Build 4508 - Ultra4 Racetruck Build

[nukegoat]

The arms I had on my Early Bronco were .313 thick 2" tube, that's a tubing thickness that is available if you dont want to chance quarter wall. Are your factory arms straight still?

FWIW I run 0.25 wall tube. Never bent a link but I've destroyed tons of tie rods. Not saying it's impossible - it may happen but the failure mode seems benign enough. I should mention not all DOM is created equal - but high quality stuff that comes with MTRs will generally be good to 70-90ksi which is far better than scrap structural tube I've tried using that yields very early and easily (30-35 ksi, etc).

 

[snivilous]

Yeah, so I opened up mine, emptied the emulsion, let it stop foaming, then poured the oil back into the can, actuated the bump gently a few times, then set it to fully compressed, added oil till full, actuated it a few more times, then set it to fully compressed and added another 5 or 10ml or whatever it took to bring it to "almost full" and then capped it back up. Then I went to some 50-60 psi. It's a very very nice and gradual onset but it provides a *LOT* of resistance at full bump, which I was concerned about. In stock form, the rising rate goes from like 200 lbs to 600 lbs by the time it bottoms out. I wanted something more like 50 lbs to 1500 lbs. Anyway, sounds like you get what I'm saying. Very few people talk about tuning their bump stops, even in the desert racing circles. Like shock tuning - seems to be trade secret kind of stuff.

I had/have (is parked) a 3rd gen 4Runner that I designed and built a LT front end for and then never ended up getting to the rear due to school, so my solution was to buy some 2.5" bumps to mask the effects of the blown shocks. My figuring was stopping it from bottoming out was more important than a good shock with only like 8" of travel haha. I played with a lot of setups with those bumps since the truck was essentially stock height but with 35s so was bumped really low. I wish I had thought about the oil capacity stuff, since I spent a lot of time changing pressure from 300 to 50, shortening the stroke from 2" to 1", swapping fluid, etc. Obviously nothing really worked since I had blown shocks, and I was trying to make the bumps not be so stiff driving around town but not so wimpy they wouldn't stop the axle when I actually bottomed out. I had some normal 2" ones with the LT that were amazing and you never could tell they even engaged, the rear was the total opposite.

Speaking of shock tuning, I'm debating what to do about that. I have no issue tuning them myself but I think it'll be more efficient to go out with someone who's a dedicated tuner and I'm strapped for time. I just don't know if I should try and tune it in Colorado, or try to tune it at Hammers. At Hammers obviously I could get it perfectly dialed for that environment, but it's a gamble since I'll have a lot less time but at the right spot... vs back home tuning it with more time (assuming I can find decent areas to tune at speed) but not having the hybrid rock/desert area. At least I'm getting into the fun stuff though, I love how simple yet detailed you can get when it comes to suspension design and setup.

 

[nukegoat]

I had/have (is parked) a 3rd gen 4Runner that I designed and built a LT front end for and then never ended up getting to the rear due to school, so my solution was to buy some 2.5" bumps to mask the effects of the blown shocks. My figuring was stopping it from bottoming out was more important than a good shock with only like 8" of travel haha. I played with a lot of setups with those bumps since the truck was essentially stock height but with 35s so was bumped really low. I wish I had thought about the oil capacity stuff, since I spent a lot of time changing pressure from 300 to 50, shortening the stroke from 2" to 1", swapping fluid, etc. Obviously nothing really worked since I had blown shocks, and I was trying to make the bumps not be so stiff driving around town but not so wimpy they wouldn't stop the axle when I actually bottomed out. I had some normal 2" ones with the LT that were amazing and you never could tell they even engaged, the rear was the total opposite.

Speaking of shock tuning, I'm debating what to do about that. I have no issue tuning them myself but I think it'll be more efficient to go out with someone who's a dedicated tuner and I'm strapped for time. I just don't know if I should try and tune it in Colorado, or try to tune it at Hammers. At Hammers obviously I could get it perfectly dialed for that environment, but it's a gamble since I'll have a lot less time but at the right spot... vs back home tuning it with more time (assuming I can find decent areas to tune at speed) but not having the hybrid rock/desert area. At least I'm getting into the fun stuff though, I love how simple yet detailed you can get when it comes to suspension design and setup.

