| tyler heredia |
| Do any of you guys know if the 2009's with take high test. Im very sure the 2008's do and this might may me ture away from my honda roots. Also what kinda milage are you guys getting? And one more thing can I have the sport model without the tech or do I have to get it with the tech before I can add the sport? |
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| rsnaider |
If the '09's have the same engine as the '07 and '08 then you will need to run 91 octane which usually translates to premium.
As for the packages, yes you have the base and in order to get either the Sport or Entertainment you need to add Tech first. |
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| csmeance |
| agreed, the mdx can run 87, but is highly not recommended. The motor is very high compression and will knock on the slightest bit of bad gas. |
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| G. COLTON |
quote:
Originally posted by csmeance
agreed, the mdx can run 87, but is highly not recommended. The motor is very high compression and will knock on the slightest bit of bad gas.
????Very high Compression???? The 2007 and 2008 have a compession ratio of 11:1. Higher than many but certainly not into the VERY HIGH category. For most driving the computer controlls will prevent knock.
I gave up long ago on my 2004 running anything but 87.
G |
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| Needsdecaf |
quote:
Originally posted by G. COLTON
????Very high Compression???? The 2007 and 2008 have a compession ratio of 11:1. Higher than many but certainly not into the VERY HIGH category. For most driving the computer controlls will prevent knock.
I gave up long ago on my 2004 running anything but 87.
G
I bet your car feels great down 10-20 HP. :rolleyes: |
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| Squishy |
Not an issue when you don't need those horses.
Mine's been on 87 since around 2003. |
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| Needsdecaf |
quote:
Originally posted by Squishy
Not an issue when you don't need those horses.
Mine's been on 87 since around 2003.
Then why buy the car? Why not buy a Pilot instead? |
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| Squishy |
1 - same engine in both
2 - there is no 2001 Pilot
3 - just because :D |
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| highcountrymdx |
Squishy brings up a really good point about the merits of 87 octane. About the only place you might get a few extra horses is in the extreme upper end of the rpm band, and then only under warm/hot environmental conditions. He's also correct to note that the Pilot and MDX have identical engines(except for the exhaust system in the MDX). The Pilot is designed by Honda powertrain engineers with regular gas.
Obviously, longevity of the engine is not a consideration. With EPA fuel economy essentially the same between the marques, about the only thing separating the two is an ever so slight increase in peak power with the 91 octane engine. Would you like that same power output in the Pilot? Just fill her up with the high test stuff.
Y'all do the math. |
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| Squishy |
Depending on the ECU, you may or may not get MDX-like power in a Pilot with 91 octane. The difference between MDX and Pilot programming is probably advanced ignition timing in the MDX. Knock sensors can retard that timing when knock is detected, but the Pilot ECU will probably not advance timing when 91 octane is used.
Another thing is that the Pilot seems to have gotten the 2001-2002 MDX engine, which is what I'm running. In 2003, MDX engines were bumped up to around 265 HP and the 240 HP engine went into the Pilot. I'm not familiar enough with these cars (the Escape is my daily driver) to know what exactly changed to account for the extra 35 HP and why the 240 HP engine needs 87 octane in the Pilot but 91 octane in the MDX, yet is rated for the same output. Do SAE test standards specify that the recommended fuel must be used in the test? |
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| tyler heredia |
| Ok thanks guys but know one has really answerd my question. If I do use the cheap stuff will I kill the car? |
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| rsnaider |
quote:
Originally posted by tyler heredia
Ok thanks guys but know one has really answerd my question. If I do use the cheap stuff will I kill the car?
Eventually you might do some damage as the knock sensors are doing their thing to make up for lower octane then recommended.
It boils down to how long you plan on keeping the car. If you lease it, the next person has to deal your decisions today as any damage will occur as the miles go up. If you own the car, how much are you really saving when you consider a major repair in the future by saving afew dollars with each fill-up?
These engines do ping on lower octane and pinging is not good for the engine if you just ignore it.
Bottom line, try 87 and if the engine does not ping, don't worry about it. You are going to get less power, but that is cost of saving on the octane you choose. |
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| Needsdecaf |
quote:
Originally posted by tyler heredia
Ok thanks guys but know one has really answerd my question. If I do use the cheap stuff will I kill the car?
