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

Holy hell! Glad your Dad is ok, sorry about the race.

 

Glad to hear that the old man is okay. A flight for life heli is not normally the place one wants to find oneself.

 

What a story! Hope everyone makes a full recovery.

 

Was just going to see how the race went and oh man! Glad your dad is doing well. Great EMS service for sure! My prayers are with you and your family.

 

My parents went back to Colorado today. My dad is still very banged up but doing much better.

Here's a bunch of jibberish jotting down my thoughts on the buggy. I had taken my mom for a ~30 mile ride a few days ago, and then today did ~20 miles by myself and tweaked on a few more things. It's running really well. Today I was able to isolate the front vibration issue down to the front driveshaft--its not the axle and it's not the carrier bearing/shorty shaft/Atlas vibrating. Looking at it, the front and rear yokes are quite a bit out of alignment with each other. Not sure how I fucked that up, but I'm suspecting that's most of the vibration. I've been wanting to order proper driveshafts anyways once I got all the suspension geometry where I wanted it. With the front driveshaft in it's not comfortable to push past 60mph, and with it out I was able to go over 90mph on the highway with surprisingly minimal vibration. The shafts I made will be good spares.

I've also started playing with the interior setup a bit. I'm pretty happy with it, and how I have the Lowrance setup I can angle it towards me as kind of a single seater configuration which actually works pretty well. I've also found out that the 7" Holley dash in the center console needs some kind of water shield, since pretty quickly I couldn't read anything on it. The little 3.5" Holley dash mounted to the steering column stayed pretty dry. Which on that note today was a good test if the systems could handle a bit of water since it's been dumping lately and the front end absolutely yeets water into the cockpit.

My two biggest complaints with the handling is the turning speed and the body roll. I have some sway bars here but they're too short, so I ordered a TK1 "medium Ultra4" bar which should be here next week. I think that will make a big difference and it will be mounted behind the fuel cell and then connect to the trailing arms. If need be I can run a front sway bar too. In regards to the steering I'm running a 3 turn orbital, and Howe has a 2 turn which I think is completely plug and play, though I'll have to call them if the pump would need to be changed out. I could also get a steering quickener but from what I've heard those can cause issues trying to over speed the orbital essentially.

There's another Bonneville Off-road race that's in Vernal UT on October 7th that I'm heavily leaning towards attending. Though that'll be fairly dependent on getting the handling under control. I can also tweak the shocks a bit but right now they feel pretty amazing so I'm hesitant to stiffen them up yet.

And lastly I'm thinking of getting a good transmission or sending off one of the 4L80s to get rebuilt. Once I get that Im kind of thinking to fully tear the buggy down to sand blast, inspect, and paint the chassis. And then I'll drop in the new engine and transmission. If I'm going to pull the powerplant that seems like as good a time as any to tear it down to paint it. I'd like to do that before the end of the year, but who knows when that will actually happen.

And here's a couple photos from the test drive today.

 

I hope your Dad is ok!

 

Been a hell of a week traveling, but I was able to come home to my new sway bar yesterday and installed it today! As is tradition, literally nothing on this project has had any future planning because every single component I have zero experience with. So in this case, I welded this tube on what, two weeks ago? And it would've to the sway bars I had laying around, but since I bought a larger sway bar it didn't fit, so first task was cutting out the rear lower tube.



TK1 offers a few sway bar sizes, with their largest bars being 1.5" in diameter (I got a 1.25"), so finally a bit of forward thinking was applied and I put a 2.0" tube in so I'm not limited if I want a stiffer sway bar.



The 1.25" bar included bushings meant for a 1.75" tube though (and they're aluminum bushings which is weird to me), so I machined some bronze bushings for the larger tube I'm using. Additionally, this is a 48" bar but there's an option for a 46.5" bar and I'm guessing it's the 48" bar cut down since there's a lot of extra spline length not being used. Because of that I actually cut the chassis tube down to the shortest length allowable if I were to shove the sway bar arms all the way inboard, and then the new bronze bushings have a 0.5" "spacer section" between the tube and the arm so I have some adjustability to move the arms in and out (the arms are also offset where the linkage attaches and where the arm clamps the bar, so if the arms are flipped left/right there's additional adjustability in/out). All of that to say, I tried to set it up so I wouldn't have to cut anything up for awhile!



