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Dodge Ram 2500 eco build
Been a while since I posted here so I thought I'd share some results.
Truck is a 2005 Dodge Ram 2500 4x4 QCSB Short version... gave the truck a make-over starting back in Dec 2017, details of the entire change over can be found here https://www.cumminsforum.com/forum/3...-makeover.html With all the mods done and all the miles put on it, mpg went from 18-19 mpg in the winter to its current 21-22 mpg List of changes:
Each time there was a throttle response change, I changed the tune to leverage the throttle response change. Injection pressure has been dropped significantly in the cruise range to bring throttle response back to what it was prior to the changes, meaning I want it to drive like it did the day before I did the swap. Other changes included duration reduction and remapping the throttle table, pilot timing, pilot quantity etc (etc = I forget all that I did). I took a look at all of the receipts from various years, dumped them all into a spread sheet and averaged it out per year (dont ask for exact numbers, file is not handy). MPG went from ~18.5 mpg up to a solid 20.9xx mpg over a 20k mile window. All of those miles ARE NOT eco drive miles. Many trips included DGAS (Dont Give A ****) where time was important. Lots of tuning during that period as well. The rest of the mods on the truck include 50 HP injectors, ATS Arcflo intake elbow, modified stock airbox (have an electric exhaust cutout bolted to the bottom of the air box for more air when DGAS tanks are in effect), AFE Torque tube, HTT stage 2.5 turbo (64mm comp wheel & 10 blade turbine), AFE SS exhaust manifold and a 200*f t-stat. Only aero mod on it right now is the 2nd air dam under the swaybar mount, rear tire spats and front wheel liner vents. Current problem = not being able to get CTs (coolant temps) up to where I want them, the EWP (electric water pump) flows at a steady rate and is pretty good at cooling the motor off. I need to either reduce the current/voltage to it or do a PWM controller for it. My commute route allows for pretty consistent mpg numbers when driving 100% eco. The sample window is 300~400 miles on eco drives, speeds are capped at ~62 mph, neutral on downgrades when steep enough to support speed, short shifting to leverage all the torque in the 900~1400 rpm range. Next up, going to look at rail pressure vs mpg, I've gone down the "reduce rail pressure for mpg" path and seem to have hit a ceiling. So, the next path is to experiment with the different rail pressures & reducing the duration. The 04.5-07 pistons have some special design for emissions and I am beginning to wonder if higher rail pressures would help mpg vs hurt. Only way to find out is roll with it and see what I get. Current odometer = 425K miles Anyways...there it is... for the next guy looking to mod a 6800# truck for daily driving mpg |
Before:
https://photos.smugmug.com/Dodge-Ram...1956-X3-XL.jpg After: https://photos.smugmug.com/Dodge-Ram...IMG2240-X2.jpg Pulleys https://photos.smugmug.com/Dodge-Ram...IMG5205-X2.jpg Electric water pump https://photos.smugmug.com/Dodge-Ram...IMG6158-X2.jpg 220A alternator upgrade https://photos.smugmug.com/Dodge-Ram...IMG5967-X3.jpg Driveshaft https://photos.smugmug.com/Dodge-Ram...IMG0758-XL.jpg Fans https://photos.smugmug.com/Dodge-Ram...IMG2035-X3.jpg wheels https://photos.smugmug.com/Dodge-Ram...IMG1957-X2.jpg Air Box https://photos.smugmug.com/Dodge-Ram...IMG1126-X3.jpg 2nd Air dam https://photos.smugmug.com/Dodge-Ram...1927-X3-XL.jpg https://photos.smugmug.com/Dodge-Ram...IMG1965-X2.jpg Rear wheel spat https://photos.smugmug.com/Dodge-Ram...IMG0277-XL.jpg Wheel well vents https://photos.smugmug.com/Dodge-Ram...IMG0275-X3.jpg |
Looks like it's time for aero mods.
You will likely have a few simple aero mods giving more mpg boost on the highway than all of the mechanical ones. |
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I know about going all out on the belly pan & whatnot but thats not practical for the use cases... What would your suggestions be? Considering a piece attached to the trans cross member to divert air down below the axle. needs testing for sure. |
Probably a partial grill block for winter since you said the engine is not getting warm enough.
