Pete, assuming your gas wasn't bad, I believe what you were hearing was the high pressure direct injection. At low rpm's I can sometimes hear a pinging/ringing noise but that is normal operation of DI. If you remove the plastic engine cover, it will be slightly louder. If it were actual detonation the knock sensor would have immediately put the engine in a fail-safe mode and the noise would not have persisted.
Pete, assuming your gas wasn't bad, I believe what you were hearing was the high pressure direct injection. At low rpm's I can sometimes hear a pinging/ringing noise but that is normal operation of DI. If you remove the plastic engine cover, it will be slightly louder. If it were actual detonation the knock sensor would have immediately put the engine in a fail-safe mode and the noise would not have persisted.
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- Plano, Texas, USA
piotrek91 is correct. Only 2.0L SkyActiv-G has 14:1 compression ratio in other regions. 2.5L is 13:1 all around the world, including in Germany and Japan. In fact, Mazda has dropped 14:1 2.0L SA-G entirely and only offers 13:1 2.0L on CX-5 in Japan. German version 13:1 2.5L SA-G has 192 PS/189 hp @ 5,700 rpm and 256 NM/189 ft-lb torque @ 4,000 rpm.
CX-5 Brochure 2015 Germany
CX-5 Specification 2015 Japan
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Good info guys on limited use of 14:1
So does the 13:1 euro 2.5 still require higher octane than the NA 13:1 2.5L?
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- RDX Aspec Adv.
It sounds like a header leak to me, and is very noticeable. My vote is injectors, as well.
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- Plano, Texas, USA
According to German CX-5 brochure, the minimum gasoline requirement for 13:1 2.5L SA-G is RON 95 E10! This is equivalent to US AKI 91 octane as the premium gas. US version 13:1 2.5L SA-G has 184 hp @ 5,700 rpm and 185 ft-lb torque @ 3,250 rpm with AKI 87 regular gas; whereas German version 13:1 2.5L SA-G has 192 PS/189 hp @ 5,700 rpm and 256 NM/189 ft-lb torque @ 4,000 rpm. By using premium gas, 2.5L gained 5 hp and 4 ft-lb!
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- RDX Aspec Adv.
...or by using less restrictive emissions components, a freer flowing exhaust was worth 5hp and 4 ft-lb.
We just dunno...
If you know a bit about internal combustion engine tuning then it's not a very significant leap of faith to conclude the extra 5 HP/4 Ft/lbs. came from slightly different spark advance/valve timing/fuel mixture allowed by higher octane fuel and slightly different emissions goals. Lower octane fuel in North America is more prone to detonation so those parameters must be dialed back slightly.
This results in 2.1% less torque and 2.7% less peak hp, an amount your average driver may or may not notice, even if they were driven back to back. Considering that premium fuel in my area currently costs $0.30-$0.40 more per gallon (or 15-20% more expensive), I'll take the ability to fill up with regular grade over the 2-3% boost in power any day of the week!
Good news! You'll be saving yourself some money!
Not likely. Said dyno runs haven't surfaced yet. Sticking to 87 octane.
Mazda engineers announced that with the new CX9 vehicle and the 2.5L turbo engine it will have different HP #'s based on what octane fuel you put in. If you run 93 octane the computers will recognize it and the tune will change to produce 250HP. If you run 87 octane the engine and sensors will detect the lower octane fuel and de-tune the engine to make only 225HP.
So Mazda engineers stated that it will be up to the driver/owner and what octane fuel they choose. The computer will tune it to the octane you put in the tank.
So Mazda engineers stated that it will be up to the driver/owner and what octane fuel they choose. The computer will tune it to the octane you put in the tank.
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This was the artical that prompted me to start this thread. I inadvertently stated it was the Miata, so thank you for restating it correctly and I fixed my original post.
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If your engine is knocking on the 87 then the timing will be knocked back a little and you'll lose some power. With the higher octane you won't have this retarding of timing so maybe that's where you feel the difference. Not all engines run the same on the same fuel, and there is that possibility that the fuel was bad to begin with as was mentioned before. My understanding is the new CX9 is spec'd to run on premium, either 93 or 91 if 93 isn't available, I don't recall seeing it being able to run on 87, it can detune itself to run on the lower octane.
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Perhaps Mazda would provide us a computer update in the future. Option for ECU to recognize and react to various grades ranging from 87-93.
Yes, Mazda has said the CX-9 turbo Skyactiv can run on 87-93 octane (your choice). They expect most owners to try premium once or twice and settle into using regular for it's more cost effective operation.
I've said this before but it bears repeating because there are a lot of misconceptions presented as factual here. The 2.0L and 2.5L CX-5 engines will not make any more power on higher octane unless your 87 octane is out of spec or something is wrong with your engine. Do not run 85 octane, even at high altitude. The CX-5 compensates for altitude while expecting 87 octane minimum.
OK, but I'm talking about a knocking problem, if it's there, or poor fuel causing him to LOSE his existing power, and then the higher octane might be compensating to make it run up to par, thus making it seem to run better, which is what you just said in different terms. Right, you can't add anything fuel wise to increase power designed into the engine. I see this being discussed a lot on other forums and it just occurred to me that the higher octane might be correcting another problem making the car run the way it's supposed to and that was what the person was experiencing, not an increase in DESIGNED horsepower.
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mazdadude
ZOOOOOOOOOM ZOOOOOOOOOM
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- '16.5 Mazda CX-5 Touring
Yes, high amounts of carbon deposits in the cylinder will cause knock / pinging also.
If your engines knock sensor has detuned the engines timing because of knock, then using a higher octane fuel will allow the computer to put some of the advanced timing back in.
Correct, but since it's designed to make peak power/torque with 87 octane using higher octane is not correcting the underlying problem.
Exactly!
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- RDX Aspec Adv.
...if there is carbon on the pistons causing increased compression ratio causing ping mitigated by higher octane fuel...is OP now making MORE power than OEM, due to higher CR's? One wonders...