The sway bar linkage I then mounted to the trailing arm. Two reasons for this, one being there's only so many tube locations I can possibly mount the bar and that then limits what the linkage can actually go to. The other reason is TK1 states the arm length should be at least the travel length the sway bar linkage sees, and these were either the longest or second longest arms available (22" as I recall) so I had to mount the sway bar linkage to something that would only travel 22" or less---so axle mounting is out of the question since it's strapped at 24". With all that said, the best packaging that seemed like it'd stay away from the tire and be within the constraints of the sway bar's claimed elasticity was going to a rear chassis tube and part way between the shocks and the axle on the trailing arm.



And I took it for a rip and it rips! Way better feeling! I was getting worried it might not be cut out for the to fast life, but the sway bar erased that thought. It still has a good bit of body roll, I don't know how much other vehicles have since I have absolutely zero point of reference, but it rolls over a couple degrees and then the sway bar hand of God pushes against the chassis and says that's good right there. I think the body roll feels fine, though I'm comparing to how it was before so that's not saying much.

I did do a 32 mile drive on my usual test route and it seemed pretty quick and much more controlled feeling. I'll have to do a timed lap with the can am for some reference. The buggy will cruise at 50mph and it doesn't feel like, where as the can am being so much lower and smaller feels like you're going a lot faster.

I don't know if it's a complaint or even how to fix it, but it seems extremely over steer(y?). It would be happy drifting everywhere it goes. The slow steering doesn't help things, and maybe I just need to learn to drive it better, or maybe the tires have no traction since they always seem to be spinning, maybe it's from how rear weight biased it is? Like I keep saying, I have no comparison. Trailing arms, full hydro, tires, sway bar, lots of rear weight, for all I know how it handles is an inherent characteristic about something I did but I have no idea since it's different than anything else I've driven. The one notable thing is so far I've been in 2wd which certainly doesn't help with the ass sliding out.



I am having an absolute blast with it. I'll have to play on some rocks soon to see how it handles with the spare tire, or pull the spare and/or sway bar and see if it still crawls alright like it did at the beginning of the summer. Though converting between go fast trim and rock crawling trims sounds kind of lame, so maybe I'll just live with the limits of it's current configuration.

 

So cool!

 

Finally starting to cool off enough to go wheeling in the rocks. But first my front axle seals had long abandoned me, and of course that requires disassembling most of the axle.



While I was in there I decided to pull the pinion and install the oil slinger. That was a bit of a confusing cluster fuck because I thought you had to remove the same amount of pinion preload spacers as depth spacers removed due to the inner bearing position moving, but that's not the case since the pinion itself didn't change position. That took a lot of reassembling and confusion and calling people and then I figured out what was happening, so a nice hour wasted there. I also backed off the pinion preload a bit from what it was to play it safe since I was gonna be running less fluid than before with the oil slinger. All of that said, the bearings are running nice and cool and the axle seals haven't failed yet! I also cut the front driveshaft and welded it together to clock the yokes correctly, I took it up to 70mph with the front driveshaft installed and while there's some vibrations it's a lot better than before and everything seems to be running great! I'll still get a properly made driveshaft but I can't complain right now.

I met up with the two guys I've been wheeling with and we decided to do a trail called Chain Reaction rated a 9. This was the first time any of us had been in the rocks since our last time together (though granted mine has maybe 200 miles on it since then but just on fire trails essentially).

I decided to keep the buggy in the "high speed configuration" to see how compromised it'd be crawling, meaning the spare tire and sway bar were hooked up. And of course it has a few hundred other pounds of shit now installed.

The first obstacle I ended up bypassing after a few attempts. It's severely undercut, and while I was able to get my front tires up, I couldn't get the rear up and over without the front end coming up and trying to roll backwards. One of the other guys had the exact same issue.





Though the third guy walked through it without issue!




The next obstacle I also had to bail on, but at least this time all three of us had to bypass it. It was super slick and no matter where any of us went we'd always end up falling back into these slick bowl type features that the tires always seemed destined for. We have a lot of setup variety among us too so I was surprised none of us could make it. Might be a 9 rated trail but the first two obstacles on this day were a bit beyond that.






After that I had no idea where I was going but found this cool little obstacle that was close to the limit of what mine could do. It was a lot of fun and super tippy with a lot of 2 or 3 wheel action. On my last attempt I did a front dig and that somehow pulled the front end down and over the obstacle and it crawled through!





