[Renegade3064]

Contemplating a 12 Valve swap. What kind of highway MPG's (70mph) can I expect from a 12 Valve in a 2000 F250 4x4 Crew Cab 8' Bed with 3.55 gears and an NV4500? This would be my ideal application, using the stock tire size and stock engine besides maybe a straight pipe turbo back 4" exhaust and BHAF. Any input would be greatly appreciated.

 

[chasewhite05]

from my research anywhere from 15-22 depending on the mods done,your driving habits and the terrain you drove

 

[Renegade3064]

Destroked thinks mid twenties with this setup. Just wanted to see what peoples real world experiences were. I drive mostly highway and like I said I'd like to keep it mostly stock besides intake and exhaust, but we all know how long that lasts

Anyone else?

Joe

 

[chasewhite05]

a 4 inch exhaust will def help keeping smaller tires will too(stock size) but i still doubt that you would get mid 20s unless your truck was a single cab 2wd.not trying to be a jerk but i plan to do this with my v10 cc/sb fx-4 and it wieghts about 8k.not to mention your added more wieght with the cummins,ive read they are a good 300 pounds more than a ps 7.3. add on the bigger gas tank and the extra 2 feet of bed space that you have it will add up.there is a 4 cylinder cummins that will net you that though.same thing as the 6bt just 2 less cylinders

 

[Renegade3064]

Thanks Im well aware of the 4bt I just really want the 6bt. Call me crazy but ive been able to find more 6bt's and at a cheaper price than 4bt's. I know the whole point of this thread was MPG's but I still want some power too. Everyone keeps saying a 4bt will be enough power but im not convinced. Yes I know they haul around delivery vans and such but have you ever driven one of those things? If I was doing a Ranger or half ton then yes I would entertain a 4bt, but for a 3/4 ton truck, I really feel the dirty dozen is the way to go. Maybe I'm wrong? Plus I think it will be easier to get parts later on if im using a dodge 12 valve, dodge clutch, dodge trans, etc. Even though I know alot of parts are interchangable. Im assuming to make the same power as a 6bt with a 4bt i'd have to increase fueling, which would decrease economy. A modded 4bt to achieve the same power as a stock 6bt would probably get around the same economy right?

 

[chasewhite05]

i agree with the 6bt as a better option but i have seen a guy running a 4bt in his superduty for mpg and he still tows with it but towing is the only time he reallyfeels a minor lack in power.he says hes getting anywhere from 25 and up which is your goal mpg wise so thats the only reason i suggested it.i myself decided to go with th 6bt though because the power/mpg plus i plan to mod mine to about 500 hp or so

 

[Renegade3064]

Im sure a 4bt would get the mileage I want and work just fine. I rarely tow anything. I just know i'll kick myself for not doing a 6bt if I ever want to add a bunch of power down the road like your saying. My only solution... build two trucks, one for MPG and one for power! :rock Haha I wish I had the cash for that. So you think 20 mpg would be feasable with the truck I mentioned above and a stock 6bt? I'd be happy with that.

 

[chasewhite05]

i think its easily attainable with that setup considering you keep your foot out of it.most guys ive talked to say they average about 18-20 regularly just cruising around.it will be hard though cause the low end grunt the cummins makes.are you doing the swap yourself or having it installed at a shop?

 

[Renegade3064]

I'll be doing it all myself with the help of fellow co-workers. Im a tech at a Mercedes-Benz dealer so I'll have all the equipment and tools I'll just be working on it after hours and on saturdays etc.

 

[neeltburn]

Not saying that staying stock isnt a good idea, but with the right P=pump mods, IE DVs and fuel plate coupled with the right size injectors, (say 5x12s) and a nice turbo with everything tuned correctly and timing set up right the neighborhood of seening 18- to low 20s mpg would be pretty easy.

 

[Renegade3064]

Nice! What kind of power do you think I could make while still staying in my 20 MPG goal?

 

[Renegade3064]

Bought a '99 regular cab V10 ZF5 4x4 with 3.73 gears. Hopefully I can locate a good engine soon for my 12 valve swap. Thanks for your help gents.

 

[neeltburn]

Nice! What kind of power do you think I could make while still staying in my 20 MPG goal?

Post up what you want to do with the truck in the 12valve dodge section and and the 12V guys can help you out. I still this mild build would net you close to a 20 MPG rig, but I am not sure what kind of numbers maybe close to 300HP

 

[04_6.0]

I am consistently getting 19-20 at 75mph. 4.10 with 35x12.50 tires. I have a 12v with he351 stock injectors, dv's, 3.5" exhaust and a finely tuned afc. Before I got the afc spot on I was getting around 17.