See my quote of the owner's manual in the octane poll which states that long term use of regular grade, 87 octane gas will result in permanent damage to the engine |
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| Needsdecaf |
quote:
Originally posted by highcountrymdx
Squishy brings up a really good point about the merits of 87 octane. About the only place you might get a few extra horses is in the extreme upper end of the rpm band, and then only under warm/hot environmental conditions. He's also correct to note that the Pilot and MDX have identical engines(except for the exhaust system in the MDX). The Pilot is designed by Honda powertrain engineers with regular gas.
Obviously, longevity of the engine is not a consideration. With EPA fuel economy essentially the same between the marques, about the only thing separating the two is an ever so slight increase in peak power with the 91 octane engine. Would you like that same power output in the Pilot? Just fill her up with the high test stuff.
Y'all do the math.
As Squishy said, this is NOT correct.
To say that they are the same engine is a disservice. The big difference is tuning and, more importantly, compression ratio. The MDX engine has a higher compression ratio 10.0 vs. 9.6 vs. the Pilot engine (the 07 and up MDX has a fairly high compression ratio of 11.0). And yes, that is fairly high for an engine of this size.
The importance of the increased compression ratio is that you need higher octane to run it. For those of you not familiar with the correlation between compression ratio and octane, remember that octane is the fuel's resistance to compression detonation (think diesel). Engine designers can get more power by increasing the engine's compression ratio (the ratio between cylinder volume at TDC vs. BDC), but if your fuel doesn't have a high enough octane rating, it will ignite on it's own before ignited by the spark plug. This is what's called ping.
The way modern ECU's control ping is by dialing back timing. This dials back the power as well.
If the ECU is tuned for 87, it may or may not be able to take advantage of octane higher than that. Usually they are not designed to advance timing beyond the octane that they are designed for. They might eek out a couple more HP, but they're not designed to advance the timing aggressively. The fact that the compression ratio is lower is indicative that the programming likely is not of that nature. |
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| Squishy |
quote:
Originally posted by Needsdecaf
See my quote of the owner's manual in the octane poll which states that long term use of regular grade, 87 octane gas will result in permanent damage to the engine
Not "will," "can". Semantics play a part in how these things are written.
quote:
Originally posted by Needsdecaf
From the manual:
Your vehicle is designed to operate on premium grade gasoline with a pump octane of 91 or higher. If this octane grade is not available, regular gasoline with an octane of 87 or higher may be used temporarily. The use of regular unleaded gasoline can cause metallic knocking noises in the engine and will result in decreased engine performance. The long term use of regular grade gasoline can lead to engine damage.
So what's cheaper, saving $166 a year on gas (12k miles a year, 18 MPG, $0.25 difference) or an engine rebuild because of a holed piston. :rolleyes:
Hey, $166 is $166, but if you can't afford the gas, don't buy the car.
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| Squishy |
quote:
Originally posted by Needsdecaf
As Squishy said, this is NOT correct.
To say that they are the same engine is a disservice. The big difference is tuning and, more importantly, compression ratio. The MDX engine has a higher compression ratio 10.0 vs. 9.6 vs. the Pilot engine (the 07 and up MDX has a fairly high compression ratio of 11.0). And yes, that is fairly high for an engine of this size.
The importance of the increased compression ratio is that you need higher octane to run it. For those of you not familiar with the correlation between compression ratio and octane, remember that octane is the fuel's resistance to compression detonation (think diesel). Engine designers can get more power by increasing the engine's compression ratio (the ratio between cylinder volume at TDC vs. BDC), but if your fuel doesn't have a high enough octane rating, it will ignite on it's own before ignited by the spark plug. This is what's called ping.
The way modern ECU's control ping is by dialing back timing. This dials back the power as well.
If the ECU is tuned for 87, it may or may not be able to take advantage of octane higher than that. Usually they are not designed to advance timing beyond the octane that they are designed for. They might eek out a couple more HP, but they're not designed to advance the timing aggressively. The fact that the compression ratio is lower is indicative that the programming likely is not of that nature.
