Torque dip common to NA boxer engines?

[zdr93523]

Here's some food for thought... It appears that our torque dip is common to NA boxer engines. It is just very apparent in the twins because the hp/tq is so low. Here is a shot out of my Cayman S owners manual. You can't feel the dip in the Porsche.


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[Kostamojen]

Subaru's have always had the torque dip. Its due to the intake manifold configuration and can be eliminated with ITB's. This was discussed here on this forum even before the car came out, LOL!

[zdr93523]

What I'm getting at is that it isn't just Subarus. It's the general nature of the boxer.

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[FR-S Matt]

Or it can be eliminated by an intake, good header, and full exhaust. Find a good tuner with those parts and your dip is gone. Otherwise, get FI. ITB's I have not researched so I can't comment on them.

Also, let me emphasize GOOD tuner.

[zdr93523]

I agree that it can be easily eliminated. Just wanted to add to the knowledge base of the forum for those who assumed the dip was unique to Subaru motors.

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[wparsons]

A lot of non boxer DI N/A engines have torque dips as well. Oddly, the 2015 WRX has a dip as well, which I figured wouldn't show up with the turbo.

[zdr93523]

Yea that's kind of strange.

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[zdr93523]

Those Porsche charts are not DI for what its worth.

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[Black Tire]

Originally Posted by Kostamojen

Subaru's have always had the torque dip. Its due to the intake manifold configuration and can be eliminated with ITB's. This was discussed here on this forum even before the car came out, LOL!

Cool!? What's an ITB?

[Luis_GT]

Originally Posted by Black Tire

Cool!? What's an ITB?

Independent throttle bodies

[Trettiosjuan]

Originally Posted by zdr93523

Here's some food for thought... It appears that our torque dip is common to NA boxer engines. It is just very apparent in the twins because the hp/tq is so low. Here is a shot out of my Cayman S owners manual. You can't feel the dip in the Porsche.
Attachment 73654

Consider the left graph. Look at the scales, the torque scale has the bottom 170Nm cut off, in other words, the torque fluctuation is amplified a lot. The actual torque dip here is 10Nm at most before it rises again. Or 4% of total torque. Nobody would notice that. On the S, it's relatively even smaller.

On the FRS, the torque dip is aorund to 40Nm. That's around a 20% reduction. Like someone lifts off the trottle for you...

[FRSure]

Originally Posted by Luis_GT

Independent throttle bodies

This may sound dumb but... If it's easily fixable, why don't Toyota/Subaru does it for us? Is it for emission ?

[86-tundra]

Originally Posted by FRSure

This may sound dumb but... If it's easily fixable, why don't Toyota/Subaru does it for us? Is it for emission ?

ITBs are not an easy fix, unfortunately

[FRSure]

Originally Posted by trevorovert

ITBs are not an easy fix, unfortunately

I see headers and tune get rid most of the dip. Why didn't Toyota do it?