After this climb, I had to drop through this crack back into the canyon, which involved a 4000 point turn and I decided to just lay the chassis into one side of the crack and slide down it, which gave the driver's side some nice rock rash. The second guy decided he didn't want to do that, so picked a much more elegant way of reentering the canyon.





Quick winch over and good to go!



Quite a bit of oil was lost, and his rig was having some brake issues so we headed back to the trucks at this point.



Bit of a short outing. I had run this trail in my 80 series a long time ago but I must've bypassed everything possible since it was a lot trickier than i remembered. Will be fun to go back and finish it off, maybe see if I can massage my way through the first obstacle.

As I said at the beginning, the front axle seems a lot happier at the moment at least and is running nice and cool, no leaking, and the front driveshaft is improved. I also shortened the front limit straps by an inch since they were a bit long before. It still seemed pretty stable with the spare and sway bar cancelling each other out. Not sure if I'll always run it like that, but it seemed fine. The shocks need a bit of tuning, in the whoops it was definitely too soft and getting into the bumps, but overall it was way smoother than before. Last time I was at sand hollow the sand trails were brutal from all the UTV washboard and would beat the shit out of you, most of that I can barely feel now and I can just watch the front drivers tire hopping all over and the chassis staying nice and composed. I think the bypasses just need a little tube adjustment, and the tubes are pretty open right now so lots of adjustment in them. I also didn't tweak on the rear since adding the spare so it's still extra soft in the back.

Overall very happy! 4wd is working great, suspension is doing work, it's still crawling and more capable than I am at picking lines, and with the new interior configuration and the engine tuned it's a lot easier and more relaxing to drive.


And here's a picture of my fat creature because why not.

 

Amazing to see what those vehicles are capable of. Very Nice!

 

@snivilous just plain sweet awesomeness! Sweet dogo too.

 

So very cool!

Say hello to your jolly creature!

lol

 

I'll give it's stress-ball type head skin a good squeezing from you

 

Haven't done anything to the buggy since I took it out two weeks ago. There's a race in northern Utah I'm going to on Saturday, so the past couple days I put some miles on it to make sure everything was working good. I also took it to Sand Hollow to do some shock tuning in the whoops.





This was the first time I had a chance in the whoops to try and dial it in. I only spent an hour or so running that section, but was able to bump my comfortable speed from 35mph to 45-50mph which is pretty good. Even in the Can-Am I don't usually go much faster through that stretch. I think I've pushed up against the steering as my limiting factor for wanting to go faster. The 3-turn orbital just isn't responsive enough to feel like I can correct in time going over 50mph. I'll play with the shocks more, so maybe it'll settle the chassis down a bit more but I don't know how much more speed I can pick up safely.

Other interesting points: the rear is extremely soft, the back was originally valved without the spare tire in mind. I have the rear bypasses almost fully closed and it's still using more of the bump stop than the fronts. Will need to bump the rear compression stack. I also feel like the rebound isn't fast enough, but it's hard to say since I didn't mess with it, but from some of the videos it seemed like the axles weren't drooping out fast enough. I think the rebound tubes are fully open, and not much rebound valving anyways, so it might just be a limitation of the axle inertia and not a lot of spring rate. The front I stiffened up a lot, but not as much as the rear. Right now the front and rears use about 1" of bump stop travel during hard hits which I think is good. With all of that said, the washboard and UTV mini whoop compliance definitely took a hit. Still a lot better than before I revalved the shocks, but due to stiffening the compression tubes to handle the whoops I then loss the squishiness for the small stuff. I'll try and bump compression valving on the front and rear so I can open up the ride height compression tubes more to get more of a compression ramp up than I have now and see how much that will help. And lastly, the front coilovers don't have any valving in them at all, and the front bypasses after just a handful of passes were probably approaching 200deg. They were the hottest I've felt shocks (not that that's saying much), and I know the shocks have a lot of temperature capacity left but this was literally a couple miles of running this section and already getting that hot. Not surprised by this fact, but worth noting. The rears were quite a bit cooler and not concerned much.

My plan for the race on Saturday is to prerun the course and then adjust the bypasses for the course. If there's not really any whoops I'll go back to the original tube settings, if there's whoops and hard hits then I'll keep it in the current stiff configuration.

After the tuning I did a quick sprint around Sand Hollow running up West Rim then through the dunes and back to the park. This was the fastest and hardest I've pushed the buggy, just due to all the baby heads and rocks (we weren't even going that fast, maybe 30-40mph through most of it) but it was a good little brutality test compared to what's near the house. At the end of all of this, I had lost a limit strap bolt but otherwise everything was good!