So between the 01-02 MDX and the 03 Pilot engines - different head design? That makes it even more odd that they are both rated for the same power output yet the Pilot has lower compression and runs on regular gas. Then again, I'm getting numbers from Wikipedia so feel free to correct me. |
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| Needsdecaf |
quote:
Originally posted by Squishy
So between the 01-02 MDX and the 03 Pilot engines - different head design? That makes it even more odd that they are both rated for the same power output yet the Pilot has lower compression and runs on regular gas. Then again, I'm getting numbers from Wikipedia so feel free to correct me.
I am not that versed on this particular set of engine, honestly. But you would more likely lower the compression ratio by installing a shorter or dished piston rather than re-doing the head design. Much easier.
Also, what are the engine speeds for the peak power / torque figures? Can't find those. |
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| Squishy |
From cars.com for the 2001 Acura MDX:
Horsepower: 240-hp @ 5,300 rpm
Torque: 245 lbs.-ft. @ 3,000 rpm
Nothing was listed there for the Pilot, so I had to go digging on Google. From here:
Horsepower: 240 @ 5,400 rpm
Torque: 242 ft.-lbs. @ 4,500 rpm
So at first glance there does appear to be a difference, but, when did Honda re-test their engines to conform to SAE J1349?
By the way, I wasn't referring to a completely different head design - just a taller mating surface. That should be easier to do through CNC programming than retooling for different lengths of rods or pistons. |
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| Needsdecaf |
quote:
Originally posted by Squishy
From cars.com for the 2001 Acura MDX:
Horsepower: 240-hp @ 5,300 rpm
Torque: 245 lbs.-ft. @ 3,000 rpm
Nothing was listed there for the Pilot, so I had to go digging on Google. From here:
Horsepower: 240 @ 5,400 rpm
Torque: 242 ft.-lbs. @ 4,500 rpm
So at first glance there does appear to be a difference, but, when did Honda re-test their engines to conform to SAE J1349?
By the way, I wasn't referring to a completely different head design - just a taller mating surface. That should be easier to do through CNC programming than retooling for different lengths of rods or pistons.
Aha. There's the telling tale....look at the RPM of the torque peak, it's 1,500 RPM higher. To me that says the car is tuned differently from the MDX, and they are sacrificing low end torque for a higher quoted peak HP rating.
In other words, the engine in the Pilot isn't as gutsy down low as the one in the MDX.
Interestingly enough, the engine in the new MDX, despite gaining 200 CC's of diplacement, is still a bit of a screamer. Not exactly a weakling down low, but my Volvo has a turbo 2.5L making 300 HP and 295 ft-lbs of torque at 2,000 RPM. The difference in power delivery is remarkable...kicks you in the pants off the line, but runs out of steam over 5,500 RPM. |
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| csmeance |
quote:
Originally posted by Needsdecaf
Aha. There's the telling tale....look at the RPM of the torque peak, it's 1,500 RPM higher. To me that says the car is tuned differently from the MDX, and they are sacrificing low end torque for a higher quoted peak HP rating.
In other words, the engine in the Pilot isn't as gutsy down low as the one in the MDX.
Interestingly enough, the engine in the new MDX, despite gaining 200 CC's of diplacement, is still a bit of a screamer. Not exactly a weakling down low, but my Volvo has a turbo 2.5L making 300 HP and 295 ft-lbs of torque at 2,000 RPM. The difference in power delivery is remarkable...kicks you in the pants off the line, but runs out of steam over 5,500 RPM.
turbo -> whole bunch of torque.
NA honda motors - low torque on low end |
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| Squishy |
Actually I feel the 3.5 L's torque curve isn't too bad. Having grown up with torquey GM engines, I can't bear to drive something like a Civic. Even my Escape's engine is a little too rev-happy for my liking. But the MDX pulls very well at 1500-2000 RPM, and it's part of the reason why 87 octane is usable. The engine has never seen past 4000 RPM, and that's just when I'm driving it. The MDX is my parents' daily driver; I'm only on these forums to stay ahead of common issues, etc. When they drive it the engine stays below 2500 RPM most of the time.
