All-New 2022 Subaru BRZ Makes Global Debut

[anticubus]

Originally Posted by Yoshoobaroo

From quickly looking up the 2 on reviews, the 10th gen was about a second slower to 60 than the 9th gen. No wonder it feels slower. The 2.4 has more torque down low but when you're wringing it out that doesn't matter if you still make the same power up top, and weigh 300lbs more. I'm sure it feels quicker around town accelerating in the lower rev range, but that's probably it.

This is exactly what I'm referencing. It doesn't look like the FA24 is going to enjoy being up towards the 7K range, but it definitely resolved the torque issues. I like revving it out so the torque dip wasn't a huge issue in daily driving but after focusing on my cornering there are lots of times where it becomes a choice between landing in the the dip or a shift mid-corner.

I wasn't making a direct comparison to the 2.4L out of the 10G XRS, just noting that the two BRZ generations have followed a similar engine pattern. The FA20 and the FA20DIT landing in the BRZ and then quickly the WRX means they saw more performance oriented design aspects like the high redline and in Toyota's case the focus on extracting all the NA performance regulations and engineering margin would allow them. Then the next generation we get an NA version of a turbo SUV engine with a more hands-off approach from Toyota. I'm worried it's going to drive like one. With the announcement their model is getting pushed back I'm definitely not buying first year.

[ZDan]

Originally Posted by anticubus

This is exactly what I'm referencing. It doesn't look like the FA24 is going to enjoy being up towards the 7K range,

It makes peak power at 7000rpm. That is where it wants to be. And it makes 23hp more than the current gen at that rpm. We get another 100rpm before the rev limiter, so it will stay (slightly) further up in the powerband after upshifting. I don't see any downsides. Here's what relative rear wheel hp and torque should look like:

[Yoshoobaroo]

Originally Posted by ZDan

It makes peak power at 7000rpm. That is where it wants to be. And it makes 23hp more than the current gen at that rpm. We get another 100rpm before the rev limiter, so it will stay (slightly) further up in the powerband after upshifting. I don't see any downsides. Here's what relative rear wheel hp and torque should look like:

This shows perfectly that the motor should be similarly rev-happy as the FA20

Another good indicator is that the stroke (86mm) was unchanged, and only the bore enlarged (86mm>92mm). Typically engines with larger bore/stroke ratios like revving more than ones with lower bore/stroke ratios.

[ermax]

Originally Posted by Yoshoobaroo

This shows perfectly that the motor should be similarly rev-happy as the FA20

Another good indicator is that the stroke (86mm) was unchanged, and only the bore enlarged (86mm>92mm). Typically engines with larger bore/stroke ratios like revving more than ones with lower bore/stroke ratios.

Especially when that extra space is used for larger valves. Most of the time when getting a displacement bump OEMs go with a longer stroke which negatively impacts high revs. Fortunately they didn’t go that route. There’s no reason this new engine should be less rev happy.

[nikitopo]

The only issue I can see with this engine is the higher compression ratio (13.5 vs. 12.5), which it could affect performance more with lower quality fuel. Such compression ratios were used in the past mainly in racing applications, where someone had access to racing quality fuel. It looks they went into that direction to extract the best possible performance figures under this displacement level and latest emission regulations. E85 and Flex fuel kits could be a solution for those having access to such type of fuel. And of course the worst option would be to supercharge such a high compression engine ...

[Yoshoobaroo]

Originally Posted by nikitopo

The only issue I can see with this engine is the higher compression ratio (13.5 vs. 12.5), which it could affect performance more with lower quality fuel. Such compression ratios were used in the past mainly in racing applications, where someone had access to racing quality fuel. It looks they went into that direction to extract the best possible performance figures under this displacement level and latest emission regulations. E85 and Flex fuel kits could be a solution for those having access to such type of fuel. And of course the worst option would be to supercharge such a high compression engine ...