An air dam, how high or how low it goes is up to you. GM claimed on their 2000s trucks that came with a factory tonneu cover increased fuel economy 6% on the highway. Ford claimed that on their 2000s trucks that going from a 75mm chin spoiler or air dam to a 100mm air dam chin spoiler increased fuel economy by 1.5%. When I put a 7 inch air dam on my suburban it was good for at least 1 full mpg no more than 1.5mpg. Thereare also plug in heaters, block heaters and coolant warmers. |
Go with PWM for the water pump.
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Coolant temps too low should be an indicator of your thermostat, which should continue to recirculate the water until it hits the desired temp. Unless you have a crazy big oil cooler on it. Do you have a controller on the electric fans?
Auto transmission or stick? Your best results would be from a sloped aero bed cover, on my old truck for a while I had a partial bed cover that only was from the cab back the first couple feet. It really didn't impact usability much, but I got a 5% MPG boost. Spats out of conveyor belt in front of the front tires would also help out. |
What's your final gear ratio?
That Cummins can live with a staggeringly low (numerically) ratio. My 7.3 Powerstroke thrives of (3.08 x 0.8 =) 2.45:1 plus the ZF6-550's overdrive gear. Low gear ratios are very potent for diesels. |
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trans is a manual. fans are controlled by a hayden radiator probe controller. Cheap, variable and easily disconnected for tune downloads. |
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The way the truck is now with the light weight parts and the huge overall bump in throttle response, it would be way better. Still are faced with the grades everyday on the way to work. As of now, fueling is dialed back significantly to tone down that throttle response change and it still has room to be dialed back. Dialing back = dropping rail pressure & adusting timing, then trimming duration to cut smoke output. |
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I have a pace edwards tonneau, rollup canister type that will stay. Love it and not willing to part with it. |
Have you tested your thermostat on the stove in a pan of water with a thermometer? If it only gets to 200 when climbing a hill, I think the thermostat is opening too early. Very common for thermostats to not do what is advertised.
I understand about wanting to keep the tonneau, I have a bakflip on my 2001 2500HD. Have you considered building something like the off road sports bar they are putting on Chevys. It could mount on the top of the bed rails, to not interfere with your tonneau. You could style it to look like a superfluous off-road accessory, but use angles and slopes to make it lower your drag coefficient. Make it 12" long on the top with a slight downward slope, and make the sides angle back as they go down to about 24" long where it meets the bed. My 1994 Diesel Suburban has 4.10s and a swapped 0.643 OD in the NV4500 running on 31.8" 235/85R16s. It is way overgeared even for the NA 6.5, I can lug up a steep hill at 35MPH in overdrive turning less than 1200RPM, much less 55 on the highway. I want to swap to 3.42 in the differentials, which is the lowest factory ratio available. |
Yes on the t-stat, but not lately. That stat was OK prior to the EWP install. The way the tune is setup now, I can pull 6th @35 mph running ~900 rpms. never a complaint unless the hill is too steep
I have another version of the tune I am about to dump in, further reducing the rail pressure on the bottom end and extending beyond the 1800~2000 rpm cruise range. |
May need to go up to a 202 or 205 degree F thermostat if you can find one.
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I was having problems with my engine not getting up to temperature this year too.
I replaced the 1.0L with water cooled exhaust with a 2.4L motor, and found that when it started getting colder, with the wind blowing through the grille over the front of the engine block it would never warm up enough to open the thermostat, nevermind running heat. I found that putting some plastic in front of the engine block to deflect air away from it helped tremendously, it now warms up to the point the thermostat opens and stabilizes there. Anyway, this is great. Following with interest. |
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1). Since the changes started for FE = Odometer Miles?
