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Type of fuel for Turbo engine?/Direct injection.

12K views 29 replies 13 participants last post by  lhsonic  
#1 ·
Anyone have any thoughts on regular vs premium?
I'm currently running premium "brand name gas". Sunoco.
Also any thoughts on the maintenance of direct injection engine?
 
#2 ·
Anyone have any thoughts on regular vs premium?
I'm currently running premium "brand name gas". Sunoco.
Also any thoughts on the maintenance of direct injection engine?
It’s really tough to say the impact or performance difference between regular and premium gas without datalogging the car. I would suggest using a top tier gas like you are doing and change your oil frequently with a high quality oil. Also, don’t let your car idle for long. Not a good thing for direct injection cars.
 
#3 ·
Id personally always recommend premium in a car with a turbo unless it recommends 87. The Subaru 2.4 for example has no benefit using 91 over the 87 recommended. And actually runs better on 87 which is amazing. Ive had 2 STI's in the past and even on 91 they had issues because they recommended 93, in Ca we only get 91.
Ive noticed after the 1000 mile mark and only using shell 91 it seems to have opened up a bit more in a good way. And speaking of shell 91, my two local dealers ( san Diego)dont have the 10% ethanol in fuel lables anymore. And one of those two have 0% ethanol listed.
 
#5 ·
I did some testing using exclusive Exxon gas. 93 Vs 87 and I have to say I can't tell the difference but I drive car very gently. I did some research and some say that car needs to be pushed to around 5000RPM to get a feel in HP difference. My car never seen 3500RPM so I put premium every other tank just to feel better I guess.

On another note (Can Anybody confirm it please) - CX50 Turbo is air cooled only???? Most turbos these days are both liquid and air cooled but I found info that 2021/2022 Mazda CX5 turbos are exclusively air cooled!!!!
If that's the case, we better keep these things running for a minute or two before turning the engines off.....
 
#8 ·
The CX50 does have an intercooler if that is what you mean. I believe the turbo also has coolant lines running to it. I am not sure if it continues to run coolant through the housing once the car is turned off. You don’t need to run it for long when you come to the end of your drive. 30 seconds after a hard run is long enough.
 
#20 ·
The key to the fuel is using a top tier fuel. Google it. That doesn't mean top tier OCTANE. Fuels that are certified TOP TIER have detergents in them that keep the engine clean and free from carbon build up, which direct injection engines are prone to.

Your best defense, to the above, is top tier fuel and regular synthetic oil changes...
 
#21 ·
The key to the fuel is using a top tier fuel. Google it. That doesn't mean top tier OCTANE. Fuels that are certified TOP TIER have detergents in them that keep the engine clean and free from carbon build up, which direct injection engines are prone to.

Your best defense, to the above, is top tier fuel and regular synthetic oil changes...
Yes, I remember researching this many years ago. I narrowed down here in Canada to only going to Costco and shell as the ones with top tier gas.


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#26 ·
Folks.. No one mentioned this directly but it's proven that if we use 87 Octane we get the 227 HP and 310 Tq but if we use 93 Octane we get 256 HP and 320 TQ so yes.... this engine there is absolutely a difference..... This is information from Mazda, not some 87 Octane vs 93 Octane forum...


Use 93 Octane!
Yes, those are the performance figures with 87 and 93 octane fuel but you need to consider when those numbers are hit.

The engine makes 250 HP at 5000 rpm. How often do you hit 5000 rpm? The engine makes up the difference between 227 and 250 HP between 4000 and 5000 rpm.

The engine hits peak torque at 2500 rpm. The main difference between 87 and 93 octane is a much sharper drop off after 4000 rpm. How often do you drive past 4000 rpm?

Because HP peaks at 4000 rpm and because torque starts to fall off sharply, the engine starts to feel real anemic past 4000 rpm on 87 octane. 93 octane provides significantly more oomph after 4000 rpm. This is really the only significant difference. The torque and HP curve is near identical up to 4000 rpm so for most drivers and city driving, there shouldn’t be much of a difference.
 
#27 ·
Costco in Canada sells top tier fuel, true.
Costco does not have an oil refinery, as such their fuel supply comes from various top tier suppliers.
It could be Shell, Coop, Esso, etc.
In severe cold temperatures the octane differences have very little effect on performance.
In my CX 30 turbo I found 93 octane ran smoother with a slightly better fuel economy (negated by the higher price), and if you don’t drive often or have the need to fuel up often it stays fresher. (Apparently).

Every jerrycan I own has premium regardless if it is mixed or pure, the longer shelf life theory is my reasoning.
If I am just going back and forth to work 5 days a week with an occasional trip elsewhere, I can make a tank of fuel last a month.

I run premium, but really don’t notice the performance increases at all.
No dyno, just seat of the pants.