CX-5 Turbo: 87 vs 91 vs 93

acidbug

ZoomZoom CX-5
Contributor
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‘19 CX-5 GTR Tu
Recently I took a trip to Florida. I dropped the backseats and filled the trunk and backseats with luggages, some boxes for my bro, and multiple coolers due to my medication needs. I did not take the time to put it on a scale, but I even had stuff on the front seat but after a while, I got tired of the chime about not having Seatbelt done on the passenger seat, even though it was just my junk food, small cooler with easily accessible drinks, etc. (anyone know how to disable to passenger seat belt chime).

Before heading down to Florida, I filled with 93 octane +AC on low temperature air temp Was mid 70’s and medium humidity and the car pulled really well up to 100mph. Easy passing at 80+mph + high humidity +running the AC further south I got. My 2nd and 3rd fill were 87 octane + 24/7 AC with outside temps upper 70-low 80 degrees+ high humidity the car pulled hard off the line but didn’t seem as fast. During my time in Florida on their highways, I found the car felt sluggish with the 87 octane and the AC running, yeah it had god pick up off the line but felt slower acceleration above 75+ mph( even at night low 70 degrees to upper 60 degrees +high humidity the car felt like it was struggling above 80mph) and on the way back car felt sluggish especially passing above 75+mph. I waited till the gas low light came on and filled with 93 octane +AC 24/7 on local FL highway & for the ride home and the car felt more powerful up top rpm. After the 2nd 93 octane fill the car felt even more pepper above 70-80mph. MPG was very similar with 87 vs 93 hand calculations. I tested via fuel calculation on 93 octane cruise control set at 80mph+AC & with 87octane 80mph cruise +AC and found the 93 octane got me 2-3 extra mpg. Also, found the cars digital mpg reading was pretty close. Only off by 1-2mpg. Typically I run 93 at top tier gas stations unless I’m running low, I put 1/4 tank 87 octane until I find a gas station with 93 octane.

I purchased my car at the end of summer, and I could tell they filled it with regular because the car did not pull hard on the highway (above 4k rpms)whenever I would run the AC the car did not feel nearly as peppy. After one or 1-2 93 octane fills I could definitely feel the car felt quicker especially up top.

BTW, near my house I have access to 100 octane zero ethanol. I drained my gas tank past the low fuel light. I filled up half a tank. (Over $10 a gallon.) and did not notice any additional power or happiness from the car as I’ve noticed on other cars like my old BMW 33i twin turbo , Mazda speed 3 & 6, but all of those had tunes on them.

I’m tempted to run 25% the E85 and fill the rest with 93 octane but don’t feel like being a guinea pig. Anyone try it or willing to try it.

Back when I had my BMW, I would fill 1/2-1/3 of a tank of E 85 and the rest of 93 noticed I was able to cut off ~1 -2 tenths off my 0 to 60. Was unwilling to do 1/4 mile pass as I would be over 100mph. Also, was able to beat my buddies Audi A4 that was just running a tune with DCT transmission. We both only had one person in each car. Before adding the e85 he would always take me by 1/3 car length. My only change was the addition of e85 (1/4 tank and the rest was 93). The BMW mods were dual intakes and CobbTuner. I was able to pull nearly a full car length. Both vehicle were autotragic so it was easily repeatable.

BTW, the only performance mod on my Turbo CX-5 is K&N drop in filter. Come spring I plan on installing an autoexe strut, JB4 and meth injection kit (for summer months due to heat soak/ carbon build up on into valves) sitting in city traffic. And if I can get my muffler shop to drop the center cat and install straight pipe with a qtp cut out that can be opened and closed from inside the cockpit.


Final note: at one point in time I had 4 Mazda cx-5 (3 na & my turbo) and a Mazda 6 na in the family with zero issues except my aunt and my car were totaled. The one purchased from rental company, she was able to work out a warranty on her car (through Mazda alongside apple car play) and she’s had zero issues. She’s over 45k miles. The other person bought a cx-50 na and she loves it better than the cx-5 na but because of the panoramic sunroof (women…lol). She has about 13k miles on it. Funny thing is she paid more for hers as it was brand new vs my CPO. Mine was a dealer demo and purchased with under 8k miles.

Finally, if you find yourself, living in high heat temperatures, especially with high humidity or traveling up mountains, as I did during my trip, I would definitely recommend putting 93 octane in. Also, if you live in an area where they use lots of salt, be sure to rinse off/wash the car as it will cause the paint to become thinner and more prone to chipping. Since I live in the north I got the PPF on the front end, bumper & mirrors. Also, I installed some mud flaps. Finally, if you live in a place with a lot of dust or off-road. Be sure to replace your Air filter every oil change or as needed.

P.S. please forgive any of my typos as I’m using voice dictation.
 
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Found from another foreign member:



Map Guide:
Map 0: JB4 disabled, factory tuning
Map 1: +3psi, suitable for all pump fuels
Map 2: +4psi, suitable for 93+

Up to 30% E85 can be used on map1 or map2 for increased performance vs pump fuel alone.

V1 Application Dyno Testing: N54Tech.com - International Turbo Racing Discussion - View Single Post - JB4 for Mazda 2.5L Turbo

BMS Intake Dyno Testing: N54Tech.com - International Turbo Racing Discussion - View Single Post - JB4 for Mazda 2.5L Turbo

How to update firmware:

Download firmware using the new JB4 Mobile firmware database or externally by clicking this link.
 
The ECU needs some time to add timing (If you add in higher octane)

But it will pull back timing almost immediately whene it has to.
 
excellent observations!
2 extra mpg is about $3-4 difference per tank (with 15gl tank it will go 30 extra miles)
87 vs 93 is about $15 difference per tank
93 gives better acceleration, but there's no point if all you do is highway driving
it's amazing that CX5 allows us to have options
 
Back when I had my BMW, I would fill 1/2-1/3 of a tank of E 85 and the rest of 93 noticed I was able to cut off ~1 -2 tenths off my 0 to 60. Was unwilling to do 1/4 mile pass as I would be over 100mph.
You think so? The Camaro and Firebird Trans Am were just hitting 100mph with the LT1 in the 1990s. Those were putting out about 275hp and 325lb-ft. Plus they weighed about 350lb less and had better aero. I would think the CX-5 would be around 95mph at best.
 
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