I had wanted to get 80-100 miles of driving in though, which I wasn't able to do on Sunday. On Monday one of my friends was going for a ride up the mountain so I decided to take the buggy out, even though it would mostly be dirt roads but it'd be a good endurance test of the buggy putting a lot of miles on and running non stop for an extended period and everything getting up to and maintaining temperature.



We drove from the house up to Brianhead to find some snow. The only prep I did was a quick bolt check and I wired in the driver's heated seat (owned these seats for like 6 years and never hooked the heating elements up) which was a great idea! Jump suit, helmet, gloves, and the back and bottom heater running and I was totally comfortable and it was down into the 20s at the top.



Also a good test of resistance to the elements.





At the very top at 11,300 feet





At the end of the day we did 65 miles, and no issues whatsoever. Buggy is running absolutely great!



After a bath yesterday I went out again for a final test drive, putting another 40 miles on it. I also found a dirt bike track type thing, though maybe it's from the Legacy offroad race that's put on locally, but there were some sections with some pretty big and nasty whoops. I ran through that area a few times, and might go back there in the future to layout a short course and get some timed laps in to try and really dial it in a repeatable setting. Interestingly this section the front shocks didn't warm up as much as I was expecting, not sure what about the Sand Hollow stretch was working them so hard.



The handling is feeling really good too. A few posts back I had commented on the oversteer issues I was having in corners but that was before hooking up the front driveshaft. I had done some reading and having too large a rear sway bar can cause oversteer since the outside rear tire gets overloaded trying to keep the chassis flat, and the solution is a smaller rear bar/larger front bar so I was thinking I might have to do that. But with 4wd engaged the oversteer is nearly non existent, it's just barely there on the throttle like I want but none of the hyper drifty tendencies it was doing before now that the front can help pull it out of corners. The whole thing feels really planted, a bit of body roll that feels fine in really tight stuff, and in larger turns the chassis is really flat. I am extremely happy how it's handling and glad I was able to get 100+ miles in the past two days to get a bit of seat time and learn it. It finally feels like I wouldn't be the slowest person at a race and it's a ton of fun and a lot easier to drive compared to a few weeks ago.

I don't plan to do much prep to it for the race. Check the fluids, check some bolts, and that's about it. The one thing I do need to fix is the driver's upper link was rubbing on the exhaust (a known issue) and finally rubbed through the header tube. Now that it has self clearanced I'll go in and weld a plate in---besides that though it's ready to rock I think! The race on Saturday is 8 laps of 17 miles, I'm not sure what the terrain is like but probably pretty similar open desert and shrubs. Should be a fun and chill little break in race.

 

Wednesday and Thursday I did a little prep to the buggy, mostly just checking bolts and fluids and got it loaded up to go racing on Saturday.



The race was put on by Bonneville Offroad Racing and was in Vernal UT, about a 6 hour drive from me. I got up early Friday and got up there around noon, with prerunning starting at 2pm and followed by tech inspection. The race was 8x 16 mile laps, so around ~128 miles total. Not much had obviously changed on the buggy since I had attempted to do the Knolls race, the only functional difference was the addition of the rear sway bar.



It went through tech without issue, and nothing exciting about the prerun lap---though I did get into the bump stops more just during the prerun lap than I would've liked, so I decided to increase the compression on all the bypass tubes. Both rear tubes ended up with only one turn out on compression (so barely functioning as bypasses at all), the front top tube had two turns out, and the front bottom tubes were threaded out quite a bit so I just added two turns in on them, and then the bump stops stayed at the 300psi I always run. This was definitely a smart choice. The course didn't really have any whoop sections, a lot of it was literally driving across big fields and then really deep gullies. At first I wasn't a huge fan of the course and thought it was kind of bland, but I actually had a ton of fun on it. There was a lot of corners, a couple good higher speed straight aways, running down a couple graded roads, even dipping into a circle track, across some parking lots, quite a bit of variety at the end of the day and utilizing everything from the gullies to man made spots which I thought was unique and made it fun.

Of course I don't have any photos of anything, hopefully some photographers grabbed some that I can post, so I'll just do a quick summary and some aftermath photos.

