| 87 octane okay for MDX?
- Click HERE for Original Thread
|
| uboltpb |
| Can using 87 octane negatively effect the vehicle in any way? |
|
|
| eurohazard |
There are quite a number of opinions on this site.
Since you asked, I'll give you my take. When I 1st bought my MDX, I only used premium fuel. But after reading the posts here on this site of guys using regular, I switched to regular.
For around town, easy highway travel regular works fine. I could tell a small horsepower decrease, but it was not a lot. For long trips through the mountains, I switched back to premium.
Only one time did I have "pinging" around town using regular. It could have been crappy gas, but it's a bad feeling knowing that I tried to pinch a few pennies, at the possible risk of engine damage.....or at least premature wear. Also I noticed a decrease in gas mileage using regular vs. premium............and that darn near negates the money saved on the fuel itself. |
|
|
| Echo2625 |
Here we go again......
Do a search...... there is more than enough information on this topic as it has been beaten to death! |
|
|
| QRTLOW |
quote:
Originally posted by uboltpb
Can using 87 octane negatively effect the vehicle in any way?
Yeah, I Guinea pigged myself and put in a full-tank of 87. It was substandard, I got 18.9-19.2. Then from an empty tank, I dropped 2 bottles of STP octane booster. Went from 19.2 to 20.5 on mileage with 87. Cost me $8 for the additive for a full tank. Not cost effective.
Here's a quote:
The octane rating of gasoline tells you how much the fuel can be compressed before it spontaneously ignites. When gas ignites by compression rather than because of the spark from the spark plug, it causes knocking in the engine. Knocking can damage an engine, so it is not something you want to have happening. Lower-octane gas (like "regular" 87-octane gasoline) can handle the least amount of compression before igniting.
Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.
It turns out that heptane handles compression very poorly. Compress it just a little and it ignites spontaneously. Octane handles compression very well -- you can compress it a lot and nothing happens. Eighty-seven-octane gasoline is gasoline that contains 87-percent octane and 13-percent heptane (or some other combination of fuels that has the same performance of the 87/13 combination of octane/heptane). It spontaneously ignites at a given compression level, and can only be used in engines that do not exceed that compression ratio.
During WWI, it was discovered that you can add a chemical called tetraethyl lead (TEL) to gasoline and significantly improve its octane rating above the octane/heptane combination. Cheaper grades of gasoline could be made usable by adding TEL. This led to the widespread use of "ethyl" or "leaded" gasoline. Unfortunately, the side effects of adding lead to gasoline are:
Lead clogs a catalytic converter can render it inoperable.
The Earth becomes covered in a thin layer of lead, and lead is toxic to many living things (including humans).
When lead was banned, gasoline got more expensive because refineries could not boost the octane ratings of cheaper grades any more. Airplanes are still allowed to use leaded gasoline (known as AvGas), and octane ratings of 100 or more are commonly used in super-high-performance piston airplane engines. In the case of AvGas, 100 is the gasoline's performance rating, not the percentage of actual octane in the gas. The addition of TEL boosts the compression level of the gasoline ..
Footnotes:
http://auto.howstuffworks.com/question90.htm
Moral of the story..... Fill up at the airport |
|
|
| DougsMDX |
quote:
Originally posted by uboltpb
Can using 87 octane negatively effect the vehicle in any way?
I use regular unleaded and have had no problems, other than the lower mpg. IMHO, it was more economical to run regular unleaded vs. the lower mpg. (Assuming 20+ cents difference betweeen the two grades of gasoline) |
|
|
| gt854t5 |
Thanks QRTLOW for the Treatise on Gas - lol
:confused:
I've said it b4 on many forums and i'll say it again, there is NO DAMAGE that will result from using 87 octane gas in ANY MODERN engine. All gasoline is unleaded today; If ANY damage could resulted, they would not sell that gas. ALL GASOLINE come fron the same place; it's only the additives by the oil companies the makes them different. The end result is 87* burns faster & 93* burns slower. I wont quote any reports or surveys, cause they all have different agendas. So, how do i know this: My brother is a chemical engineer for a oil company in Texas, and HE said so. I would trust my brother over any ADs or car manufacturer any day. He says, buy "fresh" gas and the octance you can afford! and yes you probably will "see" a SLIGHT decrease in performance from 87 octane, but how many KNOW when their car is putting out 200 horsepower to the wheels; then it dropped to 195 horsepower when they used lower grade fuel( :rolleyes: ) |
|
|
| eurohazard |
| So would you tow a 4,500 lb boat up a mountain pass using 87 octane regular unleaded in your tank? |
|
|
| shootist |
quote:
Originally posted by gt854t5
, but how many KNOW when their car is putting out 200 horsepower to the wheels; then it dropped to 195 horsepower when they used lower grade fuel( :rolleyes: )
The difference is greater than that. THe MDX and most modern engines have a knock sensor. When it detects pinging, it retards the timing. When the timing is retarded, the engine's performance drops.
