my sct and gas milage
Administrator
Joined: Apr 2010
Posts: 87,550
Likes: 4,230
From: Clayton MI
what size tires? It seems many people dont understand the gears mean nothing without combining them with a tire size to produce a final drive ratio....3.55 gears and smaller than stock tires can have the same effect as say 33" tires and 4.56 gears...and your engine wont be able to tell tha difference between stock gears and tires and say 35" tires and 4.56 gears...the final ratio is the same one compensates for the other.
I use torque pro and havent had good results with accurate mpg reading...I guess I have to double check my settings...
Another member here "Beeker" recently had a half a dozen dyno runs done both with factory death flash and with different sct tunes ... the highest HP gains that were had were 4hp with the 93 tune and I believe like 20 lbs of torque and the power curve is almost identical....... It has been proven on a dyno that you can get up to 7hp gains just by replacing worn champion plugs with new colder autolite 3923 plugs.(according to a thread I read here posted by silverbullet a few years back)... The plugs would be the smarter choice at under $20...or at least a properly functioning CAI which also averages 3-7 hp gains depending on vehicle and stock setup.
how much money do you save if you spend more on 93 octane vs 87 at the cost of 1 or 2 mpg? thats anothoer question you have to ask... most power mods arent going to do wonders for mpg....
I have newer generation 3 bosch injectors coming in that spray a wide fine mist instead of the straight liguid sqiurt like our old style stock injectors....many on the jeep forums report averages of 2-4mpg increases due to better fuel atomization since the engine wont burn the liquid well and pushes it out the exhaust for the cat to burn... the trick is not to go too big on injector size...(I've read about the fuel supposedly hitting the back of the valve and all being turned to vapor for the engine to use but I'm skeptical on how efficient this really is.. especially since its an abandon technique no longer used by dodge... I guess I'll have to calculate my own results and see what happens...
I use torque pro and havent had good results with accurate mpg reading...I guess I have to double check my settings...
Another member here "Beeker" recently had a half a dozen dyno runs done both with factory death flash and with different sct tunes ... the highest HP gains that were had were 4hp with the 93 tune and I believe like 20 lbs of torque and the power curve is almost identical....... It has been proven on a dyno that you can get up to 7hp gains just by replacing worn champion plugs with new colder autolite 3923 plugs.(according to a thread I read here posted by silverbullet a few years back)... The plugs would be the smarter choice at under $20...or at least a properly functioning CAI which also averages 3-7 hp gains depending on vehicle and stock setup.
how much money do you save if you spend more on 93 octane vs 87 at the cost of 1 or 2 mpg? thats anothoer question you have to ask... most power mods arent going to do wonders for mpg....
I have newer generation 3 bosch injectors coming in that spray a wide fine mist instead of the straight liguid sqiurt like our old style stock injectors....many on the jeep forums report averages of 2-4mpg increases due to better fuel atomization since the engine wont burn the liquid well and pushes it out the exhaust for the cat to burn... the trick is not to go too big on injector size...(I've read about the fuel supposedly hitting the back of the valve and all being turned to vapor for the engine to use but I'm skeptical on how efficient this really is.. especially since its an abandon technique no longer used by dodge... I guess I'll have to calculate my own results and see what happens...
Keep us posted please.
Champion
Joined: Aug 2009
Posts: 3,015
Likes: 8
From: Western NY,
they just arrived in the mail and are the bosch "703's " I was hoping they were which the jeep guys use on the 4.0 and magnum 5.2/5.9 in the cherokees...
I'm interested in this as well keep us updated
Legend
Joined: Jul 2007
Posts: 7,843
Likes: 13
From: DFW, Texas
Hemifever's tunes are based on the octane you run. The 93 octane is meant to be max performance, not max MPG. Even if you try to baby the 93 tune you won't get good MPGs, that's not what he wrote it for.
The 87 octane tune is written specifically for MPGs, the performance bonus is a removal of torque management and taking out the leeway that DC left in the stock tune, which is why Hemi's tunes will ping if the plenum is blown.
If you want mileage, go with the 87 octane tune. Honestly, unless you're a red light racer or a track truck, go with the 87 tune.
Though I will admit the 93 octane tune is just like crack cocaine, once you try it, you're hooked.
The 87 octane tune is written specifically for MPGs, the performance bonus is a removal of torque management and taking out the leeway that DC left in the stock tune, which is why Hemi's tunes will ping if the plenum is blown.
If you want mileage, go with the 87 octane tune. Honestly, unless you're a red light racer or a track truck, go with the 87 tune.
Though I will admit the 93 octane tune is just like crack cocaine, once you try it, you're hooked.
