Bad milage cv713...

[Yenko boy]

Hello all, first I would like to say I did search and found some similar post on this issue but decided to start my own, and not grave dig plus didn't find all info i'd like. I have a 2005 Mack granite dump with 6speed auto love the truck the performance is just fine for what I need but the milage is now killing me. Because of the industry hear in Fl im having to drive longer distances to work and 4.70 mpg is starting to really hurt. I thought I red on here that there is an injector upgrade for these trucks that may help? How about different tunes? Basically im looking to increase this trucks fuel econnomy if possible so any tips in the right direction would be appreciated. Thanks...

Anthony

[Norway]

Anthony I have a 2005 Granite that was built at Hardee in FL. AI375A w/ Allison 6. Ft axle 18 / 20 tag and 44 rear, 4:64 ratio, on 22.5 rubber, with a 20 ft outer wheel base.

I haul Asphalt or other aggregates, so I'm loaded in 1 direction and empty on return. We are pretty hilly around here but not mountainous. I haul right at 77K GVW every run.

Last year was my first season with truck. This is where I'm at.....

I get 5.25 to 5.5 MPG. I use the button selector for the transmission ( 1st / 2nd / 3rd so on ) all the time. The sweet spot is at 1700+ RPM. To pull the hills here I will shift into 5th to keep up RPM's up and run at 1900 or whatever. Most trucks up here are spec by dealer to have 5:33's.

I will be adding the stage 2 injectors & Granite turbo from Rochester Fuel. They should arrive in the next couple days. Will be adding boost gauge and possibly going to a 5" exhaust or at a minimum replacing the factory muffler.

I get paid hourly but we can't really drag out feet. We drive into and around Boston everyday, heavy traffic. I try to stay above 55 but hardly ever over 65 when I can cruse. I'm hoping these improvements will help make the truck run easier not faster. I can get upto 75mph and she still got more but anything over 60 will start eating diesel like crazy. When I have to drive to get to a job or home I leave early and go 55 - 60mph.

There is other info on this web site about getting the 12B upgrade etc and I have done most of that and the truck still really struggles.

However, I really like the truck and the Allison. It's great for city driving, small streets and paving operations.

My truck will be heading to the shop next week. I will post back with how it runs. However, I won't have any fuel mileage for another couple months because of winter. Road construction just stops and there is no snow or sand / salt to haul..... Rob

Edited February 24, 2012 by Norway

[Yenko boy]

Thanks for your input Norway, my truck also has AI375A w/ Allison 6 Combo My truck sits on 24.5 Rubber. I will check into the 12B program and Throttle recalibration but seems after searching further on this site there are tunes that even surpass 12B's performance? But from what I read it's hard to get dealers to upgrade past this program? Also curious about your new turbo injector setup and how that will effect performance and milage anyone have any oppinions on that setup from Rochester Fuel? Thanks...

Anthony

[Norway]

Are you suppose to sit on 24.5 ? I bought a FL. truck because they are built heavy enough but don't have the rust like up here. What I notice is most FL's are sitting on 22.5 and that gets you to 65MPH at 1700 with 4:64. If your ended up with 24.5's but should have 22.5's that may not be helping your mileage.

I went with the engine improvement opposed to changing the carrier. Carrier swap at 5K and engine work 4K. It's not saving the thousand so much as, my engine really doesn't come alive until I get well past 1700RPM and I'm hoping that the increased HP will allow me to back off the RPM's.

[Mackpro]

On our CV's around here with manual transmissions they get 5.2- 5.4 overall at best. I think it's the AI engine that's the problem. The RD's and first CV's with the regular ETECH engine seems to get better MPG. We have 5 or 6 CV's here with Allison automatics in them but I have never checked the MPG on them.

[Norway]

Got the turbo and injectors today. The Turbo is something else....

[Yenko boy]

Looks massive........... Interested in knowing the results after you drive it please stay in touch .

