Legends Class 4800 Build - “Tinkerita”

[FSU Off-Road]

Back in September 2020, I made a rash decision to take our stock TJ aka "Tinker" (as I always tinkered on it per the wife) and converted it to a 4600 Stock Class car and raced it at King of the Hammers 2021. As if I wasn't crunched for time already, I also created a YouTube channel to documented the whole experience from start to finish.



After racing this past year with a podium finish and a 2nd overall in the Eastern Race Series, our team was offered an opportunity to build another car. After some difficult discussions, budgeting, and a change in life plans, FSU Off-Road partnered with TMR Customs to build one of their chassis for a 4800 Legends Class car in Ultra 4 Racing.

With that said, our journey to the 4800 class begins. Tinkerita as the wife's named it (a mixture of tinkering and garage margaritas) showed up back in September 2021, and ever since its arrival, I've been non-stop fabricating, welding, researching... repeat! Our goal is to have a "budget" friendly 4800 car that can serve as both a racer and weekend warrior for the wife and I to enjoy. Now, we also know anything "racing" is never budget friendly, but by doing it yourself you save a lot of money in the long run. Also to help with the budget aspect, our team has a list of key sponsors and partners that we've established over the last year of racing to help save us some money. In a project like this, every little bit helps.

Tinkerita Specification:
*TMR Chassis (Estimated 113 WB)
*LQ9 6.0 LS Based Engine
TH400 Transmission
*D300 Colossus Case (32 Spline Outputs)
*S&S Fabrication 9" (Front & Rear)
GearWorks 10" Centers (5:43 Gears)
*Branik Motorsports Axles (40 Spline)
*Branik Motorsports Brakes (Hats & Rotors)
PSC Full Hydro Steering (10" Ram)
*Locked Off-Road (2.5" Coilovers & 2" Bumps Stops)
*TMR Sway-Bars
*Method Race Wheels
BF Goodrich 37" KM2/3 (Race Tires)

There are still a few unknown's for the build, however we will address those when the time comes. We have committed to a new build series on YouTube for Tinkerita to hopefully encourage others to just start doing what they love. To see more in detail as the build progresses, make sure to subscribe to the channel.

 

[FSU Off-Road]

Now then, to date, we have assembled and completely welded the chassis. We started with the top half and worked our way down until we installed the back and front portions. From start to finish, the chassis took approximately 26 hours to assemble and weld together.

Note the margarita to help ease the pain of frustrations.

With the chassis assembled, it was time to start thinking about gussets, shock mounts, link mounts etc. For the ease of complexity, we went with a mixture of TMR Customs and Barnes 4WD brackets as I notched 1.5" and 1.75" .120 DOM tubing for our gussets. If you're familiar with Ultra 4 Racing, then you know the Miller Pro Chassis is top dog as a solid axle car. With that said, I wanted to mimic a lot of Eric's support/gusseting system in our TMR chassis. Although different in overall design, I was able to come up with a flooring design to help strengthen the chassis as well as the lower subframe portion. I also wanted to utilize quick clamps to allow easier access to the transmission, transfer case, etc. from the bottom. In order to achieve all Ultra 4's safety rules and incorporate my design ideas, I used masking tape to help visualize where everything needed to go.

Little by little, I worked through the tape until I had most of the gussets complete. This included the flooring design, dash bar, shock brackets, link mounts, and sway-bar locations.

This can all be watched here:

 

[BRUISER]

Sweet

 

[FSU Off-Road]

To continue on past what's published on YouTube, I've been in the works of skinning the chassis while I wait on critical components. To date, this has been the most exciting thing for me personally, to see how Tinkerita is going to look in the end. With a bunch of cardboard, I made templates for the flooring, firewalls, and outer skins. I had a piece of aluminum for the roof and some scrap sheet metal that used for a front visor. Along with this, I was able to purchase a fiberglass hood and cowl from marketplace. Although too wide, we narrowed up them up to make them fit the chassis.

This past weekend we were able to start narrowing a stock TJ grill for Tinkerita. With my sidekick, we didn't get much accomplished, but it's more important to invest in the future of the sport for sure!

I don't suspect we'll get much done with the Christmas weekend ahead, however I'm hoping we'll be receiving our axles and brackets before the New Years and we'll hit it hard come the first of the year.

As mentioned, the axles are S&S Fabrication's 9's. Also running his outers as well.