2). Engine Hours (looking for Average MPH over that span of miles as a change in Average MPH can account for all claimed MPG improvement). 3). Fuel cost (CPM; cents-per-mile; adjusted to a constant dollar figure per gallon). Against: A). Net income used to purchase supplies, gear, equipment for FE changes. B). CPM adjusted accordingly (for, as a “fuel cost”, vehicle expense has increased) It’s one thing to talk of improvements, but it’s only after their advantage has recouped cost that savings begin. (This would include those things removed) Net income, is the thing. 12% reduction has meaning. In a 20,000-mile year at $3/gl it’s almost $500 in fuel (160-gals). The real questions are: I). What’s the CPM trend, in other words? Conjecture is that it hasn’t improved at all in spending-to-save (miles held constant). II). Have e-fans (all changes) been put to the test? Towing greatest trailer frontal area and/or weight? Max axle loads with or without trailer? Otherwise need to add a note that truck has been de-rated to half-ton status regarding ability to do work. Optimization of “empty” isn’t an FE goal for a pickup truck. And I suggest you put the truck on a CAT Scale. My ‘04 2WD weighed more than 6800# when new. (CAT SCALE app. As the heaviest tire load per axle is the single accurate method of setting cold tire pressure it’s a necessary tool). . |
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The area from rocker panel edge inward to frame (truck-length) does most of the job. Combine with skids and a minor flexible dam or two. . |
I recall that you’ve upgraded steering (now have ZERO play?), then it’s control over body motion that is the next step in reducing degree & duration of steering input. The minimum acceptable test is 3-seconds at 65-mph. On the count of three, are you on road or in ditch (crosswind tells truth)?
Optimize steering by: 1). HENDERSONS LINE-UP, for rear axle Panhard Rod (track bar). 2). ADDCO, for smallest rear anti-roll bar, plus up-sizing front bar smallest step (both required). 3). BILSTEIN 5100 a typical upgrade to stock shock absorbers, but better can be had. Controlling spring action vital to smooth (near-linear) steering response. No bed wag, no body roll = less effort at all times, plus cleaner transitions per any application of what matters: A). Steering B). Brakes C). Throttle You’ve been focused on the least important of these attributes. What can the truck do if we eliminate driver-introduced problems? A 2-300 mile loop with a 17-year old girl at wheel back to same pump otherwise on cruise control at 55 to 58-mph with ZERO acceleration, braking or lane-changing EXCEPT as law requires. In other words, where is the baseline? (Which is lane-centered, steady-state. Cruise-control, no changes from this at all). How many course corrections in 100-miles? I’d bet it’s still SIGNIFICANTLY more than with the rack & pinion on mine. Which would tell me there is still work to do. But the test is needed. How one chooses to drive otherwise doesn’t matter. So long as the truck — left alone — is “better”. . . is what’s at stake. Ever owned a rifle better than you? Same principle. What can it do without hitting the 60-mph aero wall? Any driver. Simple rules . |
Brakes (on the early HPCR) is still MOPAR PREMIUM parts line. I’ve seen nothing better on any forum (RAYBESTOS rotors a possibility, but I never saw any follow up).
They’ll last well over 100k with ease. Where one has MORE THAN 1-2 emergency braking situations annually, is a driver problem badly in need of correction. Not applicable. Same for trailering. Bad trailer brakes are just that (not a truck brake problem). How well the brakes moderate speed given a decent payload (50% of rating) is the test. (Degree & Duration, again). Big toe or a big boot, to effect slowing momentum? As it’s a downshift that’s more at stake (getting out of OD into Direct) sensitivity will come to regular exercise given new truck spec brakes. . |
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https://www.cumminsforum.com/forum/3...eed-ideas.html I dont tow and dont haul anything heavy. If I did, I'd adjust as needed. Truck is my only ride and my baby (since 2006). Its been lifted, dropped, go-fast modded, air-borne at one time and continues to serve. These days its only seeing mountain dirt roads and lots of hiway miles getting there (trail heads for trail work & hiking) RE: optimization statement... it is for me :-) <- I did the math at a co-workers request, saving $1100/yr for 35K & up miles driven over when I started. Since some mods paid for others, its a huge gray area as to where it sits $ wise on expenses. And to be open, the $ is not a concern... the challenge of getting the most mpg out of it is where the fun is. The $ saved just buys me another beer in the end lol. I weighed my truck years back with different heavier wheels and a heavier tonneau cover, came i right at 7k. The pink slip showed something like 6850 so I'm betting its probably now at 6900 or so #. Went from 18-20 mpg year round to 21-23 mpg year round after all the changes. These days, I have to drive real stupid to get to approx 20.5's for mpg. |