Anthony

[Norway]

Hopefully will have truck running on the road by the beginning of the week. The extras.... When replacing injectors it's recommended to replace injector lines. I was able to upgrade the exhaust to 5", turbo to tip, with all off the shelf parts from our local Grand Rock supplier. Will post back with more info and pictures when I get the truck back.

[Olivetroad]

That turbo looks like a backpack leaf blower! Impressive!

[Mackpro]

Hopefully will have truck running on the road by the beginning of the week. The extras.... When replacing injectors it's recommended to replace injector lines. I was able to upgrade the exhaust to 5", turbo to tip, with all off the shelf parts from our local Grand Rock supplier. Will post back with more info and pictures when I get the truck back.

I found that the first CV's had a 5" turbo exhaust pipe all the way down to the very end of the pipe where it then necked down to 4", this necked down part could be trimmed off to allow for 5" flex pipe to be slid over. The later CV's some with ETECH's and all with AI's (like yours) had the turbo pipe neck down to 4" an inch or two behind the turbo. I finally came across a CV with the 5" pipe and got the VIN and looked up the part and Mack still has it instock but it's $500 and is drilled for pryo sensor. Would like to see your 5" setup before I gather up all the parts for my buddies CV 5" high flow system. I did find some 5" in/out high flow mufflers that are the same size as the stock muffler.

[Norway]

The GR pipe at the turbo was a $130 or so pipe including the pyro inlet. It wasn't listed for the Granite but it slid right in. I will post parts when I get truck back.

We used a Walker muffler $70, that was 5 in and 5 out. Two problems here were.... Need a new heat shield $170, stainless, because the new muffler is 10". We neded to get 2 extra heat shield bands to secure the new muffler (10") to the side of the cab in existing factory mounts. Bands will need slight fabrication to make work. I have about $700 in parts for the exhaust system.

Rob

[Mackpro]

The GR pipe at the turbo was a $130 or so pipe including the pyro inlet. It wasn't listed for the Granite but it slid right in. I will post parts when I get truck back.

We used a Walker muffler $70, that was 5 in and 5 out. Two problems here were.... Need a new heat shield $170, stainless, because the new muffler is 10". We neded to get 2 extra heat shield bands to secure the new muffler (10") to the side of the cab in existing factory mounts. Bands will need slight fabrication to make work. I have about $700 in parts for the exhaust system.

Rob

You dont know the part# of that Grand Rock pipe or know what model it was for ? Thanks

[Norway]

Deleted.... multiple postings

Edited March 16, 2012 by Norway

[Norway]

Deleted.... Multiple posts

Edited March 16, 2012 by Norway

[Norway]

Picked up the truck today. I was planning on posting all the part # etc but can't find a couple receipts. This is what I have and I will post back late tomorrow.

Muffler, Walker W22920 5x10x51"

Heat Shield Grand Rock MG1048RS, comes with 2 band clamps in box. ( stainless, still has wrap on )

You need to get 2 extra heat shield band clamps for the to secure the larger muffler to the cab mounts. Bracket # GR MG10ZBRKT ( double check that part )

You need 4 X 5" 90's to make bends in rear by cab. They will go in the exactly the same route as the stock pipe. There is the piece of 24" flex pipe and the pipe to the turbo.

I got some self stick heat shield for fire wall. Pipe wrap for turbo pipe and a boost gauge from Summit Racing. To wrap that front pipe you need less than 1 roll 2" X 50' foot of wrap.

I had a hour+ ride back from the mechanic. Highway and rural road. I'm happy so far. This is without a load but, the truck pulls great. I was able to set truck on cruise control and just roll along the highway. On rural roads I never felt as if I had enough power when it up shifted and the RPM's dropped to 1000 or 1200. Now she just pulls right along and back up to speed nicely.

Sounds good too. Little bit loud, but the muffler is strait through, no restriction and no potential for soot build up.