These are our axles... just waiting on them to arrive right now.

Took a half day to get more done though. Mocked up the initial skid plates and rub rails and got those installed. Nice tight fit so I was happy. Also did a little aluminum work as well. Trying to get as much done as possible before the big components arrive.

I'm off the week after Christmas, so I'm look forward to some big progress.

 

[FSU Off-Road]

Sweet

Figured I’d bring the build here as well. Unicorns and TJ’s for the win.

 

[BRUISER]

Figured I’d bring the build here as well. Unicorns and TJ’s for the win.

At this pace you may beat me getting it done.

 

[Mojones915]

Excited to see this come together. I was actually looking at the TMR chassis before I went all in on the 4500 car. Hopefully @BRUISER, you and myself can all be on course at the same time next year....

 

[BRUISER]

Excited to see this come together. I was actually looking at the TMR chassis before I went all in on the 4500 car. Hopefully @BRUISER, you and myself can all be on course at the same time next year....

I just picked up a set of race scales to see if XJ can actually pass weight limits and if so there is a good possibility I will run the XJ for the east series in 2022. As each race is less than 11hr drive for me

 

[Mojones915]

I just picked up a set of race scales to see if XJ can actually pass weight limits and if so there is a good policy I will run the XJ for the east series in 2022. As each race is less than 11hr drive for me

I hear you. I am currently trying to figure out how I am going to put in a 2in cage and put the TJ on a diet at the same time.

 

[ghost]

This looks like fin! In for the build and updates....

 

[FSU Off-Road]

As it always goes, I didn't get as much done as I wanted to, however we did manage to knock a few things off the list. I did finish the rear back paneling (excluding the mesh for ventilation). Everything lined up well and should be enough cut out to keep things cool. I left enough room for additional cutouts for the shoulder harnesses when the time comes.

While trying to finalize the cowl placement, I had the wife hop in and help me out. Unfortunately she was too short to see the hood due to the height of the cowl. Yes, there are adjustments to the seat brackets, however I agreed the cowl was too tall for my liking as well. In order to "lower" the cowl, I had to add some speed holes haha. I'll go back and fiberglass over these later. This allowed me to lower the cowl 1.5" from the original position. As a result, everything aligned better than expected once we installed the hood.

As a nice surprise, my dzus 1/4 turn fittings arrived quicker than expected. This allowed me to work on the body panels for a couple of days. Although not 100% complete (cowl/hood fender & rear fender), at least the main body panels are done.

To finish off the days I had to work on it, I focused on narrowing up the grill again. Since I lowered the cowl and hood, I had to do the same to the grill. Then worked on a few custom tabs to mount it to the chassis. Tinkerita officially has a face! I honestly surprised myself on how well it lined up and other than some bondo and pain, it looks better than I imagined.

With this complete, it's time to shift my focuses. Unfortunately the LQ9 6.0 we have has a busted rod and piston. I don't know the severity of it yet, so while we dive into that, I went and pulled a LM7 5.3 from a local junkyard for mock-up purposes. This should keep me busy for a while as I figure out the placement for it all.

 

[FSU Off-Road]

Before I got too carried away with the motor, I had to finish my video.



I got the mock-up/back-up motor on the stand and stripped it down as quickly as possible. I wanted to clean and inspect everything so it wasn't so dang dirty in the chassis. Completely tore it down and cleaned everything, it was NASTY! Seems we have some bearings to replace in the future. While I cleaned, I also used some parts laying around the garage to make some mounts.

Although not completely reassembled, its clean enough for mock-up purposes and will allow me to continue progressing on the build.

Built a home made lift and started getting the motor installed into the chassis. Used some scrap tubing to get it initially in place before we get the TH400 and Colossus Case installed. Although tight, we shouldn't have any issues with exhaust, firewalls, flooring, etc. Also worked on some quick disconnect clamps for the shock supports and making sure we wouldn't have any clearance issues over the motor.

I picked up our TH400 yesterday, so I'll be working on that install next as well as getting things prepped for our axles, they arrive Wednesday!

 

[Scottal]

Man this is awesome! Cant wait to see the final product. Me and my dad have been kicking around this same idea of 4800 for a few years now. We are to the point of trying to make his buggy make weight limit all while he wants a new chassis to. Its extremely difficult to to have a buggy that can be raced and is comfortable enough to trail ride in also. Keep pushing and good luck!