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Suspension has Rancho RS9000's & sumo springs front & rear. Rear is setup to come in contact with the axle early so there is little movement back there. The front & rear is stock height, considering going to a softer oem spring pair that I have which would lower the front a tad bit more. I practice some of what you preach... minimal lane changes, found that CC works best for minimal load changes. The reduction in rotating mass allowed me to dial back fueling quite a bit. I'm cruising now at 60 mph, 1775 or so rpms doing 11~11.5k psi. Room for improvement there still. Quote:
What would be interesting to see is what you could pull out of a tank with an optimized truck. Yours is not even close to being optimized. 4 years ago when I first started using HPTuners I had basically the same tune I have now but was miserable. truck was a smokey mess and had no power. mpg was in the 18's with me trying to milk every mile.. Now with the updates & reduced rotating mass, it is significantly better and still have room to pull fuel back more. Zero daily driving issues, still plenty of throttle response to execute passes, hill climbs etc. |
If you can do without, those tow mirrors are horrible for aerodynamics. swap to smaller mirrors and sell yours for a dolla dolla bill to some 16 year old looking to squat his truck and put on diesel mirrors.
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Nope, need those tow mirrors and I have the stubby ones in a box.
making progress... fans are killing me so i fixed it, well not quite, i unplugged them. now it runs more consistent and closet to the target CT https://photos.smugmug.com/Dodge-Ram...G0078~2-XL.jpg yesterday while out all day i noted that timing is off in the cruise rpm region of 1750-1800. rattling when up at temp. a recent drop of RP in that area and the lack of consistent temps led to the timing being off. 1 quick fix & download and no more rattle. timing is still not optimized for it though but at least no more rattle. ...and, it is a pretty smoke free tune at this point |
Where did you get those vents in your wheel wells?
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My opinion:
Tires. Use highway treads and pump them up to max cold pressure or a little more. Slow acceleration. 55 mph or less, preferably stay at the speed overdrive gear shifts to. Don't use the A/C. Don't use the heater til you reach operating temperature. If you have a programmer, set it to the one that gives the highest timing advance. Aero mods and such will just nickle and dime you to death. |
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Speeds are at 60~62 for best mpg Whats A/C? Takes 20 minutes to get to operating temp IF outside ambient temps are 45 or higher. And even then its not at my target temp of 200*f. I need to get a PWM controller on the water pump to fix this. Tuning, I do my own using HP Tuners Aero mods, did those back in 2018 (the bet from co-worker that I could not get 5 tanks to average 23+ mpg) so the nickle has already been spent. The dime would be spent to clean up the flow under the truck, only have the 2nd air dam I made under the front swaybar. As it sits, I am lucky to hit 70*f IATs, this sucks for FE, I also dont heat soak the coolant except on longer trips, 40~50+ miles before I get there. Once I do get there it is pretty stable @ +/-5*f. My best bet is to slow the water pump down to a minimum speed at CTs below ~160-180 then bring speed up based on CT. I also thought about blocking or diverting airflow to the motor behind the fans. Had a battery cable go bad which put one of my fans on overdrive speed (was on low setting) and dropped engine temps down to the 170*f range pretty quick. The other fan was slowed down as it was hooked to the other battery that was not getting charged. Alt charges passenger side batt, crossover cable connects the drivers side batt, that cable went bad. Fan on overdrive was on the passenger side batt. Since I have already been close to 23 on winter fuel in cooler temps, I would suspect that once I get the cooling 100% under control, 23+ under all conditions should be attainable. |
Mine was “optimized” before the dealers lot (ha!).
