Regular Gas for 2008 CX7

[techspeak]

that' 'rep at MNAO' is like most reps, clueless narketing agents. They parrot what they hear and what regional reps and managers tell them. Theyre just like a really big dealer with a reputation for the same attitude and screwing the North American Mazda market up. Yes, Mazda developed a new catalyst called "single nano technology". It is simply a method of manufacturing durable high efficiency catalysts with less precious metals. It's being introduced on all Mazda models. A catalyst will not be different between regular or premium.

It comes down to the old "consumer trust" issue. Some consumeristic people have a need to trust percieved "officials", ie doctors, service writers, office monkeys, well beyond reason. They will not think about it, for they need not think about it. A figure they percieve as authoratative has said something, and thats about as far deep as you should bother looking, right? (but thats another sociopathic phenomenon, for another day)

Look, I fully understand preignition and detonation, but what I don't understand is why people are worried about it, when the ECU will not, and can not allow knocking or detonation to occur If the ECU could not stop knocking or detonation by adjusting, then you would be bucking down the road all day as the ECU shuts the throttle. NOT GOING TO HAPPEN, because BOTH 07 and 08 CAN EASILY, WITHOUT DANGER, RUN ON REGULAR GAS. I'm not going to say that anymore, if you can;t understand that, you deserve to pay the high price of premium. The ECU (on data loggers) show that it responds to knock after ONE knock condition. To understand how fast this can happen, lets do some calculations:

4000rpm = 2000power strokes.
2000 power strokes * 4 cyl
=8000 overall engine power strokes per min
/ 60 = 133 power strokes per second

If the ECU responds to ONE knock condition from ONE cylinder at 4000rpm, before the next knock cycle could occur means the ECU has seen, and corrected for knock in... 0.0075 seconds!! THAT IS FAST! The people who say regular will ruin or even injure the 2.3L DISI are the same people who havent a clue of the hardware they are working with. I guess it's only karmic justice that you pay the premium for premium? lol

 

[SuperStretch18]

I know the talking points, but the fact is that knock has to occur before it can be detected...

Whatever though; we'll just have to agree to disagree. Like I said, I'm not really concerned with what others do with their cars. The extra four dollars I spend once a week buys me peace of mind. I'll happily spend it; karma or not. [insert.whiteflag--->here]

 

[erhayes]

I have had my engine knock loudly when I was in third gear and decided to accelerate. The AT did not downshift under the medium throttle and the knocking started. I let off imediately. I will not try 87 or 89 octane again. This on a top tier fuel. The ECM may be fool proof, is not idiot proof in my opinion.

 

[Zoom49]

I also have had my CX-7 knock loudly on several occations. I have used onlypremimun fuel (91 here in Calif) I have taken it to the dealer twice for this issue and they say that there is nothing they can do. I have tried several different brands of fuel to no avail. Seems to happen more often in the summer but does not seem to be related to heat soak as it has happened on highway during an extended drive cycle.

 

[Rick's CX-7]

regular will work fine, boost will drop off a little earlier, the ECU will never let anything BAD happen, and it doesnt fall into 'limp mode'. Limp mode is an emergency running condition in the absence of key sensors or unresponsive solenoids/outputs. Using regular gas on ANY MY CX-7 will simply trigger the regular fuel maps from the ECU. If you wanna be super sure about your MY's compatability, just get the latest ECU flash.

Likely the smartest, most informed post in this whole thread!
Thanks for your input.

Rick

 

[Rick's CX-7]

Well, I totally agree with techspeaks comments. The thing most people here need to understand is the total control the ECM has on these cars. The minute the computer detects something "weird" it shuts the throttle partially or completely; not to mention timing, fuel, etc.

The best way to confirm this is to drive on ice. Floor the car from a standing still on ice and the throttle closes instantly. You can hit the gas all you want, but you won't go past ~2k RPMs. That is control!

I also agree the cats have nothing to do with fuel. Too lean or too rich a mixture could burn the cats, but octane difference doesn't make a difference. Heavy oil burning can also kill a cat, likely it's biggest enemy.

Rick

 

[SuperStretch18]

One of the changes that the ECU is going to make if it sees detonation is to dump more fuel into the mix to cool the combustion chamber. In doing so, the chances of unburnt fuel making it to the cat and burning there increases. If you know that you are going to be running ultra rich more frequently, then you can change the cat to one that would stand-up better to the heat.

I agree that melting your cats is not catostrophic engine failure, but it does seem likely that Mazda was trying to avoid the issue. Seems pretty logical to me...

 

[AWmustang]

Gas is expensive. Premium gas is more expensive. Mazda does not make gas.

What motivation would Mazda have for requiring (2007) or even recommending (2008) premium gas?

The only things I can think of is that the loss of sales was outweighed by improved longevity of the various engine components or the increased power the engine makes on premium.

Well I want that power available to me so I'm going to use the premium. Until I see some dyno runs that prove to me the car makes just as much power on regular, I won't believe that there's no difference.

 

[wannabe]

Gas is expensive. Premium gas is more expensive. Mazda does not make gas.

What motivation would Mazda have for requiring (2007) or even recommending (2008) premium gas?

The only things I can think of is that the loss of sales was outweighed by improved longevity of the various engine components or the increased power the engine makes on premium.

Well I want that power available to me so I'm going to use the premium. Until I see some dyno runs that prove to me the car makes just as much power on regular, I won't believe that there's no difference.

i agree.

 

[marciano]

i use premium in mine...i knew what i was getting before i bought it...alot of the other suv/crossovers may run on rugular, but have no persoanlity or styling..ala the rav4...or get sucky mpg like the explorer. i love mine and i think getting 23-25 mpg out of mine is well worth the extra 5 bucks at the pump for the performance and mpg