| From | Message |
Scottyhawaii
Dodge Dakota
JOIN HERE
11/25/2004
12:07:21
|
 Subject: When to use overdrive on my Y2k?
IP: Logged
Message:
Aloha dudes and duddettes,
I was wondering when should i use my overdrive on my 2000 Dodge Dakota 3.9L? Any help is appreciated!!!
|
?
Dodge Dakota
JOIN HERE
11/25/2004
12:56:53
|  RE: When to use overdrive on my Y2k?
IP: Logged
Message:
For best fuel mileage = let it ON as much as possible.
|
Gears
Dodge Dakota
JOIN HERE
11/25/2004
20:09:56
|  RE: When to use overdrive on my Y2k?
IP: Logged
Message:
Leave it on for mpg.You'll get the feel for when to shut it off climbing uphills.
|
Shepp
Dodge Dakota
JOIN HERE
11/26/2004
12:44:24
|  RE: When to use overdrive on my Y2k?
IP: Logged
Message:
1998 3.9 here, automatic w/OD. I only use my OD for highway driving, jsut don't get that nice seat of the pants feel on local roads w/OD off... lower RPM, and pickup is slower to respond w/OD off... IMHO of course...
Shepp
|
furball69
Dodge Dakota
JOIN HERE
11/28/2004
16:29:38
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
Overdrive at 30 or 40 mph can actually be inefficient because the engine isn't making enough torque at 500 rpm to do anything when you step on the gas. sure it will speed up eventually but more energy is wasted than is saved by using OD.
to make the concept understandable, imagine an engine with a torque wrench on the crankshaft and a certain amount of weight suspended above the handle.
The suspended weight has energy stored in it and when it is dropped on the handle the energy is released. you can equate higher elevation of the weight to the torque of an engine at an higher rpm.
So you drop the weight from 5 feet and it has no problem turning the engine, now drop it from 2 feet, the weight hits the handle and bounces off without turning the engine which only means one thing, you just wasted the energy it took to lift the weight because it had no effect on the engine.
|
agree
Dodge Dakota
JOIN HERE
11/28/2004
16:36:28
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
The "set it and forget" method can actually end up hurting gas mielage. Engine RPM isn't the only thing that determines fuel mileage. Load has more to do with it. Under certain conditions, the load is too high and you have to hold your foot down more.
I live in very hilly terrain and I use mine only on the highway or flat roads above 50MPH. I've noticed my mileage increase from when I used to just drive with it on all the time. O/D with CC is especially bad on hilly roads. Couple of times I thought my heads were going to fly off the thing revved so high.
|
furball69
Dodge Dakota
JOIN HERE
11/29/2004
02:54:20
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
On my last trip about a week ago, OD on, CC on, slight uphill grade and coming up to a truck, I dediced I was going to take over and accelerate to pass, so I step on the gas... or at least tried to step on the gas. The thing was matted and it was still in fifth... kinda scared me to feel the gas pedal down to the floor. not sure why it didn't downshift. Anyway, I disengaged CC and passed as normal. That happened twice, exact same thing.
|
Dan M
Dodge Dakota
JOIN HERE
11/29/2004
11:15:47
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
I don't see where anyone said they turn off O/D for towing, I do. I have '95 CC 4x4 3.9L V6 auto. And I never use CC for towing either.
and my truck idles over 500 RPM.
I agree about disableing CC and OD on non flat roads - I don't like the unusually high reving that can occur when trying to climb even the slightest of upgrades.
- Dan M
|
daffydak
GenIII
11/29/2004
12:40:10
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
I don't think the origonal poster specified if he was talking about a 5 speed, or an automatic transmission... but you should use OD when you aren't on a hill, or are not towing.
just my .02
00 CC Sport Plus 4.7L 4X4 Auto, 3:55 LSD
Flowmaster orig. 40 series (2 chamber) muffler, adjusted tps to .76V, ported TB, home brew intake setup w/K&N filter, more mods to come!!!
Dan
MOPAR=More Power!!
|
Bob Lincoln
Dodge Dakota
JOIN HERE
11/29/2004
14:44:07
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
"I agree about disableing CC and OD on non flat roads - I don't like the unusually high reving that can occur when trying to climb even the slightest of upgrades."