The biggest differences between your modded and my stock trucks: 1). IFS, plus rack & pinion steering as it’s 2WD vs 4. 2). Lower ride height plus weight within 40-lbs each corner (50/50 weight balance). 3). Suspension upgraded for handling (larger anti-roll bar front and altogether new at rear) (No tail-out. Yours does. Load the bed and see for yourself. Even with more power you couldn’t keep up with me if I decided to leave. Mine needs LESS EFFORT per design, first; improved handling, second; far better tires, third). 4). Highway-only tires (where yours always loses 2+). What’s less desirable for MPG on mine is a bed-height topper for the 8’ bed. And that I outweigh you by 1,000-lbs. (15%). My dead-certain, just leave-it-on-cruise planning MPG is 24 (25 actual). Ranges to 27-mpg over same conditions. If I drop it to 54-mph I break 30-mpg with ease (showing 33 which is 31.5). I’ve spent nothing on the drivetrain past maintenance. I’d recommend you drop down to 58/9-mph. Try a run after a fuel top-off (auto stop) and a Cat Scale weigh. Out 100-miles and back to same pump. Get 50-70 miles warmup done before fuel/weigh. It’s the right baseline number as aero has taken over at 60. Get wind resistance pushed aside as it’s never the same. Over a 250k range, with $3 diesel, I’m $9,000 ahead in fuel savings versus someone 4-mpg less in annual average MPG than me (and who is himself above average). I’m on tire set number two, battery set number two, one brake pad change, original clutch, ball joints, tie rods, etc. $500 otherwise in repairs at 16-years. It’s the overall savings. Not just fuel. Depreciation is now $4k in 12-years based on current ads and condition. Optimized? I could walk away now and the vehicle cost was free past fuel + insurance, etc. I know you’re aiming that word at EEC, but I only drive 5-6k miles annually. An improved FE profile won’t really matter. The truck has always bee n grossly overpowered for my needs; solo at 8k, towing at 18k. (I used to hitch up to trailers that — alone — weighed 22k when running hotshot in another man’s truck. Didn’t lack then either). I haven’t ruled it out . . . but improving ONLY steady-state highway MPG means a trade-off elsewhere. I can do 21-mpg around town as it is I believe a conveyor belt front air-dam and side-skirts will take care of that. And until that test is administered, there’s NO point to changing engine timing and fuel delivery. Getting the driver out of the equation remains the most difficult task at EM forum. Inordinate belief in “skill when it’s really the vehicle. Inadequate testing. Now, all that out of the way, I’m on the same page as you. For me the fun will be once I’m retired. Maybe before then. Because I want to get my TRAILERING average up to the 18-mpg others with Third Gen see while solo. 17 I’ve hit. Just not consistent my. It’s more the trailer at this point. As the RV’ers eyes pop out already with my 15-mpg AVERAGE pulling a 35’ travel trailer, ha! . |
Well done I see more progress.
The rotating mass reductions you have pursued add up to ~60#, I'd venture to guess equates to ~500-1000# of static weight reduction Quote:
I found this out when researching parts for an 05 medium duty Cummins with a misbehaving EGR valve the wealth of information that is the internet could only tell me I was not seeing what was in front of me and EGR hit the Dodge/light duity in 04 the physical valve didn't show up until the 08. Re cam the motor is the only way to remove the non cooled exhaust gas non-recirculating system. By closeing the exhaust valve early they were able to trap spent hot exhaust in the cylinder displaces fresh air on intake stroke making a valveless EGR --- Quote:
IAT 70° ,that would be a wet dream -2to 20 above ambient with the itty bitty baby intercooler the first gen came with.worst seen so far this winter (its been mild) 11° air filter, 120° post compressor, 9°f IAT @70mph crossing the ID/MT Continental Divide pass |
My setup (AFE exhaust mani + the HTT 64mm HE351) starts spooling (off ambient) at 900ish rpms. Seems like the only time there is no spool is off throttle.
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Update: Went back and entered in all the fuel receipts that I have in hand, (have them all, just not in one spot) averaged the monthly mpg across all months & over 32K miles the truck is averaging 21.1 mpg. The last 3 months on winter fuel in the PNW area (mild winter), it continues to average 21.
My 2nd air dam mount broke last week, for the 2nd time. Going to need to fab up a better mount for it. Interestingly, it is on the same side as the last time (passenger side) which is telling me there is more force on that side for some reason. Kind of a head scratcher, if anyone has any input on it I'm all ears. other aero mods still in place, wheel wells, rear tire spats...the bed seals & rear bumper are off, need a permanent solution to the rear bumper issue. |
Update...
