Two overdrives?

[Frank Lee]

Originally Posted by t vago

Hey, if you don't like what we want to do with our property, with our money, on our own time, then you don't have to comment on it.

Especially you, Frank, and after complaining about me making cutsey remarks, too. Get the hell out of my thread if you don't have anything constructive to say.

Oh, but I do have to comment on it.

Why not make a dump truck into a sports car while you're at it?

BTW I didn't even have you and whatever junk you work on in mind. I was thinking of this guy that drives a Ram all around town with a big wing on the back of it. I'd feel like a douche riding around in that thing.

[Frank Lee]

Originally Posted by Big Dave

Secondly, GVs are very heavy-duty pieces of machinery (originally built for Bedford military deuce-and-a-halfs) and are priced accordingly.

And, that heavy-dutiness means big heavy innards which means more internal drag.

[comptiger5000]

Keep in mind, many of these big V8s have reasonably flat torque curves in stock form. The torque curve in mine doesn't drop off a lot until you're under 1400 or so (probably still 280+ ft lbs, vs 345 at peak). At 1750 rpm doing 60, it'll accelerate up 7% grades without downshifting or unlocking the TC.

What really tells me that the engine is under way too little load at cruise is that I get much better mpg in mild hills (doesn't gain more than 2 mph coasting down them) than on flat ground (steep hills are about the same as flat). I've seen a bit over 21mpg with a very light tailwind and the right set of hills with the cruise set at 59. However, if I set the cruise to the same speed on flat ground with no wind, I get about 18mpg.

And yeah, I know this brick will never get great mpg, and the city mpg probably won't get any better with an auto, but if I can help the mileage a bit when cruising 50+, that alone would save me a good bit of money, as currently it costs about $80 each way in fuel to drive home from college (which I don't do often).

I'll be curious to see what it gets for mpg in a few weeks when I tow a 3000 - 3500lb 6x12 cargo trailer for the 350 mile trip home (probably going down NY-17 as thruway tolls with the double axle trailer would be brutal for the whole run, so lots of steep hills).

[Big Dave]

Frank Lee posted:
“…that heavy-dutiness means big heavy innards which means more internal drag.”

Big Dave says:
Indeed so.

If I were not backed into a corner by lack of better options, I would have used something else. I thought of swapping in a T-56 but it did not have the torque rating and bellhousing size necessary for an International 444 engine.

I do occasionally tow trailers and haul fairly heavy bed loads. That and the engines capability of making enormous torque for protracted periods of time would make scrap metal of something lighter.


This is why I recommended t_vago use a T-56. It is lighter than a GV (and less expensive). There is a variant of the T-56 (Tremec 6060) that is used in Vipers and Z06 Corvettes that will stand up to anything his engine and truck can dish out and still give him a huge 0.5:1 OD ratio.

[t vago]

Originally Posted by Big Dave

This is why I recommended t_vago use a T-56. It is lighter than a GV (and less expensive). There is a variant of the T-56 (Tremec 6060) that is used in Vipers and Z06 Corvettes that will stand up to anything his engine and truck can dish out and still give him a huge 0.5:1 OD ratio.

While it would be nice to have a T-56, I don't see any non-Viper Mopar applications for the T-56. As I don't want to stuff a V10 under the hood, and I am not at all sure how much a one-off bellhousing adapter for my own engine would cost, I am inclined to regard this option with some reluctance.

A GV, on the other hand, should be simpler to mount. I see two possible mounting options.

On the one hand, Gear Vendors offers an option for the 47RE whereby the overdrive is mounted directly to an transfer case adapter. This option looks promising for me, since the 47RE adapter and the 45RFE adapter look like they have the same bolt pattern for the transfer case adapter end. Both transmissions also have 23 spline output shaft.

On the other hand, I could get a three-piece driveshaft (it was an option for my truck), and replace the forward driveshaft with a GV overdrive. It certainly looks simpler than the transfer case option, but it seems to be a bit flimsier.

I am still thinking an extra overdrive could be beneficial, for several reasons.

First and foremost, I take readings with my ScanGauge II on the drive back from my work, which is a 59 mile commute. I have several landmarks which I use to determine fuel consumption. These numbers are pretty consistent over the past month.

MP - fuel consumed - FE
3.3 - 0.25 gallons - 13.2 MPG
8.9 - 0.50 gallons - 17.8 MPG
42.7 - 2.25 gallons - 19.0 MPG
52.2 - 2.75 gallons - 19.0 MPG
58.0 - 3.00 gallons - 19.3 MPG
59.2 - 3.15 gallons - 18.8 MPG

I loaded down the bed of the truck with about 120 lbs of scrap metal that I've been meaning to take to the scrapyard. However, they made the work commute along with me for the past two days. Interestingly, my FE went up because of the extra weight.

MP - fuel consumed - FE
3.3 - 0.22 gallons - 15.0 MPG - 12% reduction in fuel consumption
8.9 - 0.45 gallons - 19.8 MPG - 10% reduction in fuel consumption
42.7 - 2.10 gallons - 20.3 MPG - 7 % reduction in fuel consumption
52.2 - 2.60 gallons - 20.1 MPG - 5 % reduction in fuel consumption
58.0 - 2.85 gallons - 20.4 MPG - 5 % reduction in fuel consumption
59.2 - 3.00 gallons - 19.7 MPG - 5 % reduction in fuel consumption

[cleanspeed1]

What's the lowest numerical ring and pinion that you can get that will fit both the axles?