Champion
Joined: Aug 2009
Posts: 3,015
Likes: 8
From: Western NY,
ok 703 injectors are in and it runs.(Idles fine so thats a good sign) ..I cant test drive today because I have to finish tightening the valve cover down I took off to check the valve spring and I have dinner plans...I will report my findings on the other thread that was discussing the whole injector replacement thing a couple days ago rather than Hijack this one any further...A soon as I find it I'll post a link here...https://dodgeforum.com/forum/2nd-gen...ml#post2719522
Last edited by Augiedoggy; Feb 15, 2012 at 06:18 PM.
Champion
Joined: Jun 2004
Posts: 2,811
Likes: 2
From: Ft Campbell, KY/TN
retard your fuel synch by 2*. Mopar advanced the fuel synch because the injectors were pencil type and did not spray a mist. WHy? Because if the fuel is sprayed down a runner with the intake valve CLOSED, it will hit that valve (which is hot) and help atomize the fuel.
Since you are getting injectors that do not need the hot valve, you can actually get better gas mileage by making the injectors fire 2* slower (retarding).
I have been meaning to do that, but I don't have the scanner and i don't really trust guys at a shop to ACTUALLY do it. Plus, it might break something.
With Bosch genII 24s (4 hole pintle, not disc like the IIIs) I get 11 city and 16 HWY. The sticker on my 2001 says 12 city and 14 HWY. So I am not that far off.
WHen our trucks are inefficient:
1. Severe stop and go city driving under 40 MPH. If you have 12 turns to make when driving 3 miles to work and half are at stoplights, you are gonna get about 9 MPG.
2. Driving over 65-70 MPH. Gas mileage goes from about 15 all the way down to 11 MPG or lower (the faster you go). That is what my instant economy outputs from my screen because my truck has that option.
3. Anything over 2500RPM from a stop will burn gas. If I floor my truck, my instant economy output is about 3.5MPG. If I am traveling at 2500 RPM from a stop it is about 9MPG.
Driving habits have more to do with gas mileage than anything else.
I will say this:
After getting my SCT, I went from 8.9 MPG to 11 MPG. I am getting 9.7 MPG right now because I warm up my truck a bit. I forget to plug in my engine block heater when I wake up most days. So that is getting me.
i just put on my 87 tune and filled up with 87 gas, prob havnt put 87 in for about 2 years now . just out of curiousity
and now i remember why i have never done this. it seriously feels like i put on a 3000 pound slab of concrete to the back of my truck. i cant even break my tires loose from a stop as with the 91 or 93 tune i can fry to 4 k and and it will grab and go like a bat outta hell.
its even hard to burn em coming outta a corner. so imma finish off this tank and reinstall 93 gas and 91 tune. summer time good to use 93 on 93 but when its slippy and near freezing i try and not be a lead foot .
i couldnt imagine if i put on my stock files with the death flash :0
i know when i sell my truck i will have them test drive it on 93 and give it too them stock lmao. they will be like i thought this truck had more power than this
good selling point
and now i remember why i have never done this. it seriously feels like i put on a 3000 pound slab of concrete to the back of my truck. i cant even break my tires loose from a stop as with the 91 or 93 tune i can fry to 4 k and and it will grab and go like a bat outta hell.
its even hard to burn em coming outta a corner. so imma finish off this tank and reinstall 93 gas and 91 tune. summer time good to use 93 on 93 but when its slippy and near freezing i try and not be a lead foot .
i couldnt imagine if i put on my stock files with the death flash :0
i know when i sell my truck i will have them test drive it on 93 and give it too them stock lmao. they will be like i thought this truck had more power than this
good selling point
Champion
Joined: Aug 2009
Posts: 3,015
Likes: 8
From: Western NY,
i just put on my 87 tune and filled up with 87 gas, prob havnt put 87 in for about 2 years now . just out of curiousity
and now i remember why i have never done this. it seriously feels like i put on a 3000 pound slab of concrete to the back of my truck. i cant even break my tires loose from a stop as with the 91 or 93 tune i can fry to 4 k and and it will grab and go like a bat outta hell.
its even hard to burn em coming outta a corner. so imma finish off this tank and reinstall 93 gas and 91 tune. summer time good to use 93 on 93 but when its slippy and near freezing i try and not be a lead foot .
i couldnt imagine if i put on my stock files with the death flash :0
i know when i sell my truck i will have them test drive it on 93 and give it too them stock lmao. they will be like i thought this truck had more power than this
good selling point
and now i remember why i have never done this. it seriously feels like i put on a 3000 pound slab of concrete to the back of my truck. i cant even break my tires loose from a stop as with the 91 or 93 tune i can fry to 4 k and and it will grab and go like a bat outta hell.
its even hard to burn em coming outta a corner. so imma finish off this tank and reinstall 93 gas and 91 tune. summer time good to use 93 on 93 but when its slippy and near freezing i try and not be a lead foot .
i couldnt imagine if i put on my stock files with the death flash :0
i know when i sell my truck i will have them test drive it on 93 and give it too them stock lmao. they will be like i thought this truck had more power than this
good selling point
I guess 20 lbs of torque makes more of a difference than I thought....
