700hp, 40s, bypasses, tube chassis rock buggy build

Wow, can't believe all the changes & progress. Awesome is too small a comment!!

 

Went out to Vernal this weekend to race with Bonneville Off-road! The course was similar to the same one last year, and was 8x laps at 18ish miles per lap so around ~140 total. This was also the first race with the semi, just got a mini bike, first time sleeping in the semi, we bought a projector to play movies on the back of the semi, just tons of fun planned all around!

I did extremely minimal prep beforehand. I joke that it doesn't need much prep since it's not a dedicated racecar. I spent most of the time messing with the semi and making improvements to it, and only an afternoon after work really screwing with the buggy. I made a new brake pedal and adjusted the gas pedal, moving them back around 3" which was really nice. I also threw a hi lift mount on the spare tire carrier. Otherwise it was just checking bolts, new oil filter, and a tape measure and string alignment!



The semi worked great, the gear pass through had all the race gear, the passenger box had all the tools, and the driver's box had some random stuff like fire extinguishers. Then we threw a cooler for food on the deck and strapped the Jerry cans on and that was about it. Picked up my buddy to codrive and he slept most of the way to the race with the wife riding shotgun.

It ended up raining or snowing most of the drive which was great.



As soon as we arrived the race director told us to go do our prerun lap since it wasn't raining at that moment, so we quickly unloaded the semi and took the buggy out!



This was the first time my buddy had been codriver in anything, and since it was starting to rain and get muddy he got a quick speed run how to mark hazards in the low rance and then we putted around the course. We also got the custom molded ear plug/speakers which are an absolute world of difference, and this was the first time with both of us having them in the car so got to make sure everything was playing well together. And that was about it!

This whole race was extremely chill compared to any other race I've done, even this same race last year. There was no wrenching or screwing with things, no late nights leading up to it, just everything was happy and the prerun lap went great! Which really worked out since it started raining quite a bit after we got back.



We went to the driver's meeting, I got shit because the course now went through the whole in the fence I created last year you could say I was directly involved building the course the course! There was only a dozen or so people racing. Super tiny turn out, they almost pulled the plug not to do it. Quite a combination of vehicles, a full on trophy truck (actually pitted for that guy for the Baja 1000 in 2019), a class 7, 5, 11, 12, and some UTVs, and I guess a pseudo-Ultra4!

After the meeting we chilled and went to bed. The race was pushed back the following day until a 10am start to try and let the course dry a bit. I actually was hoping into turn into an absolute cluster of mud since it'd give me a big advantage with 4wd



We ended up starting 2nd behind the trophy truck, the starting order was mainly based on the heavier guys up front.



The trophy truck of course ran away instantly. It was cool to see how it compared to the buggy, since I think it's taller and of course wider than the buggy. Maybe similar power to weight, similar tires, closer in wheel base than I am with most crawlers, lots of similarities and differences. Same thing with the class 7 which was a Ranger, he passed me after a few miles and it was similar, I could easily outrun the Ranger in the straights, but corners I at least wasn't confident or even know if the buggy could keep up, and the Ranger would take off through the chop and I just didn't trust the hydraulic steering and my abilities to keep up.

Overall I was really happy with the buggy, and it was cool to be on the same course before and see the changes I had done to them buggy. The shocks were way better this time being setup a lot stiffer, before I would drop into things and bottom out even with the bypasses all the way closed and this time I could carry 50-60mph through those same dips and be fine which was wild. I have everything to revalve the shocks stiffer too so I'm excited to make the suspension handle better, but it didn't feel like it was slowing me down for the most part.



The engine is an absolute animal, I am so happy how well it does considering I built it the bypass valve on the supercharger is still being weird but I hooked it up so it wouldn't get so hot by always being in boost, plus tame it a bit. I call it "low boost mode", and even setup this way it's so powerful compared to what I'm used to. There were very few places I would actually floor it, and when I did it was only for a few seconds, it'd get up to speed plenty fast before something else or myself was the limiting factor. And to think the blower isn't making much boost, and the engine is built that it could handle 4-5x the current boost. Needless to say, power will never the limiting factor on this buggy I don't know if the engine got over 195 the whole time. The trans was like 185 for a bit I think. Oil pressure fine. Even the dashes were fine and not randomly jumping around from getting wet and dirty which was a first! Not a single complaint about the powerplant whatsoever, not once was it a concern or doing anything I didn't like. The transmission still has 4th turned off since this is that fucked 250k trans, so on one straight I'd wind it out in 3rd to 4000rpm or so but we'd be going over 80mph and the steering just seemed so sketchy I didn't push it more.

The brakes I ended up having an issue early on, I think lap 2 the brakes became extremely squishy and I pulled into pit and turned out the front brake line going down the upper link got pinched by the header and was spraying. I forgot to grab my spare brake line so we vice gripped the front line and kept going. The braking wasn't great, had to usually double pump the brakes, but I could work with it and apparently my lap times improved even with that handicap. I also realized part way through why the brakes still seemed kind of fine, since I only had rear brakes but with 4wd coupling the axles it made the braking handling behave the same. That's why I don't run a proportioning valve, and never thought of that being a benefit with a brake line going out. With that said I do think I'll add either a proportioning valve or just individual shut offs right at the master to turn off the front or back in case this happens again. That was the only issue I had the whole race though!

