Good work. My Dakota (4.7) wouldn't get anything better than 15 mpg unless on a long highway trip. That said, I'm not even trying to get better mileage anymore. With all the price drops, I got an EV some months back and the Dak now sits mostly, making home depot runs and weekend drives to the park, etc. I no longer buy gas... well maybe every few months with the Dak, if that. The nice thing is that with an EV rate plan from my utility co. the electric bill hasn't gone up either, so I'm basically driving for free now (cost of EV notwithstanding).

 

I was shocked at what the 2 mods did (turning vanes and the IM expansion aka potato launcher). I am going to experiment further with adding another small IM expansion piece off the unused vacuum port on the IM. When I reinstalled the vanes it seemed like the bottom end torque shifted, or got flatter. Not sure which but... climbing the hills around town it does not perform as good as each mod installed individually. I will go grab 2 caps and add that section I removed off the 2' pipe and see how it does before next weeks drives to work.

the current tank with mixed driving (2x work commute + trailhead for hiking) is also looking like it would be in the 19's. I will post up #'s if its anything other than expected (filling up again today).

 

Oh, and I still have aero to work on...

 

Update, working on the dak today, did a trans service with a new trans pan with drain plug. Why designers dont put that in from the get go i will never understand.

Installed the 2nd 1 1/2" tube, now 2ft total added, vane still in there. I now have all that bottom end toraue back. I am guessing the vanes moved the torque back up the rpm range and the added volume off the intake brought it back down.

Checked the ce light to see if any change and found a gross leak code in addition to the expected small leak code. Now i will need to find out how that gross leak code is determined. If it is related to the leak detection pump, i may have a hack i will try.

If anyone knows how the ecu tests for the gross link please chime in... 😃

Intake temps are unacceptable with too much heat in the engine compartment. Going to isolate the iat sensor, insulate the coolant lines under the intake tube and insulate the intake tube. If that does not get it under control then will insulate the throttle body. Iats with ambients in the low 80's are in the 110-120 on the hiway.

 

Yeah you do.... cause they want to discourage the diy type and have you bring it in for service. Us DIY types are determined though. My Dak has NEVER been to a dealer or mechanic, at least not while I owned it.

Just went for a drive for the first time in two weeks. Felt good. The old boy sure is smooth.

 

Wrapping the intake tube and coolant lines under the intake tube was good for a 15-20* drop in low speed iats ... What was 135-140 is now 115-125...

Iat sensor next...

 

Victory is mine... went for a hike/run this morning and there are 2 steep hills on the hiway on the way back. In both cases the trans would want to downshift to hold speed going up the hills. This morning, on the 1st hill under my control, no downshift and ever so slight speed change at the steepest part. On the 2nd hill however (close to home so I know it well), there was no way I'd make it to the top w/o a downshift. This morning had CC on and expected a downshift but got none. It held speed up and over the hill. Pretty happy with that.

Next... going to block off the area by the trans controller to force more air from the fender in an effort to get IATs lower. in 80* temps this morning IATs were floating around 100~104*. Remember this truck has 3.55's and 265/75-17's on it so its a double whammy.

I suspect 2 things:
1) the intake manifold is getting heat soaked externally
2) the actual intake air is still too hot.

2 possible solutions (will play with both):
1) Block off the air box area near the trans controller to force more air in from the fender
2) feed air under the intake manifold from the front of the truck

I want actual IATs no more than 10* above ambient.

Edit: IAT sensor... there is no solution for that one, it is getting heat soaked from the IM. Need to find a way to prevent the heat soak on the IM. I would investigate the '04 & up manifold to see if it was ever relocated. If so then it would be another strong argument for going with it to continue that goal of getting the bottom end torque up and upper rpms performance improved.

 

Update...

Yesterday, new coils & plugs went in, have an injector (#7) that is not spraying well as indicated on the plug tip, have oil on #2 plug from the valve cover.

I started an effort to see how more airbox flow would impact things. With the existing setup there is a ton of bottom end torque, mpg's are consistently in the 19-20 mpg range. Power wise it drops off in the 2500 & up range which got me motivated to play with the airbox again. So to start I pulled the airbox intake horn and added to 1/4" nipples to test pulling air from under the IM. That worked however did not work well enough and IATs while they were lower, were still hotter than I'd like so I pulled it. Without the airhorn on the box, truck pulls noticeably stronger on in the 2000-3000 rpm range but as expected, bottom end torque drops off a bit. Overall it is up very noticeably on power... should have come like this from the factory.

Going to run 3 trips to work for an mpg check in its current config, then add a longer "potato launcher" pvc in place of the short section I last added. I expect the bottom end may come back some at the cost of that mid range bump it just got with the airbox horn removed. I'm expecting 18's.

Edit: keep in mind the 265-75-16's are still on there and weigh a ton (E-rated) and the truck has the 3.55 gears. Worst case scenario and the setup rocks...

 

Another followup... been looking at how I could implement the rams Cheap Airbox mod V3.0 (3" valve with no velocity stack like the V4.1 mod) and have found a 2.5" valve that is normally closed with high vacuum that should fit on the firewall side of the box. I would have to block off airflow from the exhaust manifold side & force air in thru the fender well. I think this can be done but the issue I see is control over the valve. I want it to be fully open at say 7~10" inHG and closed otherwise. The user review on it states that it opens gradually as vacuum drops. I want it to act more like a switch like the Rams boost controlled valve does. On the ram I used a couple of bleed valves to slow the boost signal to the actuator and was able to get it to open at 5~6 psi which was perfect for that application. With vacuum that might not be so easy, might need a larger chamber in front of the actuator with an in-line valve to get better control over the actuators action.

Anyone have other ideas on valve control?

I gotta say I am shocked at how much power came out of the latest mods (turning vane in intake tube, vacuum reservoirs off intake manifold & airbox snorkle removal) . Fuel trims still look good and power is excellent between 1500-3000 rpms.

edit: ordered the 2.5" vacuum actuator valve... "I want it all..." bottom end power of the closed airbox and the midrange power of the open box...

 

18.346 mpg with air box open & no other changes. Got stuck at work 2x and thus had rush hour traffic 2 trips home. This meets my expectations from experience, open air box = shift in power & drop in mpg's.

today the snorkle goes back in and this weekend, if I can determine how the valve is working and I can get the flanges for mounting it, the 2.5" valve will go in. The goal behind it is to keep the valve closed during high vacuum conditions and open as load increases. I believe this will be a compromise between the stock air box flow and the added flow from removing the snorkel. Once installed, if it bottom end torque is not still quite right, I plan to lengthen the 2nd potato launcher off the intake manifold (should bring torque down even further).

Also, there is enough torque on the bottom end now to make that JTCM work more effectively. Just not sure I like how it is setup with the TC locking & lack of 4th gear access.