I have not cracked the secrets of shock tuning. I haven't found any reliable engineering resources on the topic, and the experts willingly admit to me that it's either
a) a dark art rather than science for them (it shouldnt' have to be, but it means they don't know why things work, just that sometimes things do work)
b) a trade secret (so they don't want to share with me any of the details).

I would start by tuning where you know you can test the rest, and consider having to tune again at the hammers.

 

[snivilous]

So nothing super exciting has happened lately. With school wrapping up, I decided to skip doing the front shock hoops and just do them when I get home and not in a rush. I made some bump stops for the front, so will just strap the axle to the frame so it doesn't bounce around and then I can move it around while fully bumped. After getting that done it was time to try and fire it up again, which after a few times figuring out what needed to be grounded she fired right up without any issue! Open headers sounds MEAN, obviously I won't run it like this but probably the most bad ass a stock 80 will ever sound haha

I then rigged up the brakes for the front end as well as connecting the tranny cooler and power steering lines so I could move and she ended up driving out of the shop today which was cool! Except that I needed to work on my Tundra a little, so parked the 80 in the corner of the shop parking lot which right now is a big ice sheet, and when I went to pull it back into the shop it didn't have any traction... I haven't put on the front driveshaft yet, and it's so icy that even with the 40s at ~8psi right now and locked it couldn't move itself. So I ended up using my stock Tundra to pull my Ultra4 rig around until it was lined up -_- I even tried putting the front driveshaft on, but it turns out the head of the bolt for the upper link mount on the frame hits the driveshaft so I couldn't get it on (and didn't spend that much time trying since it was like 20F outside and I was laying on ice). The skinny section of the driveshaft fits totally fine, and I honestly think that if both sides of the driveshaft were fully seated it would just BARELY clear the bolt head. So I might try to modify the stock driveshaft or just get a new one made.

But it drives!!

There's no coolant, or radiator, or fan, or battery tray (I have to hook it up, start it, unhook the battery, and rush to drive it before it gets too hot)---but it drives! Not that I drove much, and not that I modified anything, but it's nice to know after unplugging everything in the front end and having it torn down for the past few weeks that it still fires right up.

ALSO, I got my Ultra4 number so the 80 is now the #4508 car which is pretty exciting! I don't know if I ever said it before but I have tech inspection for KOH on February 2nd early in the morning, so that's my deadline to be finished! So I have less than 2 months and a hard deadline of needing the truck race prepped. Once I get home and have a (better) shop I should be able to make some good progress, and there's not THAT much to do really, mainly lots of testing.

I have my last final (hopefully forever!) tomorrow morning, then loading the truck up, and on Friday morning am heading back to Colorado with everything. Should be able to start making some big headway on the truck by the end of the weekend I think!

 

[tacosupreme]

You can also tune by changing the weight of the oil as well...I like the 5w blue fox oil but it's expensive. You will have a hard time tuning for race day in Colorado unless you have a 50 mile whooped out track handy. As the shocks heat up things will change a lot... Don't get too hung up on tuning, a good driver can compensate for most anything. You can make what you have work pretty easily with the bypass adjustments. Tighten the rebound until it starts to pack up at speed, then back off a few turns. Tighten compression until you get a little bounce, then back it off a few turns. Be careful it doesn't wheelbarrow or mule kick in the rear. Make sure you are running race day PSI in your tires and race weight when shock tuning, and have fun.

 

[ToyotaDon]

You know that driveshaft doesn't just move up and down, but side to side as well. You may need to reconfigure the link brackets.

Do you have future plans for the 2UZ-FE sitting there?

 

[snivilous]

You know that driveshaft doesn't just move up and down, but side to side as well. You may need to reconfigure the link brackets.

Do you have future plans for the 2UZ-FE sitting there?

Yes, however have barely any contact and it's only when everything is sitting on the bump stops. With any droop the driveshaft should swing down/away from the link bracket. I'll verify everything with the driveshaft in, but I'm not worried about contact in any other scenario (and a new shaft should alleviate that problem).

The 2UZ is my buddy's, he's been trying to sell it for awhile. I'm not sure what I'll run once I engine swap, but a 2UZ is about half the power I want to be shooting for. Doubtful it'll be a Toyota powertrain when I'm done, due to how hard it is to make power out of Toyota stuff and the ease of availability of parts for crate engines. I've toyed with the idea of throwing massive boost at the 1FZ, but feel bad destroying the engine and the associated hassle of boost and engine tuning it myself when I could just sell it since it runs great. We'll see....

