so what's your verdict on the mpg? I'm sure there are some curious folks out there...

 

Ok first of all lets get this out first, this is my opinion of my TB on my truck and does not reflect any way of the performance of Fastman throttle bodies on other vehicles

Acceleration is great, I have put approximately 150 miles on my truck since install, as for MPG I am still watching my fuel creep from 3/4 to 1/2 to 1/4 the same way, my truck has 165,000 on it so i expect its got something to do with the age of the motor, not the throttle body.

I have checked spark, plugs, sensors, tire pressure, drove with an egg on under my foot nothing seems to help, high flow exhaust, reduced drag with tonneau cover, I even wax the damn thing for aerodynamics (lol).

One good thing i noticed was the spark ping I would get ever so often is gone. Smooth acceleration with this TB is the nicest thing about it, any idea's about improving my mileage would be grateful, I dont see a cold air giving me any gains that would justify the cost, at least not on this vehicle.

I highly recommend this TB upgrade to anyone looking to smooth the motor acceleration out, and shifting changes also (much smoother) and it may benefit someone with less mileage on their truck greatly, I think my motor is getting old even tho the truck is as beautiful as new.

 

Yeah your mpg sucks. Hell even with the 4.10 rear I have in my '01 Offroad Edition 5.9L I get 10 when I'm being heavy footed. I have done nothing but a flowmaster exhaust to it as of yet but I have new Mopar pulg wires, cap, and rotor on the way and when I do that I'm gonna change the oil and maybe even the tranny fluid and filter.

 

I agree, his milage sucks and there has to be something wrong with it. Bam... if you want to go over what you've done to it again (I think you did already) something else might come to mind....

Here's the things that I know will affect gas milage...

1) MAP sensor... this is one of the key elements to how your truck is going to run, is used by the pcm to determine the injector pulse width along with the o2 sensor

2) o2 sensor... a bad one can make your truck run rich also

3) leaky or dirty fuel injectors, get some BK44 fuel injector cleaner and run it thru a 1/3~1/2 a tank of gas, higher concentration will work better then mixing it with a full 26 gallons of fuel...

4) exhaust mods... too big of outputs on the muffler, 3" max for a single or 2.25" max for dual will cause a loss in low end torque. Too big of a mid pipe between the cat and the muffler (stay with stock) will also cause a low end loss.

5) intake mods... too big of an air filter will also affect low end torque (my experience on the BMW and the Ram)

6) ignition... spark plug gap too wide and having crappy wires wont help.

7) poor compression, if your motor is tired (readings of 120psi or less) it's gonna put out less torque & HP

8) ignition timing, too far advanced (from the programmers on 91 octane setting or performance setting) and it's setup for upper end HP, try the 87 octane program with 91 octane fuel.

anyone who is concerned with better gas milage should be targeting higher low end torque. since it is what gets the truck moving... the more you have, the less your in the throttle to get it moving and to keep it moving once your up to speed.

When my truck was getting it's best milage, I had lots of low end torque. when the low end dropped, so did the milage. upper end HP is great for passing and stuff but for better milage, low end torque is where it's at... When I was on the freeway, I barely had to press on the throttle to keep my speed, if I were to put a % on it, 5~10% throttle, now with my truck in its current state, it's more like 15% and I average around 12 mpg. hiway milage doing the speed limit of 70 with cruise on I get around 14.5~15.0 and i have 33" tires with 4.11's in a QC 4x4... Reed (Silver_Dodge) was getting 16 at one point before his gear change...

One last thing for you to think about (Bruce) is cold air is denser and denser air helps build more low end torque and hp together. Great example is when I installed the 3.5" CAI kit on the M3 (upgraded from a 3" CAI), it was supposed to give something like 30+ hp which I think it easily did. However it loss some low end torque along the way. Wanting that torque back I already know that adding a fuel cooler and insulating the fuel lines and rails will help it alot so that was my next mod. Now with it installed, it rocks on the low end and is even better on the upper end. And yes it is on my truck already...

edit: forgot to add that by spraying the cold fuel on the incoming air charge you are cooling it even further than it already is.

hope some of this helps you guy solve your milage issues.

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another thing you guys may have is the death flash... it retards the timing quite a bit to stop pinging which is usually caused by a blown plenum gasket. that was the dealers way of putting a bandaid on it for customers complaining of pinging.

sorry for the double post but this might have been missed by someone who already read the last post in the tread...