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Discussion Starter · #3 ·
Thanks for the links Nemogira. I still don't know the transmission ratios for the Ody though. It seems that the MDX has 2 overdrive gears. I wonder if they will keep the same final drive ration in the 2002 ody as the MDX.
 

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With the new specs from Trevor here's how the 2002 Ody and MDX compare (engine/drivetrain-wise):

- Same Compression Ratio 10:0:1

- Torque:
MDX (245 lb.-ft. @ 3000-5000 rpm)
Ody (242 lb. @ 4500)

- Final Drive Ratio:
MDX (4.428:1)
Ody (4.2:1)

- Fuel Economy
MDX (17/23 w/ Premium Unleaded)
Ody (18/25 w/ Regular unleaded fuel)
 

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Here's the ratios for an 01.

1st= 2.534
2nd= 1.502
3rd= 0.947
4th= 0.608
final= 3.941

Rev=1.846
I'm interested in what they have done with the ratios in the 02, with regard to the added HP. I feel the 01 needed something between 3rd and 4th. The ratio change is almost the same thru each gear in the 01, but doesn't seem to allow for the extra wind resistance etc. and makes 4th gear just a "cruising with a light load on level ground only" gear. Maybe I'm just used to big displacement engines.

Also wonder why the MDX requires premium fuel vs unleaded for the Ody? Like to see the HP/torque curves for both engines. That fifth gear ratio may not do much for the downshifting-even with the added HP and final drive ratio change. Will have to drive one and see.

Regards
Al

[This message has been edited by albaby (edited 08-24-2001).]
 

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Discussion Starter · #7 ·
Thanks for the gear info Albaby.

What I felt the 2001 4 speed transmission needed was another gear between 1 and 2. The shift from 1 to 2 seems rather harsh and delayed.
I see from the 5 speed data that the ratios are almost Identical for 1,2,3 to the 4spd.
That 5th gear at .502 seems like an amazingly high overdrive just to give honda bragging rights in highway fuel economy. I wouldn't try to pass someone in that gear.

Maybe honda still has some work to do...
 

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I was wondering about gear ratios too, thanks to all who posted the specs! So it looks like (assuming the Ody gear ratios are the same as the MDX tranny) in addition to an extra 30-35 HP and more torque, the '02 will have a little better low end acceleration due to lower gears. Lower final drive (4.2 vs 3.9) and slightly lower trans gears in the first four, with a higher "effective" final drive ratio of about 2.18 to 1 (.52 x 4.2) compared to '01 with about 2.40 to 1 (.608 x 3.94)
I predict fourth gear will find a fair amount of usage on the '02 Ody, especially when loaded down.
wallstreet123456-gear ratios usually refer to the final drive ratio which is the relationship between wheel speed and engine speed. In a rear wheel drive layout, this is the ratio of the driveshaft speed relative to the axle speed. Obviously, the transmission gears affect the "effective" final drive ratio. Hope that makes sense!


------------------
On the waiting list for my '02 EX Nav in RED!

[This message has been edited by ody (edited 08-24-2001).]

[This message has been edited by ody (edited 08-24-2001).]
 

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<font face="Verdana, Arial" size="2">Originally posted by wallstreet123456:
COuld someone please explain to me what this ratio talk means in plain english. I would like to understand this.

Steven
</font>
Hi Steve,

Gear ratios in a transmission simply discribe the speed difference between the power input shaft of the tranny (driven by the engine) and the power output shaft (drives the wheels). For example, if first gear is a 10:1 ratio, the engine will have to turn the input side of the transmission 10 turns to get 1 turn at the output side.

It gets a little confusing at first because the higher the number (20:1 as apposed to 10:1) the "lower" the gearing. A higher gear ratio will have a smaller number (5:1 is a higher gear ratio than 10:1) etc.

That's why they start with relatively low gear ratios (higher numbers) for first gear because that multiplies the power of the engine making it easier to get the car moving. Once it's moving, the amount of power needed to hold speed is much lower so they can go to a higher gear (lower numbers) so the engine doesn't need to spin as fast to perform the work. That equates to better gas mileage (usually) and a more relaxed ride because the engine isn't spinning up close to red line all the time.

In Albaby's post above, he lists the '01 and earlier Ody's gear ratios as:

1st = 2.534:1 (I know he didn't say the ":1" part but that's considered to be understood)
Anyway, it means the engine is turning 2.534 revolutions for every 1 turn of the output side of the tranny.

2nd = 1.502:1

3rd = 0.947:1 Here it gets a litte interesting. You've no doubt heard some of us refer to "overdrive (OD)". In this case, 3rd gear is a mild overdrive gear. It means that the engine is actually turning slower than the output shaft of the transmission.

4th = 0.605:1 This is a pretty healthy overdrive gear ratio. It's one of the main reasons the Ody EPA's at 25 mpg on the highway. The engine is only turning just over .6 revolutions for every 1 full turn of the output side of the tranmission. While it's great for mileage, it's lousy for performance but then again, we can't have it all!

Final drive = 3.941 This is the equivilent of the rear differential of a rear wheel drive car. It's where the power from the output side of the transmission is turned and sent to the drive wheels.

Now having said all of that, one of the big advantages the '02 Ody should enjoy over it's older sibblings is that, with the 5 speed transmission, they can run a lower first gear (higher numerically) which will allow the van to launch from a standing start with a lot more snap. Second, third and fourth gears can be spaced closer together to keep the engine in the heart of it's power band and thus keep the performance strong. Then they'll have that 5th gear overdrive so the engine can loaf along at highway speeds and keep the EPA fuel mileage on up where we'd like it to be.

I hope all this makes sense!


FWIW,
Drive Safe,
"Another"
Steve
 

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Intrepid175- Makes great sense to me, I realized my explanation was inadequate, but I was limited by time
The '02 Ody should feel stronger off the line with the lower gearing and additional power too, but 5th gear is REALLY overdriven-a stiff headwind would probably kick it down to 4th!

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On the waiting list for my '02 EX Nav in RED!
 

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<font face="Verdana, Arial" size="2">Originally posted by ody:
Intrepid175- Makes great sense to me, I realized my explanation was inadequate, but I was limited by time
The '02 Ody should feel stronger off the line with the lower gearing and additional power too, but 5th gear is REALLY overdriven-a stiff headwind would probably kick it down to 4th!
</font>
Thanks!
Actually, I would hope that they don't overdo the 5th gear too much. If it's so high that the van has trouble pulling a stiff headwind (I'm thinking in the 20 to 25 mph range) then it seems to me that it's usefulness would be reduced. I have no problem with the need for a downshift while passing but it should hold the top gear while simply maintaining speed against a headwind or a freeway overpass.

My '01 LX will hold 4th gear under these circumstances most of the time. What it will do on a fairly regular basis is release the torque converter lockup. I've had a couple of times when the hill is steep enough or the transition from level to up hill is abrupt enough that I would get a downshift to 3rd. Fortanately, that's not been very common in the part of the country I live in.

FWIW,
Drive Safe,
Steve


[This message has been edited by Intrepid175 (edited 08-24-2001).]
 
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