2021 Subaru Crosstrek with 2.5 engine

[Donald]

If these are the specs it would seem it's best run with premium fuel. Ours seems to run fine with regular.

FB20D (DI): Impreza 2017+, Crosstrek 2018+
Compression: 12.5:1
Power 152 hp at 6,000 RPM
Torque: 145 lbf⋅ft at 4,000 RPM

 

[supton]

With VVT they can bleed off cylinder pressure and thus static compression isn't quite as big of a deal as it was. And with DI they can inject in right before ignition, so preignition should be less of a problem. Maybe it'll make more on premium, maybe it won't.

 

[Quattro Pete]

If these are the specs it would seem it's best run with premium fuel. Ours seems to run fine with regular.

FB20D (DI): Impreza 2017+, Crosstrek 2018+
Compression: 12.5:1
Power 152 hp at 6,000 RPM
Torque: 145 lbf⋅ft at 4,000 RPM

Your title states 2.5 engine, but the specs you posted are for the 2.0 engine.

The 2.5 engine is FB25D with the following specs:

• Compression: 12.0:1
• Power: 182 hp (185 PS; 136 kW) at 5,800 rpm
• Torque: 176 lb⋅ft (239 N⋅m; 24 kg⋅m) at 4,400 rpm

 

[Triple_Se7en]

If these are the specs it would seem it's best run with premium fuel. Ours seems to run fine with regular.

FB20D (DI): Impreza 2017+, Crosstrek 2018+
Compression: 12.5:1
Power 152 hp at 6,000 RPM
Torque: 145 lbf⋅ft at 4,000 RPM

Best indicator of 'running fine on 87', is when you turn a corner slowly and re-apply the gas pedal to resume a 40-45MPH speed limit. Does it hesitate momentarily? Even using the best 87 octane on the planet (Shell)?

Our Kia & Hyundai do. So now smooth re-acceleration exists again, using the next grade up....... 93 octane.
I used to hate having to give either vehicle more gas pedal and see the RPMs jump to around 4, thus avoiding further hesitation.

No more jumping instantly to around 4k RPMs. Now it resumes power and acceleration slowly and smoothly and stays around 2.5k RPM when accelerating again.

That's the true sign we are using the correct grade of gasoline. If you want more stress on the transmission and don;t plan on keeping the vehicle into old age, then continue with 87 octane.

 

[joekingcorvette]

I use premium in the Corvette but I don't think the Subaru needs it.

 

[Donald]

Your title states 2.5 engine, but the specs you posted are for the 2.0 engine.

The 2.5 engine is FB25D with the following specs:

• Compression: 12.0:1
• Power: 182 hp (185 PS; 136 kW) at 5,800 rpm
• Torque: 176 lb⋅ft (239 N⋅m; 24 kg⋅m) at 4,400 rpm

So we have a 2021 Crosstrek with a 2.5 engine. I assume it's DI. The spec I found for the 2.5 engine were the ones I listed but cannot always trust the internet.

 

[Quattro Pete]

So we have a 2021 Crosstrek with a 2.5 engine. I assume it's DI. The spec I found for the 2.5 engine were the ones I listed but cannot always trust the internet.

So you have the FB25D (2.5) engine. What you posted was the FB20D (2.0) engine.

You can see all variations here:

Subaru FB engine - Wikipedia

en.wikipedia.org

FYI, I run regular gas in mine. No amount of extra octane is going to turn this car into a rocket.

 

[Donald]

So you have the FB25D (2.5) engine. What you posted was the FB20D (2.0) engine.

You can see all variations here:

Subaru FB engine - Wikipedia

en.wikipedia.org

FYI, I run regular gas in mine. No amount of extra octane is going to turn this car into a rocket.

No burnouts?

 

[TumblrDucks]

Best indicator of 'running fine on 87', is when you turn a corner slowly and re-apply the gas pedal to resume a 40-45MPH speed limit. Does it hesitate momentarily? Even using the best 87 octane on the planet (Shell)?

Our Kia & Hyundai do. So now smooth re-acceleration exists again, using the next grade up....... 93 octane.
I used to hate having to give either vehicle more gas pedal and see the RPMs jump to around 4, thus avoiding further hesitation.

No more jumping instantly to around 4k RPMs. Now it resumes power and acceleration slowly and smoothly and stays around 2.5k RPM when accelerating again.

That's the true sign we are using the correct grade of gasoline. If you want more stress on the transmission and don;t plan on keeping the vehicle into old age, then continue with 87 octane.

Yes this is where I feel the same. User manual says 87, knock sensor shows no detonation under 87, but for some reason using 89 just feels better in the car. I thought gasoline grade is only related to knocking?

 

[benjy]

i would not be concerned with the fuel BUT you may see less performance + MPGs with 87 oct' the CVT's which are showing MORE failures lately $$$$$, myself i would NEVER buy any CVT equipped vehicle, especially a bigger one!

 

[D1sc]

On my Z06 lower octane affects ignition timing same with my Audi and procharged ram that asks for 93&95 and here in Wis. 91 is all I can get lately so retuning or relying on my alky systems methanol injection is the only solution,I use boost juice in my 11 Audi and pure in the vette It is a snow meth in the vette but switching to alky

 

[Deamos]

Yes this is where I feel the same. User manual says 87, knock sensor shows no detonation under 87, but for some reason using 89 just feels better in the car. I thought gasoline grade is only related to knocking?

I've had the same experience with my CX5 and the 2.5L Skyactiv with 89 being a better experience. With as little as I drive these days, I'll pay the extra $3-5/tank (fill-up is usually in the 10-gallon range) and enjoy the driving experience just a bit more.

 

[Donald]

i would not be concerned with the fuel BUT you may see less performance + MPGs with 87 oct' the CVT's which are showing MORE failures lately $$$$$, myself i would NEVER buy any CVT equipped vehicle, especially a bigger one!

Maybe. However I do not remember (but over 70 memory shot) anyone on this forum saying they had a CVT in their car and it failed.

 

[Jdeere562]

I always burned premium alcohol free gas in my 2018 Forester.
Not required, but I bought it to stay away from the alcohol, because I seldom drove.
Also added fuel stabilizer to every tank.

Gave the car to my Granddaughter and she drives every day
I'm sure she runs alcohol gas in it now due to cost. And that's fine. Always tried to implant top tier fuel in her mind.

 

[twX]

I'd monitor for knock with an ODB2 scanner before shelling out for higher octane fuel. GDI engines gain a lot of knock resistance from ethanol, and in many places there's a lot more ethanol in 87 than in 91. 87 E10 should provide more than enough knock resistance for that engine.

I tuned my WRX for 87 E10, since its knock resistance in this engine is almost as good as 91 E0.