Being able to follow along with your build is inspiring. Guys like you, AngryCorvair , maschinenbau , and others make it seem so simple to take a bunch of odd, mismatched parts and make an awesome machine out of them. Thanks for taking the time to post the details and great pictures of the process.
AAZCD said:Being able to follow along with your build is inspiring. Guys like you, AngryCorvair , maschinenbau , and others make it seem so simple to take a bunch of odd, mismatched parts and make an awesome machine out of them. Thanks for taking the time to post the details and great pictures of the process.
That's really high praise to get lumped in with those two! Thank you!
Started cleaning the rear frame crossmember for the exhaust.
CAD
Cut 1
Cut 2
You can probably see my plan to box those in. I'm also planning to add some strength back up top.
92 hours.
Oh fancy metal folding. Nice.
In reply to Stampie :
Metalgami?
AAZCD said:Being able to follow along with your build is inspiring. Guys like you, AngryCorvair , maschinenbau , and others make it seem so simple to take a bunch of odd, mismatched parts and make an awesome machine out of them. Thanks for taking the time to post the details and great pictures of the process.
While I appreciate the compliment, I will say that I haven't actually made an awesome machine yet.
Yet.
Well! Ian came down this weekend and helped a ton with getting the main roll hoop installed.
It's really nice to have an extra set of hands and an extra noggin to make sure you're not forgetting something stupid.
We did about 7 hours of work on Saturday. Then I spent one more hour this morning cleaning rust off the sections of main hoop we didn't clean saturday for welding. So now I'm in 100 hours!
First we put the engine and headers and rear subframe back up on the frame to find the right fore/aft position of the rollbar. We got a racing helmet, and put the seat on the floor and measured out a height on the wall, and then made the roll bar an inch or two higher for good measure.
Once we had a spot we tacked on some frame connectors.
Measure and do math carefully:
And BAM! Let this be the 100 hour picture:
Ok, so, decision time:
I think both left and right designs are similar for weight. I think they're both legal roll bar designs for nhra (but I'm reading again to triple check).
I have enought tube on hand for the right design, but I'll need to go get another stick to do the left ($20-30). Am I giving up anything to go with the design on the right?
Awesome!
Did a bit of mocking up today, used tape to mark out the extremes of possible support placement to make sure there was no significant interference. I also hopped in and made engine noises to check elbow clearance. Everything is looking great.
Next I turned my attention back to exhaust clearance.
More interference
Crude. Let's improve on that a bit, and add some strength back.
Take some scrap square and the pieces I cut out from the frame. Mark carefully.
Nice.
May not even end up half bad!
101 hrs.
Go with the longer door bars for better chassis rigidity and more side impact safety
Do you have any 2x to make that exhaust bridge with?
Being able to plate the entire bridge, down the face of the rear cross tube, will restore quite a bit more strength vs just bridging the top. I envision a fairly large torsional load on that cross tube with the swing arm pucks attached there.
"Used tape to mark out the extremes of possible support placement to make sure there was no significant interference"
I've used C.A.D., but I like the new T.A.D. !!!
We used "piano" wire back my shipbuilding days to pull reference measurements off; the prolly use lasers for everything nowadays. But the tape looks great!
You must be a bit slimmer than me. Looks too small for my fat azz to fit...
In reply to 03Panther :
Hahaha the seat is really tight. And someone smaller than me must've used it before since there is Velcro tape in spots on the inside. But this seat is in budget so I'm gonna have to cut some doughnuts and make myself fit.
More work on the bridge. I promise I won't spend much more time on this part that I have now significantly over-engineered for it's intended purpose.
102 hours.
103 hours.
Braced and made final cut. I did some highly technical metal beating as well.
Sort of welded in. Im really not happy with some of these welds and I got mad at it while I was going so I don't think that helped. Haha. Oh well. Good thing I have a grinder.
I'd just cut that off and do 2x so it all matches structurally as Gumby said.
Plus you'll get a do-over.
Please do this. lol
Nice work with the tape man! I hadn't even thought of that. Outstanding idea making planes out of thin air.
As they mention, 2x2 would be better, but they haven't addressed that ya need some clearance in top of existing frame as well. At least I think thats what I see. Fab the brace part on the bench where the fiddly parts are not as annoying, and where you don't have to weld out of position and then weld to frame. I can fab and prep much better than I can weld!
Somewhat time consuming, but ...
If your really good with a grinder and slitting wheel, you can even save the piece you cut out, and flip it to use inside the brace. but a piece of angle would be faster!
In reply to 03Panther :
Well, that is almost exactly what I did, only mine is half width. It's going to work just fine once I clean up the welding. Also, I took a few pictures to show the bigger picture here. There will be significant support on that rear crossmember.
It's hard to see from the angle, but it is 2 inches tall. I may plate it down the back, but I do want to maintan a bit of clearance there for the motor mount plates.
Also, the rear hoop supports will be landing there as well.
For now, I'm going to call it "good enough to move on to the next task".
Yeah I wouldn't bother with beefing that up. Weight is the enemy of speed, and perfection is the enemy of progress. You need both to win the Challenge.
In reply to maschinenbau :
Says the guy who just won the Challenge...
In reply to gumby :
Trust me, that car ain't as light as I would like and definitely nowhere near perfect 
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