 

[snivilous]

Moved back to my parent's house in Colorado for the near term until my girlfriend and I decide where we want our life to go next!

Got the 80 moved into my dad's shop (again). Lots to start doing, I was kind of hoping to have it fully drivable a week from today but thinking about it since I have to plumb essentially every fluid system in the whole truck, plus the front shock hoops, etc. I doubt that will happen unless I can get parts shipped fast.

And that's really it, I'm gonna start working on it tonight. Thinking I'm gonna buy a plasma cutter this coming week since I need to cut a lot of 1/4" plate for the skids, link mounts, gussets, etc. Now that I have access to my dad's assortment of tools I think I can start making good headway, plus the fact school is (theoretically) over forever, so I can just balance work and the racetruck. Lots of updates to come since there's lots to do in the next month leading up to KOH!

 

[snivilous]

I've been contemplating getting a plasma cutter for awhile, and since I'm home and have access to my dad's compressor I decided to get one today! Since I have a lot of metal cutting to do between gussets, front bumper, gas tank skid, etc. it seemed like it would be a good choice. I've never used a plasma, but within 5 minutes I couldn't believe I had gone so long cutting metal without one!

After practicing for all of a minute I got to working on the front bumper. I trimmed the frame rails back a bit, and decided to have a center tube/cross member in the front that the winch plate, shock mounts, bull bar, etc. will tie into. I am using some of the 2.5" tube I have and then building the frame out where I want it with 1/4" plate.

And that's all I really got done today. I bought a winch plate from Harbor Freight so will modify that to sit how I want it and then will build the bull bar and shock mounts, grille, etc. off of it.

 

[snivilous]

Tacked in a bull bar and cut my winch plate down and tacked it on. Everything is nice and compact, and has plenty of room from the engine. The bull bar just barely sticks out past the 40s.

The next step was to start mocking up the rest of the front end cage work, so I figured I should throw the hood on and decide how I wanted it to sit to look good with everything below it. There's a bolt hole 11" forward of the front hood hinge bolt hole, and it seemed like using that hole to bolt the hood on would move the hood back to a good spot, so I cut 11" off the back of the hood and this is how she sits now!

I think it turned out super sweet where it's sitting, so much so that my original plan of narrowing the front end was thrown out the door--having a full width 80 hood just looks awesome! I worked on some other little stuff afterwards since I haven't decided how to do the tube work on the front yet... One of my buddies sent me this photo which is pretty close to what I was envisioning:

So what I'm thinking is have tube going from the A pillars and wrapping around and being right below the hood, and then in the front have some 8" LED bars or so on each side that would mimic the look of the stock headlights, and then between them have some kind of grille. Underneath all of that would be another tube (kind of like in the picture, but more square profile like the 80's front end). So the tire areas would be tucked up super high, and then as you get to the middle it would come down with some type of grille layout... And then of course the shock hoops will tie into everything and what not. I'm not really sure how to do the grille layout, since there's a LOT of room between the winch and the hood, and I feel like it would look kind of weird having all of that be grille (but the stock grille actually fits in there quite well)--but at the same time, a short grille I think might look weird with too much gap between it and the winch... So I don't know, maybe I'll do a 2/3 height grille so there's some breathing room from the winch and have some metal with a cut out that says 4508 or FJ80 or something.

Otherwise like I said I did some other little stuff, been trimming some body work and trying to figure out where to put the fuel cell. I might just put it kind of where it was before since I think mounting it low between the frame rails would be cool, but with how the 4x4 labs bumper mounts up I would have to cut that up quite a bit. I could use the rear bumper and weld a plate between both sides that the fuel cell sits on, but I don't like that idea since if the bumper gets destroyed then the fuel cell is going with it. So undecided on that.... My welder hasn't been working lately, so today probably going to rig up a 220 adapter so it will plug into the high current 220 ones we have in the garage, hopefully that will fix it since it keeps blowing it's internal circuit breaker welding at 110.