The biggest complaint, or combination of issues, by far is the steering. I have a Howe full hydraulic setup, so I'm not sure if there's a way to make it better, but hydraulic steering just sucks ass. I don't know how the Ultra4 guys go so fast confidently, or they just say fuck it and send it. The road straight away we were in the mid 80s, and that bitch just feels like it keeps slowly drifting back and forth. And a small steering change at 80mph feels nearly impossible, it's like attempting a steering suggestion or seems like it'll way over react. And then the shit of going into a corner, hit the brakes, engine speed drops and so does assist so now you went from no effort to way more effort to rip the wheel over. I still have the 3 turn orbital and I do think the 2 turn would help...in some ways, but maybe it's not worth that twitchiness when it's already too twitchy going fast it seems like. Maybe people can tell me if something is wrong, but I think it's just the name of the game with full hydro? That's honestly the biggest thing I look forward to if/when I build a new vehicle, is either a rack and pinion or hell maybe even a 3 link. Like my can-am feels so solid and you could thread a needle, and the buggy is nowhere near that and I doubt it ever will. And that by extension mentally limits me, since I'm worried it'll roll over in a corner and I can't react with the slow steering or be confident to know the wheels are facing where I think they are to counter it. It's a pain in the ass and the biggest thing I struggle with.



Anyway, overall the buggy did great. We finished the race, which I think is the first race I've ever been in (driver or codriver) and finished the whole thing, so major victory there the buggy feels way more capable than I am, and still blown away how reliable it is. Tiny little race no one has heard of, but it's an awesome dual sport rig. I think it's so cool I can go do a race and go rock crawling with my buddies the next day.

Today I unloaded it, I didn't grab many photos. One photo I will post is the passenger front bump got nicely clearanced



When I aligned it I pushed the passenger side forward 3/8", and obviously it was tickling the link bracket to begin with! But the shaft is fine, so fuck it it'll work

The aluminum knuckles look totally fine, actually everything else seems fine. Pulled the panels off and gave it a bath.



Driving through rain for hours really did a number on the raw chassis though. I'm back to debating to paint it, I could have it torn down to a raw chassis in a day and then get it blasted.... Or maybe just go to sand hollow and let it self sand blast


Next race is in June, we'll see if/what upgrades I decide to do before then, or just take it rock crawling in the mean time!

 

Soooo freaking AWESOME!!! I'm glad it was great & you had fun!!

 

Glad those knuckles held up. But their beefy as hell. Sounds like an awesome time!

 

Haven't done much with the buggy this month. I pulled the body panels and sprayed it off and looked it over and fixed the front brake line, that was about it. Poor thing got wickedly rusty from being towed through endless rain and snow going to Vernal. It's almost tempted me to finally paint it.



I had some friends from up north go to Sand Hollow a couple weeks ago. They just had some Toyotas, but I hadn't taken the buggy out since the race so decided to bring it out for a chill day and get some miles on it.



No one wanted to wheel until the night, so I ended up taking a couple people for a sprint around Sand Hollow. Nothing exciting but I think I got 50 miles or so on it. The only thing that was weird was one or two points the engine got a slight hiccup like it lost fuel pressure. But I had a full tank, and it was so fast I didn't have time to see fuel pressure drop. One person thought maybe it was a vapor lock issue, which is possible but seems unlikely since it wasn't that hot and last year I had it out in a lot hotter weather (albeit not with the big engine).

I need to swap the filler neck, so I'll pull the hydramat and pickup and see if something has disintegrated or is leaking. But otherwise it was fine!



Otherwise we just ended up doing Double Sammy and playing around on some of the offshoots while the Toyota guys slowly made it through.







And that wraps up anything I've done with the buggy!

Today I registered for the next Bonneville Offroad race which is in Grand Junction in a couple weeks. I have a list of higher priority things to do, and then some things to do if I'm not overly lazy. I wouldn't have any issue using it as is right now, the buggy seems happy and working great.

I did just order a 2-turn orbital from Howe to replace my 3-turn. They also recommended increasing my caster to like 7deg which I'm at 4deg right now I think. Otherwise they said there's not much I can do to improve the steering feel. I also bought another Superduty Master cylinder after messing with my other one and figuring out how it worked until it was destroyed, now I know how to get it to plug and play with the iBooster so want to get that installed too. If I can make the braking more firm and the steering faster I think that will help a lot. I have some other minor things I need to do, the spare tire carrier needs to get reinforced since it's starting to crack, I need to unbend the hilift since apparently it ran into a rock and got bent, maybe fix the boost bypass valve, etc.

The Grand Junction race is another ~160 mile desert race. From what I've seen there's no whoops, it's mainly just two track and dirt trails, actually closer to a rally stage probably. Should be a fun and chill race, see if I can make a few tweaks so I'm not the absolute slowest vehicle out there hahaha

 

Buggy has been under the knife the past week or two, the goal to improve the brake and steering feel/handling.

Steering, easy. I got a 2-turn orbital from Howe. And holy fuck this thing costs its weight in gold. $1200 for this fucker!



I was expecting like $800 since that's what my 3-turn orbital (also from Howe) cost, but I guess that was a couple years ago and inflation made the price go up 50%? Or quicker turn somehow inherently costs more, which seems doubtful. The upside is I didn't have to change anything in my steering system which is great, I figured they were going to say the pump needed to be upgraded to flow more.


