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In a Sktactiv high compression engine although the fuel trims and timing tables in the ECU will adjust for the lower octane the performance level and long term MPG will decrease. So if you look at the use of lower octanes over 6 mos or a year the cost of saving using lower octane fuel is greater then just seemly paying the increased amount for 91/93 and getting overall better performance.
On average driving and close or at sea level altitudes as grim_reaper mention most would not notice a power difference but for some that live in higher altitudes or spirited dring you would notice a distinct drop in performance because of the the ECU compensating for the lower octane.
The topic is about fuel but it is a very exhausting thread...
This is carefully worded and IMO supported and useful information directly related to this thread.
Originally Posted by Callisto
Since the early 80's aftermarket manufactures have offered products to control and reduce engine knocking which can damage piston rings and burn valves. In 1995 OBDI introduced knock sensors installed from factory vehicles to do the same thing. In the 2000 and newer to date ECUs programming take information from several sensors to change engines timing fueling, load transmission shift points etc. to reduce per-ignition. Unfortunately with most ECU there are limitations and a lot of those limitation are the octane and the components that is the chemical ingredients in gasoline available and used in the engine. The higher the octane the less pre-ignition and ultimately less progressive damage to the engine piston rings and valves.
Mazda does not use the current establish “CERTIFICATION” for their engines. Therefore advertisements and even factory specification are not absolute and in most cases when independently test do not come to what are specified. The actual power out put of MAZDA engine are propitiatory and only available in you are a Automotive Engineer working for MAZDA. To work as an engineer for MAZDA you must sign a employment form that trade information is not to be copied or published in any form without legal consent by MAZDA. Media like magazines and forums often publish the specification from auto manufacture having to do with engine power rating with out an astrick(*) to define that those numbers are not “CERTIFIED”.
Gasoline additives do work however the misunderstanding is for most branded gasoline those additives are already in the fuel. Adding more does not mean a higher concentration of an an additive nor an increased effect of the additive. In fact you are likely to see spark plug indicating such higher levels of additives which using an oscilloscope may show a decrease in the efficiency of the spark plugs. Occasionally adding a bottle of the better branded names additives will not harm an engine and does have the satisfaction of supporting the thought keeping the engine in top running condition.
OIL CATCH CANS can reduce some small amounts of oil vapors . However most oil catch cans marketed are not designed correctly nor are they installed correctly to be effective in the Theory behind their designed function. Oil catch cans are one of the top items that are often extremely HYPED advertising and full of missing leading information deemed as empirical, even to the extent of showing an otherwise worn out engine and a catch can accumulating large volumes of oil. See and understand engine piston oil rings and valve guides,PCV valve. Also the measurements in micron of oil vapor at different temperatures and relate that to a filtering media needed to catch and hold any given partial size in microns.
There is absolute EMPIRICAL DATA and information how octane values work. Basically for use of a chosen octane value to want the value the either reduces or illuminates pre-ignition in an engine. Preventing engine KNOCK. The octane of gasoline does not increase horse power only supports the horsepower. i.e. If the maximum “CERTIFIED” power of a Supercharged engine from the factory is 225HP @ 5600rpm using 93 octane gasoline you are not going to get 275 hp using 100 octane only the original 225.
If you use 87 octane fuel and have a test Dyno (engine or chassis) and then repeat using all the exact perimeters(can be adjusted by the Dyno operator to match any previous tests) use 93 or 100 octane fuel you will only total the claimed(which may not be accurate) or “CERTIFIED” power and nothing more.
The Knock Sensor
A working principle to piezoelectric elements involves the transmission of an electrical current in response to detecting a change in pressure or vibration by these elements. The piezoelectric element inside the knock sensor is tuned to detect the engine knock/detonation frequency.
The knock sensor monitors the combustion process in the engine. Its signal helps the engine control to prevent knocking combustion and therefore protect the motor/engine control.
The Science Behind a Catch Can The basic theory of catching the oil from the air is a simple one. When the gas enters the catch can the volume is dramatically increased, causing reduced pressure of the gas. This decrease in pressure slows down the velocity of the gas and allows the gas inside the can to condense on the interior surfaces. The more surface area the gas can contact, the greater the effectiveness in separating the liquid from the gas. A good analogy is the steam from a hot shower that condenses on the mirror and the other cooler surfaces of the bathroom. This example demonstrates the same principles that apply to the function of a catch can. It is also worth noting that mounting the can in an isolated and cooler position in the engine bay will improve the efficiency of the catch can. Most companies use two main approaches for catch can design. The basic design is a simple can with hoses attached. The more advanced designs include internal baffling, which provides more surface area for the oil to condense. Both of these approaches work.
While there is no impartial empirical data and no testing using the proper method of testing and evaluating results a part for any catch cans offered the use of them and those that believe they work makes it one of the most talked about aftermarket parts both on forums and in car groups. I personally use them but in every case have had to modify then to work more efficiently then their original designed and claimed as well changed my PCV system which includes on Turbo and Supercharged engine adding my BLV (Boost Lock Valve offered and sold on the world wide market) I engineered and designed to support engine power increasing under boost. .