Also ordered a bunch of stuff from Cruiser Outfitters who as always are awesome to work with, the hub body where the shear pins and studs for the rear axle shaft got sheared/ripped out costs a fortune so I'm gonna have to extract the sheared studs and then Kurt is sending me some shear pins so I'll have to redrill the hub body and the axle shaft for the new shear pins. Once that's done the rear axle should be set to go!

 

[snivilous]

Boxed out the front and got it all welded up.

The welder is being a bitch, it kept blowing the internal breaker on 120V. I called up Miller and apparently there was a batch of breakers that are super sensitive. I made an adapter for our 240V plug so I could use the welder's 240V plug, and figured I could just warranty it after KOH since I need it now. Well today it decided that 240V was too sensitive too. So I can weld for like 4-8s at 240V, or like 4s at 120V before it blows the breaker. So I'm taking it in for warranty on Tuesday, and gonna have to tack everything up with a stick welder and then go in with the MIG and weld everything up afterwards (or use the stick if the MIG isn't fixed yet). Prior to the welder taking a s***, I was welding in the new fuel cell location:

Probably some of my best welds to date, not that that is saying much....

So the fuel cell is lower and further back than before. All 1/4" plate holding it in. I have a lot more to add, like I'll be gusseting everything to the frame since it's a pretty weak structure right now, and I added a plate on the back to protect from rocks and sliding out and to stiffen the base plate up. I think it's turning out nicely and will really get the tank out of the way and help move the CG down/back a bit. I'm thinking of making a big plate that goes down over the top of the fuel cell and has cut outs for all the hoses, and that plate will bolt to the cage and hold the fuel cell really snug and secure and look sexy versus those little straps I used to have.

And that's all I got done today. I might work on the truck later tonight and start on the front shock mounts. I need to buy some more steel for the front cage which sucks, but oh well. Slowly getting there though!

 

[nukegoat]

I love it all. A++ man. If i had more free time I would offer to help pit for you

 

[BlueCruiser84]

Maybe you answered it, but after all this cutting on the front end why are you keeping the wagon body and rear 2ft of frame? Wouldn't it be easier to whack it all off just behind the B-pillar and tube it out back there? Is that not allowed?

 

[nukegoat]

Is that not allowed?

Right

 

[BlueCruiser84]

Right

huh. Interesting rules.

 

[scottryana]

Not sure which rules he is following but some of the sanctioning bodies are very bizarre. I have been looking at the Stock Full class for Score and you can add to the frame but you can't subtract. You have to have a complete body, and doors, but can remove all the windows. You do not have to have a rear hatch. You can make all the internal engine mods you want but the outside has to stay stock, no forced induction. You can run multiple shocks per axle, but you have to retain the stock links. The truck can not weigh less than the stock OEM weight, etc.

I know it seems like it keeps things fair but then they start bending the rules. Like the Ford Raptor is now Turbo charged so they can have their force induction but like a Tundra/200 series can't use a TRD blower.

I don't know anything about the rock crawling sanctioning bodies since it doesn't appeal to me but I am sure they have similar rules about the 4500 class to keep them looking stock.

 

[snivilous]

Maybe you answered it, but after all this cutting on the front end why are you keeping the wagon body and rear 2ft of frame? Wouldn't it be easier to whack it all off just behind the B-pillar and tube it out back there? Is that not allowed?

Right

I don't know anything about the rock crawling sanctioning bodies since it doesn't appeal to me but I am sure they have similar rules about the 4500 class to keep them looking stock.

So the 4500 rules are super open, there's essentially three "main" requirements: 37" (or smaller) tires, manual steering linkage (no full hydro), and the frame from the engine mount to the seats has to be "stock", aka a boxed structure essentially. Everything else is more or less unrestricted.

So @BlueCruiser84 yes I could go full tube chassis from the B pillar back. You can actually buy 4500 cars from Jimmys or Trent fab that are a full tube chassis and for that section from the motor to the seats is just boxed in, and is technically legal. There's actually been lots of debate about that this year because Vaughn Gittens Jr. (he's super big in drifting, and drives the a blue IFS Bronco 4500 car) has one of these specialty built chassis that is essentially a full unlimited car with some tweaks to make it meet 4500 specs--and he has absolutely dominated the short course Ultra4 races, during Nationals he was literally lapping other 4500 cars. The rules have even been changed for 2018 specifically because of his car, to say that IFS is ONLY allowed on cars that came IFS from the factory (which a double wishbone IFS was never factory on a Bronco, TTB was though). Point being, the rules are VERY open for 4500 since it is essentially a down graded unlimited class versus a beefed up stock class. As long as the truck meets those specs I listed, and VAGUELY resembles a "stock" car--like having a hood and grille or some doors--then anything can be done like @scottryana said.