This makes no sense at all. If you leave the O/D on, and it downshifts, it revs. If you turn off the O/D, it revs to the exact same engine speed, ALL the time, thus burning more gas and putting more wear on the engine. Let the automatic do its job, and turn off O/D only when towing.
|
Dan M
Dodge Dakota
JOIN HERE
11/29/2004
17:37:06
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
bob, sorry for the confusion. I meant using CC with O/D on. When I'm driving on roads that come to a slight incline, the engine will rev high and the CC system will engage until I'm at the set speed again.
all that turkey and 10 hours or driving back from NC to GA.
- Dan M
|
Bob Lincoln
Dodge Dakota
JOIN HERE
11/29/2004
22:22:46
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
Cruise control is great, and I have it in my Daytona, which is a 5-speed manual, so it can't kick down on me when climbing hills. My Dak has no cruise control, and I feather the gas on slight hills to avoid downshifts.
|
p2gee
Dodge Dakota
JOIN HERE
12/02/2004
09:51:26
|  RE: When to use overdrive on my Y2k?
IP: Logged
Message:
I always turn OD off for in town driving, turn it on for highway driving. Also HIGHLY recommended to leave OD off when towing heavy loads.
|
Ratdog
Dodge Dakota
JOIN HERE
12/02/2004
10:00:25
|  For around town driving
IP: Logged
Message:
I leave the OD off. I also turn it off when towing.
One good way to train your ear for the "sweet spot" is to install a vacuum gauge. Select the gear which allows you to maintain a given speed with the highest amount of vacuum reading.
|
Bob Lincoln
Dodge Dakota
JOIN HERE
12/02/2004
15:52:47
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
Leave it on except towing and long, steep grades. Best gas mileage is lowest RPM (highest gear) without lugging. At 40 mph around town, it turns 1200 RPM in O/D, 1600 in 3rd. It's easy to see which maneuver will burn more gas on a level road with no load.
|
Joe. C
Dodge Dakota
JOIN HERE
12/02/2004
16:22:46
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
Bob, read your owners manual and learn some basics about automaotive engines. Gas consumpation isn't based just on engine RPM. The experiences of many posters goes against your "I know best so shut up" attitude.
Jerk.
|
Bob Lincoln
Dodge Dakota
JOIN HERE
12/02/2004
20:12:35
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
Sounds like you have the attitude, not me. And I have worked on, modified and repaired engines for 26 years. I also have a mechanical engineering degree from a top university. But I'm always willing to learn more. Pray tell, what is incorrect in my statement? Certainly, revving an engine needlessly in a lower gear WILL use more gas, all other things being equal.
|
Ratdog
Dodge Dakota
JOIN HERE
12/02/2004
20:55:25
| I'll stand by my comment to
IP: Logged
Message:
learn your vehicle's sweet spot by watching a vacuum gauge... and learning which gear selection allows you to maintain a given speed with the least amount of throttle application. Sometimes... the higher RPM is better.
|
Bob Lincoln
Dodge Dakota
JOIN HERE
12/02/2004
21:58:59
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
Right. And usually highest vacuum coincides with lowest RPM, only to the point where lugging begins. Once it's slow enough to lug, the advantage is gone. But with no lugging, vacuum will be highest at lower RPMs (throttle closed more) in higher gears. Hence my example. With the 3.55 axle, my truck turns 1200 RPMs at 40 in 4th, 1600 RPMs in 3rd. On level ground, with no lugging, gas mileage will be higher in 4th. This is verified by actual measurements, when my O/D wasn't working, vs now when it is. 20 mpg with O/D on, 17 mpg without.
In a situation where the tranny would keep shifting back and forth, such as climbing a long grade, it makes sense to lock out O/D to save wear and tear and give a smoother ride.
|
Ratdog
Dodge Dakota
JOIN HERE
12/02/2004
23:33:50
| LOL I'm not certain whether it's
IP: Logged
Message:
the 137,000 miles, or what... but I don't dare try a long grade in O/D with mine. Little by little I'm going through it and seeing what I can improve upon (before any "mods"). It's gettin' better, but this ol' girl, she ain't a hotrod. ('Course... I'm rather used to the acceleration of my "Valkyrie"... motorcycle). LOL
|
grouh0jr
Dodge Dakota
JOIN HERE
12/03/2004
08:33:48
| RE: When to use overdrive on my Y2k?
IP: Logged
Message:
O/D off is a deffinate during towing. Not too many people have mentioned city driving though, While driving in a lot of stop and go traffic it can put less stress on the transmission.
|
| | P 1 |
|
Post a reply to this message:
Username Registration: Optional
All visitors are allowed to post messages
|
