What if anything is wrong w/ my truck?

[Jmoore1225]

Ok, so truck spun a main back in April. Several thousands of $$ later I have a new long block & 8 new injectors. Truck to me runs great, I have no other basis to compare it to as its the only 6.4 I've ever been in. It's the fastest, strongest diesel I have been in, all my friends have cummins & duramax's & older Fords.

My concern is my MPG's!! Reading around on this forum & others, it seems the norm for a tuned truck is to average 14-16 around town & even better on the highway! All I can get out of mine is low 12's & maybe 13's on the highway. Averaging 320-340 miles a tank? Most I have ever got the tank to take was 25 gallons. This is all driving conservatively!!! 1 other thing is I see all these guys talking about how easy their trucks will light up the rear tires. I have never floor boarded it from a dead dig, but from a 5-10mph roll its never lit the tires up. Starts to but always ends up hooking up. Do I seem down on power?

I'm running Gearhead hot street, 4inch turbo back, AFE CAI, ARP's & full EGR delete. 35's on 20's & 3.73's. All my gauge #'s are & stay where they should be. Could possibly use some insight on where FRP should be reading on an SCT, say cruising @ 70 @ 50-55? W/ full throttle & converter locked it spikes to 170's & drops & holds in the 160's. Also fuel filters have maybe 1,500 miles on them before I'm told to check those.

Do I have any cause for concerns, anything I could diagnose? Or am I just over reacting? I just want the truck to be right!!! Sorry for such a long post.....

 

[Cory S]

thats about the same as what i get

 

[BBottoms]

I get about 13.5-14 on average, 15.5 is the best i've seen on the highway running 75ish. Running gearhead race.

 

[91turbogsx]

I can get the lie-o-meter to read over 20 after a long trip and consistently get 500-550 miles out of a tank. Spartan 310 tune, 3.73 gears, on 35's.

 

[MINK]

Sounds fine to me.

 

[Jmoore1225]

What makes these trucks so inconsistent across the board? I understand w/ a new long block I won't see optimum MPG's. W/ the beating the previous owner seemed to give the long block that spun the main, I'm sure my trans is sub par as well. I have yet to take a long trip w/ out towing anything, so I have no basis on what I'm really getting on a highway run.

91turbo, what about your trucks ability to break the tires loose?

 

[MINK]

What makes these trucks so inconsistent across the board? I understand w/ a new long block I won't see optimum MPG's. W/ the beating the previous owner seemed to give the long block that spun the main, I'm sure my trans is sub par as well. I have yet to take a long trip w/ out towing anything, so I have no basis on what I'm really getting on a highway run.

91turbo, what about your trucks ability to break the tires loose?

Traction bars and built trans, rolling burnouts no problem - I also have hard azz and wide atzs.

 

[BBottoms]

Long bed trucks have bigger fuel tanks (38 gallon instead of 30, I think?) So don't take his miles per tank as a goal. I would love to get 500 mile out of a tank in my shortbed, but that would be 20mpg with my typical 25 gallon fill up!!

 

[Jmoore1225]

Long bed trucks have bigger fuel tanks (38 gallon instead of 30, I think?) So don't take his miles per tank as a goal. I would love to get 500 mile out of a tank in my shortbed, but that would be 20mpg with my typical 25 gallon fill up!!

Ya, I took that into consideration!! Traction bars are certainly on my list, especially since I tow my boat 10-12k lbs on hot street.

Thanx for easing my mind guys!! I love this truck but it makes me a nervous wreck... Haven't even owned it a full year yet!!

 

[cory151]

Will it spin the rears from a dead stop? If Im doing anything under 25mph and stomp it the rears go up in smoke. Having said that Ive not seen many 6.4s lighter than my work truck. If you want to know how the truck truly performs take it to the track for test and tune. If your best runs arent in the low 13 sec there may be an issue.

 

[jdgleason]

There's more left on the table with tuning. Might try the race tune and see if mileage changes, and i'm sure you will be able to light the tires up at that point as well.

 

[Jmoore1225]

Ya, motor is still "new" not wanting to beat on it that hard.... I have never just put it to the floor @ a dead stop. From a deent roll it wants to break them loose, they just don't roll smoke. The Nitto's are very, very sticky & it seems its always on a good rough service as to nothing like fresh blacktop!!

 

[Jmoore1225]

There's more left on the table with tuning. Might try the race tune and see if mileage changes, and i'm sure you will be able to light the tires up at that point as well.

I have race stored on the computer, purposely didn't put it in the tuner as not to be out beating on it!! Just basing things off what I've been reading about people running hot street.... I'm just a noid having to replace a long block & injectors not even 6 months into owning the thing!

 

[Strokin6.4]

My truck ran 12.4 and if I'm doing over 10mph I can't get them to spin with my terra grapplers. When I have super swamper sts' on though it will spin easily at higher mph.

Sent from my SCH-I535 using Tapatalk 2

 

[Jmoore1225]

My truck ran 12.4 and if I'm doing over 10mph I can't get them to spin with my terra grapplers. When I have super swamper sts' on though it will spin easily at higher mph.

Sent from my SCH-I535 using Tapatalk 2

Same tires I've got... They sure are tacky!!! Under 20 or so if I romp it, they'll try to break loose but always end up catching. Nice to know.

 

[Dustball8504]

My Gearhead Hot Street got right under 18mpg running 80mph on the way to TS this past spring for reference. This tune always seemed to do 14-15 on normal driving for me which is backroads and a good bit of hills mixed in.

 

[madman1234509]

The most Ive ever really been able to put in my tank from E was 25 gallons, and that was sitting there for an extra 5 minutes squeezing every little bit I could in the tank, slowly to avoid foam. I recently went from where I live, Mayfield, NY to Washington DC. Down I81, the trip one way was approx 450 miles. I filled up and squeezed 23 gallons into my tank. Made it to my destination in DC with "7 miles left to E". Now if you take into account that I may have had a gallon of fuel in my tank when I filled it. 24 gallons for 450 miles in a 8000lb+ truck with 3.73s, 35" tires, 2.5" lift, 3 people. Id say its not too bad. This was on the 275 LL tune from spartan at 75-80 mph. Anything over 75mpg and my mileage drops. 310 tune I get a tiny bit better mileage highway, but around town its worse.

 

[Jmoore1225]

My Gearhead Hot Street got right under 18mpg running 80mph on the way to TS this past spring for reference. This tune always seemed to do 14-15 on normal driving for me which is backroads and a good bit of hills mixed in.

How much do you think your 71 atmo had to do w/ this? A lot of my driving is 10-15 miles 1 way in the city. Which I know is putting a big hurt on MPG's. I just need to make an excuse to go for a nice long drive & see how it's does!!

 

[Dustball8504]

How much do you think your 71 atmo had to do w/ this? A lot of my driving is 10-15 miles 1 way in the city. Which I know is putting a big hurt on MPG's. I just need to make an excuse to go for a nice long drive & see how it's does!!

71mm Atmo was not on the truck going to TS, it had a Batmowheel in the stock atmo charger though. I don't think that had anything to do with mileage though. We ran Xrace on the way back for a comparison and didn't even get 14mpg running the same roads back.

 

[superstroked]

How much do you think your 71 atmo had to do w/ this? A lot of my driving is 10-15 miles 1 way in the city. Which I know is putting a big hurt on MPG's. I just need to make an excuse to go for a nice long drive & see how it's does!!

You will be very happy to see the mileage once you get it out on the road. Stop and go at 7500-8000lbs is not going to be economical or efficient in any sense of the term.