Gear Vendor's and Smarty Jr Stack = MPG!

[ronman]

Recently I installed a GearVendor OD followed by Smarty Jr. Today I took the truck on it first mini-highway trip (510mi). Before I get to the stats, let me say that the GV OD and Smarty Jr are two great mods!!! Each totally transforms the truck, and "stacked" the truck is just awesome!!!



Today I went from Fishkill NY to State College PA, roughly 255 miles each way of nearly all highway driving. I decided to do a very unscientific test. First leg of the trip would be baseline MPG with stock Software and no OD. Second leg would be stock software with OD. Third leg would be Smarty Jr on Economy setting with no OD, and fourth leg would be both Smarty Jr and OD.

I kept my crusing speed at 70 mph (I used cruise control to do that).



Now before the staticians amongst us get their shorts in a knot, I realize this trip was too short to be statistically significant. I make no claims that it is... these are just my raw unscientific (but hand calculated) numbers. I realize many factors like headwind, tail wind, cross wind, terrain etc can influence the numbers. For the record, it was a clear day with almost no wind in either direction but there were hills... The route was I84 to I81 to I80 and back. Legs one and two were down and three and four were return legs. When I refueled, I filled up to the top of the neck (thanks to the tank vent kit!!! It's great too!!!) Now for the numbers:



First Leg 140. 3 miles: Stock SW, No OD: 17. 92 MPG



Second Leg 134 miles: Stock SW with OD: 21. 01 MPG



Third Leg 102. 6 miles: SW = SJR Economy setting, No OD: 19. 43 MPG



Foutrh Leg 123. 2 miles: SW = SJR Economy setting, with OD: 21. 96 MPG



Conclusion: I loved the way the truck felt on the highway!! Unscientifically, looks like GV OD is good for about 3 MPG, and SJR Economy mode is good for 1-2 MPG. I'm ecstatic over the results, cost aside. In all fiarness, I got the GV OD second hand, but new in the box/uninstalled for a screaming deal and I got the SJR for the intro price. Probably will still take several years to break even, but, in the mean time, I have a truck that I love driving many times more than I did before. My only hangups on the truck before were OD on the G56 was too short, and I wanted to get a few more MPG's. Mission accomplished !!!

 

[PGarrett]

At 70 with the GV on what RPM is she turning? Stock tires?

 

[ronman]

At 70 with the GV on what RPM is she turning? Stock tires?

70 MPH is smidge over 1700 RPM. Stock tires, yes. Forgot to say that!

 

[MrBee]

Ronman ... . You will be very happy with the gear vendor. Great product and I put over 220,000 miles on one without a single issue.

 

[ronman]

Ronman ... . You will be very happy with the gear vendor. Great product and I put over 220,000 miles on one without a single issue.

Actually, I had one on my '98 12V, but I neglected to post that. They DO really transform the truck!! So, you had no issues wth GV in 220K miles??? That's awesome!!! My old one did develope a leak after about 80K but was otherwise great!

 

[BGlidewell]

I wonder how this would work with an auto... .

 

[ronman]

I wonder how this would work with an auto... .

Can't say for sure, but I'd imagine it would work just fine. You might drop another hundred or so revs below what the G56 goes down to though since your OD is a bit taller. I'm sure someone here has one on an auto. Maybe they will chime in. The GV will fit up to one and comes with all of the needed controls, so it is do-able.

 

[Matthysse]

I wonder how this would work with an auto... .

The Gear Vendors OD unit drops rpm by 22%, with your 4:10 gears it might be a good choice, the G56 coupled to 3:73 gears the rpms should be close to your 4:10 gears/rpm. I turn 2600 rpm OD off at 80 mph & 2000 rpm OD on. Very smooth engagement in & out of OD, unbelievably quiet in the cab at 80+ mph and still able to maintain 20 mpg average city/hgwy over 1300 mi that i get out of a tank full non towing. I like my OD.

 

[ronman]

The Gear Vendors OD unit drops rpm by 22%, with your 4:10 gears it might be a good choice, the G56 coupled to 3:73 gears the rpms should be close to your 4:10 gears/rpm. I turn 2600 rpm OD off at 80 mph & 2000 rpm OD on. Very smooth engagement in & out of OD, unbelievably quiet in the cab at 80+ mph and still able to maintain 20 mpg average city/hgwy over 1300 mi that i get out of a tank full non towing. I like my OD.

On my G56 w/3. 73, 70 MPH is 2200 with OD off. and 1750 with OD on!