Came full circle on the rail pressure strategy and found I had bottomed out with the mpg's never really changing from the 20.5~21 mpg range. Would occasionally get 21.5. Decided to go the other direction with it and saw positive results right away getting into the mid 22's. Looking to go further I revisited the bed seal issue I had and decided to put those bed seals back in play but only down to the body line on the bed that goes the length of the truck. Effectively removing turbulence at the cab/bed area above that body line with everything below it was unchanged. I also reinstalled the 2nd air dam I built. What that (2nd air dam & bed seals) gave me is the ability to now coast down a lot more hills that I couldnt otherwise (same as back when I was in the bet with co-worker). With 90 miles already on the tank, I milked the carp out of it and was rewarded with a 2nd best tank ever of 23.654 mpg's. Thinking that maybe 24's might be achievable on a regular basis as IATs are no where near ideal (70's to 80's, best for my truck is 95+). Anyways, updated for the next guy... |
Another update...
Friday I made my own lower bed seal (to the cab) to finish off the 3 seal install that the newer rams have. Was surprised by how much farther I can coast before loosing too much speed. It made a noticeable difference. It is all detailed in this thread... would need to go back to the previous friday in that thread for pics of what I did. https://www.cumminsforum.com/threads...#post-29492601 After the install I short filled the tank so I have good data for 4 days of commute driving to compare against. Was surprised to get a 21.1 mpg out of the 125 miles on that tank. That is high for my truck given that 90% of the miles were all in town... (nothing is flat here so I get to coast a lot). Looking at doing some ducted cooling changes in an effort to relieve the high pressure at the front of the truck. If that is successful then I also want to see about leveraging the heat extracted to feed a rear diffuser I plan to build a the back of the truck. The goal there being to help reduce the vacuum pull at the back of the truck. I think there is some decent gains to be had there if I can get the diffuser fed with air correctly. That is a long term project. I did manage 3 tanks of 23.5-23.6 mpg's in a row, followed by a 22.x tank on a road trip, AC blasting on the return & both e-fans on. Not bad for a 7k # 4x4 truck (I think anyways). Walking up to my truck, you'd have to have an eye for aero mods to notice anything is different from the factory. |
Another update...
I am a bit confused by the performance of the horizontal bed seal, it showed a benefit at lower speeds but then ultimately created more drag & downforce on the bed. Truck was very stable at 60~70 mph with vs without. With that though came added drag. I ran a full tank with an eco milkman mentality behind the wheel and mpg's were still in the low 23's. I ended up pulling that seal, watched that stability go away and can feel drag being reduced... (truck feels "lighter"). I explored and tested several things in the back bumper but ultimately, open and left alone was king. anything I did back there just caused drag and that heavy feeling that goes with it. I have concluded that the bumper bracket could be opened up to relieve air pressure back there, how much that will help will remain to be seen. To date I have 9~10 (would have to go back and look at receipts) tanks over 23. Pretty happy about that given that its a 4wd truck, and a heavy one at that (7k#). I want to make a front wheel air curtain by pulling air from the front bumper insert and routing it to the wheel well, not sure if that is feasible or not, need to look behind the bumper and determine a route to the fender. |
Got pictures? It would help.
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Pics...
Here is the horizontal bed seal I just mentioned... https://photos.smugmug.com/Dodge-Ram...d%20Seal-L.jpg Here are the vertical bed seals that I trimmed... https://photos.smugmug.com/Dodge-Ram...Seal%201-L.jpg Here is my version of that horizontal bed seal, used garage door seal from home depot and 1/4" plastic panel fasteners. https://photos.smugmug.com/Dodge-Ram...IMG1429-X3.jpg |
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MPG took a hit by 0.2~0.3 mpg. How I tested it... I can feel the added drag removed (when I pulled it off) when I tested it out on the hiway & the neutral coast down a hill. How it is doing it, I am unclear on. Ram felt the need to add that seal sometime back in 2011~2012 on their trucks so they must have found some benefit from it for mpg's. |
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