I've said in the past that "spirited" drivers may run into problems with lower octane gas, but we bought the MDX mainly as a comfortable and heavy snow-capable family hauler. |
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| Needsdecaf |
quote:
Originally posted by csmeance
turbo -> whole bunch of torque.
NA honda motors - low torque on low end
Erm, no kidding. :D |
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| Needsdecaf |
quote:
Originally posted by Squishy
Actually I feel the 3.5 L's torque curve isn't too bad. Having grown up with torquey GM engines, I can't bear to drive something like a Civic. Even my Escape's engine is a little too rev-happy for my liking. But the MDX pulls very well at 1500-2000 RPM, and it's part of the reason why 87 octane is usable. The engine has never seen past 4000 RPM, and that's just when I'm driving it. The MDX is my parents' daily driver; I'm only on these forums to stay ahead of common issues, etc. When they drive it the engine stays below 2500 RPM most of the time.
I've said in the past that "spirited" drivers may run into problems with lower octane gas, but we bought the MDX mainly as a comfortable and heavy snow-capable family hauler.
4k plus RPM does not qualify as "spirited" in my book.
Maybe I'm just used to a different engine, but the MDX is definitely a bit gutless down low, and that's not just compared to my Volvo turbo....that's my feeling compared to the CX9, which has LESS HP (although I think that may be the 6 speed gearbox gearing advantage). |
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| Squishy |
I'm not spirited at all. I'm more on the "angry grandmother" side, if anything :D
Unless it's in heavy traffic and merging is an issue (which isn't often out here on the edge of the boonies), the MDX hardly ever sees above 2000 RPM in the city. Normal acceleration is around 1700 RPM for us. My Escape at 1700 RPM is hardly moving. A Civic at 1700 RPM is probably rolling backwards. :D |
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| Squishy |
quote:
Originally posted by Needsdecaf
Maybe I'm just used to a different engine, but the MDX is definitely a bit gutless down low, and that's not just compared to my Volvo turbo....that's my feeling compared to the CX9, which has LESS HP (although I think that may be the 6 speed gearbox gearing advantage).
I've been paying more attention and I think I'm starting to agree with you. The MDX downshifts at the slightest hill. It's probably just the gearing that makes it seem like it pulls well at low RPMs. If that's the case, sure fooled me. |
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| gmc74 |
quote:
Originally posted by rsnaider
If the '09's have the same engine as the '07 and '08 then you will need to run 91 octane which usually translates to premium.
As for the packages, yes you have the base and in order to get either the Sport or Entertainment you need to add Tech first.
This is a bit misleading, the Sport package contains all of the features of the tech package. You aren't adding one on top of the other. |
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| gmc74 |
quote:
Originally posted by G. COLTON
????Very high Compression???? The 2007 and 2008 have a compession ratio of 11:1. Higher than many but certainly not into the VERY HIGH category. For most driving the computer controlls will prevent knock.
I gave up long ago on my 2004 running anything but 87.
G
The computer will control the knocking, but the price is horsepower. |
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| rsnaider |
quote:
Originally posted by gmc74
This is a bit misleading, the Sport package contains all of the features of the tech package. You aren't adding one on top of the other.
I guess it depends on how you read the brouchure. There are 3 packages you can add to the base truck; Tech, Entertainment and Sport.
In order to get Sport for example you can either view the options sheet as adding Tech first or assuming Sport includes Tech. I justed wanted the OP to know that he cannot have a base truck with the Sports package. If he wants that package, he needs to have Nav, ELS, etc. that is contained in the Tech package first. |
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| csmeance |
quote:
Originally posted by Needsdecaf
4k plus RPM does not qualify as "spirited" in my book.
Maybe I'm just used to a different engine, but the MDX is definitely a bit gutless down low, and that's not just compared to my Volvo turbo....that's my feeling compared to the CX9, which has LESS HP (although I think that may be the 6 speed gearbox gearing advantage).
Agree, The MDX is gutless down low, but as soon as you get past 3K RPM's you can feel it come to you. The motor would be perfect for a car with a 2WD set-up as it could harness the torque better, but with the SH-AWD system, 30% of the power is lost by the drive-terrain. My TL feels alright on the low end, nothing amazing really, but you have to remember, it is honda tuning, Low torque at the low end, more power on the high end. |
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