Oil in the gas? And more knock control questions.

[topher_fc3]

Alright civic fam, I just got my car back from the dealer. It’s been in service since this past Friday.

I was told that the car had bad gas in it. I did fill up the night before it had stopped turning over, right before tuning the car with a ktuner to a 19.5/21.5 tune. I put about 15 miles on it that night and saw a knock control between .65-.73ish. The next morning the car wouldn’t start. It would try to turn over but just wouldn’t fire up.

Fast forward to today, I get the car back and got a fuel sample from them and you can see an oily substance in there. I’ve read about oil dilution being a thing with these engines, but that seems to be more about gas getting in the oil. Not the other way around, is this possible?

Since the dealer is saying it was the gas causing the issue it wasn’t covered by warranty even though the car has less than 2300 miles. With the labor I am out almost $900.

So I get the car back today, swear off ever getting gas from an Arco again. Put 5 gallons of 91 in from chevron (only 91 here in vegas) and I flash the 19.5/21.5 tune back to the ecu again. Now with the chevron gas and after Honda cleaned out the fuel system, I put another 10 or so miles on the car after the tune and my knock control is still around .65-.71. The lower end for the 19.5 tune and up over .7 when 21.5. This is almost identical to what it was with the “bad” batch of gas.

So I guess with that in mind, is this knock control normal? From what I read it seems like it is but I’m concerned it’s the same as the alleged tank of bad gas.

Might flash it back to a stock/19.5 tune to see where it goes.

No data logs available at the moment but I’ll get one next time I drive it.

Any thoughts appreciated.

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[gtman]

First of all, understand that about the best you'll see on 91 octane is generally the low to mid .5 range. When you first fire up a new tune, it will start at .59 and should go lower after a while. Those .65-.71 numbers you're seeing aren't horrible depending on stuff like ambient temps, load and how hard you were on throttle. Although, If you were just cruising along for 15 miles and saw .71 consistently, I'd say that seems a bit off.

 

[topher_fc3]

Thank you for the response. The .7+ would only blip when getting into the teens for boost. It’d stay mostly around .66 or .69 though so not too far off. It did start at .59 briefly and went up once the car got over 20mph. Good to know about mid .5s being normal on 91. I’ll keep that in mind as a target to look for.

Ambient and it2 temps are both around 78 degrees.

 

[Syntek]

My knock control typically hovered around .54 on shell 91, and spikes to .60-.70 when I was beating on it.


Since then, I have switched to using Chevron 91 and a splash (1-1.5 gallons) of e85 and my knock control is pretty solid at .54 most of the time including spirited driving.

I am tuned on TSP Stage 1 using Hondata.

 

[gtman]

OP, Syntek makes a good point. Using maybe a gallon of E85 per tankful might keep your K.C. in a better place.

 

[topher_fc3]

OP, Syntek makes a good point. Using maybe a gallon of E85 per tankful might keep your K.C. in a better place.

Awesome. I’ll give that a shot. I wasn’t sure if that was safe without being tuned for it. I’ll see if I can find some e85 today.

Anyone have any thoughts on the oil in the gas situation?

 

[gtman]

Anyone have any thoughts on the oil in the gas situation?

I honestly don't know. I'm assuming that somehow that bad batch of gas contained some small amount of oil?

 

[Syntek]

Awesome. I’ll give that a shot. I wasn’t sure if that was safe without being tuned for it. I’ll see if I can find some e85 today.

Anyone have any thoughts on the oil in the gas situation?

Our cars are able to run up to E15 perfectly fine without using flex fuel mods. I'm not sure how gas is mixed in Nevada but in Cali, most stations are already using E10 in their 91 fuels, so when you're mixing e85 just keep in mind your percentages of ethanol as it's content will be higher already due to the fuel carrying E10. (Then there's also other varying factors such as e85's actual ethanol content can vary between 50 to 84 percent I believe)

 

[topher_fc3]

Put another 20 miles on it or so tonight and the knock control has settled down a good bit. By the end of the drive it was around .60 pretty consistently, even when I switched to 21.5 and got on it a little.

Thanks for the replies!

Gtman I got a couple more things going in tomorrow, I’ll add to the tuning survey next week. ?

 

[topher_fc3]

So it’s proving pretty difficult to find any E85 near me. Can’t find any within 10 miles. Would some octane booster have a similar effect?

 

[retuks]

So it’s proving pretty difficult to find any E85 near me. Can’t find any within 10 miles. Would some octane booster have a similar effect?

No.


Last time I was in vegas (2017), E85 stations were hard to find as well. did find one within a 10 mile radius of summerlin though. Might just be your "ritual". If you don't wanna do that, I highly suggest you look into Torco. that IS a real octane booster. the ones at the gas station/pep boys and similar stores are a scam that don't add much of anything. they're snake oil with fuel injector solvents.

 

[topher_fc3]

I tried some STP octane booster (not a full bottle) and the car seems to like it. Combined with shell 91 the knock control has been steady around .49 and occasionally up to .51 on the 21.5 tune. I saw it blink at .48 a few times but never stays there.

Going to do the next tank with just the same shell 91 again and see if it changes at all. Feels great right now though and the cooler weather has been nice.

 

[retuks]

I tried some STP octane booster (not a full bottle) and the car seems to like it. Combined with shell 91 the knock control has been steady around .49 and occasionally up to .51 on the 21.5 tune. I saw it blink at .48 a few times but never stays there.

Going to do the next tank with just the same shell 91 again and see if it changes at all. Feels great right now though and the cooler weather has been nice.

If i were you i'd find a race shop somewhere in vegas that is well schooled with AFRs and tuning. just try to absorb as much of an understanding as you can from them. Being that it's cold right now, STP booster or not, it's hard to tell if it did much of anything because you're already boosted. the dense air is just going to further build on this effect, but as far as knock is concerned, knocking a little here and there isn't something at all to ignore. Ideally, you want a set up that doesn't do it at all. if you push it often, it will only take a little knock event to cause damage in those moments.


The general consensus shows that those boosters from the autoparts store and gas stations have all sorts of nothing beneficial in them in regards to actual octane and racing. I myself got my cars very intimate with seafoam in the past. It's more of a placebo and habitual ritual than a total necessity. But in racing, there's truly nothing more beneficial than basic maintenance and inspecting your ignition and fuel delivery system and fuel quality as often as your wallet will allow. I never once thought of these gen 10 civic (spare the Type R) as a platform to subject any serious race duties to myself.. it's inconvenient for a daily driver/commuter. Gas and go. oil changes. check the maintenance intervals (or take it to the dealer) when intervals are near. Honda engineers didn't leave anything on the table that an OTS octane booster will rectify.

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