I have no idea what I'm doing aka the worst Ultra4 4400 build thread on Earth.

FlatlandFSJ said:

If you plan on racing east coast woods stuff, I'd almost say 120 is gonna be longer then you want. Healy's new car is a 116 wheelbase and the miller chassis cars tend to be 113-116 in east coast trim. I doubt you see many 120+ cars unless its in the desert. Long rigs that dont turn well tend to get hung up in the trees pretty bad.

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Ok I'll definitely shorten it up a couple inches and try to stay at 120. You're the second suggestion I got to bring it down to 120".

I will be racing on the U4 East series the majority of the time but my goal is to make it to KOH.

So I took 23 measurements of the XJ body after cutting it up. This is the chassis design I ended up with. I need to stick the drivetrain together and get a more accurate measurement to finish out the tunnel width/height to confirm seat mounting options with helmet to roof clearance. If I need to I'll cut the roof off and raise the roof (aaay) bars and make a new roof.

Should be able to end up with a completely flat belly and have a 120" wheelbase. I may have to go slightly longer depending on how I feel about the drive shaft lengths at 120" for the amount of travel I want. This setup will allow me to have 48" rear lower links. Once I have the measurements of the drivetrain dialed in I'll start working on the lower engine cage.

This is still what I'd consider a rough draft as I'm sure I'll make 100 changes between now and when it's a roller.

Please give me any suggestions about the chassis design. If I built a death trap please tell me.











I uploaded a video of the chassis on my IG if it makes it easier to see it. https://instagram.com/dobermanracing

Looks like that window hole to climb in and out is tiny. Is it big enough to get a seat through?

Jduck said:

Looks like that window hole to climb in and out is tiny. Is it big enough to get a seat through?

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It's 27" wide. The fx1 pro seat is 23" at its widest. I was thinking about putting a small bend in the a pillar support tube that's currently straight to get a little more room.

I'd probably run that 2nd A pillar at a straight line down to the node by your feet and ditch the horizontal bar all together.

Made some changes with Beerj's suggestions. Some others were pointing out concerns with egress and tech inspection.




I also cut the dove tail. Tomorrow I'll clean up the plasma cuts. I need to cut a strip about 1.5" out of the center section to shorten it up to line up with the sides since they arc in. Then I'll get it tacked back together.

No bends in the cage, nice!

How about some updates?

It's been a minute since I updated the thread. I changed up the design a little bit and started building the frame yesterday until I ran out of day light.

Today I'm going to finish the x bracing and get it under the body and make drivetrain mounts.

ridered3 said:

How about some updates?

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Done

Made some trim for the dove tail. Got the drivetrain positioned for measurements. Didn't realize these weren't posted.

DobermanRacing said:

Done

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Good timing

Are you legit building this on the easement just outside of your house? I'm impressed. I feel like all of my stuff would get stolen over night if I did something like that.

The Luke said:

Are you legit building this on the easement just outside of your house? I'm impressed. I feel like all of my stuff would get stolen over night if I did something like that.

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Yeah I don't keep my tools outside though I bring them in at the end of the day or lock them up in my shed.

It's also not my house. I built my buddies cage in exchange for letting me use his backyard and he paid for some of my tubing. After I finished his cage in his backyard it somehow turned into the easement... Not about to bitch though as it's been parked there for 2 months while I was waiting on parts to be delivered and they're putting up with a cut up Jeep outside the house.

I don't have 240v at my house and they have a flat yard which is why I wanted to do it there. Normally I do all my work in the street in front of my house.

My only complaint about the spot is I get "fans" stopping by several times a day that don't understand what personal space is telling me about every irok z they had in their youth or to ask if I want to rebuild their astrovan rear axle or if I want to rebuild their wj trans or if I want to change their dirt bike tire or if I want to go to their house and replace their ball joints.

I just quote them a ridiculous price. Ball joints? Sure $500 labor/corner. Axle swap? Sure $500 labor. Some get its my I don't want to do it price. Others get upset and complain which I find hilarious.

Not as big of an update today as I'd have liked. I'm going for my CDL, but was waiting on a replacement social security card to come in. I got it yesterday so spent about 7 hours at the MVC today paying for my CLP/Written test.

Got a few tubes burned in and then ran out of wire. Then broke my 4th HF notcher. Eventually they'll stop giving me warranty replacements and I'll invest in a quality one. Normally they break the arbor where the hole saw screws onto. This time the threads pulled out of the clamp.

Ill pick up another 12lb spool when the welding supply shop is open in the morning, and get the notcher swapped out.

I've been welding completely around the joint but I've seen some cages where they leave a 1/4" unwelded, I've been told this is to prevent blowout from air trying to leave the tube. Can anyone vouch for this or should I keep doing what I'm doing?

Weld the tube all the way around.

I like it, reminds me of when I got started. Your drawing seems different than what your building. To me there's way too much tubing in the drawing. But I'm nobody and nothing special so take that with a grain of salt. With that said what size tube are you using? And have you looked over the rules for 4400?

ranger11 said:

Weld the tube all the way around.

I like it, reminds me of when I got started. Your drawing seems different than what your building. To me there's way too much tubing in the drawing. But I'm nobody and nothing special so take that with a grain of salt. With that said what size tube are you using? And have you looked over the rules for 4400?

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You are special to many people. You are just misguided on the Ford part......

ranger11 said:

Weld the tube all the way around.

I like it, reminds me of when I got started. Your drawing seems different than what your building. To me there's way too much tubing in the drawing. But I'm nobody and nothing special so take that with a grain of salt. With that said what size tube are you using? And have you looked over the rules for 4400?

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I believe he's running 2" for most or all of the structural stuff.

Yes I'm running 2" as I expect this to break 4400lbs and anything that's under a 30" span can be 1.75". I've read the U4 rules and there's nothing saying you can't have a partial body for 4400 class.

Yeah Idk what I was thinking. I think I just got excited after buying bendtech and put tubes everywhere I could fit one. If found it easier to just design single parts on it. I'm sure as I keep building and getting experience Ill be able to make a full assembly design with it.

Right now I just have the engine/trans sitting on top of the lower tubes. I think I'm going to push the chassis back a bit as there is a lot of clearance between the first cross member and the drive accessories. I plan on making the front cross member flanged so engine removal will be easier. Right now the trans would need to come out through the top or out with the engine.

Top rail interferes with the thermostat housing. I'm going to have to Google and see if they make one the comes out at a different angle. Tho the top rail isn't welded yet so I still have time to cut down the vertical tubes to lower it. I will also need to make some changes to the pass header down pipe to dodge the upper rail.






I was able to fix my HF notcher's clamp with a M12x1.75 bolt. As the threads only pulled off the T handle while the hole was still good.

Leaving Fastenal I spotted this fun day happening.