In my opinion, it feels like the air conditioning has turned on: on very familiar roads with rolling hills, I know the hills where the vehicle will downshift. If I use 89 octane, it downshifts much more frequently on the same road.
But this has all been said before. Many, many times. |
|
|
| uboltpb |
| The car has never "pinged" or "knocked". A friend thinks I may cause valve damage by using the lower octane. This is not a performance vehicle, and my wife usually drives it and she doesn't care about such things. |
|
|
| microman |
| I've been using 87 Octane rated gas for 2 years of my 3 years ownership of my 03 MDX. I have had absolutely no negative effects from it's use other than a slight decrease in power and about 1 to 1 1/2 mpg lower mileage. Saved lots of bucks at the pump and my X is still running just fine. Long trips to the mts I pump in the good stuff for xtra oomph. I also use Chevron to keep it a bit cleaner and use Techron when I remember to put it in. |
|
|
| NSXBill |
quote:
Originally posted by eurohazard
So would you tow a 4,500 lb boat up a mountain pass using 87 octane regular unleaded in your tank?
My experience towing a 4000 lb boat/trailer using summer-blend 87 gas on hot days up hills is that it pings. If I know ahead of time that I am going to be doing this, I will use 91+. Otherwise, use 87... |
|
|
| DaleB |
Fuel grade is one of the most discussed topics.
Here is the reason (from an automotive technology website)
why Regular is recommended for the Pilot, but Premium for the MDX:
"Modified Powertrain. When it came to the engine, the Pilot team's job was to replace some of the premium elements of the MDX's excellent 3.5-l V6 and tune the powerplant for fuel economy and smoothness as opposed to off-the-line performance. The three-rocker setup for the variable valve timing system was replaced with one based on two rockers per cylinder, and the dual stage intake system was jettisoned. In its place a new intake and exhaust system was developed by Honda R&D Americas (Raymond, OH) to optimize the power characteristics of the modified engine. (Though Honda has stated in the past that it has no intention of moving fundamental engine development outside of Japan, this project clearly shows that the powertrain staff in Ohio is increasing its capabilities.) According to Paluch, "The low- and mid-range rpm are completely different than the MDX, which has a flat, broad torque curve. The Pilot's torque curve is more gradual but it peaks out in the same area." Knock sensors were also adjusted so the new SUV could avoid the premium fuel diktat of its upscale predecessor. The result: the Pilot achieves fuel economy of 17 mpg in city driving and 22 mpg on the highway, peaks out at 240 hp and runs on regular fuel." |
|
|
| mdxforever |
| y'all just wait till I get my obd-2 reader. Then we can see how the timing behaves with lower octane fuel! |
|
|
| DaleB |
quote:
Originally posted by mdxforever
y'all just wait till I get my obd-2 reader. Then we can see how the timing behaves with lower octane fuel!
Actually, a member did that some time ago. Don't remember who..but I do remember they saw more advance starting near WOT with premium.
Also, model year may have an effect. Would like to see more recent data myself. |
|
|
| QRTLOW |
mdxforever's reference refers to a 2003 thread from mogul. He states that the results from the test subject vehicle was a 2001-2002 engine. I'm wondering what results we will get from a new test with newer motors and computers.
Engines and diagnostic electronics have improved in the last 3 years, what OBD-2 analyzer did you get? Digimoto or what? |
|
|
| mdxforever |
no not digimoto. I will be getting this - www.obd-2.com
besides just checking if the timing retards or not, my goal is to also find out how and when does the timing advance back up. I intend to plot timing curves for both types of fuels if possible. |
|
|
| DaleB |
| Yes, we wait anxiously for your data and see if the later models are as tolerant about lower octane levels as the earlier ones seemed to be. :) |
|
|
| jim.mdx |
quote:
Originally posted by mdxforever
no not digimoto. I will be getting this - www.obd-2.com
I have an older flavour of the same (ISO version). Are you getting a model which is CAN-enabled? My version won't communicate with my MDX and am wondering if CAN is required or if my hardware is just too old.
jim |
|
|
| mdxforever |
noticed your's is a 2006 MDX. Chances are it IS indeed a CAN.
I do know that CAN was on vehicles starting 2003 and later.
Email their support. They are usually quick to respond and have trade-up deals for upgrades.
Since mine's an '01 (and also a '99 accord) I will just get ISO for now. |
|
|
| mdxforever |
correction to the above. From the obd-2.com website it seems like Acura for 2006 is still ISO.
Jim, I'd be very interested in knowing if it worked for you or not.
How old is it ? I don't know if there have been hardware changes since you bought yours but download the latest version of the software and see if it works or not. Also, some hardware is picky about the sequence (ignition, obd scanner, software) in which it is initialized so follow the instructions carefully. |
|
|
|
|
|
