Can you Use Regular Octane Gas In A Honda Civic Si?

Can you use 87 octane in a car that uses premium gas? Here is what happens. Enjoy.

[BelugaCaviar]

As a honda tech i can tell you for a fact that on a stock factory tune you will have 0 issues running 87 in your si. It even says in our service information system "premium gasoline recommened" but cars from factory that ONLY take premium fuel say "premium fuel required" end of the day civic si's are still just economy vehicles with a more sporty feel to them. My customers dont like hearing it but its the reality. Running a flash pro or other aftermarket tune will require a higher grade fuel

[djs]

Honda doesn't recommend premium gasoline for their vehicles so you have to spend more money for gas. It's recommended, so the engine runs optimally. Of course you can put any gas in there you want, but the car just won't run it's best if premium is not used.

[djhightopfade]

I had a very negative experience running bad gas on my dyno tuned FA5. You should definitely flash back to stock until all the 87 octane is used. Although our cars require at least 91 octane, the factory tune can run 87 safely.

[Rob_Nasty]

My manual "recommends" premium not required! Lol 😂

But 91+ all day!

[jeremybreeden]

You make some great content for the 8tn gen si. Always enjoy your videos! I've accidentally ran 87 a few times in my 06 si and never really noticed a difference. Not to say all the other things you mentioned such as carbon build-up and other little things doesn't happen, just in my experience I didn't notice a performance issue.

[fixinbrokevws]

Couldn't agree more 👍 nice info and proof for people that think all gas is the same no matter the octane rating.

[h.a.l]

Good video! The real test is for Si owners to actually experience it themselves. I ran 87 once and I said nopety nope nope. Never again. The results lie within you as the owner. Other people wouldn't notice.

[jona_le_mus]

I have a 2013 civic SI. I got it from the dealer and it was nice, responsive and quick. I didn’t know that Premium was necessary to make it run better… no wonder I’m noticing lack of performance

[SpiderwebRob]

Good video but a few things to note. The k20z3(si) runs 11:1 compression. The k20c2(10th gen civic) runs basically the same at 10.8:1. The k20c2 recommends 87. the k20z3 has aluminium heads too which helps reduce pre detonation(knocking). Also the crankshaft uses an oil bearing so a slight knock shouldnt be too bad for engine life. If you dont lug your engine and change oil at intervals or sooner it shouldnt make much difference. My 8th gen si is at 155, 000km and i think it has used 87 most of its life(i used 87 the last 10, 000km) and it is running smooth. More than enough power for commuting. I drive a lot and if i use premium it will add $1, 000 CAD to my gas bill each year. Another thing to consider is fresh gas vs stale gas, additives, region, e.c.t. I will try running 91 for my next full oil change period and see if i notice a difference.

[zdvgnlg]

Why I need to run premium in a car that only makes 50 horsepower is beyond me

[juanclaudio]

Knocking while crusing isn't as bad. It's not good. But its better to knock when there is no load than at wot. If you made a datalog at wot comparing 93 and 87. You can see it pull timing to be able to use 87 so it doesn't knock. Ambient temp affects that too. But the cars do a good job protecting its self.

[retrac]

Dang $2.99 for 87? Thats what I pay for premium where I’m from.

[knockoutking]

91 to 93. That's what I always run even when I was a dish washer 3 years ago haha...now getting that trucking money so I have NO excuse lmao! Good video bro God bless...

[highspeedenthusiast]

Premium all day!!! High compression K20 Z3 head demands it....(ethanol FREE) if possible... after two tanks of regular the car lets me know it doesn't like it. Also 360 to 370 miles per tank with ethanol where its 430 to 440 with ethanol free premium... 440 a tank means no VTEC!!! It's going to take a few Cycles from ambient temperature for your car to register a difference in octane... I'll guarantee your tune was on a premium fuel??? ETHANOL FREE PREMIUM FROM VALARO!!! It should also be noted that this is a 100% stock base map that I am referencing from....

[drewpar]

You look like the father from Home Alone

[Adumbpriice]

"Only put premium gas in cars that DONT use premium..because it makes more power."
-every ricer in the world.

[markblanc]

I ran 87 in my 09 si for like 6 years before switching to premium. My knock sensor had to be replaced but other than that no damage. I wouldn't do it again nor recommend it though.

[angeldejesus]

great video.. was asking myself this for the past 2 weeks...

[rohinhans]

btw, when the hondata says the car is knocking, it isnt always right. my car got tuned with mic and it says my car is knocking yet i know its not

[Grafyte]

The advice to just get a regular civic to avoid buying premium is really weak. The K20 in the Si runs 11.0:1 compression and the R18 in the regular civic is still 10.6 which would be considered quite high for anything even 10 years before it came out. The economy K20 in the newer civics is now 10.8:1 and strangely the automatic recommends 87 while the manual recommends 91 despite there being no advertised power or torque difference. I firmly believe that little factoid has to do with emissions compliance, since the auto is fully computer controlled, it's much easier to control emissions with software, while on the manuals, it's much harder to control so it needs to be optimized from a more general standpoint, and optimizing for higher octane is a little trick to help with that. Regardless, the regular civic, and most everything nowadays newer than about 2017ish is optimized for premium or at the very least has the capability to take advantage of it to a degree. It's just really easy to dial back ignition timing advance and get most anything to run on whatever is available.