Just joined the forum and was browsing through recent threads, looking to see what type and level of activity there is here. I've been an active shade tree DIYer, and have spent lots of time on other forums, and it's disappointing to me that the auto forums have been losing activity over the years as social media has gained in popularity. But there's nothing to be done about that, so I'll just continue to participate FWIW.
This thread caught my eye for a couple of reasons. First off, I've had extremely good luck with port injected engines over the years, and was trying to avoid DI for as long as possible. But that's come to an end now because there are virtually no 4 cylinder port injected engines available in the North American market (I buy new and keep them 14-15 years). So after finding no history of engine problems, and also no CVT or DCT transmission, I settled on a 2020 CX-5 2.5L AWD. My daughter has a 2019, with no early issues, so that was a major factor for me as well. The CX-5 seems like a very solid vehicle, and time will tell if DI results in any additional repair issues.
The other reason this is particularly interesting to me is that the effect of DI on engines is a frequently discussed topic on the Kia/Hyundai forums, and I've read a good deal of back and forth on the impact of DI over the years. But not surprisingly, there's lots of opinion but virtually no facts. Many of those folks are fans of the valve cleaning products such as CRC and BG. It's always amazed me that these guys will dump stuff like this into their engines, but (except for 1 guy) would never take the time to learn to use a borescope to try figuring out if there's even a valve deposit problem to begin with. Personally I believe that these cleaning products could very well be a case of the cure being worse than the illness, but that of course is JMO.
So if the OP is still checking responses, here's one more vote for Top Tier fuel, along with adding Techron fuel system cleaner every 3K or so. Yes the (supposedly) better gas and the Techron won't directly touch the valves, so no idea what net effect doing this will have on reducing valve deposits. But the bottom line for me is that it can't cause any harm, which makes it an easy choice. And at some point down the road I will also poke around the cylinders with a borescope to see for myself what (if any) deposits are taking place.
m5xguy Welcome to the forum.
Yes it is sad that forums are declining in active members. I moderate a couple and the higher percentage vs members of visitors/guests only pop on forums to look to read solution to problems and don't even join as a member let alone [size=13px]participate[/size]? FB is IMHO not the best way to talk about or find solution,upgrade suggestion etc., because of how FB is structured?
What I have also found over the years when I post even if I have data and pictures is DIY will still argue or debate what they believe in "[size=13px]their[/size] own minds" what is facts?
I am for [size=13px]using[/size] a high quality fuel suppliers recomend them and I do frequently check by [size=13px]scoping[/size] different parts of my engine to see what is going on and also what if anything using quality fuels, additives of other methods to reduce or eliminate carbon deposits on the intake induction system, [size=13px]combustion[/size] chambers and exhaust system.
So if the OP is still checking responses, here's one more vote for Top Tier fuel, along with adding Techron fuel system cleaner every 3K or so. Yes the (supposedly) better gas and the Techron won't directly touch the valves, so no idea what net effect doing this will have on reducing valve deposits. But the bottom line for me is that it can't cause any harm, which makes it an easy choice. And at some point down the road I will also poke around the cylinders with a borescope to see for myself what (if any) deposits are taking place.
Here's the problem with your belief, Top Tier, Low Tier, or No Tier fuel, it matters not; since the fuel is injected downstream of the intake valves, then there is exactly zero cleaning effect from the fuel, and build-up will happen on the back of valves. Simple fact of life and there is nothing you can do about it.
Now, there are apparently some companies which have a work-around; I have heard anecdotally (as in I've never personally confirmed) Toyota DI engines actually have two injectors per port, one in the combustion chamber itself, and a second upstream of the intake valves. Assuming that is true, then their engines at least, will be relatively immune from the build-up of other DI engines.
For many years I have run a bottle of Chevron Tecron through my vehicles' engines about every three months - in addition to buying Chevron gas which has Tecron additive in it.
I once saw it "wake up" our daughter's 1989 Toyota Corolla (the last year Toyota used a carburetor) on a trip from LA to Las Vegas. Her car was running a bit rough and had sluggish throttle response. She had forgotten to periodically add Tecron to the gas as I'd advised her (repeatedly). So we stopped and bought a bottle, put it in the tank and within 50 miles the car was running well again.
Here's the problem with your belief, Top Tier, Low Tier, or No Tier fuel, it matters not; since the fuel is injected downstream of the intake valves, then there is exactly zero cleaning effect from the fuel, and build-up will happen on the back of valves. Simple fact of life and there is nothing you can do about it.....
Originally Posted by m5xguy
…. So if the OP is still checking responses, here's one more vote for Top Tier fuel, along with adding Techron fuel system cleaner every 3K or so.Yes the (supposedly) better gas and the Techron won't directly touch the valves, so no idea what net effect doing this will have on reducing valve deposits. But the bottom line for me is that it can't cause any harm, which makes it an easy choice. And at some point down the road I will also poke around the cylinders with a borescope to see for myself what (if any) deposits are taking place.
If you are of the belief Top Tier fuel and/or using Tecron additives are essential to the proper care and feeding of modern fuel injected engines, then my cars should have quit running properly hundreds of thousands of miles ago.
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