Re: overdrive trans question
[Re: 71sat440]
#2288240
04/15/17 02:48 PM
04/15/17 02:48 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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i just want better gas mileage and reliability. No OD info but in the meantime you might dial in the dist & possibly go leaner or richer depending on where the carb is at now & the most restrictive system is the exhaust. You might put in a new timing chain & adv it 4 deg. a 360 MIGHT give better mileage. what is the axle ratio?
live every 24 hour block of time like it's your last day on earth
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Re: overdrive trans question
[Re: 71sat440]
#2288269
04/15/17 03:35 PM
04/15/17 03:35 PM
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Joined: Mar 2011
Posts: 1,655 Cut and Shoot, TX
kentj340
top fuel
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top fuel
Joined: Mar 2011
Posts: 1,655
Cut and Shoot, TX
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Well, I have a stick shift, but I'll say this - 0.75:1 accomplishes little improvement and is a waste of time and money to convert. What is worthwhile is 0.5:1.
Here's what I mean. Top photo is direct drive 1:1 at 60 mph, 2,750 rpm
Next photo is 0.75:1 at 60 mph, 2,300 rpm, a savings of 450 rpm. Meh.
Bottom photo is 0.5:1 at 60 mph, 1,550 rpm, a savings of 1,200 rpm. Perfect.
This is what you get in the cockpit in real life, not what the math says it ought to be.
If you don't see two dolphins, you need a vacation.
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Re: overdrive trans question
[Re: 71sat440]
#2288677
04/16/17 11:43 AM
04/16/17 11:43 AM
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Joined: Aug 2005
Posts: 6,018 Salem
Grizzly
Moparts Proctologist
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Moparts Proctologist
Joined: Aug 2005
Posts: 6,018
Salem
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Since you mention gas mileage and reliability, there are 2 other options:
1. a833od manual. I have a few of these and they are awesome. 2. 318 Magnum + it's transmission + all the factory computer stuff. Nothing beats tapping the key on a Magnum and having it light up right away compared to these Carter-carbed POS 318's.
Or, for what the cost and time involved to do this, you can pick up a 2nd gen for $1500.00
Mo' Farts
Moderated by "tbagger".
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Re: overdrive trans question
[Re: kentj340]
#2288791
04/16/17 01:41 PM
04/16/17 01:41 PM
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Joined: Jan 2005
Posts: 3,699 Newport, Mi
Evil Spirit
master
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master
Joined: Jan 2005
Posts: 3,699
Newport, Mi
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Well, I have a stick shift, but I'll say this - 0.75:1 accomplishes little improvement and is a waste of time and money to convert. What is worthwhile is 0.5:1.
Here's what I mean. Top photo is direct drive 1:1 at 60 mph, 2,750 rpm
Next photo is 0.75:1 at 60 mph, 2,300 rpm, a savings of 450 rpm. Meh.
Bottom photo is 0.5:1 at 60 mph, 1,550 rpm, a savings of 1,200 rpm. Perfect.
This is what you get in the cockpit in real life, not what the math says it ought to be. Sometimes when the RPM is too low, it lugs the engine and actually gets worse mileage than slightly higher RPM. The O/P has a 318 truck and may not like too much OD reduction.
Free advice and worth every penny... Factory trained Slinky rewinder.........
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Re: overdrive trans question
[Re: Evil Spirit]
#2288929
04/16/17 05:06 PM
04/16/17 05:06 PM
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Joined: Jan 2003
Posts: 25,995 Rio Linda, CA
John_Kunkel
Too Many Posts
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Too Many Posts
Joined: Jan 2003
Posts: 25,995
Rio Linda, CA
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Sometimes when the RPM is too low, it lugs the engine and actually gets worse mileage than slightly higher RPM.
Classic example is the Viper; 3.08 axle ratio with .5 OD in 6th gear. You gotta be doing 85 mph to use 6th and then the throttle is like mush.
The INTERNET, the MISinformation superhighway
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Re: overdrive trans question
[Re: 52savoy]
#2288984
04/16/17 07:00 PM
04/16/17 07:00 PM
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Joined: Dec 2009
Posts: 20,673 in a cattle trailer down by th...
Guitar Jones
Paddle faster! I hear banjo music!
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Paddle faster! I hear banjo music!
Joined: Dec 2009
Posts: 20,673
in a cattle trailer down by th...
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I'm doing this swap right now for my '77 440 D200 and have posts about this. Read the current one about my 518 reverse drum problem. If you choose to do it, find an early 90s(46RH). I like this swap and with a lock up converter it's even better. I would suggest a trans no earlier than a 92 model though as they had the larger cooler lines which lubes the rear clutch drum and O/D unit.
"Follow me the wise man said, but he walked behind"
'92 D250 Club Cab CTD, 47RH conversion, pump tweaks, injectors, rear disc and hydroboost conversion. '74 W200 Crew Cab 360, NV4500, D44, D60 and NP205 divorced transfer case. Rear disc and hydroboost conversion. 2019 1500 Long Horn Crew Cab 4WD, 5.7 Hemi.
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Re: overdrive trans question
[Re: 71sat440]
#2289167
04/17/17 12:48 AM
04/17/17 12:48 AM
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Joined: Jan 2010
Posts: 669 Los Osos, Ca
CKessel
mopar
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mopar
Joined: Jan 2010
Posts: 669
Los Osos, Ca
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Stay with a 95 or older unit as they are not electronic like the 96 and newer which will require a trans controller. 95 and back you can use two toggle switches, one each for the od and lockup. Some people have rigged up ways to operate them so they are a more automatically done shift to od/lu otherwise if you don't have a way to switch the new features it will just shift right in to od/lu when you are hardly moving. Some of the earlier units were od only and ran a standard non lu converter. Trans Go had instructions in their shift kits to modify the lube passages in the earlier units to prevent lack of lube issues that were a problem on some transmissions. If you run the numbers down, some applications had a more hd trans than others with features like more frictions discs, stouter planetary assemblies etc. The best v8 units were behind the 5.9's aka 360's. Even better for internals were the v10 and cummins units if you are going for the gusto. Since the 95 and older units were hydraulic, shift kits were easier and make more of an improvement which will help trans life. Another cheap and sometimes free improvement for the 97 and older units is to get a pan off the 98 and newer trans which is deeper and adds 2qts to you fluid capacity. You can find them at the diesel specialty shops or trans shops when someone puts a deeper aluminum pan on their cummins trucks. Do this for the regular 727's also but for them you need a filter extension.
Carl Kessel
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Re: overdrive trans question
[Re: 71sat440]
#2289238
04/17/17 03:08 AM
04/17/17 03:08 AM
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Joined: Aug 2005
Posts: 6,018 Salem
Grizzly
Moparts Proctologist
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Moparts Proctologist
Joined: Aug 2005
Posts: 6,018
Salem
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At the end of the day, it's tough to win with any Dodge overdrive auto from 1988 to 2003. The 545rfe is the best thing that ever happened and WHY nobody can make one to work with a Magnum/LA I'll never know.
Mo' Farts
Moderated by "tbagger".
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