Dodge Ram 2500 diesel engine comp mods...
 

Truck... 2005 dodge ram 4x4 diesel with 3" lift, 34" tires & AT. Started another thread in the aero forum regarding mods I have in mind to clean up the underside of the truck. [pfth... cant post a link to the other thread... Its over in the aero mod forum if anyone wants to read it, I will up date this once I have 3 more posts :p ] http://ecomodder.com/forum/showthrea...tml#post336473

Under the hood I have a few other ideas I need feedback on... 1st off there are performance mods that have brought me from 15~16 up to 17~17.5 mpg. Have the stock airbox, AFE Torque tube down to the stock turbo, AFE Arcflo intake horn, smarty programming, stock DP into an Aero 4040 muffler into a 30" magnaflow muffler.

So... mode 1, port the airbox and attach a hose to it in such a way that it would draw air from the back of the engine by the firewall so it is warmer than what it gets from the front... (I'm convinced the motor gets the best performance when ambient air temps are at 80~85F). I have the torque app that I can monitor intake air temps with and am thinking of a 2~3" electric exhaust cutout to control flow in the event it gets hotter than what I'm after.

Second mod would be to draw that warm air across the fuel rail to warm up the rail a tad bit. Going this way as I think it's the best way to use the heat that is under the hood vs adding an electric heating method. On the flip side of the coin...one mod I did a while back on my last gas truck was to cool the fuel. This gave me a 6% average bump in mpg over the 1600 miles I tested the mod on... did approx 800 w/o the cooler than 800 with, cant argue with the data. This plus other mods took that truck from 11.5 mpg up to 14.5, 2000 ram 1500 4x4.

Again the truck is getting about 17.5 mpg on the hiway, this was before swapping out wheels & tires, had 33" 12.5 wide 18's on chrome wheels. Now there are taller, narrower tires on a different wheel that shaved 9# off ea wheel. I have not measured the current mpg yet so I dont know where it sits now. The goal is to get up to 20~21 mpg on the hiway doing approx 65 mph.

Anyways, what do you guys think?

You don't want a warm air intake on a diesel. As long as you can keep your intake manifold temperatures above 30'F to 40'F its all good.
You don't want warm fuel unless you can heat it to about 300'F. There was a study posted on here that showed fuel economy and power dropped off as fuel was heated, until it hit 300'F.
The only time warm air and warmed fuel will help you is winter cold starts. Besides that your injectors are burried inside the cylinder head, the fuel gets plenty hot before it gets injected when the engine is warm. You dont want too hot of fuel going to that expensive CP3 injector pump.

What I think is don't try gas engine eco mods on a diesel and loose that muffler and run the shortest possible straight pipe you can get away with.

hummm interesting. So cooling the fuel to a point would probably be good then...??? Are you aware of anyone actually putting warming fuel to the test?

the idea I have for the air hose plumbing would be that it is flexible so I could go either way with the hose. As for the air temp... while the butt dyno is not ever calibrated ;) performance is noticeably better every time it is in the upper 80's, low 90's. Just cant control it since it's ambient. The goal would be to be able to get better control over the intake air temp and measure fuel economy.

The lift is hurting your FE more than anything else. It seems funny to talk about an underbelly when the truck is standing so tall and has such large tires.

Sure we can argue with the data. We have no idea how you controlled other variables or how you measured anything. In one sentence you say warm fuel will improve FE, the next sentence you say cold fuel improves FE. Which is it?

On what principle of physics does heating or cooling the fuel improve the thermodynamic properties of combustion?

I think you should chart your current MPG so that you have a baseline to compare with. Even better yet, do ABA testing with any mod that might affect aero or rolling resistance. Without this, there will be no evidence that any work you do has any benefit.

20mpg at 65mph should be achievable from a stock truck. Stop modifying the truck in ways that hurt FE, and improve the efficiency of the driver; this will help the most.

Warming or cooling fuel just isn't something worth bothering with. It's not going to make a noticeable difference, and the truck is already designed to operate within a range of temperatures.

One of the other diesel guys posted a study about fuel heating. I think it was by some university.

The only OEM that tested fuel heating/cooling that I know of was cummins marine, they found that fuel sent to the pump at a tempertuare of 75'F seemed to preform best.

Ignition
 

Any one know about the plasma ignition system. I want to make plasma ignition myself, Thanks

I understand that the lift hurts FE, thus the reason for the other post. Since my truck sees off road enough to bump up the ride height to begin with, it needs to stay. The other post I did was intended to get some feedback on the ideas I had about helping out under there as much as possible.


Well the data was pretty simple since I did the mod in the middle of the trip... 800 mi going up mpg = x, 800 mi going back, mpg = 8 + 6.5%. It was the posts I read here that are claiming the FE goes up with warmer fuel, all of this relating to gas engines only. I do know that testing I did do on a dyno with a fuel cooler setup on a stock engine yielded a max gain of approx 13% in both hp & tq. Every gas motor I did this mod to had a nice butt dyno felt bump in the low-mid range rpms, only 1 motor did I dyno it before & after on the same dyno on the same day w/o pulling the car off the rollers. I believe there should be an ideal number to get the intake air temp & fuel temp to get the most out of it (diesel). Since when the ambient temps are in the 85~95ish range smoke output drops and motor feels stronger it leads me to believe that at those temps it is getting the best burn in the cylinder.