Turbo pipe... It's for the CH and the GR # should be MK4946

3/16/12 Hauled a couple loads today at 22 tons. Two hours round trip each. I got to drive in a direction where the highway hills used to bog me down to 35 or 40, regardless how fast I went into them. Felt like I was barely going to get over the top. I started them at 55 to 65 mph intentionally to see how she'd pull. I did do some manual shifting to lock it into 5th but was able to easily maintain speed. With the back roads I had the same outcome. Stop lights at bottom of hills, and she'd pull right up them. I was doing this with out mashing down on the gas. When she'd up shift and end up at 12 to 1400 she still had power to keep pulling.

I did have 1000F pyro temps. This is higher than I used to get. I not an engineer but I'm guessing that if you do the injector / turbo upgrade you seriously consider the exhaust upgrade at same time.

The belching black exhaust leaving stop lights is all but gone too.

When I get some MPG info I'll post back. Our season is still a few weeks away so it might be a while.... Rob

Edited March 16, 2012 by Norway

[Norway]

I found the exhaust to be too close to the fire wall. The indent in the exhaust pipe doesn't quite line up where it should be. The larger turbo exhaust sits outboard more than factory. While the pipe is off you could change the position of the indent or you can nip the corner of the firewall. Once once turbo is installed the pipe isn't coming back out so I nipped and painted.

[Yenko boy]

Thanks for the updates....

[Norway]

Have put about 500 more miles on her. Things are good.

The Walker muffler is REALLY loud. Not to bad with the windows up and A/C on but....Windows down...... Right now I operating under "Loud Pipes Saves Lives" for when I'm in the City with pedestrians. I would suggest looking into the mufflers from Pittsburgh Power ? I will likely change mine out when I see some $$$$ from the boss.

[Yenko boy]

Are mpg's looking the same if not better? Truck run any hotter/cooler?

[Norway]

MPG. Have put on very few miles (600 total) but they seem to be better. Don't have my log book with me but these are about 180 mile days. 2 days were hauling 1 way one. They were 5.8 mpg and 6.0. The 3rd day I hauled loaded both directions and got 4.8. I think I will be able to squeak better MPG once I get use to the new set up.

I still use the button on the automatic but not nearly as much and able the run at slightly lower RPM's in general.

Heat. The pryo definitely climbs higher on long pulls but stays below the red 1000 to 1100F. Most of the time still in the 700 - 800 range. Radiator / antifreeze runs a bit hotter but doesn't make the fan cycle any more often, possibly stays on a bit longer during a cycle. Engine oil around 200 to 220, same. Transmission the same.

It has been unusually hot around for here 78-84F so this has been a good test for the summer to come.

3/28/12. Have run some more miles. Starting to average around 5.75.... so I'm up some.

Edited March 29, 2012 by Norway

[Norway]

Wanted to post an update. Truck has been running great. Have had no problems with the new injectors or turbo.

As far as mileage goes ?

That is a tough call. I've been doing road patch work and the mileage has dropped back to just below 5MPG however if you look at it from a gallons per hour point of view I'm probably around 3 GPH.

In general I'd have to say that consumption has improved.

It certainly hasn't gotten worse and it's a real pleasure to drive.

[lucerne tractor]

Thanks for the updates, been talking to Rochester Fuel today, thinking stage two injectors and the turbo for the Vision. They said a customer, who is in love with his upgrade"stage 3 and turbo" had a pyro heat problem, getting a little hotter then he wanted, he crimped the waste gate line and it improved alot, they said if I have it done in their shop they can set the waste gate for me. I think it's something I'm going to do soon. Love the truck, just need more for the hills, even 1 more gear from the 18 spd would be great. I think I'll stick with stage 2 though.

[Norway]

I could see how stage 3 would cause a problem. My stage 2 with an upgraded exhaust will still bring up the pyro. I have not had it redline, but could see how it would be possible.

Good luck with whatever you decide. Rob