Sharing some lessons learned, I'd expect you guys already know this.
Truck:
2002 Dodge Dakota 4.7 with 45RFE Trans 3.55 gears with 265/75/16 tires (worst case scenario, stock tires are a bit shorter and a good bit lighter as the tires on there are E rated tires, heavy)
Mods @ start of these lessons learned:
70mm Throttle Body
Air Aid intake tube between stock air box & TB
Fuel rail wrapped
Inspired by lessons learned on the Ram relating to the intake tube I set out to add a turning vane at the elbow on the intake tube. The change in performance was very noticeable and immediate. Power was up everywhere I used it. Fuel trims were up into the +7~9 range and if I'm not mistaken that is dumping fuel to compensate for a lean condition. Used simple 5" garden edging for the parts.
Pics...
Motivated by the performance bump I decided to play with expanding the manifold capacity by adding what I call a potato launcher tube off the brake vacuum hose. The original idea was to smooth out the vacuum variations in the intake manifold. The benefit was again immediate and to my surprise, bottom end torque jumped quite a bit. Further experimentation with the trucks setup taught me that I could shift the torque peak up & down the rpm range. Was pretty shocked by that.
Again leveraging lessons learned on the Ram I pulled the air box snorkel with the expectation that the upper rpm range for where I use it would get a bump in performance and sure enough it did. Below is a pic of how it was just prior to me wrapping the 2 1.5" tubes added. I used exhaust wrap for everything under there including the fuel lines.
So what did all this get me in the end...
mpg pre-mods were in the 15-17.0 mpg range. I'd really have to baby it to get 17 and even that was a stretch. Mpg's tracked over a 3 day commute period of 210~215 miles for all of the testing. When I enjoyed a DGAS tank mpg's would be in the 13~14 mpg range.
mpg post-mods are now in the 18-20 mpg range over the same 3 day commute test window. DGAS tanks are getting me 15-17 mpg now.
Now the downside... I do have a CE code for a large evap leak which was not there before. At some point I will be attempting to defeat the system on startup in an effort to prevent the code. No idea when it is testing for the leak, the only thing I can think of is at startup it is measuring the rise rate of the vacuum signal.
There has been no ABA testing, I dont have time for it so if someone here is motivated to do it feel free.
Anyways... lessons learned and lessons shared...
Forgot to add... I pulled the airbox snorkel and power shifted up the rpm range. That has motivated me to duplicate a Ram mod I did and put a vacuum controlled exhaust cutout onto the air box. there is room on the firewall side of the box. Here is the Rams setup.
