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Volvo D13 fuel mileage in your rv config?


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First off 18 DO is killing you, if your running in 18th gear. People think OD gets you the best MPG. It will not do it in any truck. Now you can take that 18OD and run it in direct. That is where your going to do best on Fuel.

Not sure the model # of your trans, but 14th should be direct for you. With your gears you should be turning around 1350 at 65 +/- 2 or 3 MPH. But that can depend on if the truck is still running the factory tire size. As some change tire sizes to do a poor man's gear change.

But your driving a brick, and not going to get the MPH the better air stream trucks can get. Used to run a 1989 379. 18 DO top gear was back to the dash. 24.5 tall rubber, 3.36 rears. Fuel was turned up beyond hot. I had to drive by the Exhaust temps even empty.

That truck was a triple digit truck. And had it running those numbers a lot back in the late 80's early 90's. Got a unreal 3.1 MPG. But fuel was cheap, speed make money. Left lane truck it was, fuel sipper it was not.

Went into a T600 right after that truck. Set up the same way, run it the same way for 6 months. That truck would bet 5 MPG running hard all the time never shut off while on the road. But run it normal and seen 7 out of it easy. But when fuel is no though. And we all ran outlaw, it was fun. But no way would I run a brick today. If I wanted to get great MPG.

My 1995 T600 11.1 Detroit series 60, 400HP, 10 speed direct, 2.93 rearend along with 295/22.5 tires. 65 MPH is only cruising. And gets unreal MPG, but it was set up that way in 1995. By a company that wanted to save on fuel.

Edited by Pete Kildow
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48 minutes ago, Pete Kildow said:

First off 18 DO is killing you, if your running in 18th gear. People think OD gets you the best MPG. It will not do it in any truck. Now you can take that 18OD and run it in direct. That is where your going to do best on Fuel.

Not sure the model # of your trans, but 14th should be direct for you. With your gears you should be turning around 1350 at 65 +/- 2 or 3 MPH. But that can depend on if the truck is still running the factory tire size. As some change tire sizes to do a poor man's gear change.

But your driving a brick, and not going to get the MPH the better air stream trucks can get. Used to run a 1989 379. 18 DO top gear was back to the dash. 24.5 tall rubber, 3.36 rears. Fuel was turned up beyond hot. I had to drive by the Exhaust temps even empty.

That truck was a triple digit truck. And had it running those numbers a lot back in the late 80's early 90's. Got a unreal 3.1 MPG. But fuel was cheap, speed make money. Left lane truck it was, fuel sipper it was not.

Went into a T600 right after that truck. Set up the same way, run it the same way for 6 months. That truck would bet 5 MPG running hard all the time never shut off while on the road. But run it normal and seen 7 out of it easy. But when fuel is no though. And we all ran outlaw, it was fun. But no way would I run a brick today. If I wanted to get great MPG.

My 1995 T600 11.1 Detroit series 60, 400HP, 10 speed direct, 2.93 rearend along with 295/22.5 tires. 65 MPH is only cruising. And gets unreal MPG, but it was set up that way in 1995. By a company that wanted to save on fuel.

 This is fact. Direct, though OD is but parasitic drag, will always be the most efficient. To prove this to myself, this last trip I did in fact run in 16th any time speed fell below 60 or so. Prior trips were 7-4 and 7.6mpg running in 18th at all speeds over 55.

 According to gps speed, my truck speedo reads 2-3 mph fast. So 68ish is 65. It does have low pro 22.5s, not sure original spec as I have not looked it up.

 Reason for 16th vs. 17th, is the thumb splitter valve leaks when in low position. Soon as I fix it, I will try running in 17th when possible.

 Trans is RTLO-18918B

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At 52,000 lbs, and an 18 ft gap between truck and trailer, going 63-65, it does 7.0 to 7.2 mpg by the mileage guesser, 3.36 rear and OD Ishift.    7.5 mpg from top off to top off if you calculate.   D16 engine.  Your mileage may vary.   As long as I don't have to stop for fuel to get half way across the country,  don't really care about whether I am at 7 or 12 mpg.  Considering the other HDT costs, even if you do the work yourself, fuel ain't that big a deal.  For example, had ours for 8 yrs.  Did 10 new tires before this summers adventure cause 8 yrs is pushing it....makes the difference between 7 and 10 or 11 mpg seem like noise.   My routes are all Colorado, Az, Wy, Montana, SD, so no Kansas flat data to report.