 

[77GreenMachine]

@Van-go has an all aluminum LS1 for sale if you wanna switch gears a little bit

 

[Van-go]

@Van-go has an all aluminum LS1 for sale if you wanna switch gears a little bit

We’ve been talking. He was gonna get it so I held onto it for a while til he decided what direction to go.

 

[paradisePWoffrd]

Been following along the build thread, and just noticed that you are in Hickory. Let me know if you ever need a hand, or just want someone to come drink a beer and hand you tools.

 

[FSU Off-Road]

Been following along the build thread, and just noticed that you are in Hickory. Let me know if you ever need a hand, or just want someone to come drink a beer and hand you tools.

Absolutely! Up in Bethlehem to be exact. I’ll be putting in some long weekends coming up and I’ll keep the cooler full.

 

[FSU Off-Road]

Over the past week I've been a little distracted as I watched KOH 2022. So many many memories from last year! Watching also motivated me more to get this thing done in record timing. I don't want next years KOH to be our first outing, so full steam ahead! Like I mentioned before, I picked up our TH400 and starting working on installing this. After getting it bolted to our 5.3, I wanted to design a lower cross member to not only add support but be easily removable for working on the transmissions/transfer case if need be. I mimicked MM again from a design standpoint, however I utilized TMR's transmission mount instead of incorporating an additional cross member. Once the transfer case is installed, we can adjust the fitment of everything accordingly and get it all welded up.

Now for the exciting part! Our axles have arrived and it's time to get these things underneath the chassis. S&S Fab did a great job on these housings. These are their Race Series 9" housings with 4" tubes, 3/8" welded skids and internally gusseted, yet still allowing a 10" ring gear. As for the knuckles and rear bearing cups, these utilize the 05+ super duty unit bearings allowing for whatever size axles we can afford ha! I've already started on the rear, so I should have it initially mocked up under the chassis soon.

 

[WARRIORWELDING]

Absolutely! Up in Bethlehem to be exact. I’ll be putting in some long weekends coming up and I’ll keep the cooler full.

Really. I grew up on Teague Town. Few old wheelers and fabricators in that little hood.

 

[gslander]

Really. I grew up on Teague Town. Few old wheelers and fabricators in that little hood.

That's just up the road from me, I'm off cemetery loop.

 

[FSU Off-Road]

If your curious about the motor and where it came from, then check out the video below:




With that said, I've been hard at it on with the rear axle. Since this is the easier of the two, I wanted to start with this one. I started by gusseting the rear of the axle with a Trail Gear truss. Unfortunately this wasn't long enough as I wanted it to be full width for maximum strength. So I decided to chop it up and made partial sections in order to achieve the full width I desired. To add extra some extra strength into it all, I decided to internally gusset the truss as well. Lastly, I topped the truss with individual plates so I could weld them onto the internal gussets maximizing overall strength.

Not going to lie, this took up quite a bit of time, however I think in the long run, it will be worth it. With the truss completely welded, it was time to install the link brackets. The 4800 class is limited to 37" tires, however planning ahead, I went with an overall 10" separation in order to run 40's in the future. To minimize overall height, I started with the lowers and only allowed them to hang 1" below the axle tube for clearance. It looks like more in the picture, but the housing is rotated. For now, I just put some large tack welds on there to make sure we don't have to adjust anything when we get it under the chassis.

The next step I have to again give credit to MM and their upper link design. Our axle has an offset pinion in order to have equal length shafts, makes it easier on spare shafts as well as offsetting the diff just a little for rocks. With that said, I had to design custom individual link brackets to make up for the offset diff. Used some cardboard to get an idea then transposed it onto our 3/16" material, added a bend for a little extra clearance, made them tall enough to have our 10" separation, and long enough to integrate them onto the rear truss. After a little back and forth, I was able to template out the outers and finish with one more gusset for strength.

After all of that, I cleaned up a little and I finally got the axle initially set up under the chassis. Installed our mock up unit bearings and I believe this is going to workout well. Now it's time to mock up some links, possibly build our trailing arms and make sure there isn't any interference with our fuel cell (no yet in place).

 

[FSU Off-Road]

Over the past week we've made huge progress. Since we had the rear axle completely mocked up, it was time to get some links under it and see it flex. My big concern was the fuel cell location and shock mount interference. To keep everything as low as possible, I mounted our fuel cell mount to the bottom of the chassis.

