol in these cars. Some even run straight E85 but that is typically recommended against. Not due to corrosion, but because it over works the fuel system and leads to misfires.

Even without a flex fuel kit, the ECU can handle having 1 gallon blended in without issue.

California gas is really not that bad, when I was on TSP's stage 1, even on map 3 I was mainly hit .49 and occasionally on very hot days at WOT I would occasionally hit .51 for briefest of moments. My IS350 which recommends 93 runs fine on Costco 91 and knock is a zero issue for me. Something else may be going on with the OP

 

[Beach civic si]

No man just stock except for Ktuner and tsp stage 1
Ya maybe it’s the gas I’ll try maybe different station and hit chevron or 76 and see if that helps
I’ve goiing to local station and maybe it’s shit gas
Thanks for the info

 

[Beach civic si]

Thanks for the info

I live in Northern Cal, but travel to SoCal frequently and I ran my 2018 Si with Ktuner TSP's Stage 1 for 15K on California 91 from Costco and I usually fill with Arco 91 when I hit near the Santa Clarita area, and never had an issue with knock. K control mainly stayed on .49 most of the time an occasionally hit .51 at WOT max but mainly stayed on .49. Now I drive a 2010 IS350 where 93 is recommended but of course you can't get that here so I use 91, again no issues with knock at all. Maybe it's the gas station you are using? Instead of adding Ethanol, maybe figure out what is causing the issue. Do you have an aftermarket intake or any other bolt-on?

Ya maybe it is bad gas I’ll probably try new station and see if that helps before adding ethanol
Been using a local station so I’ll try chevron or 76
Thanks man

 

[360glitch]

Maintaining knock control levels near .49 with a tune such as TSP1 should not be expected when using 91 octane.

Blending a small amount of E85 in will increase your octane level, decrease your knock control reading (due to less knock), and give back the power you lost by having a knock control level of .49.

If you already maintain a knock control level of .49, this would not help you.

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