I bet it's still fine running on 87AKI. It may be optimized for 91/93 but I kinda doubt that being that the US public has such an aversion to using higher octane fuel for some reason. We'll see I guess. I'm excited about the C/R bump, I always run 93 in my cars anyway since they all have at least a 93 Octane tune on them anyway.

[Tcoat]

Originally Posted by Yoshoobaroo

I bet it's still fine running on 87AKI. It may be optimized for 91/93 but I kinda doubt that being that the US public has such an aversion to using higher octane fuel for some reason. We'll see I guess. I'm excited about the C/R bump, I always run 93 in my cars anyway since they all have at least a 93 Octane tune on them anyway.

The current engines, at the lower compression ratio, recommend 93 and require 91 so there is no way that they are going to increase the compression ratio and reduce the octane requirement.

[Cephas]

I doubt they'd lower the recommended octane, but that doesn't mean the car won't run sorta okay on lower grade fuel. The ECU is smart enough to pull enough timing to make it work.

[Tcoat]

Originally Posted by Cephas

I doubt they'd lower the recommended octane, but that doesn't mean the car won't run sorta okay on lower grade fuel. The ECU is smart enough to pull enough timing to make it work.

The current engine runs sorta OK on 87. The new one is a substantial increase and would probably be pushing even the ECU to it's limits as far as correction goes. In other words it would probably run like crap. Even Joe and Jill Generalpublic would notice the difference.

[ZDan]

They likely have the same basic requirements regarding how well it runs on 87 for the new model as for the current one. Could be improvements to combustion chamber design, fueling, and spark control make it possible to have the same "driveability" with lower octane fuel with the increased compression ratio.

long/short: I wouldn't worry about it... Especially since we're all gonna use 91 octane minimum anyway!

[Transport3r]

Another point to consider is that just because the static CR is now higher doesn’t necessarily mean that the minimum dynamic CR that can be achieved by valve timing is any higher than before. If they’re going to sell the cars in NA, they have to be able to at least run reasonably well on 87, I’m sure that requirement is the same as before. Between valve timing, ignition timing, and advances in DI tech over the past 10 years, I don’t think it’s unlikely at all.

[Tcoat]

Originally Posted by ZDan

They likely have the same basic requirements regarding how well it runs on 87 for the new model as for the current one. Could be improvements to combustion chamber design, fueling, and spark control make it possible to have the same "driveability" with lower octane fuel with the increased compression ratio.

long/short: I wouldn't worry about it... Especially since we're all gonna use 91 octane minimum anyway!

Originally Posted by Transport3r

Another point to consider is that just because the static CR is now higher doesn’t necessarily mean that the minimum dynamic CR that can be achieved by valve timing is any higher than before. If they’re going to sell the cars in NA, they have to be able to at least run reasonably well on 87, I’m sure that requirement is the same as before. Between valve timing, ignition timing, and advances in DI tech over the past 10 years, I don’t think it’s unlikely at all.

They were concerned enough with the old ones to say NOT to use 87 so even if it "stays the same" they are not suddenly going to say it is OK.

[ZDan]

Originally Posted by Tcoat

They were concerned enough with the old ones to say NOT to use 87 so even if it "stays the same" they are not suddenly going to say it is OK.

Yeah, of course they'll say not to use 87 and will specify 91 minimum. I'm just saying they likely haven't changed their requirements for how the engine deals with lower-octane fuel should it find it's way into the engine. I would guess that the new engine's susceptibility to damage or poor-running from lower-octane fuel is the same as the current lower-CR engine. I.e., nothing to worry about for most of us.

[Sasquachulator]

Originally Posted by Transport3r

Another point to consider is that just because the static CR is now higher doesn’t necessarily mean that the minimum dynamic CR that can be achieved by valve timing is any higher than before. If they’re going to sell the cars in NA, they have to be able to at least run reasonably well on 87, I’m sure that requirement is the same as before. Between valve timing, ignition timing, and advances in DI tech over the past 10 years, I don’t think it’s unlikely at all.

IF the gas cap says recommended 91+ or whatever you might be able to get away with using 87.
If it says required 91+ dont even dare put less than 91.