Or if you don't uses the 4x4 feature, disconnecting the driveshaft to the front axle and using a different ring and pinion in the back only?

[t vago]

Originally Posted by cleanspeed1

Let me explain real world experience to you.

Feel free to go off your theory, because that's all it is. You haven't designed anything if you merely fixed it. Bringing a vehicle up to its designed operating condition is not the same as modifying it for whatever purpose one had in mind. I could quote ASE study guide material too, but it won't help one bit. This is exactly the in-the-box thinking that prevents people from trying new ideas. So much for nefarious control freaks that kill inventors and suppress new developments - it's rather people like you who refuse to consider anything outside of what they understand.

I got 23 MPG once on a "high-speed" run from Canton to Detroit last year, and I commonly get about 19.5 MPG per tankful. That's with a "propensity for high speed." This is remarkably high for a "big, heavy, high powered, high drag vehicle with high frictional losses in the driveline and high road friction because of the tires." Tell me approximately how much loss I'm experiencing in my driveline. Tell me how much more loss I could expect with installing an overdrive. And tell me what happens to bsfc when you choke the living hell out of a "high powered" gasoline engine, such as driving down the interstate at 72 MPH and getting a manifold vacuum of around 7 or 8 psig.

Here's the thing. I'm much more inclined to listen to whatever Big Dave and comptiger5000 have to say, because they at least put out the effort to experiment and find out what worked, and what could be improved. You? Not so much.

Originally Posted by cleanspeed1

What's the lowest numerical ring and pinion that you can get that will fit both the axles?

It looks like I can easily get a 3.23 diff. Why should I downgrade my towing/hauling capability?

Originally Posted by cleanspeed1

Or if you don't uses the 4x4 feature, disconnecting the driveshaft to the front axle and using a different ring and pinion in the back only?

Notwithstanding the fact that I have a 2WD truck, why would I want to cripple a 4x4 vehicle in this manner?

Not that I really expect you to answer...

[Big Dave]

I think your engine's bellhousing is the same as the one on a Viper V-10.

[cleanspeed1]

Originally Posted by t vago

Feel free to go off your theory, because that's all it is. You haven't designed anything if you merely fixed it. Bringing a vehicle up to its designed operating condition is not the same as modifying it for whatever purpose one had in mind. I could quote ASE study guide material too, but it won't help one bit. This is exactly the in-the-box thinking that prevents people from trying new ideas. So much for nefarious control freaks that kill inventors and suppress new developments - it's rather people like you who refuse to consider anything outside of what they understand.

I got 23 MPG once on a "high-speed" run from Canton to Detroit last year, and I commonly get about 19.5 MPG per tankful. That's with a "propensity for high speed." This is remarkably high for a "big, heavy, high powered, high drag vehicle with high frictional losses in the driveline and high road friction because of the tires." Tell me approximately how much loss I'm experiencing in my driveline. Tell me how much more loss I could expect with installing an overdrive. And tell me what happens to bsfc when you choke the living hell out of a "high powered" gasoline engine, such as driving down the interstate at 72 MPH and getting a manifold vacuum of around 7 or 8 psig.

Here's the thing. I'm much more inclined to listen to whatever Big Dave and comptiger5000 have to say, because they at least put out the effort to experiment and find out what worked, and what could be improved. You? Not so much.



It looks like I can easily get a 3.23 diff. Why should I downgrade my towing/hauling capability?



Notwithstanding the fact that I have a 2WD truck, why would I want to cripple a 4x4 vehicle in this manner?

Not that I really expect you to answer...

I'll answer, it's not as if I'm afraid to, because despite you getting personal, I'm going to keep it technical.

If you are getting 20-23 mpg in a heavy pickup with 4x4 at 70+ mph, congratulations and more power to you.

Are you using the stock programming in the motor?

Are you using the stock wheel and tire sizes and the same ride height?

If someone else were to drive the truck, could they produce the same mpg result as you?

Did these results come from using standard E10 pump gas fuel?

Were there any fuel additives added?

The numbers generated, were they from a Scan Gauge or some other device that can measure the fuel consumption or were they done by hand, and what proves their accuracy?

I can get behind Big Dave because I have owned Powerstrokes and with the type of powercurve they have, the fact that it's a diesel ( and a big one at that ), their tuneability and the fact that if you slow them down they won't lug.

So, back to the original topic. You should go ahead and spend the money and get that GV installed.

[t vago]

Originally Posted by Big Dave

I think your engine's bellhousing is the same as the one on a Viper V-10.

Nope. LA-style and V-10 bellhousing bolt patterns are not interchangeable.

However, I was able to stumble upon this little item here:
Quick Time RM-6076 LA Mopar Bellhousing adapter for T-56 transmission - Only $541.95 plus shipping.
I found some other interesting information here: 5.7 Hemi/ viper trans bellhousing

How would this compare, pricewise, with a used GV overdrive off of eBay?