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- San Antonio, Texas
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- '15 CX-5 Miata AWD
Yea, if you run e85 in an engine not mapped for it, of course it will run like s*** lol.
The problem with small engines is very well known... as recently as 2013 Consumer Reports (http://www.consumerreports.org/cro/...ethanol-can-make-small-engines-fail/index.htm) advises against using ethanol blended fuels with small gasoline engine appliances.
Fuel phase separation is a well established phenomenon with ethanol blended fuels. There are plenty of articles available... just google it. And oh yes, and I have a friend currently dealing with that very problem on his boat right now.
Yours is the fuzzy, funny logic: the beauty of that can of ethanol you put in your tank to remove the water was that once it passed through your system it was gone. The ethanol in your regular fill-up, in contrast, is always there, holding water in solution. Add in acurious habit of many owners: to fill up whenever the tank is 1/2 full. It never fully removes the water charge. In fact, it just picks up more when the tank is opened. Until it can't anymore...then it falls out.
There are pluses and minuses to almost all things more complicated than a pacifier; just because I point out a few of the minuses doesn't mean I'm knocking it.
Would love to find some 93 in CALIFORNIA... (wow)I switched back to 93 octane a few weeks ago and the CX-5 is much more tolerable. The throttle response is improved, the transmission doesn't have to downshift to make it over the hill by my house, and mpg (25mpg hwy) has not decreased even with the more spirited driving. I find the engine noise with 93 octane to be less bothersome when the cruise control is set in the high 80s/low 90s, and the car feels much more refined when idling (much less vibration & shaking).
My 2.5L CX5 is so smooth at idle that I often must look at the tachometer to see if it is running and, this on 87 octane with 10% ethanol. I suspect something is wrong with a CX5 engine if one feels vibration and shaking with the recommended fuel.
Would love to find some 93 in CALIFORNIA... (wow)
One thing that people forget, is that it will take some time to get the highest octane number in your tank and to the motor. It also takes several drive cycles to get the engine computer adapted to the highest octane rating.
Imagine you run 87 octane...you decide to try 91 octane, your 15 gallon tank fills up with 12 gallons of 91octane and adds to the remaining 3 gallons of 87 octane in the tank.
you are not running 91 octane fuel yet...but rather a mix of 80% 91 octane and 20% 87 octane. Giving you a 89 ish octane? Now over the course of a few drive cycles the motor adapts to the 89 ish octane.
now it is time for another tank of fuel, you fill up again with 91 octane, giving you a mix of 80% 91 octane and 20% 89ish octane...now you have 90ish octane... Now over the course of a few drive cycles the motor adapts to the 90ish octane.
now it is time for fuel tank #3, you fill up again with 91 octane, giving you a mix of 80% 91 octane, and 20% 90ish octane... now you are very close to a 91 octane fuel. And over the next few drive cycles, the motor adapts to the 91ish.
So as you can see, it takes a while for both the fuel mix to rise, and engine to adjust to it. You can not try it for just a single tank, and expect an accurate result.
Engine is constantly adjusting intake/exhaust timing based on knock.
If you really want more power on any octane, then a tune is the way to go..
... If you really want more power on any octane, then a tune is the way to go..
Do you mean a custom tune? Do you know a suggested vendor with 'tunes' on offer to otherwise stock owners? I'd check it out: but there had better be some before/after dyno runs backing up claims.
... They have extensive engineering and development talent and equipment at their disposal and, if they leave a wee bit of performance on the table you can bet they have a competitive reason for not extracting that last little bit...
MFR's very frequently 'leave performance on the table', as you put it, for various marketing reasons, not due to any engineering concern. Fuel economy and use of regular fuel are of course considerations in this line of reasoning as is product positioning. I know of three specific cases myself and wonder what it takes to 'tune' the 2L in the CX3 to output the same HP/Tq as the 2L in the M3 making a 4rth.
The CX-3 2.0L has 9 less HP than the Mazda 3 2.0L due to a more compact exhaust manifold. It has less efficient cylinder scavaging because there was not room for the regular Skyactiv header.
This is an engineering constraint and Mazda couldn't simply "tune around it". I'm not sure what you're getting at here.
I think you just helped make my point There is indeed some performance 'left on the table' in the CX3 too. There are compromises and they can be exploited. Sometimes as easy as new performance maps alone, but frequently coupled with intake and exhaust. I consider those relatively easy 'bolt on' mods part of the 'tuning' process.
I'd be curious to know if the decision to go to market with a restrictive exhaust was an engineering decision alone.
The Skyactiv header required too much room to fit in the engine bay. Getting the last 9 HP would have required moving the engine forward which would have involved a whole host of other compromises. If you want to "exploit" that, be my guest.
Given a choice, go with ethanol free if you can find it. (more BTU and less damaging to engine parts)
That 10% ethanol will damage engine parts is an old wives tale created when fuel systems had rubber/plastic parts that were not alcohol resistant.
All late model cars are DESIGNED to be run on gasoline with 10% alcohol!
No damage will occur. None.
Being in the great white north, I can attest to that first hand.SMALL ENGINES, however, are where the problem comes in. Many lawnmowers, weed eaters, chain saws, outboard motors, etc. are rush-imported to NA market and don't have rubber parts in the fuel system that are ethanol compatible. The ethanol eats at the rubber and you have problems starting and smooth operation. Around here, back up generators are a very particular problem as they sit idle for long periods and only used when you NEED them, so after a severe storm you get to hear all the sputtering generators (or cursing owners trying to start them LOL).
Also, alcohol is hygroscopic: it will attract and hold water in solution. This a good thing in that it readily carries water through the system (keeping your system water-free) but it's also bad if you don't burn water contaminated fuel quickly as the water can corrode fuel system components as previously noted. Also as noted before: modern auto/truck engines are generally made to handle that (some better than others). BUT, those pesky small engine mfr's are exempt from those EPA rules.