MS# Fuel Requirements

R

rhan696

Member
I saw somewhere that the new 08 CX7 does not require Premium fuel and it is only suggested. It can be used with regular without any issues. I wonder if this is the same with the 08 MS3 and could the 07 MS3 be reflashed to use regular.

Before anyone says, I know in the manual it says you can use regular when premium is unavailable, but switch back the next time.

This is different. The new CX7 allows you to use regular all the time.
 
By choosing a fuel that has less octane modifies your A/F curve from what the car is programmed for.

You may tune it at a shop to have the curves adjusted but the MS3 should be running on premium. If you can afford an MS3, you should be able to afford the gas for it.
 
The car can handle 89/91 octane if its what you got, but it prefers the higher stuff. Gas prices in my area are good (all things considered), so I'll suck it up and pay the 2.80-2.90 for 93.
 
the higher the octane the better the engine runs on a turbo car stop cheaping out and try to put the gas that will save you 3.60$ at every fill up... if you didn't know what you were getting into with a performance car you should have done your home work...
 
I have been in Africa for 4 months and my wife has been driving my car. The car through a CEL and she didn't mention until later that she had put regular gas in the same day. I would say the regular is not good for the car. She took it to the dealer and they replace the purge control valve for the second time. Anyway moral of the story don't let your wife drive your car and don't use regular gas. She mentioned that it felt a lot slower with the regular gas as well.
 
I let a family member borrow my car to run up the street to get some brews, and he came back smiling, and said "I filled it up for ya!" I asked, "with what?", and he said, "Gas!" I said, "I understand, but with what octane?" A puzzled look came over his face, he thought for a minute, then he re-enacted the events at the pump with his hands, thinking which pump he grabbed. He paused, then said, "Um, Regular?" I smacked my hand to my head, and quietly murmured a few curse words, then told him, "Well, it only runs right on premium. When you were driving, you felt it had a ton of power, right?" He says "YEAH! It was a blast!" I said, "Well, that's because it is a turbo car, and it needs premium to run like that." He asked me if he broke it, and I told him "No, but I need to get that stuff out of there!" So I hopped in the car and drove around in low gears, and higher RPM and low load, until I was using 8mpg or so. About 30 minutes later I bought a thing of octane boost and refilled with 92, and called it "good for now."

It didn't behave right for about 3 tanks after!

Keep in mind, in Vegas it is HOT, and that heat can cause cheap gas to really wreck havoc on this engine, I've found.
 
The 08 CX-7 allows you to use regular, but the ECU takes a heavy hand in adjusting your performance to allow it. They still recommend using premium all the time! If you are going to buy a performance car, pay for the good stuff and drive to your heart's content. Assume .25 cents a gallon; fill once a week, you are looking at less than $300 for a year! It's not as big a hit on your wallet as most people think...
 
basically, the higher octane gasolines are needed for cars that run higher compression. since our turbocharger adds crazy compression, that means we need to run the high octane stuff, or bad things can happen. the car is smart enough to shut off boost when it detects that the engine is knocking (basically means your car won't allow you to boost when using regular gas), but it's a BAD thing that it gets to detect that knock at all. use regular gasoline if it's an emergency, but if you have any choice in the matter, go with the high grade stuff!

there's not many "performance" cars that don't require the high grade stuff, and the only ones that don't are heavily under-utilizing the potentials of their engines. the mustang gt has a 4.6L V8 engine that only makes 300hp...THAT'S LITERALLY TWICE THE SIZE OF OUR ENGINES! >_<;
 
MS 3 Gas Requirements

It is not about the money. I can afford the price difference. It is just annoying. There are many high performance cars that don't require premium gas.

I had a 1988 Mazda 323 GTX which was turbo intercooled and 16 valve with 4wd (would be nice on the MS3) and used regular gas. It was a 1.6 liter running a peak of 11 psi. It had 132 hp, allot for the time. So turbo engines don't necessarily require premium.
 
rhan696 said:
It is not about the money. I can afford the price difference. It is just annoying. There are many high performance cars that don't require premium gas.

I had a 1988 Mazda 323 GTX which was turbo intercooled and 16 valve with 4wd (would be nice on the MS3) and used regular gas. It was a 1.6 liter running a peak of 11 psi. It had 132 hp, allot for the time. So turbo engines don't necessarily require premium.
Click to expand...

87 Octane in 1988 was probably a little different than 87 octane now.
 
rhan696 said:
I had a 1988 Mazda 323 GTX which was turbo intercooled and 16 valve with 4wd (would be nice on the MS3) and used regular gas. It was a 1.6 liter running a peak of 11 psi. It had 132 hp, allot for the time. So turbo engines don't necessarily require premium.
Click to expand...

132hp is also done now using NA 1.6L engines running regular gas.

quite honestly, the comparison is just not valid. by today's standards, if you're making 132hp with a 1.6L turbocharged car, you're REALLY underperforming, which means you're not running enough compression to that engine. the reason that today's engines require high octane gasoline is because they have pushed the limits of hp coming from an engine of a given displacement much farther than they did in 1988. ie: way more compression.
 
The old comparison is not valid. The MS3 engine with high compression, forced induction and direct injection is a different animal than anything from 1988. As someone else said, any engine that does not require premium is leaving something on the table with regards to performance. And to say that it is not due to cost is a flop. Why would it be annoying otherwise? It's not like you have to go out of your way to get it...
 
why wouldnt you want to run premium its only 1.00 more per fillup avrage .10 more expensive times 10 gallons for fill up thats my average and rough guestemating. the cx7 is also pushing less boost now beacuse of it. dose anyone know what its hp and torque numbers are off the top of ther head ill try and find it in the next hour or soo. imagine what a tune and 100 octane or higher would do for us.
 
more octane = less flamabale. for instance you can drop a lit match into a barrel of race fuel and the fuel will put out the match like water. But try that with regular 87-89 octane and you will explode before the match even hits the gas because the cheap fuel is so much more unstable. thats what happens in your combustion chamber when u use cheap gas it explodes before its supposed too!! / pre-detonation / pinging ect..... dont be a jack ass and put a cheap fuel in a turbocharged engine the cylinder pressures are way too high for it. So whoever says its OK to use regular fuel is a retard and doesnt give a s*** about his car.
 
dkswim said:
why wouldnt you want to run premium its only 1.00 more per fillup avrage .10 more expensive times 10 gallons for fill up thats my average and rough guestemating. the cx7 is also pushing less boost now beacuse of it. dose anyone know what its hp and torque numbers are off the top of ther head ill try and find it in the next hour or soo. imagine what a tune and 100 octane or higher would do for us.
Click to expand...

Base HP and torque numbers are the same (244 and 258 respectively), only the ecu programming has been adjusted for when it detects detonation (cats and some other minor changes have been made too). However, you are right; with the lower octane, you take a heavy hit in performance.

We've had these conversations ad-nauseum on the cx-7 boards and I have called Mazda USA myself to confirm. They also confirmed that there is no update they can do to make the 2007's operate the same way and you can cause long term damage to the older models with lower octane fuel.
 
if your not boosting it is ok to use lower octane fule but personaly i dont have the self controll to stay out of boost let alone its only a doller more a tankfull why worry about it do as recomended.
 
dkswim said:
if your not boosting it is ok to use lower octane fule but personaly i dont have the self controll to stay out of boost let alone its only a doller more a tankfull why worry about it do as recomended.
Click to expand...

Ah, this is a very important fact that many "premium is SOO expensive" types overlook. Even if the result of too-low octane wasn't catastrophic, there's no good reason to not spend the extra buck per tank. Even at a tank a day that's about $5 per week more for premium!
 
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