With that out of the way, onto the brakes which is the real meat and potatoes of the work I did. First some pictures of my "current" (well now previous) setup:





The plan was to modify this setup so I could try a Superduty master cylinder. I outlined that process specifics in the iBooster thread. To recap though, I wanted more pedal feel. The car master worked great, but since it was so small (7/8" I think?) it was just really squishy the whole time. It was so squishy you would think the brakes didn't work and needed to be badly bled, but it would lock up the tires easily---too easily. It was disconcerting how the feel was, and when someone pointed out the Superduty master was a "plug and play" option I figured it was worth a shot to try it.

I ended up buying two masters, the first one I dissected to figure out what I could and couldn't do to adapt it, and the second one I bought since I fucked up the first one while learning about it. The Superduty master requires a 3/8" spacer, which in my first attempt looked something like this:



This setup though is 3+ inches longer than the car master, and I was already tight on leg room so there was no way to make my previous brake mounting setup work. Out came the plasma and grinder and I cut the brake mount off (again). The plan was to flip the whole brake setup 180 so it extended towards the nose of the buggy. This got me two things, a lot more room for my left knee, and enough space that I could try a whole variety of brake setups in the future without having to cut anything off. I started off making a plate to weld to the chassis.



You'll notice I have two mounting patterns. My goal was to make this fairly modular, so again I wouldn't have to cut stuff off. The car master is parallel to everything else, the Superduty master at first blush is ~13deg clocked off for its bolt pattern---so I put two bolt patterns in the mounting plate so I can flip back and forth between masters easily. And spoilers, I didn't use either of these mounting patterns and drilled a third into it!

Chassis cleaned up and new mounting plate on.



And initial test fitting of the new setup.



The Superduty master is absolutely huge, and if you use the stock mounting points on the booster you end up with only one orientation that works since the rearward banjo fitting would run into the big plug on the motor, which is why in the above you can see the motor hanging down. With the master and booster mounted, next was to figure out the pedals since now the booster pushrod needed to go the opposite direction. I had an idea what I wanted to do, but this seemed like a good time to get out the computer and scan it so I could get everything dialed in CAD first.





And that resulted in this contraption:



Which is this in a more clear view:



I have two brackets coming off the chassis with three holes, a weird pedal looking thing, and then the booster pushrod interface which also has holes spaced vertically the same as the chassis brackets, plus front to back holes. All the vertical hole spacing would let me change the motion ratio of the pedals, and then I threw on the front-back mounting holes that interface the pushrod so I can adjust the pedal position. In reality that ends up looking like this:



And since I had the right size combination of tubing laying around, I added another feature by having a piece of 1.5" stub coming off the pivot assembly, and that just has a hole in it. A 1.25" piece of tube (which I have a lot of, and have a die to bend) slides into that, and then a single bolt holds the pedal on. This makes it so you can further easily adjust the height/rotation of the pedal without making a new one, and you can make an entirely new pedal without redoing anything else. In this case, I have a simple bent bar going down which hugs the left side body work, and then a stub for a foot pedal that comes over. This way my foot never runs into part of the pedal that's "above" my foot.

Oh and you can also see at this point I've now rotated the booster 180deg because the motor hung down so far my foot barely fit under it to reach the pedal.



Additionally, the pivot assembly spins on a 1/2" bolt, so a lot more stiff than my previous pedal setup. I have a 1.25" tube that is the pivot tube, and I machined some delrin bushings that slide into the end. That coupled with the little "Push to Brake" plate and it's really stiff and spins easily.

As mentioned above, the master is forced to one position if you use the factory mounting holes, and as just shown I had flipped the booster 180deg to get the motor up, so that wasn't gonna work. What I settled on was rotating the booster so the motor was about horizontal with the booster body, this way the master would clear the motor plug and the motor would be away from my left foot.



This required changing how I was mounting the booster since the bolt holes for the master and booster studs were no longer concentric. I made another 3/8" spacer and welded some nuts into it, I then took my first master body (the one that had the guts get fucked up) which still had the factory mounting holes (because the second master had the mounting holes drilled out) and used the first ones body with the guts from the second one to make this contraption!



Following? Good. Point being, it worked out having two masters since I could try concepts and then flip back around. But at the end of the day, this setup uses a 100% unmolested master. That 3/8" plate clocks the master to the right spot, and the master then clears everything.

And from a side view to get your bearings, it looks like this:



Which works out great! The booster is about the same spot it was originally, the master has room which means any smaller master if I want to try other ones will fit for sure, and the brake pedal gives my foot tons of room since it's like a one sided swing arm.

I might make a new reservoir, but the stock one is fucking huge and actually tucks in pretty nice so I think it'll be fine. I could also tie the fluid level into my Holley dash which would be cool.



There was a lot more shit as always, but that's the highlights there.

In regards to the steering, something Howe said was to run a lot of caster and that might help the feel and should backdrive the steering wheel a bit so it wants to center itself. Howe said to do like 8deg of caster. I checked my CAD model and another benefit of the knuckles I learned was the steering arm is exactly 90deg from the kingpin axis! So all I have to do to check caster is put a level on the steering arm!



I overshot the 8deg a bit, but I was at 3deg to start with. We'll see how that does.

And after bleeding the brakes, bleeding the steering, fucking with some stuff, it was time to run the loop again!



And my god, it is so much better in every way!