We started the race as the lead vehicle, which is based on registration and nothing else. At first I thought it'd kind of suck since everyone would be hunting us down, but it was actually amazing since the course turned out to be extremely dusty. Since this is a very small race, it's effectively broken into two classes: truck/buggy and UTV. There were a couple people in our class, most notably was a V8 ford thing with beams and trailing arms and everything right behind us, followed by a 6200 (class 1 with a LS3), and some other red truck that seemed to have a V8 and looked like a mini trophy truck kind of but I wasn't sure what class he'd technically fall under. I had the largest tires of anyone and only one with 4WD, but was certainly lacking in the front travel department, so possibly a fair stack up against the other V8 guys. We ended up staying in the front until halfway through lap 3, which I think is pretty amazing since the time splits showed the guys behind us catching up (1 minute splits) but it wasn't very consistent. Sometimes you'd see them a turn or two back and other times we'd lose them. Halfway through the 3rd lap I ended up tipping it on its side, which was insanely stupid. There was a gully you'd pop out of, and straight ahead was a motocross track which the UTVs took but the big trucks bypassed, so we'd take a sharp 90deg right, so I cranked the tire and floored it and it didn't slide like I expected and all of a sudden had a bunch of traction and just threw the body over and tipped onto the drivers side. Some volunteers came over and pulled us back over, no issues though a bit of some fluid had leaked out (still not sure what it was, guessing from a valve cover?). Fired her up and we were off again!

We had talked about pitting once (there was three of us total, my passenger and then a third guy at the pit) mainly since I didn't know if I could do the whole course on a single tank so I wanted to get gas at some point, and this was the perfect time to get gas and inspect everything. We dumped in 10 gallons, and the two guys with me decided to switch for some reason (I think the guy with me when we flopped was traumatized after that hahaha), and I looked over all the bolts and checked some fluids and everything seemed totally fine so we took off again.

Did another 1.5 laps (partway through the 4th lap now) and something was feeling a bit weird. I was suspicious a tire had blown, and I had seen a rock at one point that had worried me a bit but it looked like a relatively small rock and not that jagged and I figured the 40s would care (not sure if I even hit it, but I had noticed it). Since the laps were so short, I hadn't even bothered to pack a jack or really much of any supplies since if something happened just go to the pit. Because of that, I didn't bother to stop to check the tires since I figured we would stop at the pit and if a tire was blown change it then (I wonder if the Holley can pick up tire pressure sensors....). And it was extremely subtle if anything was actually wrong, just one of those things where certain corners or bumps didn't quite feel right, an extra little bump like the wheel was hitting the ground maybe. I get to that same spot where I tipped it, which leads into a big long left hand turn as you run through this gravel parking lot, and we are cruising at probably 60-70mph and the vehicle just goes insane. And I'm going fuck you, I'm not rolling again. I don't know if the rear let loose or the front, but it reached the traction limit and began to slide/spin/go up on two tires and I was able to get it under control but the trade off was either go through a fence or try to turn left and all but guarantee it would roll so I picked the fence. Of course, the whole fence is just flimsy fence posts except the part I hit which was where a gate normally would be and consisted of ~3" ~0.25" wall steel pipes two feet into the ground, and somehow I ended up hitting all four of them! Three of them got ripped out of the ground, but one decided to stay and fight and got flattened.



My thought running into the posts was hopefully this doesn't stop us instantly! I didn't even feel it run over the posts, but they did their work on the front end. At first I thought everything was fine but quickly found out the steering was fucked up. And fucked up it was!



The steering arm I had welded on got ripped off. And at first glance the driver's tire was also flat. I would not have guessed a front tire was flat when it was feeling weird, I would've thought the driver's rear was flat but that's not saying much. I'm not sure if the driver's tire was flat before we hit the fence or was punctured due to it. We ended up grabbing the trailer and coming back, and during that time the passenger tire decided to also go flat. The passenger wheel has a pretty serious bend on the inner lip, the driver's wheel has a much small bend on the inner lip. I don't think the driver's wheel is compromised, that tire had a hole on the inside wall of the tire, and from people that were around while getting the trailer they said the passenger tire was fine and then there was a hiss and it went flat, so the passenger tire I think is (or was, prior to driving it onto the trailer) fine but the wheel probably broke the seal and let the air out. And I'll mention it here too, the passenger rear tire had a nail in the tread and when I got home at least was definitely at a lower pressure than the driver's rear tire. Ironically the one tire I was suspicious of was the only tire that currently has full pressure in it! Did the driver's front go flat and cause it to let go? Did the passenger rear lose enough pressure that on the left hand turn it folded over? Do I suck at driving? Well the first two we'll never know.



