Experience Running CX-90 Turbo S With US 87 Octane?

[youri]

That’s interesting, because (on paper at least) the PHEV only gains a 4hp gain from 93, and i don’t believe the skyactiv 4 cylinders are known from benefitting from high octane fuel.

The premium fuel must provide benefits lower in the powerband then, which wouldn’t show in the HP rating. Maybe this 4 cylinder is a different engine than the 2.5 NA found in the rest of the mazda lineup.

 

[Lazy2.5]

The premium fuel must provide benefits lower in the powerband then, which wouldn’t show in the HP rating.

Bingo.

 

[TimelessMazda]

That is good as the CX-90 needs some help in the everyday 20-40 30-50 jaunts.

 

[roundle1979]

Run several tanks of both, compare MPG to help determine true 'value case' for using 87 vs 91/93.

 

[Puckdoom]

As a CX-9 owner I've switched to 93 (0.02 cent higher than 91 in WNY) from 87 a thousand miles and noticed about ~10% better MPG. I mostly drive city, so from 18.5 to 20.5 combined now. Biggest difference is what I perceive a smoother power delivery with even in 2k-3.5k range without any "roughness". If I drove mostly highway miles maybe I would stick with 87. There is price to happiness. This could all be placebo effect. But I would think the same would apply to 3.3 inline 6. But of course it would be interesting to hear from CX-90 Turbo S owners. Cheers.

 

[Lazy2.5]

As a CX-9 owner I've switched to 93 (0.02 cent higher than 91 in WNY) from 87 a thousand miles and noticed about ~10% better MPG. Biggest difference is what I perceive a smoother power delivery with even in 2k-3.5k range without any "roughness".

Yep, I've found the same, even though my 2.5L NA runs on 87 only. Nearly 15% improvement in MPG, and far smoother operation, particular below 2000rpm, which is virtually the only part of the rev range this drivetrain wants to be in.

Fast forward to getting fully tuned on 91 octane, I am averaging even better fuel economy, 40mpg+ consistently, with, not to mention, considerably more torque, and at a lower RPM.

 

[Magnumcello]

Has anyone been regularly running one of the Turbo S engines (nominal 340 HP) on US-standard regular unleaded (87 octane)?

I know there'll be a drop to 319 HP on the lower octane, and max torque caps at 3500 rpm vs. 4500 on premium, but have you experienced knocking or other things?

Given that Mazdausa does list the HP/torque for both premium and regular unleaded, it sounds like it should operate okay with it.View attachment 326102

CX-70 Turbo-S here. We've had ours since July and just turned 5,000 miles. I use Premium when we're towing the boat, and 87 Octane the rest of the time. We've seen no discernible difference in driveability when not towing the boat.

Granted, we have not been pushing the performance too hard during the initial break-in period. Overall, we love the motor. We previously owned two V-6 equipped CX-9s. Our new 70 has way better acceleration along with substantially better gas mileage. We routinely see 30+ MPG on highway trips, along with 26-27 MPG around town.

 

[mjstef]

CX-90 Turbo S Premium Plus. Almost 2,000 miles since we picked it up 6 weeks ago and we've only run one tank of premium through it. That was the first tank after the dealer fill which I'll guarantee you wasn't premium. Didn't see any difference when we switched back to 87. Will throw premium in it when we pull the pontoon boat in the summer....

 

[ceric]

This is the torque/hp curves for 2.5T on 87 vs 93.
No benefit below 4k except for maybe faster response to gas pedal.

Sorry. Could not find similar plot for the inline6 Turbo. One can assume.

 

[N7turbo]

This is the torque/hp curves for 2.5T on 87 vs 93.
No benefit below 4k except for maybe faster response to gas pedal.

According to Mazda. Not necessarily saying I don't believe them, but I would much rather see some independent dyno tests to confirm rather than a synthetic chart.