What kinda fuel milage have you guys gotten from a 12 valve and what was done to achieve this milage. I am about to put a 12 valve in an 04 F350. Don't care about a lot of HP, just want to know what is the best set up for getting the best milage. If I could get 250hp to 300hp it would be nice, but depending on milage, hp is optional. The 12 valve is in a school bus. It has a P7100 pump. Also wonder if the turbo on it is usable for the swap. Thanks for nay advice.
Best combo for MAX fuel milage.
- Thread starter AllanB
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kawi600
got Coal for Christmas
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my advice is to stay away from oversize gaskets (swap heads or cut seats if you have to), cams and large turbos. Porting too.
a cam may cause the valves to ramp up faster which means less duration of that period were the small opening causes high velocity and swirl. Porting the intake might cause lower velocity too. Probably not with stock valves and cam, but thats a weird combo.
an oversize gasket will only increase the squish a tiny bit, but if it lowers compression it lowers the heat and tends to make the truck a dog on the low end of the rpm range.
anything you do that raises fueling has a chance to screw up mileage.. depends if you have the air to burn it all even at part-load operation (tooling around in city traffic).
Not sure where youre at, but be careful of emissions laws, you wont have a working OBD for them to plug into.
a cam may cause the valves to ramp up faster which means less duration of that period were the small opening causes high velocity and swirl. Porting the intake might cause lower velocity too. Probably not with stock valves and cam, but thats a weird combo.
an oversize gasket will only increase the squish a tiny bit, but if it lowers compression it lowers the heat and tends to make the truck a dog on the low end of the rpm range.
anything you do that raises fueling has a chance to screw up mileage.. depends if you have the air to burn it all even at part-load operation (tooling around in city traffic).
Not sure where youre at, but be careful of emissions laws, you wont have a working OBD for them to plug into.
95ram
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It's not necessarlily state law/emissions you have to worry about, it's federal. Now I relize they more than likely aren't going to bother you, but by putting the older motor into your 04, legally you have to meet 04 emmisions standards. Just some food for thought.
couple questions about truck. auto or stick? 2wd or 4x4? what cab setup?
thanks for the info hope mines that good when I get it done. one more question what kind of speeds do you run getting that mileage
TxDiesel007
Uncommon CR problemed
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stock on my 95 is great
about 25 mpg at 70, but its a two door long box... my old 12v had a small set of twins, and with 16.5 degrees and 181s get about 22 on the highway...
about 25 mpg at 70, but its a two door long box... my old 12v had a small set of twins, and with 16.5 degrees and 181s get about 22 on the highway...
crazyrunner33
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The best way to increase fuel economy is to change driving habits, in my '96 12v stock and 300k it would get 18-20 at 70-75 mph, but at 60 mph it'll get up to 24 mpg. My half ton with a 318 will get 14 mpg flat at 75 mph, but it'll get 19 at 60. With that said we'll talk about mods to the truck.
1) Tires: Tall skinny tires aired up to the max, like 235 85 16 with a highway tread. They'll have less rolling resistance and less aerodynamic drag, even with the highway terrain they'll outperform 275 all terrain tires in the snow due to the greater pressure on a smaller area.
2) Injectors: Stock injectors are fine, but it wouldn't hurt to have them cleaned and have them pop tested. I've personally had luck with DDP3 injectors, but I'm looking at some 5x14 injectors with the correct spray pattern in order to safely run higher timing.
3) Timing: Anywhere between 16 and 22 degrees will have the potential for greater fuel economy. If still running the stock head bolts it would be safer to run around 16 unless if you over tighten the bolts like some people do.
4) Tuning the AFC: If you have amazing self control and take 30 seconds to accelerate to 60 mph then there will be no gain from tuning the AFC. I've personally found that backing the preboost screw and tightening the AFC enough to where there's barely a haze under hard acceleration to be the optimal setting. The plate position should be at a position to allow enough fueling for the boost you want to run without overfueling it, but if you're foot is pushing the pedal enough to hit the plate then fuel economy will take a hit.
5) Turbo: The current turbo will work, but an S300GX or S256 will have a better and more efficient design and would be perfect for your horsepower goals. They'll also help out while towing since your EGT will be a little cooler.
That's pretty much it, there's a few other maintenance items that'll help like making sure there a healthy supply of fuel pressure, putting in new fuel filters, changing the overflow valve, better fluids in the differentials, a cold air source for the air filter rather than a filter in the open drawing in warm air. Then there's aerodynamics and dropping weight. From personal experience we've have seen an increase in fuel economy from a port and polish along with a stock marine cam on my father's '97.
1) Tires: Tall skinny tires aired up to the max, like 235 85 16 with a highway tread. They'll have less rolling resistance and less aerodynamic drag, even with the highway terrain they'll outperform 275 all terrain tires in the snow due to the greater pressure on a smaller area.