Additionally, and actually the biggest issue, is the front crossmember broke the welds (presumably when we hit the fence?) and got shoved back.





Which I haven't fully investigated, but I'm hoping I can just shove it back to its home and weld it and call it good. That crossmember had no bracing or gusseting, so needless to say time to do that.



Once I got home I backed the trailer under the lift and hoisted the buggy off to avoid fucking with it.



And then stripped the panels off just to see if there was any additional carnage, which I have YET to find.



Though looking at the steering arm is VERY telling:



I would've thought the knuckle welds would've been some of the best since I was able to preheat and post heat and wrap in a welding blanket unlike a lot of other cast things I've welded, but alas not. Which makes a lot more sense why it broke. I was talking to someone and they said 99% Nickel filler is good for welding cast since it's very ductile? I'll have to try that.

All in all, on the surface looks like simple fixes. I'm hoping I can just weld everything back to its home, and the only real monetary casualty is a tire and maybe a wheel. Though part of me also debates that maybe this is prime time to fully tear the chassis down to sand blast and paint it, and I can go in and gusset everything at that time, then swap in the new engine plus the bypasses need to come off to revalve them since they need a bump in compression at a minimum. I'm not sure entirely what my plan moving forward is, I need to clean the chassis up and inspect it and see if anything else is fucked up.

With all of that said though! The buggy was absolutely amazing, it was incredibly reliable, the hottest the engine got was 205 and the trans peaked at 185. I didn't watch the IAT but I saw 106 after a couple laps, so the supercharger/full hydro cooler was working great. It handled really well, I had it up past 75mph and it was just cruising. Soaked up a lot of stuff really well actually for what it is, the shocks I put temp stickers on but they didn't even register the low end 219F (albeit no whoops and stuff) so that's great. The sway bar worked great, I think a small front bar and maybe downsize the rear might help a bit but honestly with how it's handling I'll leave it as is for awhile. The steering I still want to go to a 2 turn orbital, though the 3 turn wasn't as bad as I thought going fast but still some spots where more turns would help. I think a 2 turn may have helped prevent it from flopping since I had turned into the flop direction but it wasn't enough where as a 2 turn would've given the tire a lot more motion. The cockpit was really comfortable, my only complaint is the radio and intercom sometimes hit my elbow if I'm trying to fuck with the shifter and they're also all but inaccessible to the passenger because my arm is in the way, so I might move those. The engine and trans and 4WD did great, this was by far the hardest I've pushed it and lots of full throttle use. The diffs were happy and not too warm. The steering wheel extension was great, I didn't think about it's position at all so happy with where it's at. The brakes worked extremely well, very happy with them. I never wanted more brakes, I could lock them up all day long. I have the brake pedal on the left foot and I really liked that. My only complaint with the brakes is maybe a bit more bite would be nice, the assist is so powerful it's almost hard to feel much feedback so maybe a lower pedal ratio or grabbier pads or a larger MC, but I never once thought I needed more brakes--just like how the steering is, I'd prefer less motion and more action so I don't have to move as much. The transmission shifting was pretty good actually, though I want to hook up the paddle shifters since sometimes it felt a bit delayed downshifting and no way was I going to put a hand on the shifter and fuck with selecting the correct gear.

What else.... really not a lot to complain about, out of the box I am extremely happy and impressed with how it performed. Granted this was a very small field of competitors, but considering it was at least able to hold off similarly or higher end vehicles gives me a glimmer of hope that it's not the absolute slowest racecar ever built. It doesn't have to win, but not being the slowest would be an accomplishment! I had an absolute blast, and even with the flop and then busting the front a little, it was a ton of fun and I couldn't be happier with the vehicles performance.

 

Nice write up and finding a few weak areas after the build is a plus. Sucks it was at the expense of ripping a few posts out...

 

The owner of the posts came over and said they were planning on removing that fence anyways

 

Awesome write ups! Fun to read!!

 

Glad you had fun & weren't hurt!

 

I got a couple cool photos from a photographer (Kyle McArthur) from the Vernal Race:















This one is my favorite photo. The last racecar I built had absolutely horrible cornering ability and was the single biggest reason I chopped it off and decided to build a buggy. The fact I can now go around a corner without falling over is a huge win.