Unfortunately this didn't allow the rear axle to travel up as much as I wanted. So without hesitation I moved it to the top of the chassis tube to get it out of the way. In the near future, I'll do some trimming to lower it some more. With that said, I took my old crawler links and put together a quick suspension for mock up purposes. At full bump and full droop, we have almost 24" travel with 16" coil overs (12.5" up/11.25" down).

After our initial measurements, I started cutting tubing for our upper links to get the correct length we needed. Got those all drilled, inserts welded up, heims installed, and put them in their place under the chassis. After that, I worked on the design of our custom trailing arm. Going with an anti-wobble in the front, 2" .25" wall tubing with a ripped 2x4x.25" square tubing for a shock mount/strength, and heim in the rear for adjustments.

After getting the first one tacked together, I placed it back under the chassis for final adjustments. Wanted to verify clearances again, measure full bump, full droop, and full flex. Moving forward, we have to move the rear lower axle brackets a little wider for our 2.5" coilover springs to clear full flex (clears 2" springs), however everything else works nicely. We will limit up travel to 11.5" at full bump, and strap full droop at 9.5" initially until we verify drive shaft angles. Even still 20"+ inches in the rear.

Just because curiosity killed the cat, I threw a tire on there to see how it'll look. Although a little wider and taller than our race package, I'm pretty happy how the rear turned out.

 

[FSU Off-Road]

Custom Trailing-Arm Design:
TMR Customs Anti-Wobble (4 degree rotation)
2" x .25" DOM Tubing
2" x 4" x .25" Square Tubing (1.5" Interior Width)
1.25" Heim Insert

Used the 2" DOM for the main structure and attached both the anti-wobble housing as well as the heim insert. Note: make sure you drill a couple of holes at the end and weld those up with the insert installed to hold the insert in place before welding up completely. As mentioned, we ripped the 2x4 in equal halves for the "top" shock mounting location. Used 1.5" wide plate to add a back and interior plate to keep mud and water out of the overall design. Also used the same material to build a wrap over the anti-wobble housing for additional support. Lastly cut out some overlay plates to use as additional support and strength to the mounting location of the coilovers. Drilled a hole for drainage and completely welded everything up then duplicated this on the other side.

Can also be watched here:

 

[FSU Off-Road]

Now with the rear done, it's time to tackle the front. In order to achieve the full 50 degree steering, 16" of travel, and have all the clearances I need for 2.5" coilovers, I knew I had my work cut out for me. Before I started cutting anything, I ordered a 9" axle measuring tool as well as a Method MR101 to help with this process. I also went to Spidertrax and got as much input as I could from their tech support as well as used the front axle calculator they supply (highly recommended).

With all of that, I started mocking up the axle under the chassis to see if my initial pinion offset would suffice. Luckily through the years of mishaps, I measure twice and cut once (sometimes still not enough) but in this case I did moved the pinion offset to -8.5" over the initial -9.5". This helped with the clearances I needed for the lower mounts as the steering knuckle assemblies are just massive and take up a lot of tube space. With all of that said, I took a BUNCH of measurements and finally started cutting the axle tubes for our outer C's. NOTE: For WMS you have to add everything (2x unit bearing, 2x C depth, 2x knuckle) to get the correct measurements.

Typically you'd "press" the outer C's onto the axle tube, unfortunately I don't have access to anything like that, so I improvised as I usually do. I took a belt sander to the outer edge of the axle tubes until I had enough clearance to literally beat the C's onto the tubes, it's basically press fit haha. Regardless, it was a long day but worth it as I was able to get the C's in the correct location as well as the desired caster angle.

After installing a unit bearing, I threw the axle back under the chassis with the MR101 and KM3 to brainstorm some more about all the mount locations. Initially tacked up some lower link mounts to verify a few things, to say the least, it's going to be snug, some custom brackets will be made in the processes, but definitely possible. Instead of pushing through, I decided to sit back, have a cold snack, and admire how far we've come. In these small moments, I get really excited about the finished result.

 

[Zsavage81]

Do you feel like the wobble stopper in the trailing arm limits travel more than say a heim at both ends with delrin bushings on the shock eyes? How important is the axle heim in the equation with the wobble stopper up top? Would a 1" heim with a 1" bolt get bound up? Is that high misalignment spacer the key to the whole deal?