So to answer why I haven't done that, it comes down to benefits vs time. I had strongly considered cutting the back completely off and building a tube chassis from the B pillar hoop back, but besides being a lot of work and me being very strapped for time, there wasn't a lot of advantages I could see. For example, the front end can only bump so high due to the engine (that's literally what is the limiting factor on my up travel). And the rear end can EASILY bump higher than the front ever can--with my current/old bumps that are dropped 3" that it's sitting on right now, the rear has the same or maybe an inch more up travel than the front. So what does a full tube rear end really gain me? I can have 3-4" more up travel in the rear with it being 100% stock frame/links than the front, but since the front and rear shocks are the same then the front and rear travel numbers won't match. Additionally, I would have to either make or weld in the stock link mounts, which the stock links (should) work totally fine for the travel I'm pulling so not like I'm gaining much there. And since I'm keeping the stock body, not like I would really gain any room going to a tube chassis rear. There's not really a lot of benefits for me, especially with the time it would take to do all that work.

Now where I do agree with you, and what I plan to do, is to shorten the very rear of the frame probably a foot. I want to cut the body at the windows and shorten the body and splice it back together and try to make the body still look as stock as possible, but like a short bus. Obviously having like a 80deg approach angle and like a 50deg departure angle doesn't make a ton of sense. The reason I haven't started cutting the rear is I think that's more work than I can do before KOH. Once KOH is done, I will definitely be chopping the rear and moving it forward to try and get the best departure angle I can. I plan to move the tail gate as close to the fuel cell as I can, maybe even have it hinge off the fuel cell tray and have that essentially dictate the departure angle. If I somehow got the truck totally done tomorrow, I would definitely go in and cut everything up, but a better departure angle is super far down the priority list.

 

[BlueCruiser84]

So the 4500 rules are super open, there's essentially three "main" requirements: 37" (or smaller) tires, manual steering linkage (no full hydro), and the frame from the engine mount to the seats has to be "stock", aka a boxed structure essentially. Everything else is more or less unrestricted.

So @BlueCruiser84 yes I could go full tube chassis from the B pillar back. You can actually buy 4500 cars from Jimmys or Trent fab that are a full tube chassis and for that section from the motor to the seats is just boxed in, and is technically legal. There's actually been lots of debate about that this year because Vaughn Gittens Jr. (he's super big in drifting, and drives the a blue IFS Bronco 4500 car) has one of these specialty built chassis that is essentially a full unlimited car with some tweaks to make it meet 4500 specs--and he has absolutely dominated the short course Ultra4 races, during Nationals he was literally lapping other 4500 cars. The rules have even been changed for 2018 specifically because of his car, to say that IFS is ONLY allowed on cars that came IFS from the factory (which a double wishbone IFS was never factory on a Bronco, TTB was though). Point being, the rules are VERY open for 4500 since it is essentially a down graded unlimited class versus a beefed up stock class. As long as the truck meets those specs I listed, and VAGUELY resembles a "stock" car--like having a hood and grille or some doors--then anything can be done like @scottryana said.

So to answer why I haven't done that, it comes down to benefits vs time. I had strongly considered cutting the back completely off and building a tube chassis from the B pillar hoop back, but besides being a lot of work and me being very strapped for time, there wasn't a lot of advantages I could see. For example, the front end can only bump so high due to the engine (that's literally what is the limiting factor on my up travel). And the rear end can EASILY bump higher than the front ever can--with my current/old bumps that are dropped 3" that it's sitting on right now, the rear has the same or maybe an inch more up travel than the front. So what does a full tube rear end really gain me? I can have 3-4" more up travel in the rear with it being 100% stock frame/links than the front, but since the front and rear shocks are the same then the front and rear travel numbers won't match. Additionally, I would have to either make or weld in the stock link mounts, which the stock links (should) work totally fine for the travel I'm pulling so not like I'm gaining much there. And since I'm keeping the stock body, not like I would really gain any room going to a tube chassis rear. There's not really a lot of benefits for me, especially with the time it would take to do all that work.