Cant answer that, can only point to the before & after data I collected. I can say though that the "after" data had ambient air temps close to the 90's (gas engine) so if anything the gains might have been higher.


Heading up to Washington Thursday morning with a light load so I will be seeing where it sits then. I have seen 20 mpg 2x in this truck, 1st it had 2.5" of lift with a wider well worn set of tires that were heavier than what I have on there now. the other time was with a tire 1" taller than the 34" tire that I have on there now, that had the same 3" lift thats on there now. At 65 mph the motor is spinning right around 1700 rpms which is around where the peak torque is. Another thing I can do is run a loop I"ve run in the past which was something like 100~120 mi and do before & after runs on the mods. Since I'm not working, regular runs like that are out of the question for now.


I disagree on this one... it's an area of opportunity IMO. Someone also suggested straight piping the exhaust, also a bad idea (already did it years back & lost mpg) Free flowing exhaust like that will help develop the most power under WOT conditions.

I believe the OEM testing back then wouldnt be targeting the best FE, look at what they are doing today with full size trucks with it being common to be getting over 20 mpg .

Funny thing though about the 75F number you posted, the heater in the fuel filter housing is set to turn off @ 70~80*... I read something like that a few years back which made me think it might be worth looking into. On another diesel forum guys started putting fans on a cooler that was on the return line to the tanks to keep the in-tank temps from climbing to much. Some (but not all) reported back better FE from it.

I will go and do the testing anyways and see what it looks like. If no gains, then at least there will be a thread on it that someone can refer to.

whats ABA testing?

Something you cant test unless you are willing to undo a mod after its been put on and tested.

The A test is the control. Data is gathered before the mod is added to the vehicle.

The B test gathers the data collected after a modification has been performed.

The last A test undoes the modifications and brings the vehicle back to the same condition it was in when doing the control test. This should confirm the original A test data. If it does not, then some condition has changed which should cause the B test to be questioned.

An example of why the second A test could be significantly skewed is changing wind conditions. If the wind changed during testing, then the B data is invalid.

yeah that makes sense...

Grille block, electric fans, and driving slow were worth the most for me.

1997 Dodge Ram 3500 Dualie Cummins - Diesel Power Magazine

Update... did the grille block, 2nd air dam, tonneau & tailgate spoiler and got a consistent 20.2 mpg on my test run. Then went to the Smarty UDC for engine control and got that up to 22.2 on that same run and it is repeatable. I expect that with a 22 mpg on tap doing 65 I should be easily able to get the 20 mpg on the hiway I was shooting for.

Truck still has the 3" lift, 34" tires and a 180* t-stat. I may test further with a hotter t-stat once I get a new radiator (mines leaking)

Thanks to everyone for their input! (greatly appreciated)

Good how-to here: http://ecomodder.com/forum/showthrea...ery-11445.html

I always thought turbos like large exhausts...

You might want to look at my garage picks for some aero ideas. Check Big Dave's truck also.

just read the link you provided, I pretty much did just that. Always the same time of day, out & back on the interstate at a part of the day where traffic would be dropping off, let cruise control handle the throttle over the route as much as possible (95% of the way if not more). Didnt do ABA testing because of the costs involved (unemployed ATM) but I did find that during the testing I was able to get repeatable runs. I picked days that were similar in temps and forecasts and avoided windy rainy days. I also logged each run for various parameters in case I wanted to pick thru the data (using LabView to analyze/pick it apart).

I wish there was a way to give a good measure of the city mpg so I could check out the rest of the tune I modified. Would be sweet to get into the 17's in the city but I wont hold my breath.

Turbo diesels love wide open exhausts.

Unlike a N/A gas engine a turbodiesel is trying to put its full displacement or more out the exhaust every 2 crank rotations.

You don't really want a 180'F thermostat in a diesel.

Wide open exhausts are best for competition use in my experience, no restrictions equal great top end power and lower mpg. I have had both an unrestricted intake & exhaust and just the exhaust and both times fe sucked. I have found that anything that reduces part throttle low end torque will reduce mpg...

Since blocking the grille i have seen coolant temps rise approx 5-8*f overall, i tried to get a definite answer thru searching the web & forums to find out if a hotter stat was worth swapping in and could not find anything. Any personal experience with it on a diesel? I have a leaky radiator that i will need to swap out with an all aluminum one soon and plan on fitting the truck with a couple of taurus fans so i can ditch the oem fan. I could probably go experiment with the hotter tstats before i do and get my own answer before i get it done...

http://www.dieselsite.com/dieselsite203thermostat.aspx

Here is some info on the themostat. This is for Ford but it gives you an idea of the temp range diesel trucks prefer.

Thanks I saw & read that. Researched part numbers and found a 200* stant that should be a drop in. I may go try it sooner rather than later.