Moving on; I decided to strip the chassis down. I've been wanting to do this for awhile, but I wanted everything pretty dialed in first so I wouldn't end up grinding a bunch of paint off adding extra stuff down the line. After how well the buggy has been performing, the fact the transmission needs to come out, and having full access to the front crossmember to fix it would be nice, this seemed like the opportune moment. Over three nights I pulled everything off.























The whole harness actually came out without having to cut anything up, which I was worried about!



Drivetrain came out as one unit, perfectly balanced picking it up from the back of the heads.





I then weighed the chassis, and it's a fat pig at 617lbs!



And here is everything to build a buggy:







That catches us up to now! Still a couple things to pull off the chassis, bump stops, horn, mirrors, orbital. This is the first time in 5 years I think that I've had it torn all the way down, and I'm really stoked actually! My plan is to clean it up, add in gussets and reinforcements, add a couple upgrades, go in and second pass weld on anything that was missed or I couldn't reach before. Once all that is done I plan to get it sand blasted and then paint it.



I haven't been looking thoroughly, but so far the only major issue is the front crossmember. It did turn out to be bent, it's not bad but I'm undecided on bending it back or just cutting it out and replacing it.



I'm also thinking of welding in the middle removable cross member so I can brace all the bottom tubes off of each other, and then the transmission mount will be on bushings off of that middle cross member instead of the whole crossmember being on bushings. Having the crossmember removable has never simplified removing the drivetrain, so it's a pointless feature.

As far as all the other parts are concerned, a couple of them will get some upgrades and improvements. The wiring I will simplify again and try to make into a more cohesive harness (I may add a big plug between the engine and harness so I don't have to unplug all the sensors to remove the engine). Some of the line routing will get improved. I will fix the steering knuckle that's busted but will most likely retire the knuckles as spares and get some machined high steer ones. I'll probably get the axles sand blasted and painted while I'm at it too. I'll probably swap in the big engine while I'm here (I also think it was only running on 7 cylinders since one of the plug wires was barely held on I found out, so that's great!). The big question is the transmission, I either rebuild this one, send it out to get rebuilt, or buy a new one. Not sure which path to go down for that yet, and I'll get a new converter while I'm at it. I will also rebuild the bypasses and bump the compression valving. It all sounds like a lot, but at the end of the day the vast majority is small incremental improvements and mostly this is life extension and inspection so I hopefully don't have to do this again for a couple years. I don't plan to make any big changes because at this point it's running and handling good, and even though the rear of the thing is a jungle gym of tubes, I'd rather save my time from redesigning this and put that effort into designing a new chassis in the future and embracing what this one is and using it.

Which on that note, since I was tearing everything down I decided now was the time to buy a 3D scanner that I had been looking at. This is called the Einstar and costs $950!



I just got it yesterday so did my first scan ever with one of my seats.





And here is the file imported into SolidWorks:



I am super excited for this! With the buggy torn down my plan is to scan all of the components so I can build a duplicate in CAD that is identical to the real thing. Moving forward this is huge because I can design an entire vehicle and scan all the parts into it and know everything will fit, all the brackets I need, how hard is to remove the transmission, how's the suspension move, etc. before ever building anything. And granted, I could do that before, but it will be a lot easier being able to import parts into CAD instead of measuring with a tape measure to get a rough shitty blob model. I have high hopes for adding this technology to my arsenal and really stepping my game up. After how much time it took to build the buggy, I wasn't sure I'd ever do that again, but if I can design and visualize every component of the vehicle and then order all the tubes and brackets as a CNC cut flat pack and glue it together, and then I would be at the same point I am now with a chassis sitting here and a bunch of parts that just need to be bolted in.

Anyways, that was my tangent into the next cool technology that will be used on the buggy and my future builds and I think wraps up this update!

 

As we said in the 80's...that's so Rad!
So when do we see some hard to find parts get scanned? sweet build for sure!

 

Well the world now has access to a PRP seat which I've never seen publicly available, is that not hard to find enough?

I'm gonna try scanning some smaller stuff today, like the brake booster which I already have a blob tape measure model of. I'm figuring out the post processing a bit more so will try to optimize the work flow, and maybe crank some of the settings and see what happens. The real test will be trying to scan the chassis which I imagine will be a trip since it's a space frame as opposed to a clearly solid block of material, and is pretty large.

 

Did you bag and tag everything?