 

[MEGATRK]

I myself have a 06 Mega Cab 4x4 with the G56 and have been wanting an OD for the truck. But I have been debating between the GV and U. S. Gear units. From what I'm gathering is that the GV shifts smoothly and quietly? What are the pros/cons to either unit? Can you still tow with the unit engaged? Up to what weight of trailer 20' boat or 12' enclosed trailer? My truck is stock except for 315/70r17 BFG AT's and complete AMSOIL change.

 

[ENafziger]

myself have a 06 Mega Cab 4x4 with the G56 and have been wanting an OD for the truck. But I have been debating between the GV and U. S. Gear units. From what I'm gathering is that the GV shifts smoothly and quietly? What are the pros/cons to either unit?

The con with U. S. Gear, is that they don't make a unit for the G56 transmissions, and have no plans to do so, as of 2 weeks ago. The pro for this unit is that it can be used in 4x4.

The con for the GV unit, is that it cannot be used with an exhaust brake engaged. Since the effectiveness of the exhaust brake is greatest at higher rpm's, I was looking forward to splitting gears on the deceleration as well to provide maximum braking; however, this is not possible with the Gear Vendors unit.


--Eric

 

[ronman]

I myself have a 06 Mega Cab 4x4 with the G56 and have been wanting an OD for the truck. But I have been debating between the GV and U. S. Gear units. From what I'm gathering is that the GV shifts smoothly and quietly? What are the pros/cons to either unit? Can you still tow with the unit engaged? Up to what weight of trailer 20' boat or 12' enclosed trailer? My truck is stock except for 315/70r17 BFG AT's and complete AMSOIL change.

GV shifts smoothly and quietly as long as you use the clutch and shift it like it's another gear in the trans. On the way down, you have to get into the habbit of turning the GV OD at some point before you slow down to 20MPH because it shuts itself off then, like it or not... I just make turning it off my first downshift, and all is well. One other thing is that you cannot use GV OD in 4x4 mode either. There's an interlock built into it to prevent it from going on if you're in 4x4. You can still tow with the GV OD engaged. No idea on trailering limit. Go to their website, or call them. I'd bet it's pretty high though since they put the GV OD on some pretty big RV's.

 

[MEGATRK]

Can the exhaust brake be used with the U. S. ? I'll have to visit their websights when I get a chance. Wondering which unit has what gear ratio for best fuel economy? I have driven my truck (03 6-speed) for 2 days straight each way in 6th gear 4 wheel drive going hunting in the dead of winter in North Eastern Quebec, so having OD in 4x4 would be an advantage. Is there anyone here who has a U. S. Gear to ask some questions to?

 

[Regcabguy]

GV '91 3500 CTD in classifieds.

I've ridden in a '91 CTD w/NV4500 conversion and GV. It's an unbelievably smooth unit especially hooked up to the 5-speed transmission. My buddy's selling this truck for peanuts. The NV 4500 is darn near new as is the GV unit. We were hitting 1650 rpm@80mph the other day. Anybody looking to upgrade their Getrag or GV should snatch this thing up.

 

[DGamelin]

I like the US gear you can split any gear any time, jack brake would work fine. They dont shift smooth like a GV. When you get good at shifting it you can rock the gas pedal like in a big truck to shift it. US gear doesnt recommend it they want you to clutch it. I went on a ride with a customer one time he wanted me to hear something. He puled a mini float for a living. He split gears up and down with out the clutch so smooth it was cool. I have wanted one but just cant find the money for it. Years back I installed a few of them on hot shot trucks, only got to drive them on test drives. This was back in the 80s when big blocks and no over drive was the norm.



04. 5 3500 cc 4wd dully 373 6speed 50k

93 2500 xc 2wd 354 auto 250k

 

[chris7694]

The Gear Vendors OD unit drops rpm by 22%, with your 4:10 gears it might be a good choice, the G56 coupled to 3:73 gears the rpms should be close to your 4:10 gears/rpm. I turn 2600 rpm OD off at 80 mph & 2000 rpm OD on. Very smooth engagement in & out of OD, unbelievably quiet in the cab at 80+ mph and still able to maintain 20 mpg average city/hgwy over 1300 mi that i get out of a tank full non towing. I like my OD.

What size tires do you have? I'm turning 2000rpms @ 84mph in OD. My speedo's reprogramed for the 285's too.



My mods get me 19mpg all the time with a heavy foot and lots of 85mph interstate cruising. That kind of driving style netted me about 15. 5 mpg bone stock. I'm absolutely certain 20+mpg would be easy if I didn't like to go fast all the time.