Starting with the brakes, they have a lot more feel to them. This is running at 4:1 pedal ratio roughly. There is a wall at ~70% of motion, which seems a bit odd, the force really climbs up at that point but that's also around the point the tires want to lockup so it's actually kind of nice since you don't just slam through the pedal and lock the tires up like the smaller master did. With that said, it's quite a force jump up and I'm worried that crawling it will be tiring if I need to use that level of brake pressure. But as for going fast, the pedal feel was really nice and felt like I had more fidelity and confidence in the brakes because of that. I also know at the wall there's still quite a bit of stroke left, so I can apply a ton of brake pressure if I really need to. The swing arm brake pedal works really well too. I was going to make more of a pad to press on, but after playing with it in the shop I left it as the straight bar and it's actually pretty comfortable. I can push my foot to the outside and rest it against the swing arm so it's kind of locked in too. I was thinking I might make a tab on the other end of the tube so my foot doesn't slide off it to the right. The brakes are awesome, and the confidence in the feel and not being able to easily blow through the pressure and lock the tires up is really nice.

The steering is absolutely amazing! It made a bigger difference than the brakes for sure. I only have to move the wheel maybe a quarter turn for most stuff, which is just what I wanted. The steering isn't even twitchy really, it seems like there's a relatively low motion zone (that quarter turn) and after that you get a ton of motion, it's like the amount of steering ramps up. It probably did this before and it's just how steering is, but it's very noticeable now. But it works out great, because you aren't getting this insane steering motion right away, like the brakes it seems like there's a wall where you're working inside the friendly zone and if you go beyond that a lot of shit happens, and you don't want to be there normally so it works out great. I feel like I didn't notice the steering wheel drifting as much either, my theory is that since the steering is so much faster that the drift of the wheel gets ignored since the wheel is moving so much. You're doing a lot of small inputs constantly, versus the three turn just was slow and lazy so it was noticeable when you had to spin the wheel a full revolution and it didn't line up, where as now you're spinning it only a half revolution so that difference from center is a lot smaller amount now. It was just great, I could flick it around easily, drift through corners in confidence, let the back end rotate, it was awesome! Though I feel like the low rpm force required has gone up too. I think I'm gonna mess with the engine tune and get it to downshift earlier to keep the rpm up so the pump doesn't run out of oomphf, since smashing the brakes and cranking the wheel is still an utter bitch as the pump loses rpm.

But overall, two massive improvements. The whole thing feels so much more nimble and I have so much more confidence in it. I took it up to 90mph on the highway which I haven't done in a long time since it used to feel so sketchy going fast. It still moves around from the steering at speed, but since you're constantly doing these little corrections it just feels more in control. And the brakes are huge, I have a ton of adjustment, they feel great, I can try other setups, it was a lot of work but I'm really happy with it. I was absolutely hauling faster than I have before, and the buggy felt totally happy and in control like never before!

 

Wow! Another amazing update!

 

Back from another race, and the buggy took a massive beat down multiple times. Last race had a minor brake issue and finished, this time made it a collective 10 miles, maybe 12 tops.

Thursday we loaded the buggy and semi following some additional upgrades to the buggy and changing the fluids.



We rolled out Friday morning and got to Grand Junction around 1pm. There ended up being a ton of people by Bonneville Offroad standards, I think the final count was 34 cars racing. There was at least three other Ultra4s, two 4400s and one 4800. Plus a bunch of class 7 pickup truck type vehicles, and a couple 6100 spec trophy trucks. Only a couple UTVs, so a lot of variety and a lot of "heavy" vehicles that had a comparable setup to us which was really cool. We set up camp and unloaded and shortly after the prerun lap started.



The course was 23 miles, and I thought was gonna be a lot of fun. It was mostly dirt trails in typical desert racing fashion, but not a lot of big bumps. There was a ton of tight turns driving up on ridges and back into little valleys and snaking through the hillside. It felt like something where we might not be the slowest vehicle for once and where a lot of suspension wasn't going to dictate how fast you could go, which having a low amount of travel was great for us! It was insanely dusty though, even going 20-30mph. Lots of silty sections, including one hill that some people couldn't make it up during the prerun since it was so steep and so silty. I even started to worry going up the hill as I was waiting for the transmission to kick down and give us the horsepower to power through. There was going to be 8 laps again, so just shy of 200 miles total. After the prerun we grabbed our gear and went through tech.





Quick check of the fluids and I reconfigured the digital dash so it only had a handful of gauges in huge font that could easily be spotted if something was going wrong, but otherwise the buggy was ready to rock!



We ended up starting first because we were the only full size vehicle that also raced at the previous race in Vernal, so we were the "attending points leader" which is hilarious considering we came in last at Vernal and only three people were in our class. But I was fine being up front with how dusty it was going to be. The starting sequence was in 30s intervals one at a time, with the deemed faster vehicles being up front, then UTVs, followed by the sportsman and VW bugs (which a lot showed up, I think there were five bugs racing). Immediately behind us was another 4400, the 4412 who I've never talked to, but it was cool to actually stack up against a fancy Ultra4 for the first time.

We took off, and for the first 5 miles everything was going great! I was driving the buggy faster than I ever have, the new steering upgrades and the brake changes made a huge difference, especially on this course where it was almost continuous tight turns and really slippery. The buggy felt absolutely great, and my codriver was doing awesome calling out the turns and stuff we had marked. And then shortly after race mile 5, went through a corner followed by a G out and something started banging and feeling weird, and my codriver said he felt something hitting him? We jump out, and the welds on the bung for the wishbone in the back had ripped out, and the wishbone had been shoved into the floor/back plate which got shoved into the passenger seat.



