Torque curves for 2.5L Mazda engines

Not the best quality but you can see it at 10:56 of this video for the CX-9 2.5L turbo 2016 ( same engine as the cx-5).
The CX-9 2020 torque has now been bumped up to 320 so the curve might have changed a bit for 2020 models.

 

Chris_Top_Her

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San Antonio, Texas
V
'15 CX-5 Miata AWD
The bottomline is like the OEM curve on on the 2.5NA, and the top is a good tune.
 

erhayes

Contributor
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Mazda CX-5 FWD Touring
Now we need the torque curve for the 2.5L non turbo. I want to compare torque at the lower RPMs of each.
 
V
2014 Ford Explorer Sport, 2009 CX9(Wife's)
I'm actually surprised the torque curves are the same at low rpm for either fuel.
Based on my experience, high load at low rpm (r.e. turbo) is more prone to detonation than high load high rpm.

If I remember right, torque peak is where you need to be most cautious regarding detonation, so typically timing is reduced the most at peak torque. If that's the case, it seems like the high octane could benefit in low rpm in addition to the high rpm.
 
I tought this was the big “breakthrough” with this turbo engine. The fact that it didn’t need higher octane to produce the same high torque at low RPM.

You are right with regards to detonation, but i think there are too many factors in play between different engines to apply a one rule fits all principle to knocking. Knocking is ultimately based on heat, and these engines have a lot of heat management solutions in place to attempt to prevent it (exhaust scavenging, cooled EGR, etc). It is possible that these solutions allow the engine to run at peak torque without having to rely on high octane fuel, but that they aren’t as effective at high RPM. This is all speculation on my behalf of course, but that’s how I see it unless we can get an actual Mazda engineer to dig into the details for us.

good info here if you are interested, although very similar to the youtube video above.https://www.wardsauto.com/engines/mazda-s-innovative-4-cyl-engine-pulls-big-v-6
 
V
2014 Ford Explorer Sport, 2009 CX9(Wife's)
I tought this was the big “breakthrough” with this turbo engine. The fact that it didn’t need higher octane to produce the same high torque at low RPM.

You are right with regards to detonation, but i think there are too many factors in play between different engines to apply a one rule fits all principle to knocking. Knocking is ultimately based on heat, and these engines have a lot of heat management solutions in place to attempt to prevent it (exhaust scavenging, cooled EGR, etc). It is possible that these solutions allow the engine to run at peak torque without having to rely on high octane fuel, but that they aren’t as effective at high RPM. This is all speculation on my behalf of course, but that’s how I see it unless we can get an actual Mazda engineer to dig into the details for us.

good info here if you are interested, although very similar to the youtube video above.https://www.wardsauto.com/engines/mazda-s-innovative-4-cyl-engine-pulls-big-v-6
Seems reasonable. I'm sure direct injection has something to do with it.
Spraying fuel into the cylinder near TDC of compression stroke?
Compared to port injection where the fuel is sprayed ~during intake stroke and no fuel enters after intake valve closes for compression stroke.

And high rpm could be due to injector pulse width vs. rpm. You have less time to get more fuel into the cylinder, so you have to start injecting fuel earlier during compression stroke.

Again, just blabbering about what I think is happening. I'm lucky that the engine tuning that I do is on my 89 5.0 Mustang, which is relatively simple.
 
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