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Having pulled 2 different RV's with the same truck, the shorter, 6000lb less weighing, more aerodynamic rear of the Carrilite gave us better mileage than the DRV which is 46', 24800lbs, and a flat straight roof.  The Carrilite was a tapered roof that I believe had less drag.  Our truck bed is short, which keeps the cab and front cap about 2 foot apart.

 

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17th is main box in overdrive and aux box in underdrive, which is the most inefficient combination in the upstairs - something like 90-92%.  So it should be worse numbers.  Worth a try though as it won't hurt anything in a 9-series to run it and it'll see if your numbers can see the resolution.

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16 hours ago, Scrap said:

17th is main box in overdrive and aux box in underdrive, which is the most inefficient combination in the upstairs - something like 90-92%.  So it should be worse numbers.  Worth a try though as it won't hurt anything in a 9-series to run it and it'll see if your numbers can see the resolution.

 Great info. I had not looked up the actual selection configuration for this trans. Typically, at least in a smaller torque trans, the OD drag is small enough to be considered parasitic, and in many cases, the gain of putting the engine in a more efficient range would outweigh the small loss. If your 90-92% range holds true however, it may be a wash or even a further loss as you suspect. Gunna try it when I get the valve fixed though just for the knowledge. Thank you for the reply. I appreciate them all.

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 Ok, so.......I'm pretty sure "Leroy" belongs to an Escapee. ?  Here's a video that states mileage even with a D16.

 If my 379 were'nt so darn awesome styling, I'd be even more excited to look at the Volvo. But my gf and I are plus size and the gap between the seats, though tolerable for our younger age, is not the most friendly. We're weekend warrior types at this point and will continue to run solo without trailer for a while yet. So the sleeper is our main cabin. Spent 5 days in it over the labor day weekend and we feel we could easily do a 10 day run given the amount of driving we prefer.

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4 hours ago, Deezl Smoke said:

 Ok, so.......I'm pretty sure "Leroy" belongs to an Escapee. ?  Here's a video that states mileage even with a D16.

 If my 379 were'nt so darn awesome styling, I'd be even more excited to look at the Volvo. But my gf and I are plus size and the gap between the seats, though tolerable for our younger age, is not the most friendly. We're weekend warrior types at this point and will continue to run solo without trailer for a while yet. So the sleeper is our main cabin. Spent 5 days in it over the labor day weekend and we feel we could easily do a 10 day run given the amount of driving we prefer.

Howdy Deezl Smoke,

Like I said in an earlier post for everyday practical reasons, my Freightliner was a better truck for RV purposes including passage between the seats and general cab space, if it had been able to carry a Smart Car, on the deck I would not have bought-built another truck.  The cost to rebuild the Freightliner to be able to carry a Smart Car, would have never been recovered when I eventually sold the truck so to me when I decided to carry the Smart Car, on the truck it made sense to sell the Freightliner, which I ended up selling for pretty much what I paid for it less the cost of the repairs I had put into it. 

As I was going to build a truck I thought I would build what I wanted not what someone else had built.  I remember three years a go I started a thread stating that I was thinking real hard about selling the Freightliner and building a classic truck that I KNEW would not be as practical for RV use but it would be the type of truck that "I" love, I decided then that it would either be a Pete 379, extended Hood or a Kenworth 900, extended Hood nothing else would be considered.  It took a year to find the truck I wanted and another six months to build it but I am HAPPY with it.  My aero Freightliner and the Volvo's are good trucks of that there is no doubt but as a life long gear head to me they just have no soul, they are an appliance that does a great job of moving freight but they have no style. 

I KNOW style is in the eyes of the beholder but to me nothing beats the LOOK of a classic "Hood" everything comes at a cost, that cost is something that has to be considered whenever a person does anything, I am 71 years young, I am a hot rodder of the old school, I don't plan on ever growing up no matter what age I live to so darn it I am going to enjoy my remaining driving years in the truck that "I" want and enjoy.  Hopefully when the time comes to hang up the keys I'll be able to find another person who will buy my truck who will enjoy it as much as I do and treat it well.  Here's a photo of my Freightliner, a great truck in its own right but which would you rather drive, the Freightshaker or the Pete?