It was obvious there was nothing we were going to do, so we got back into the buggy to limp it forward a bit (a bad idea in retrospect). And to add insult to injury, the Ultra4 that had started 30 seconds behind us was just now cresting the hill we had just gone down, so in 5 miles we had gained maybe 30 seconds on him. Of course that doesn't matter since we broke right away, but the silver lining I guess is we were a lot faster than the 4412--which isn't surprising, it's about as tall as a skyscraper.

But I digress... we drove forward a bit to get on top of the ridge in front of us and called in that we would be returning to pits off course. A guy on the radio said if we turned around, he was a few hundred yards behind us and we could get on the road he was parked at and take that back. Up to this point, the wishbone had just been jammed into the seat, so seemed like it wasn't going anywhere. This is obviously a stupid assumption, but at the time we had been racing, it broke, we kept driving, pulled over, drove up a hill, and it hadn't move. So turning around to get to the course worker didn't seem like that big of a deal. We went back down the hill, crossed the course, and started going up the hill to the worker and then the rear end decided it didn't want to get shoved forward and now the wishbone had gotten yanked backwards as the axle tried to rotate back. The rear driveshaft separated, which then broke the retaining plates off the U-joint caps on the axle. Soon after this, a recovery buggy came over to give us a pull up the hill which that combined with front dig we were able to make it up. But in that process, the rear axle shifted over, and the passenger rear tire got sliced open by the bump stop can. We had now quickly gone from a heim that ripped out and sucked but everything else was fine, to now the rear driveshaft is fucked up, and we've blown a tire.



Once the recovery buggy got us onto level ground, we wrapped the winch down and under the chassis to pull the wishbone forward to at least keep it shoved forward the whole time (should've started with this right when we pulled off the course initially, but hindsight is 20/20). Though being retarded, we did this with the buggy turned off since it's so loud with it on that it makes it a bitch to talk to people. Well this killed the battery (a repeated theme with the buggy), to a horrible spot where we could get fuel pressure or crank the engine, not both. At this point the course worker we were trying to make it to was able to come over with jumper cables and rescue us, and he had a floor jack that we were able to use to change the tire. Luckily the spare tire we had, which doesn't hold 25psi of air, but seems to leak down to like 5psi, was able to be used and actually had 5psi so wasn't totally useless! On the plus side, I had prepared for the buggy having a flat--hoping that'd stop that from ever happening since we only have the one spare tire--so we had everything to change it, though granted I learned a lot from attempting to do that in "short order" about how the whole jack/spare tire setup can be vastly improved, and positioning of tools, mounting of the spare, etc.

Finally moving on from this cluster fuck, we're on the road again. We have front dig, so we leave the rear driveshaft flopping around and drive back to the pit in front dig. Our pit crew (one friend, our wives, and my parents) knew what was up, and had found some guys with a welding truck --- from some place called RMB4x4.com that's out of La Sal or Moab? Awesome dudes --- and when we pulled into the pits these two dudes went to fucking down putting in work. The first order of business was to pull the heim and bung out and shove it back into the wishbone, and weld that together. That was a cluster fuck of using their winch and ratchet straps to move the wishbone around. The wishbone in concept works fine, but fuck, from an ease of working on things it is a bitch since you have two frame side mounts that have to be perfectly spaced to slide into the chassis, it's not like a normal suspension link where it can be any length and slide in and then adjust it afterwards. And since the dimensions had gotten all fucked up, we had to pull both sides, slide the broken side in, weld it, adjust the other side like four times until it lined up---and every time you adjust it you have to pull the heim out of the bracket, adjust it slightly, slide the whole thing back in, etc. and since it's still hooked up to the rear axle it's not like you're doing this by hand, we're using the winch and a ratchet strap and people shoving the chassis around to massage the heim front to back to slide it into the bracket---point being, it's a pain in the ass if it breaks!



I didn't get much chance to look at the bung, I had not plug welded it, not sure how much difference that would've made but I certainly will now. The welds all looked "fine", it's not like they were rusty or anything. Our theory is it broke due to how hard we went into the corner, as opposed to just reacting the torque/braking loads but who knows.

Moving on, once that was fixed now the issue was the U-joint straps. One of the bolts had gotten ripped in half and was stuck deep in the yoke, so the only solution was to weld straps over the U-joint. The driveshaft itself was fine, so these two dudes went to town on it welding it together. Absolutely bad asses.



Oh and of course we use the winch to move the wishbone around, so after all of this we go to start the buggy and it's fucking dead again. Needless to say dual batteries and a larger alternator are high on the list of upgrades.

But at this point now, we've jump boxed the buggy (and thrown one in it), the driveshaft is welded on, the floor/rear seat panels are pounded back (the seat frame got completely bent when the panel ran into, which is why my codriver felt it, so we had to hammer the seat back into a seat shape), and the wishbone is welded back together, and the tire we swapped on that leaks I aired up to a random pressure---we're ready to go again baby!



Just take it nice and slow, let's just get a couple laps in.

