1998.5 Dodge Ram CTD - Sally

[frojoe]

Thanks! This week I'm going to try to nail down the right color for the aux gauges, to match the factory instrument cluster.. been testing different wavelength green LEDs and combinations of coloring them with different shades of blue permanent marker, to find a matching Dodge turquoise color.. more on that later when I have some good results.

I also ordered some Isspro Evo2 gauges to better match the instrument cluster, as the Autometer UltraLite gauges just look a bit tacky and are totally mismatched to the rest of the dash.

What I currently have and what I'm going to replace with:

1) TOP - Autometer electric fuel pressure, 0-30psi --> Isspro electric fuel pressure, 0-20psi
2) MID - Autometer electric pyro, 0-1600*F (was in downpipe just after turbo, now in PacBrake elbow) --> Isspro air pressure, 0-175psi
3) BOT - Autometer mechanical boost, 0-35psi (can just barely peg the needle occasionally on level 3 of Edge tuner) --> Isspro boost, 0-40psi

Hoping this week to take some triple-check measurements under the rear of the truck and confirm the design for the brackets for the Chevy 64" leaf springs swap, and maybe get started on fabricating that stuff this coming weekend.

 

[Mundo4x4Casa]

I like your build. What is the purpose of the Chevy spring swap? Are the leaves a different spring rate? Different arch, like a slight lift? More pliable for axle twisting? What about the centering hole, or hanger bolt loops? Are they the right size? If flex is in your future, see if '06-08 Power Wagon springs might work. They are very flexy.

Carrying around a loaded 2600 pound Lance on my '01 CTD caused me to assemble my own spring pack on the rear axle. Here are some particulars:
1. add another pair of 3500 upper secondaries (aka overload springs) to the single factory 2500 secondary that came with Camper Package
2. add a pair of 3 inch lift helper springs just above the actual overload spring in the main pack
3. purchase and install longer U-bolts
4. add Stable Loads to allow the upper secondaries to come into play sooner with a load
While it doesn't look like you would need that kind of additional load carrying capacity, the upper secondaries would provide for the occasional heavy load without sacrificing your unloaded ride.
5. add Rancho 9000 adjustable shocks for loads or no.


Below shows the loaded suspension and the black block past the far U bolt that engages the upper secondaries sooner.

jefe

 

[frojoe]

Hey Jefe, thanks for all that info!

My reasons for the spring swap are as follows (somewhat in order of importance):

1) on and off road ride comfort.. the current truck leaf springs are as best I can tell from part number researching the 2400 lb capacity springs.. and are incredibly hard on highway separators, potholes, mild offroad, you name it.
2) the Chevy leaf springs have a longer eye-to-eye of ~64.5" vs the stock Dodge 60" springs, so in theory this will aid with more sensitivity to deflection
3) the Chevy leafs are 5 thinner springs at 2.5" wide, versus 3 thicker 3" wide springs, so there should be a bit more sensitivity per leaf there, and trimming the length or replacing/removing a leaf for rate tuning should be easier
4) since I'd need new brackets to adapt, then I can switch from the factory tension style shackle to a more supple compression orientation of the shackle
5) above point about the shackle also allowed me to design in an adjustable, more robust shackle with better bushings.. like the Thuren 3rd gen shackle design
6) making my own brackets vs re-using the OEM leafs and flipping a shackle hanger or getting an aftermarket shackle hanger allows me to fine tune the locations of the front and rear leaf eyes, to keep the roll axis similar to stock, albeit a couple inches lower
7) making my own brackets that are lower also allows me to reduce the height of the axle blocks used from the stock 4.5" high to 2" high now.. I haven't had issues with axle wrap for my use of the truck, so keeping a block is a positive for me as it allows me to adjust the ride height up and down, as well as pinion angle, but modifying the axle block

As for the reasons and usage.. I don't really haul with my truck, and the max I have in the bed is probably 1000lbs with camping/roadtrip gear, or 500lbs with two dirt bikes in the back. I rarely tow at all, if it is then I'm helping a friend move a <20ft boat. So for me the primary use for the rear suspension is compliance vs supporting heavy loads. Added flex is welcome, but a drastic increase in articulation is not the main goal with the spring swap. I currently have Thuren-tuned Fox 2.0 shocks in the back, which helped with quicker offroad hits.. but the underlying stiffness of the springs is still the main hindrance. I'd want to stay the same ride height, or lower it by up to 1" with the new springs swap setup.

From my comparison of the current 3/1 springs, they have a 2400lb "capacity", and the new chevy springs are a capacity of 2250lbs. Judging the ride quality and spring rate just off of max rated load capacity is not the right way to do it, but after a couple months of searching I simply can't find any spring rate data so max load capacity of the springs is all I have to go on. With the new springs having more springs, it should be easy to fine tune the ride and make softer if needed.