 

Shit no, I have a pile of a 100 bolts on the table literally hahaha. But it's okay, probably 90% of the entire vehicle is held together with 1/4-20 x 1" fasteners, so when there is an odd bolt out it can only go a very limited number of places.

 

Reminds me of the time I watched my old man rebuild and engine, he just tossed everything in a coffee can! No problem!

 

Figured I'd throw these up so if there's something I'm missing someone can catch it before I drop the coin. After I broke the knuckle I looked around at options, and no one really supports 99-04 and bolt on high steer I don't want to do. I scanned the axle and drew up a knuckle, my local guy I use to machine parts said $4k for a pair which was too much. I had a buddy that recently got a big run of parts made in China, and I had him grab a quote for the knuckles and that dude said $1600, which is ballpark what the other options I was looking at are. I made a lot of tweaks today so expect the next quote to be a bit more, but sub $2k for a pair of knuckles out of 7075-T6 is worth trying for me. Pictures, with more info below:



As I said, knuckles are 7075-T6. I wasn't sure if I wanted to go that path since it makes them effectively one and done since 7075 can't be welded, but since 7075 is nearly twice the strength of 6061 I thought that was a fair trade off and it's hard to properly repair aluminum for a high stress environment.

The current weight with inserts is sub 15.5lbs. All high load bolts (steering tie rod and brake caliper) have press in steel sleeves (off the shelf and cheap from McMaster). The unit bearing does not have steel inserts due to the low wall thickness on those fasteners to begin with. On that note, the unit bearing has a steel sleeve that is a light press on the bearing, so effectively increases the unit bearing boss, this allows for the hub bore to be increased and allow my RCVs to be removed without touching the boot---currently I have to remove the boot inside the hub assembly to get the axle in and out so that alleviates that.

The brake caliper is raised slightly. I scanned a Camaro 6-piston Brembo from a friend but couldn't get it to fit, so for now I'm sticking with the stock super duty brakes with a potential plan to create an adapter plate (like Busted Knuckle does, but less janky) once I find a different caliper---not that I've had issues with the stock calipers yet.

The steering knuckle is obviously integrated to the knuckle. There are two mounting holes, the outer hole is the same position as my Artec high steer arms I already have. The inner position is 2" inboard which is roughly the position with some other tweaks to get the ~45deg of steering the RCVs can handle. With that said, due to my shock mounts I can't use all that steering so that inboard mounting hole is for down the line options since I had the space. The Artec steering arm I analyzed to a failure load of 24k lbf (as I recall, though maybe there's a FOS I put on that), so my analysis for steering has been using 24k lbf. This is the load that the Artec arm itself would begin to fail (not the welding or cast like failed on me). The other load values I analyzed was a frontal and vertical load of 15k lbf, which is based on previous suspension design loads I've used of 10G frontal and 5G vertical. In this case I assumed each wheel is supporting 1500 lbf (6000 lbf total vehicle weight, which is 20% conservative), then times 10G to get 15k lbf and I used that in both load directions to be safe. The 24k lbf steering (effectively a lateral/side load) is the highest stress state with the base of the arm as expected approaching yield but being fine.

The internal (CV area) sizing is all larger than stock to try and allow as much room to access stuff as possible. Mounting positions of everything (minus rotational position of the caliper) is identical to the stock knuckle so it should be a direct bolt in. The only thing NOT in the model at the moment is a steering stop, which I plan to have be an additional removable component so it can be replaced/adjusted as time goes on without needing to mess with the knuckle itself. The steering stop will go near the stock position and probably consist of just a tapped hole and flat mounting face on the knuckle side, and a cylinder with a wrench flat and stud for the stop itself.

If anyone has any recommendations, critique, or good reason to not try this I'm all ears. Right now I'm hoping to get it sent out for quote and presumably order it within the next day or two so I can hopefully see it by early January.

 

Photo from last week and today! So cool I had to share





Looks like the ball joint and tie rod holes still need to be machined. Dude said it should be a week and the other side will be done.

 

Those look amazing! $1600 for the pair? That's seems like a killer deal for machined knuckles. Can't wait to see the end result.

 

$1800, but yeah crazy cheap. The guy that does the supercharger pulleys quoted me $1500 in material and $2500 in machining. The few aftermarket options for steel or cast knuckles run over $1000, so I can justify $2000 since it's not much more, but $4k is too much, especially for a one off item that might not even work.

And apparently the shop in Spain we use at work is even cheaper! Will have to get them quoting the next big parts I do.