We take off, and within two miles we've caught up a UTV we didn't even know had been in front of us and pass him. That's the first pass in actual racing (not just someone broken or pulled over) that the buggy has ever done! The steering can't be over stated how much faster and more confident it is to drive the buggy, and this course is perfect, there are spots that are so silty now it literally feels like being on ice just sliding through the corner, and before that would be scary not being able to react with how slow the steering was, but now we can drift through everything and it's doing great. Reach mile three, caught up to another UTV and pass him also. And I don't even think we're pushing it that much, my biggest worry is the rear driveshaft coming apart so I'm being gentle on the throttle and brakes to try and avoid ripping the U-joint straps that are vaguely stick welded on the yoke. Those two people we passed, maybe they're just the slowest ever, but once again I'm fucking stoked at how seemingly fast the buggy is against actual real racecars.

And holy shit we've made it past where we broke last time! Here we go baby!

100 yards later.... and we're fucking breaking again.

Something is making a thumping noise, I'm wondering if the front carrier bearing has gotten loose maybe? And my codriver says something up front is spraying fluid, well fuck. Pull over. And first order is the spraying is coming from the power steering pump feed hose that goes to the reservoir, well that's definitely bad since we have full hydraulic steering so no fluid means no steering at all. Oh and the steering pump pulley is eating itself on the chassis? Well that's really weird, they sit really close but why is it hitting? Engine mount broke maybe? If only!





The chassis had completely sheared the tubes between the shock/bump stops and the engine mount. In the photos there's a tube going "up", that runs up to the shock tower and is the primary load path for the shocks. Additionally, if you go forward the next node is the bump stops, and a couple inches behind that break is where the engine mounts are.

Well fuck, I don't plan on welding that back together in the field. Plus we still have the power steering issues, which are all a byproduct of the steering reservoir being mounted to the chassis and the pump being on the engine so they're now on separate islands effectively, and the hose connecting them is super short so seems to have gotten kinked and split essentially. The power steering pulley is obviously eating the chassis since the chassis just shifted up and ran into it.



Once again, the winch is here to save the day! We run the winch around a bump stop to clear the engine and then down to the lower link mounts on the chassis and suck it in (this time with the engine running, I'm learning!) which pulls the entire front end down to a "normal" spot so we can limp back home again. Call in, tell them what happened, tell race ops we're retiring and fucked but ironically can still drive just fine! Drive back to the pits and straight onto the trailer. I'm sure everyone in the pits thought we were retarded, always entering from behind everyone and not from the course direction. But that whole drive back, still a slow rhythmic thump, not the kind of banging you'd expect from two chassis tubes railing each other...

Load up, talk to some people, thank the RMB 4x4 guys (hopefully they find the money I hid in their truck and thank you note). And we rolled out, stopping to get Chinese food as is tradition now after a race. All in all, we were in Grand Junction for less than 24 hours!



My initial plan right now is to fully tear the buggy down, reinforce everything, sand blast and finally paint it, fix some things like my four speed trans that only has three speeds, improve the accessory brackets on the engine, build a good spare tire carrier that's integrated to the chassis, etc. So first order of business for that is to clean it up since there's power steering fluid all over the place. Quick strip on the trailer to take it to the car wash.





And then let's check the front diff, lets see just how fucked it is.



Oh she's very fucked. Pinion is pretty roughed up too to add a cherry on top. I was really hoping the extra ring gear I had laying around from that time I seized the pinion on the first attempt to gear an axle could be used here, but nope both gears are fucked.

And another fun easter egg on the chassis, this tube chose violence after it and three other tubes attempted to hold the front end on after the tubes near the engine mounts sheared.



On a happy note, here's a picture of my new water mounting setup, they worked great and are on fire extinguisher releases so can be hot swapped. No more fucking with camel backs or insanely overpriced "race specific" water solutions, this whole setup was like $50.



And that leaves us with when I came back inside an hour ago. My plan is still the same, I figured the front gears were toast and those are pretty cheap so not a big deal. Though I'm not sure what broke them, maybe just the same big shock loads that broke everything else. We hit some whoops pretty hard, but I wouldn't say it was the hardest hit we've done, but going faster and taking big hits just finally did everything in I think. The front chassis I knew was weak, and had been wanting to brace it up for a long time. I was actually going to before hammers but then got into the rush to get it going to take to KOH and didn't get around to bracing the front. I will tear the whole thing down, I've torn it all the way down in a day before, and had it back together from a bare chassis in three days. So full rebuild doesn't scare me, although I don't plan to go that fast. I want to take it apart, reinforce the fuck out of the front end, truss the front end since it's a shitty trapezoid shape which is the entire issue. Take the front axle apart, inspect the knuckles, do the axle seals and regear it. The transmission I want to fix now if I have it out. I have two 4L80s that are fucked up, either send those out, combine them, buy a new one, I don't know.

The engine is totally fine, absolutely beast. Though I do want to fix my accessory brackets, they've been fine lately but had issues before. I'm thinking of designing some nice billet ones to get machined. Also fix the boost bypass valve, and I'm thinking of throwing a stand alone intercooler in the back with some fans on it so the current cooler that doubles as the power steering cooler can be specific for cooling the hydraulic fluid for the steering. As said above, I want to delete the rear tire carrier that unbolts and just weld a dedicated tail on the back for the spare, and none of that shit where it bolts down, just some straps to keep it simple and fast. Also make the hilift on quick releases instead of bolting down. And then finally I want to sand blast and paint the chassis, and the axles. The chassis got so gross after the rain storm for the previous race, and I've kind of gotten to a point where I'm not doing big fabrication jobs on the chassis and starting to hone in on a final configuration. Of course do that after gusseting the shit out of everything and adding more tubes.