 

[t.Sparks]

Why oh why did I just have to put on my "frame connecting" steering box brace and then see this.... I want one! Killer fab work man!

 

[frojoe]

Haha! Thanks for the compliment Tyler.. been watching your thread for a while and you've done a great job with yours too!

 

[frojoe]

I finally nailed down the design of the Chevy leaf spring swap for the rear.. want to get rid of the stiff leaf springs ASAP. I triple-checked a bunch of measurements on the truck before wrapping the 3D up.. it conveniently turned out that everything will bolt onto the framerails using the existing leaf bracket rivet holes, so that's nice. I think one afternoon I'll spend grinding/drilling the rivets out and replacing with gr.8 bolts, one at a time, so that when I'm ready to do the spring swap I only have to undo the bolts as opposed to all the effort of removing the the rivets in addition to the springs/brackets swap all in one day.

My previous version of the design used a lot of angle and C channel with profiles cut in it.. really for the only purpose of utilizing the nice gradual radius that's usual present on the inside of the bends on channel and angle profiles.. but then I got to thinking that really these brackets will be so beefy, if it's all cut out of plate and welded together it should be fine. On top of that, if I make as much of it out of plate as I can, then I can get it all waterjet cut.. then I just need to clean the edges and have some spacers to hold the pieces together for welding. The actual orienting and assembly of it all should be held together nicely with tab and matching slot profiles!

The forward perch still uses a 4" square tube cut diagonally to turn it into a gusset, and the outer leaf mounting plate is angle bar, but the rest is waterjet cut plate..

The rear shackle perch has two mounting holes for the shackle.. not entirely sure why I decided to do this other than to have some future adjustment, in case I need to correct the shackle angle if I ever shift the leaf spring forward or back via changing the front leaf perches.

Plenty of gussets to link the top plate to the vertical framerail plate.

Here you can really see the tabs and slots for locating the vertical gusset plates to the top plate. In theory I should just have to bolt all of the plates together to the vertical framerail plate with a single bolt, and the tabs will keep the rest oriented and locked together for welding.

As I mentioned before, I designed around the Thuren shackles as I really like the well thought-out & very sturdy design of them, several adjustment holes, and that they're robustly one-piece and not two individual side plates with no brace. Also I really like his greasable pivot design, and just want to support the guy's awesome operation.

For the 3D model, the "sag point" of the leafs was estimated, and one reason why I wanted adjustability in the shackles, shackle perch, and the use of an axle block. I'm unsure exactly where the rear end is going to sit at ride height with everything finally installed, so the axle block height and milled angle (for pinion angle) were estimated but are easily changeable to achieve the ride height I have in my head.

Here are the leafs in what I estimated was the bottom out case, which is 4.5" of compression from my estimated sagged ride height. My fox shocks have 5.0" of travel available from my current ride height, so this should be good. Also need to figure out a new rear bump stop setup.. likely using the Boogie Rated bump stops.

Here is the full droop arrangement. This is about 8" from full flat which is safely under the stroke of the Fox shocks I have. This is currently the "worst case" for shackle angle.. if the shackle is mounted to the 2nd (forward) hole on the hanger, or if the leaf is mounted to the bottom hole on the shackle, the shackle angle will improve. Note that I won't be able to use the top hole of the Thuren shackles.. for several packaging reasons, but this is okay and I've taken it into account with utilizing axle blocks that I can make shorter, if I want to lower the rear. In this picture, the shackle appears to be close-ish to inverting the shackle, however in the next picture you can see there is still room for the spring to over-extend past it's natural arch and the shackle should still avoid inverting. I'll have to do real world flex tests to make sure this is all good.

And here are all the flat pieces that are ready to be cut out of a piece of 1/4" hot rolled plate that I picked up earlier in the week. Hoping to get the plate cut tomorrow, and best case would be pick up the bits on Friday and start welding on the weekend!

 

[frojoe]

A further note, below is my estimated ride height so that the leafs have ~4.5" of compression before they go flat. Running the shackle in the forward hanger mount position should get the shackle angle just less than 90* relative to the eyes, so that as the suspension is cycled up (compressed) from this ride height position, and even when the suspension sags out 1-2" for floating over bumps, the shackle angle is "over center" and the input force from the axle isn't working against the shackle by compressing it, the shackle is instead happy to rotate deeper into the travel from any input force because of this shackle angle. At least this is how it is working in my engineering, mind and according to some internet reading I've done... not sure if anyone has any input contrary to this...?

 

[AZ4X4DUDE]

Awesome build man, just read your whole thread and im amazed at the work you've done! I'm also looking at a 98 CTD 24V

 

[frojoe]

Thanks! I realize this build isn't as "overlandy" as many others on here.. don't have big light bars and ARB bumpers and winch or a RTT (as much as the girlfriend reeeeeally wants one), but I feel there's enough modification of this truck that is deserves a build thread on here, and hopefully gives some inspiration or guidance to other people who are considering using a fullsize 2nd gen Dodge. The Cummins engine has been functionally bulletproof reliable for me, and as a whole I really think these trucks make a good base if you decide to go down the reasonable road vs just lifting it 6" and screwing everything up.

