my perspective on the 'dip'

[Lantana frs]

I think its noise/emissions related. Might be a happy spot for the motor which usually means noise, emissions and fuel consumption. All imo of course

[Lantana frs]

E85 with tune kinda cures it as well. Significantly more intake noise though.

[ichitaka05]

Originally Posted by Lantana frs

If that were the case it wouldn't be so easy to tune out.

They can, but it won't meet the world emission standard. If they wanna meet that, they need another 2 extra cylinder or .5~1 liter (ex: EZ30~36)

Originally Posted by churchx

I'm also thinking like that. UEL or Ace header and dip is gone? How it's "engine's characteristic" then?

You're right. But does all the car come with catless header? Does it meet emission standard worldwide?

Putting aftermarket part change this topic into; strawberry to Chocolate dipped strawberry (pun off Valentine's Day is near lol).

[Summerwolf]

Originally Posted by ichitaka05

Don't forget, 2.8~3 liter 6 cylinder boxer engine do kill tq dip better than tiny 2 liter 4 cylinder boxer engine.

Even the 2.5 EJ motors don't have a dip like this. Subarus weren't "known" for this until the twins.

[ichitaka05]

Originally Posted by Summerwolf

Even the 2.5 EJ motors don't have a dip like this. Subarus weren't "known" for this until the twins.

Few things to note:
1 - Yes there was tq dip even in EJ and known for this.
2 - A lot of people don't know this cuz Subaru put lil snail in there... aka turbo lol
3 - It's EJ25, which means extra .5 liter help reduce the dip. Look up NA EJ engine dynos like EJ18, EJ20, EJ22 or even EJ25, they all have dip.

[Summerwolf]

Originally Posted by ichitaka05

Few things to note:
1 - Yes there was tq dip even in EJ and known for this.
2 - A lot of people don't know this cuz Subaru put lil snail in there... aka turbo lol
3 - It's EJ25, which means extra .5 liter help reduce the dip. Look up NA EJ engine dynos like EJ18, EJ20, EJ22 or even EJ25, they all have dip.

My ej doesn't have a turbo.... and no, none of those were "known" to have torque dip. Obviously the 25 is a 2.5. Just saying, they built a motor from the ground up. They could and have done better with power delivery on boxer motors that aren't even considered performance motors. Most NA ej series dynos don't show drastic dips, not sure what you're seeing, but they were known for a somewhat linear power band.

[Teseo]

So we can blame the transition of PI to DI?

[ichitaka05]

Originally Posted by Summerwolf

My ej doesn't have a turbo.... and no, none of those were "known" to have torque dip. Obviously the 25 is a 2.5. Just saying, they built a motor from the ground up. They could and have done better with power delivery on boxer motors that aren't even considered performance motors. Most NA ej series dynos don't show drastic dips, not sure what you're seeing, but they were known for a somewhat linear power band.

You can even search NASIOC or RS25 for tq dip or flat spot. It vary (with mods), but there is tq drop in all their engines. For us, due to direct & port injection, it causes the tq dip more.

[Kodename47]

Originally Posted by Teseo

So we can blame the transition of PI to DI?

No, it's the VE of the engine.

[Summerwolf]

Originally Posted by ichitaka05

You can even search NASIOC or RS25 for tq dip or flat spot. It vary (with mods), but there is tq drop in all their engines. For us, due to direct & port injection, it causes the tq dip more.

You can search every Subaru forum to your hearts content. You're simply stating that to cure the torque dip you need another two cylinders. I disagree. Subarus have been commonly regarded as having a "flat" torque curve in the past that wasn't commonly seen in four cylinder vehicles. They dropped off in higher RPMs but didn't show the massive dip and upward swing. The FA20 has a somewhat unique torque curve. That's what I'm saying. Some of those dynographs are coming from swap threads too, so there is always that component to keep in mind.....

[ichitaka05]

Originally Posted by Summerwolf

You can search every Subaru forum to your hearts content. You're simply stating that to cure the torque dip you need another two cylinders. I disagree. Subarus have been commonly regarded as having a "flat" torque curve in the past that wasn't commonly seen in four cylinder vehicles. They dropped off in higher RPMs but didn't show the massive dip and upward swing. The FA20 has a somewhat unique torque curve. That's what I'm saying. Some of those dynographs are coming from swap threads too, so there is always that component to keep in mind.....

I doubt even adding 2 cylinders &/or more liter will cure boxer dip perfectly, if you keep it within FA engine specs. That's all I'm saying.

[Scrappydoo]

Originally Posted by ichitaka05

For the tq dip, it's just the Boxer engine's characteristic. Even look at Porsche boxer engine, they still have tq dip (very tiny, but still there)

To the point: Boxer engine is famous for tq dip

Not any boxers I've owned. No sign and certainly not "famous". What is your source for you absolute statement?

[ichitaka05]

Originally Posted by Scrappydoo

Not any boxers I've owned. No sign and certainly not "famous". What is your source for you absolute statement?

Read several post up

[Scrappydoo]

Originally Posted by ichitaka05

Read several post up

I have. They are particular items, I wanted to know what your proof was for your absolute statement that all boxer engines have a torque dip.

If I didn't see it perhaps you could guide me to it.