As usual I have the debate of if it's time to build a new chassis. But I'm continuing to learn a ton on this, so it'd be premature to spend that much time and effort and then maybe screw things up that I could learn and experiment with on here. I think the best course of action is to fix and keep this configuration of the buggy, which I do like a lot and is really getting to a good point, and once I think I've learned everything I can from it and actually know what upgrades and improvements a new chassis would give me, then maybe I'll think of building a new chassis and swapping the parts over. But for now, tear her down, do some improvements and bring it back better than before! There's another race in July, I'd be surprised if I make that one, but there's two others with BOR later this year so might make those. And it's hot as balls out right now, so I won't be losing much wheeling by tearing into it in the middle of summer.



I do find it kind of hilarious that the most catastrophic failures I've had, and the buggy still drove all the way back and onto the trailer. Huge breaks, but there's a lot worse ways to break! Thanks for reading.

 

Sorry about the failures but awesome it went as well as it did.

 

Man, you have the most upbeat attitude in the face of seemingly dire straits (to me at least). That is the shit will carry you over mountains.

 

Old girl took a beating! But man what an experience I really need a race rig soon…

 

You couldn't have scripted that shit man.

 

Yea, I guess that's true. But I guess you could say I tried to set it up that way. The buggy is purely meant to try things and have fun. That's why I don't ask, or frankly even want, people to come pit and help out. I don't want people to help build it. There's no sponsors I'm trying to appease. To a large extent the entirety of it is a solo endeavour. So when something fails, I don't feel bad that I ruined people's days that spent all this effort and money and feel like I failed them. The only motivation whatsoever to do it is to see how I stack up against other people, there's no pressure from anyone else. And I know where I stand, so there's not really any pressure from me, I'm here to have fun and if I can remotely hang with people with a lot more resources I think that is so awesome.

If it breaks, I can just park it and not worry for a single moment that someone is disappointed, or I'll lose funding or a partnership, etc. And I don't want to ignore all the people that have helped, and that do come out, of course all of that is appreciated immensely. But compared to a lot of people and teams, even small ones, this is a huge part of their life and a huge event, and I kind of try to do the opposite where it's a low key thing so it's just me going out and having fun with a couple people. Like people showed up to the race, had issues, drove home and wrenched all night, and came back and had a dozen people helping them. I checked the bolts the day before, and if something was wrong I just wasn't gonna go. I try not to view it much differently than maybe going into town this weekend, if it happens cool, if it's a pain who cares and don't do it, no need to add extra stress.

Life is stressful enough as is, i try to avoid my hobbies also being stressful

 

@snivilous nicely said. After all... have fun and enjoy the race of life.

 

@snivilous

Do you happen to know the chemistry of your frame tubing? If it's already mentioned then I missed it.

 

I don't know the chemistry, but it's all 1020 DOM mild steel and welded with normal ER70 filler.

 

NASA shit right there! Run it hard, break it experimenting on rough terrain, and better the experiment at the shop under optimizations! Way to send it!!

 

@snivilous,
Your detailed write-up is outstanding. You had me (and I'm sure everyone else) feeling like we were there with you throughout the build, testing, rock crawling, racing, and repairs. Your attitude...Just having fun with no pressure to please sponsors, etc, is what it's all about. And having no sponsors, I think you stack up better than most against the competition. Thanks for sharing.

 

The buggy is receiving some love again! It has been parked/occasionally moved around since the last race and breaking the front chassis and ring and pinion. I wasn't entirely sure what I wanted to do with it, but I've had some friends complete their buggies since then and they said I should just slap it back together so I can use it, don't worry about racing it and then start designing the replacement chassis in the background. And I said that sounds like a good idea! Plus the mini truck is waiting for its engine to get back from the machine shop, so I needed a quick project to get one of play vehicles going again! If you're not driving or building one vehicle, you better be driving or playing with the other one!



I didn't want to get sexy with fixes, so the plan was to "jank it together", and not pull the drivetrain to fix it. The chassis is frankly a POS since I didn't know what I was doing for 95% of it, so this is just to fix it to make it work. First up, the front of the chassis was a horrible design and I had meant to make it nicer and never got around to it, and that resulted in two tubes shearing. To properly fix this, the front end needed to get trussed (ie add triangles so things aren't in bending). This is a little tricky since the headers need to be cleared, but I was able to slap in two tubes on each side which gives the shocks and bump stops a MUCH better load path to the rest of the chassis.



I also added a ton of gussets, and I'm just going in and squirt gunning with minimum prep. Like I said, it's not meant to be nice, just work for some basic wheeling. I also added a big plate to the bump stop to help carry load to the front node of the truss.



This was repeated on the other side.



The driver's side truss is a lot more of a pain to fit due to the footwell. First the gusset going to the front bottom node is really compromised but I needed that huge hole for access to the spark plug and header bolt.



But then the real compromise is trying to tie in at the rear and clear the throttle pedal which moves forward really far. I ended up welding a plate flat to the floor/chassis tube, and welding the rear tube into that. I'd rather it go to the tube node, but I couldn't get anywhere near it without completely redoing the throttle pedal and potentially the orbital. I then added a little plate vertically to give the flat plate some depth so there's a bit of stiffness to carry load into the primary tube even though it's offset a little. Not ideal, but still way stronger than it was before. Also quite ugly!