Now where I do agree with you, and what I plan to do, is to shorten the very rear of the frame probably a foot. I want to cut the body at the windows and shorten the body and splice it back together and try to make the body still look as stock as possible, but like a short bus. Obviously having like a 80deg approach angle and like a 50deg departure angle doesn't make a ton of sense. The reason I haven't started cutting the rear is I think that's more work than I can do before KOH. Once KOH is done, I will definitely be chopping the rear and moving it forward to try and get the best departure angle I can. I plan to move the tail gate as close to the fuel cell as I can, maybe even have it hinge off the fuel cell tray and have that essentially dictate the departure angle. If I somehow got the truck totally done tomorrow, I would definitely go in and cut everything up, but a better departure angle is super far down the priority list.

I'd say you answered my question... great explanation! Wish you were closer so I could help out. I always loved working on a time crunch.

Good luck!!

 

[snivilous]

Got my Kings in, only took about 14 weeks from ordering. If anyone wants to buy them I'm selling them for $900/pair.

Made some shock hoops and started mounting stuff.

Both motor mounts are broken, so I pulled the passenger side one and cut it up a bit to figure out where I need to cut the new one to clear the upper link heim. Everything has lots of room now.

Today I was able to put together the whole driver's side:

A little more welding to do, and gonna brace everything up, but she's finally moving along! Flexes decently too, probably gonna have to take it for a drive to check clearance since I don't think I can fully flex the front out with the jack and jackstands I have.

Also, last week my dad and I had the brilliant idea to turn this tool box that came with the trailer into a pseudo camper. Some people will probably think it's pretty weird, I think it's pretty awesome. My girlfriend and I couldn't find a cheap camper to put on the truck, so this seemed like a good solution so I can just park where ever and crawl in the back plus get out of the elements and wind.

There will be windows and vents, and about 2ft wide, 3ft tall, and 7ft long of space to sleep. There's also a pull out tray that goes on the bottom and will hold all my tools. It's perfect size for a ground pad and sleeping bag, and I'll be able to lock everything up and if I don't want to sleep in it have the whole top level for storage. I think it'll be pretty sweet! Nothing like living in a tool box when you're racing on a budget haha

Should finish up the front axle tomorrow, and maybe get to plumbing everything. Finally feels like I'm on track and this beast will actually be running and driving in time! And no, the front shock hoops are not done--don't worry, I'm not planning on just a single tube and nothing else holding up the whole of the truck.

 

[BlueCruiser84]

Got my Kings in, only took about 14 weeks from ordering. If anyone wants to buy them I'm selling them for $900/pair.

Made some shock hoops and started mounting stuff.

Both motor mounts are broken, so I pulled the passenger side one and cut it up a bit to figure out where I need to cut the new one to clear the upper link heim. Everything has lots of room now.

Today I was able to put together the whole driver's side:

A little more welding to do, and gonna brace everything up, but she's finally moving along! Flexes decently too, probably gonna have to take it for a drive to check clearance since I don't think I can fully flex the front out with the jack and jackstands I have.

Also, last week my dad and I had the brilliant idea to turn this tool box that came with the trailer into a pseudo camper. Some people will probably think it's pretty weird, I think it's pretty awesome. My girlfriend and I couldn't find a cheap camper to put on the truck, so this seemed like a good solution so I can just park where ever and crawl in the back plus get out of the elements and wind.

There will be windows and vents, and about 2ft wide, 3ft tall, and 7ft long of space to sleep. There's also a pull out tray that goes on the bottom and will hold all my tools. It's perfect size for a ground pad and sleeping bag, and I'll be able to lock everything up and if I don't want to sleep in it have the whole top level for storage. I think it'll be pretty sweet! Nothing like living in a tool box when you're racing on a budget haha

Should finish up the front axle tomorrow, and maybe get to plumbing everything. Finally feels like I'm on track and this beast will actually be running and driving in time! And no, the front shock hoops are not done--don't worry, I'm not planning on just a single tube and nothing else holding up the whole of the truck.

Dude. The build is sweet, but I love the friggin' camper idea.