I spent a while figuring out which forum to start a thread on.. on Pirate4x4 it seems that if your truck isn't a 44" swamper and dual transfer case trail buggy then they flame you alive for not being in the "Tow Rig" sub-forum, which appears to be mainly that.. F650 and similar tow rigs, so I shied away from Pirate. Also thought of CumminsForum or DodgeForum, but for those it seems like if I'm not stacking tuners and pushing 60psi with 6" straight pipes, or have a revvy V8 Magnum mud bogger, then I wouldn't belong either. Long story short, I really like the interaction on this forum, there's a wealth of cool information on minuscule to complex truck mods, and it's the forum I go to first to check out new threads, and stay on the longest. I also don't buy/make mods and update nearly as often as some guys on here.. don't know how they do that! So in real time, this thread might be updated fairly slowly.

Got the brackets cut last week, but haven't had time to assemble them. It's super cool that they literally just kinda click together.

 

[RPhil]

Thanks! I realize this build isn't as "overlandy" as many others on here.. don't have big light bars and ARB bumpers and winch or a RTT (as much as the girlfriend reeeeeally wants one), but I feel there's enough modification of this truck that is deserves a build thread on here, and hopefully gives some inspiration or guidance to other people who are considering using a fullsize 2nd gen Dodge. The Cummins engine has been functionally bulletproof reliable for me, and as a whole I really think these trucks make a good base if you decide to go down the reasonable road vs just lifting it 6" and screwing everything up.

I spent a while figuring out which forum to start a thread on.. on Pirate4x4 it seems that if your truck isn't a 44" swamper and dual transfer case trail buggy then they flame you alive for not being in the "Tow Rig" sub-forum, which appears to be mainly that.. F650 and similar tow rigs, so I shied away from Pirate. Also thought of CumminsForum or DodgeForum, but for those it seems like if I'm not stacking tuners and pushing 60psi with 6" straight pipes, or have a revvy V8 Magnum mud bogger, then I wouldn't belong either. Long story short, I really like the interaction on this forum, there's a wealth of cool information on minuscule to complex truck mods, and it's the forum I go to first to check out new threads, and stay on the longest. I also don't buy/make mods and update nearly as often as some guys on here.. don't know how they do that! So in real time, this thread might be updated fairly slowly.

Got the brackets cut last week, but haven't had time to assemble them. It's super cool that they literally just kinda click together.

...

Agreed on your points about the forums. Pirate is a wealth of information, but the people who frequent there are a bit more hardcore, for sure. I also find myself perusing more threads here as well.

Keep up the build. Your clean decisions and work is enjoyable to follow.

I dream of dropping a Cummins into the Excursion. Already have a list of the parts together, just need to eventually get it done.

 

[toastyjosh]

post away! This is one my fav builds

 

[huntsonora]

Sub'd

 

[frojoe]

Sorry it's been a while, I've been bogged down by other projects and work. The garage at my parents' place (where I do most of my wrenching) is clogged with my woodwork projects and a 1976 Yamaha XS500 I've been neglecting since 2014.. and have been blitzing to get ready for this riding season. I need to wrap up the fab work on the bike and clear out the winter carpentry projects so I can move my other, currently drivable (12 year long) project 1972 Nova into the garage to do a bunch of upgrades to it over the summer. Long story short, the truck has been purely a daily driver for the last month or so.

That being said, I've been holding off progress on the rear leaf swap brackets until I got an ETD on the essential puzzle piece... custom front coil springs! The Thuren coils are a great spring, but with my relative lack of added aftermarket weight on the truck, and from wanting a lower ride height for better front suspension kinematics and just ride height cosmetics, I contacted Coil Spring Specialties to make a set of springs. The ID, OD, and free length of the springs are very near the Thuren springs, but there is an extra active coil and reduced wire diameter to make them ~335 lb/in rate vs the Thuren 379 lb/in rate. Idea is to lower the front about 1" (so ~1.75" lift from stock) with also a slightly softer ride.

The rear leafs will have a 345 lb/in average rate, so that will be a good starting point. Reason for holding off on rear swap progress is to get the front coils installed and sagged (if that happens, although I was told they've been pre-stressed and will not sag), and then adjust/lower the rear ride height at the time of installation, to cosmetically match the new front ride height.

 

[huntsonora]

Can't wait to see how you like these compared to the Thuren's. Perfect timing for me too

 

[c7train]

LOVE The Nova! I have a '63 convertible and a '67 4 door as daily drivers. You truck is awesome too! Such great work!