I also went in and added some gussets throughout the front end, including A-pillar and V-brace gussets. When the lower chassis tubes sheared all four of these tubes just ended up in straight bending holding the whole front on, the far one on the driver's side is cracked almost all the way through (cracked around a gusset on the bottom that was already there). The other three looked fine but are no doubt compromised. These huge gussets may be kind of ugly (I kind of like how gnarly they look though) but they are meant to help brace those tubes that took a huge beating and brace them pretty far out. Additionally I will gusset the inner two on the bottom so the entirety of the forward truss nodes will be gusseted everywhere. At the end of the day all the nose loads get dumped into either the V-brace or the tubes directly below it, which isn't a lot so big gussets on those will help a lot.



When the nose broke the chassis around the engine separated from the tubes holding the engine, which resulted in a tube running into the steering pump and chewing it up. Luckily a flappy disk was able to recover it back to glory. The feed hose from the reservoir also got fucked up, so I got a new hose made from Ron @ Hoses 'N' More in Hurricane UT. He went wheeling with some friends the other day and actually lives nearby, he was part of the inspiration to get the buggy going again and worked out that he's able to build hoses and give me some improvements for my routing!



That mostly wraps up the front chassis/engine stuff. The driver's footwell panels will need a lot of tweaking, and like I said there's a couple more gussets I'll add up front but otherwise the chassis improvements are done.

Yesterday a friend and I pounded out the front differential fixes.



This was also the first time getting to inspect the knuckles, though they only have a couple hundred miles on them but they look great! Makes getting to the differential so much nicer since the unit bearing bolts are easy to access and no fucking with the greasy CV since the whole axle can slide out as one unit.



The unit bearing sleeve seems to be working great! The fit is so good I had to tap the unit bearing out with a hammer.



One of the CV boots got eaten up from a ball joint. It still seems to be sealing fine, but the (lack of) clearances leave some to be desired. I don't know if this is a common thing or the ball joints I have just stick up further than normal?





Not a lot of pictures from the front, usual regearing stuff. The ring and pinion got properly fucked.



The bolts on the detroit locker were also really loose, finger loose in some cases. I don't think this would have caused any issue (besides the bolts getting chewed up) since the axle housing would hold the two halves together, but there's lots of wear marks on surfaces that aren't supposed to move. This is a couple hundred miles of wear for a part that is supposed to seat tight:



We took the locker apart, lock tite and tightened it back together. It took quite a bit of fighting before we figured out how to get it together, or maybe stuff was already tweaked to begin with and that's why we had issue.

We reused all the bearings and parts from before since they had minimal miles on them and seemed fine. Cleaned everything out since there was a lot of metal shavings. Took 5 or 6 attempts and got the gear pattern pretty good and said send it! I kept all the parts from the first regears so luckily I had a stack of shims laying around still. And then got the axle slapped back together!



The last "big" task to get it properly driving is to fix the rear yoke, which currently has the U-joint retainers welded to the yoke. The yoke had tapped holes to begin with which I've realized is a horrible way to go since the bolts broke off in it, I'm hoping I can pull the yoke and drill it out to run normal U-bolts and then put the driveshaft back on. If that doesn't work I'll just buy a new yoke with through holes and that should be it in the rear. Then fix the floor and a couple more gussets and she'll be back to wheeling!

 

Awesome!!!

 

Should be pretty damn solid with all those gussets. They look good, and I like the serviceability approach on the gusset with the cutout, but do you think a dimple die would be better for strength?

 

I don't think so. I have mixed feelings on dimple dies, I'm not sure how effective they actually are (generally speaking). I have a set of dimple dies and use them more for cosmetics than anything. You get a stiffness increase and bending capability increase locally where the metal is flexed, but globally I don't know if you really get any benefit since it's still flat metal everywhere else. In the case of the gusset there might be some increase in buckling capability from the section becoming a bit deeper from being flared out but you also end up flexing the whole section and have the potential to pre-buckle it and cancel out or make worse any pros you had from flaring it, and in tension it's all about area so being flared doesn't help.

In reality that gusset probably won't do much regardless, it was more of a way to try and lay more weld into the joint and in the event the tube shears again there's a bit more material it'll have to go through and more than just a butt weld holding the node together, and since I had a little area left I could use then may as well add that thin leg since it's better than nothing--but not much!

On the passenger side since the heads are the same, all the spark plugs point backwards instead of forwards, so the passenger side ends up with a lot nicer packaging of the gussets. I still had to avoid blocking stuff, but it was usually just clearing the header bolt access and not the entire spark plug and socket.

 

Regarding dimple dies: if they do what I think then what's going on is you are cold working the surface of the material and putting some strain in it. This raises the yield strength (stiffness) but robs you of ductility and fatigue life.

From your photos you were definitely suffering from fatigue life failures. Additional "strain for strength", in my opinion, is contraindicated in your application given the material provided in your kit. The gussets you added was probably your only recourse apart from cutting out the defective material and replacing it with a thicker wall section.

Still a nifty buggy.

 

That is true, I hadn't thought about the cold working of the surface but just the moment of inertia increase from increasing the section height:



I had considered heating the spots that were failing and trying to anneal it, but A. I've never intentionally done that so not sure if there's anything special besides heating the shit out of it and letting it air cool, and B. I don't have an oxyacetylene setup