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· ModFather
2019 Subaru Impreza Sport 5 Dr. Manual Shift
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Is there a reason people are using anything other than 87 in their car? Unless you are having pinging, I'm not sure I understand the benefit? From everything I've seen unless it's required or recommended it's unnecessary. If the car is knocking then you are just putting a band-aid over an underlying issue. Carbon build up can cause knock, just to stay on topic :)

Just one article but there are many like this: https://www.cars.com/articles/if-my...od-to-use-premium-occasionally-1420684149356/

I've had a number of Subaru's and they came in three types of fuel requirements. Regular, Premium Recommended, and Premium only. Unless you have the Premium Recommended where the motor programming will adjust to the octane rating, using anything other than what they say isn't a benefit and in the case of Premium only, a steady diet can be bad. With Premium only cars, the owners manual says in a pinch you can use a lower grade but not to do it all the time.

Is there new information that says using higher octane than recommended has some benefits? I'm not being sarcastic, I realize things change and there is always new info out there.
 

· Registered
2020 Subaru Impreza cvt base sedan w//ES
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282 Posts
nope. just once a month. at sheetz near us, premium and plus are sometimes within a penny. i've been paying for 93 since '09 when i switched to bmws so i'm used to it. lol
 

· ModFather
2019 Subaru Impreza Sport 5 Dr. Manual Shift
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1,768 Posts
I've been reading up on top tier rated fuel and it seems like there is a benefit to using it.
When you say top tier do you mean quality or do you mean Octane rating?
 

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2020 Subaru Impreza cvt base sedan w//ES
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282 Posts
Maybe top tier gas station ratings?

I primarily use Shell 93 in my bmw. My daughter uses 87 from anywhere. I ended up giving her a Shell credit card so she goes to Shell instead of the cheapest place in the ghetto.
 

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2019 Base CVT + Eyesight + Fogs
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797 Posts
Top tier is a federal fuel classification for gas which prevents buildup. I use Costco or Arco because they offer top tier quality and are often the least expensive..

As for octane, if its not pinging there's really no point in running a different octane once in a while. It is ideal if you can run with 87 without pinging. If you do get pinging, per warranty you get free carbon cleaning done at a dealership.
 

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Maybe top tier gas station ratings?

I primarily use Shell 93 in my bmw. My daughter uses 87 from anywhere. I ended up giving her a Shell credit card so she goes to Shell instead of the cheapest place in the ghetto.
The price of 93 is rough now. In a way I'm happy that I'm not driving my S4. Other ways, I'm sad that I'm not diriving it. But that price... Coupled with the fact that I have an issue with that car when doing all city driving that I'm lucky to get 180 to 240 miles a tank. Eventually I'll figure that out once I get it all fixed up.

As for your daugher filling up anywhere, I remember by dad would drive miles out of his way to save $.02/gal. He didn't listen when I was telling him that he was using more fuel than what he was saving and it was always those no name places. At least, now he goes to Costco.

I used the be a Shell primarily kinda guy but with prices so out of wack I use gasbuddy to see what is cheapest and most of the time it is Costco. Though, sometimes one or two of the BPs around here are the same or within a cent or 2. Or sometimes Chase has a deal like get 10% off up to x amount of dollars and it is cheaper with BP. I never see chase offer rewards on Shell. I have seen Exxon and Mobil.
 

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'17, O.Z. Ultraleggera, K&N filter, tints, LED lights, cup phone holder
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Discussion Starter · #30 ·
I posted oil/fuel because it usually comes up. I spent many years as a flatrate tech for a few German brands. I’ve done many…many… too many carbon cleans. That is why I pulled mine. I will say my engine was not as bad as I thought. Manufactures do run other injection types, just not in the US. This all took me a couple hours. Just came across this post and figure I’d share my findings.
(Also note there are blades that go in these ports which had a layer of carbon on them which were also cleaned)
How did you do this in just a couple of hours???
 

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'17, O.Z. Ultraleggera, K&N filter, tints, LED lights, cup phone holder
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Discussion Starter · #31 ·
Daughter's 2020 is at 36k now with 6k ocis. once a month she'll top off with 89 or 93. This spring, we're going to do the crc gdi ivd cleaning thing before her spring oil change. or maybe some liqui moly valve clean into the throttle body.
I was only aware of the liquid moly that goes in the fuel. Didn't know they had a valve clean too.
 

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(@Built2Drive)
Unfortunately everything is going to the toilet here in Cali, so I'm excited that they teamed up with Toyota to build the electric soltera, maybe in a few years they'll make an outback or even a nice impreza electric, something I can be proud to own,
 

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2020 Subaru Impreza cvt base sedan w//ES
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I was only aware of the liquid moly that goes in the fuel. Didn't know they had a valve clean too.
the valve cleaner is meant to go in the fuel but people have used it to soak parts. Trying to figure out how to “spray” it into the throttle body. Lol. Will probably just stick with the crc gdi ivd spray for $15.
 

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the valve cleaner is meant to go in the fuel but people have used it to soak parts. Trying to figure out how to “spray” it into the throttle body. Lol. Will probably just stick with the crc gdi ivd spray for $15.
I heard the CRC is good stuff but I have never used it.
 

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How did you do this in just a couple of hours???
Pull manifold, pull port blades, put blades in seafoam to soak. Scrape 3 out of 4 valves to let larger chunks. Vacuum ports. Fill with seafoam and let soak. Clean port blades. Scrub ports. Suck nasty seafoam out. Hit ports with brake clean while scrubbing. Suck that out. All clean. Rotate engine to close last port. Repeat cleaning. Installed port blades. Install intake manifold (I replaced gaskets) I then got the engine hot and after performed an oil change along with the rest of my 100k service.

I was a flatrate tech for 12 years before changing crafts. If you don’t have a background in doing something like this I may not suggest it.
 

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'17, O.Z. Ultraleggera, K&N filter, tints, LED lights, cup phone holder
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Discussion Starter · #36 ·
Pull manifold, pull port blades, put blades in seafoam to soak. Scrape 3 out of 4 valves to let larger chunks. Vacuum ports. Fill with seafoam and let soak. Clean port blades. Scrub ports. Suck nasty seafoam out. Hit ports with brake clean while scrubbing. Suck that out. All clean. Rotate engine to close last port. Repeat cleaning. Installed port blades. Install intake manifold (I replaced gaskets) I then got the engine hot and after performed an oil change along with the rest of my 100k service.

I was a flatrate tech for 12 years before changing crafts. If you don’t have a background in doing something like this I may not suggest it.
I just tried to YouTube this. Clearly, from the scrubbing you described, I don't see how a can of 'magic' will clean nearly as well! I'll see how much it costs for someone to do this with me.
 
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