Jus a real quick question for the vets on here. What kinda gas milage r u guys seeing. I have a twin 50s bulleyse 5.4 dohc b headed mustang with a 5 speed and 3.73 gears. i think im only gettin maybe 13 to 13.5 miles to the gallon im pretty sure that sucks but dont the pick up trucks have better milage then that i could be wrong.
so im gonna get it tuned in the spring but was wondering what can i do to get atleast 17 beside keeping my foot out of the gas pedal? is it possible to get 22-25 mpg maybe im dreaming

 

my 02 f250 5.4 only gets about 11mpg around town and 14 highway. its all stock tire size and all

 

Take the turbos off and put it back to stock. You now this shit just drives me crazy , you hang twin turbos on your mustang to get all of this power then you bitch about the gas mileage. I have twin 60s and don't really give a shit if it gets 5 mpg as long as it makes the power im looking for, i didn't drop 20 grand to get good mileage i did it to go fast.

 

i understand what you saying i have tons of fun with the car i jus thought maybe i can tune for a lil better gas mpg it takes me almost a half a tank to go about 80 miles i thought that sucks and thats not under boost thats cruising at 2300-2700 rpm

 

I am getting low 20's, 4.6 sohc 540 at the wheel. I was getting mid to upper 20's but the non lock up converter knocked it down a bit.

 

LMAO
I will have to agree.............lol :lh:

 

You guys are being too hard on the man. I would say I don't care about milage either and would put a big block in a car in a heartbeat; however if I were getting 5mpg out of it I would be concerned because I would know something was not right. 13mpg in a car with a 5.4L is terrible and something is wrong. What is the rest of the car? trans, gearing, is the longblock modified, etc

 

its a dohc 5.4 with a 5spd and 373 gears. He's not going to get good mpg without the turbos let alone with. If he wanted 20+ he should have went with am lsx motor.LOL

 

B headed, forged internals stock cams, stock heads flattop pistons twin turbos bullseye 50s. 5 speed t45 which ain't gonna last very ong 3.73 gear all this in a 99 mustang v6 body which have lighter seats empty trunk full front suspension. I'm not complaining about it I was jus wondering if something was wrong I'm talking 13 highway mpg

 

What about fuel managment -stock ecu, what inj. and what maf?

 

Nothing is jumping out at me so I am going to say your part thottle tune sucks.

 

+1


what your afr in cruze

 

Yeah man, that is kind of low, the turbos should bring up or leave it the same..I'm thibking your T Body is messing up..And flatops? What is your CR?

 

fuel management is return style with 55lb. inj. hpx maf and stock ecm, comp should be around 9.7 to 1 or 10.0 to 1 i run a felpro mls so im not sure what it is exactly. I do know one thing awhile back when i was gettin it tune my tps at ilde was 1.5v which i think is high but i cant adjust it. so any ideals on what you think it can be?
If i was to mess with the part throttle on my tune what you think i should mess with, maf tranfer function, inj slopes, i jus dont wont the check eng. light to come on ssaying its lean.
afr on wideband at cruise stay between 14.2-14.9 maybe 15 but also notice when i left off gas it will drop to 13.2 then rise back up. isnt suppose to go like stupid lean whean you let off.

 

You should monitor your kamf - fuel trims. Ideally you want them to be as close to 0 as possible. Anything less than 0 - say .870 would be rich, anything higher say 1.2 would be lean. Check your fuel tables. Are they showing a 14.7 range for your light load driving? Is your fuel table set up on a 200% scale? Are you cruising in open loop or closed loop? Some tuners will force open loop to early to prevent the ecu from causing a tip in detnation issue. This can cause a poor fuel mileage complaint. I have seen tuners use rpm as a trigger to go into open loop. With the 3.73's you would be running a higher rpm during your normal driving possibly causing it to go into open loop (if the tuner had it set up this way).

 

I understand the mpg concern. Those gears and the tune are killing you. If you figure a stock car with 3.27's and the 4.6 will get lower to mid 20's on the freeway when you're cruising. Add a little for the 5.4, add a little for backpressure of turbos, add a lot more for gears and you should still see 15-16 on the freeway. Gears and tune should put you around 17-20 freeway. This is all assuming you're cruising and not in boost whatsoever.

Comes down to physics when dealing with boost. an approximate guide is 14 psi will require 2.2 times fuel of naturally aspirated due to extra air, backpressure, and thermal inefficiencies.

 

Rodney:
Why you just give us a call at the shop.? I may be able to talk Travis into email you a tune.
He mention something the other day about you coming back....

 

If something come open with you guys I was jus gonna have travis set me up with a awesome tune. But I'm also considering a stand alone and maybe e85. Do you guys get that down there?

 

With my carbed setup I usually averaged 17mpg with normal around town driving and a few spirited blasts. On the interstate with long periods of consistant rpm driving I have gotten as high as 24mpg. This is with a blow thru 4.6 DOHC in a 3100# car with 3.5:1 gears and a 5-speed. I do not know what your timing tables look like but I had mine at 38 to 40 degrees advanced in low load vaccum.

 

Re: What gas mileage are you guys getting?

yep
Matt's car runs on e 85 with the SCT software
mine have a stand alone engine management system<F.A.S.T.>
[flash=500,400]http://vimeo.com/moogaloop.swf?clip_id=16198099&server=vimeo.com&show_title=1[/flash]
Nimis car runs on e85 with BS3
Travis new race car <the coupe> have BS3
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