2) Injectors: Stock injectors are fine, but it wouldn't hurt to have them cleaned and have them pop tested. I've personally had luck with DDP3 injectors, but I'm looking at some 5x14 injectors with the correct spray pattern in order to safely run higher timing.
3) Timing: Anywhere between 16 and 22 degrees will have the potential for greater fuel economy. If still running the stock head bolts it would be safer to run around 16 unless if you over tighten the bolts like some people do.
4) Tuning the AFC: If you have amazing self control and take 30 seconds to accelerate to 60 mph then there will be no gain from tuning the AFC. I've personally found that backing the preboost screw and tightening the AFC enough to where there's barely a haze under hard acceleration to be the optimal setting. The plate position should be at a position to allow enough fueling for the boost you want to run without overfueling it, but if you're foot is pushing the pedal enough to hit the plate then fuel economy will take a hit.
5) Turbo: The current turbo will work, but an S300GX or S256 will have a better and more efficient design and would be perfect for your horsepower goals. They'll also help out while towing since your EGT will be a little cooler.
That's pretty much it, there's a few other maintenance items that'll help like making sure there a healthy supply of fuel pressure, putting in new fuel filters, changing the overflow valve, better fluids in the differentials, a cold air source for the air filter rather than a filter in the open drawing in warm air. Then there's aerodynamics and dropping weight. From personal experience we've have seen an increase in fuel economy from a port and polish along with a stock marine cam on my father's '97.
Here are the thoughts from someone who drives a lot of miles and has to pay for his own fuel.
Not all cams are competition. I have a PDR cam installed that gave me a solid 1-2 mpg increase. It will pay for itself in approx 40k miles.
The increase in mileage when timing the pump is directly proportional to the engine RPMs you normally operate at. More is not always better. 16 or more degrees will hurt you if you normally operate under 2000 rpm. Turbo spoolup (talking HX35 here) will be sluggish and stop and go driving will be a chore. If your speed of choice puts you in the 2000 to 2200 rpm range, then 16, and possibly more, will work better than stock to 15. I have my own tools and have tried quite a few settings. For my driving style (2000-2100 rpm empty, 1700-1900 rpm loaded) I have found that 15* gives me the low end spoolup I need and the best mileage. Approx 62% of my miles are towing.
As previously noted, your foot is the best tool to increase mileage. Being the first one off the line and the last one to let off the throttle when coming to a stop will cost you. If you have to replace your brake shoes often you are wasting fuel. If 75 mph makes you feel good, then you need to feel good about the profits the oil companies are harvesting.
Not all cams are competition. I have a PDR cam installed that gave me a solid 1-2 mpg increase. It will pay for itself in approx 40k miles.
The increase in mileage when timing the pump is directly proportional to the engine RPMs you normally operate at. More is not always better. 16 or more degrees will hurt you if you normally operate under 2000 rpm. Turbo spoolup (talking HX35 here) will be sluggish and stop and go driving will be a chore. If your speed of choice puts you in the 2000 to 2200 rpm range, then 16, and possibly more, will work better than stock to 15. I have my own tools and have tried quite a few settings. For my driving style (2000-2100 rpm empty, 1700-1900 rpm loaded) I have found that 15* gives me the low end spoolup I need and the best mileage. Approx 62% of my miles are towing.
As previously noted, your foot is the best tool to increase mileage. Being the first one off the line and the last one to let off the throttle when coming to a stop will cost you. If you have to replace your brake shoes often you are wasting fuel. If 75 mph makes you feel good, then you need to feel good about the profits the oil companies are harvesting.
golfersmith
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Good to see you over here Gary. Did you replace the turbo yet?
Thanks for the info
Yeah I found the thread. Good read, thanks
Thanks for the info.
That is some good info.
I found out about the driving habits a while back. I had some kin folk in the hospital. The hospital was about 90 miles away. Me and my father in law were driving the same car back and forth. I would fill the car up and drive there and back, then have to fill it up again about 30 miles prior to getting home. Everytime I would get in the car after him it would be on a 1/4 tank. So finally I had to tell him, why is it when you stop, you only put a little fuel in the car and I fill it up for you. He said he wasn't stopping at all to get fuel. I said you are crazy, no way you can drive all that way without filling up, I have to stop about 30 miles before I get back. He said I drive the same route as you but I drive 55mph (were as I was hitting about 75mph). Well after a 30 minute arguement, I decided to try it his way. Long story short, I had to appoligize for calling him crazy. I had a 1/4 tank left when I got home.
Thanks again to all of you for the advice and tips.
Thanks. I've replaced it with a HX-35 hybrid, only about 150 miles on it but so far-so good. It looks like I'll be back on the job next week to put it to the test.