DSCF3076-L.jpg

Dave

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5 hours ago, mr. cob said:

Howdy Deezl Smoke,

Like I said in an earlier post for everyday practical reasons, my Freightliner was a better truck for RV purposes including passage between the seats and general cab space, if it had been able to carry a Smart Car, on the deck I would not have bought-built another truck.  The cost to rebuild the Freightliner to be able to carry a Smart Car, would have never been recovered when I eventually sold the truck so to me when I decided to carry the Smart Car, on the truck it made sense to sell the Freightliner, which I ended up selling for pretty much what I paid for it less the cost of the repairs I had put into it. 

As I was going to build a truck I thought I would build what I wanted not what someone else had built.  I remember three years a go I started a thread stating that I was thinking real hard about selling the Freightliner and building a classic truck that I KNEW would not be as practical for RV use but it would be the type of truck that "I" love, I decided then that it would either be a Pete 379, extended Hood or a Kenworth 900, extended Hood nothing else would be considered.  It took a year to find the truck I wanted and another six months to build it but I am HAPPY with it.  My aero Freightliner and the Volvo's are good trucks of that there is no doubt but as a life long gear head to me they just have no soul, they are an appliance that does a great job of moving freight but they have no style. 

I KNOW style is in the eyes of the beholder but to me nothing beats the LOOK of a classic "Hood" everything comes at a cost, that cost is something that has to be considered whenever a person does anything, I am 71 years young, I am a hot rodder of the old school, I don't plan on ever growing up no matter what age I live to so darn it I am going to enjoy my remaining driving years in the truck that "I" want and enjoy.  Hopefully when the time comes to hang up the keys I'll be able to find another person who will buy my truck who will enjoy it as much as I do and treat it well.  Here's a photo of my Freightliner, a great truck in its own right but which would you rather drive, the Freightshaker or the Pete?

DSCF3076-L.jpg

Dave

A hunnerd percent understood and agree on the EXHD. Hence the reason I ended up with the 2005 379X I have. I used to have a white/purple FLD120, 12.7 DD. Though it turned in less than half the radius of my X, which is the truck's name, I just could'nt get that feeling of awe that a 379, or as you mention, a W900 give.

 I'm 56 and my gf is 54. We both love improvising our own inventions and love ever so much that we can say "we made that". Don't matter what others think, it's what we think that matters. As you can see from the photo of my X, it is improvised and under construction. But we love it.

 I'm not so sure a Volvo has no soul. A bone stock 379 or 900 does nothing more me than a fld120 etc. But a drop visored, unltra cab with stacks and a texas bumper?...........wood. I've seen some really cool graphic packages and ground effects on volvos that make them stand out and really look good.

 Is the front cowl under the windshield on you Pete fiberglass or aluminum? Mine is fiberglass and the wiper shaft support bumps have been broken. Looking for a fix.

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9 hours ago, Scrap said:

Can you guys put the KW stowable armrests that fold back on your Peterbilt seats?  I've never tried it but a National seat is a National seat...  They give quite a bit more width.

img_4194-768x576.jpg

 OMG !!! That is just what I need. Thank you very much for the picture and info that that is available. I try to be price conscience, but I am willing to pay for that option.  That is awesome.

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11 hours ago, mr. cob said:

Howdy Deezl Smoke,

Under the windshield on my cab is aluminum, I can’t remember where I saw it but one of the large custom truck parts shops sells a kit to fix your problem.

Dave

 Super. Thanks Dave. Then I will be making some calls today. I already tried Peterbilt and they only sell the whole cowl.

 Don.

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3 minutes ago, Deezl Smoke said:

Mr.Cob, Dave, just saw your truck on Suite Travels west coast rally video. NICE. Very nice.

Howdy Don,

It puts a grin on my face and that's all that really matters.  Thanks for the compliment, can you post up some photos of your truck and what you have done to it?  If your bored click this link it will take you to the photo gallery detailing the build of my Pete.

https://mr-cob.smugmug.com/My-2001-Peterbilt-379-RV-Hauler/

Dave

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 Dave, I dont have to be bored to see truck porn. d:-) I'll go to your site this evening when Cari (my gf) is with me.

 I only have a few pictures so far, and I do not have a hosting site anymore since photobucket went commie, so I'll have to put a few replies with small pics, but i will keep it to a minimum.

 Thanks.

 Don.

 Oh ya, I've been calling around the big rig shops looking for the fiberglass fix for the ww, but no luck so far. Maybe there is still a chance that a fix it kit would sell?

 When I got it back from having the commercial name and number taken off.

 

de-decalled.jpg

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