Custom tubular K-member

1fastlaser · 10-19-2007, 08:57 AM

Well i saw some other people doing it with custom control arms. Alot of people were leaning more toward it with the factory control arms. So here it is.

Dont mind it not being painted its black now. This is just mild steel but overal weight savings is about 50-60 pounds, no more cross bars, no more sway bar, factory control arms and rack. My buddys looking to make these in mild steel and chromolly

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IPT · 10-19-2007, 09:13 AM

COOL!! I will take two.

pagosa dsm · 10-19-2007, 05:56 PM

Very nice work! Has the cross member been tested on the street?

InfiniteGSX · 10-19-2007, 07:05 PM

Nice... can't wait to see it installed.

project_tsi · 10-19-2007, 08:20 PM

Doesn't look very strong.

InfiniteGSX · 10-19-2007, 08:23 PM

Quote:

Originally Posted by project_tsi

Doesn't look very strong.

I say weld a X bar in between the two control arms. I'd put some more support, making it as 3d as possible for safety.

eclipsh · 10-20-2007, 05:43 AM

Quote:

Originally Posted by project_tsi

Doesn't look very strong.

I'm with you on that one. Welded in washers for bolt holes, almost no bracing. I'd be very concerned about the vertical post going down to the a-arm section. You put in a gusset at the top but the bottom side is being held together by nothing but a little welding. That is going to have a lot of side load pushing it hard towards the center line of the car during acceleration and pulling it away from the centerline during deceleration. All of that force is going to be put on the one section of welds around the base of the post. I'd at least throw a diagonal brace from the bottom of the post up towards the centerline.

I'm just being so critical because you're going to be hurting or taking a long nap if this thing gives out. I'd want it as strong and safe as possible if it were me in the car so I want it to be tough for you too.

InfiniteGSX · 10-20-2007, 08:33 AM

Thats why I say weld a X Brace between those points, and for verticle flex, two bars connected to the control arms, and welded to the top bar... that should stiffen it up.

eclipsh · 10-20-2007, 08:45 AM

Looking at it more I was thinking you should run that lower bar clear to the front of the car and bolt it to the front cross member. It'd add a couple pounds but it would be a hell of a lot stronger. You'd also have the option of replacing the front cross member with a tubular piece and making the whole front sub frame one solid unit.

EDIT: Sort of like post 51 in this thread only welded in the front and using tube steel instead of the heim joint design.

1fastlaser · 10-21-2007, 07:41 AM

Well heres the thing, its very strong. The build was done by a friend of mine who has been doing chassis for 5 years, its all tig welded not migged. Dont judge a book by its cover, heres the tubing used. www.haggardfab.com

main tubing is 1.5"od .200 wall ... tubing that the bushings slide into is
2"od .250 wall... tabs for lower control arms are 3/16 thick

I drove/ raced it last night no issues no problems. This isnt a big 16g car, this is a 60-1 2.4 car with all suporting mod, made 422 on pump. I aimed for pot holes and bumps, thats how you test things. SO far plenty good, no issues

Also the front bar was replaced with a motor mount, ill have pictures up with it in the car.

JohnTSI · 10-21-2007, 03:34 PM

Why did he not make tubular control arms with it as wel?

1fastlaser · 10-21-2007, 03:57 PM

Because i didnt want to do tubular control arms, this is still a street car. I am trying to keep it that way. Although it could have been done

absolute_DSM · 10-21-2007, 04:33 PM

I wouldnt buy anything like this unless the guy designing it has an engineering degree. NO offense at all, but any guy can weld some tubing together and call it "strong".

Hitting a few potholes probably isnt the industry standard to testing it out either.

Its a good effort and a GREAT idea, dont get me wrong.

1fastlaser · 10-21-2007, 09:00 PM

i guess his chassis building background isnt enough. www.haggardfab.com
There is way more stress put on a airbagged truck with a body dropped truck then a car just holding together. He has more experience in the chassis building department then alot of people and his work shows. This isnt just a backyard piece. Chromoly ones are getting made as we speak, have a jig setup so we dont need a car anymore. I got a gt42 on order so we are making a turbo manifold to put that in, plus a intake manifold with a little bit of a different design with a Q45 throttle body. Nay sayers just look for it on dogboxracings website, since im good friends with them and my buddy who made this is gonna be doing some chassis work on there new race car.

more pictures, some of his work

absolute_DSM · 10-21-2007, 10:37 PM

I dont think anyone is doubting the man. Anyone that has done any type of fabrication can appreciate the time it takes to do something like that. ( BTW that truck frame is sick, and Im not even into that kind of low.

THAT kind of project really shows he knows what hes doing. )

I think the good members here are trying to help with the positive critizism. We are more thinking of racing, not just driving it on the streets.

With the lateral Gs of road racing and the body twisting of drag racing, it just doesnt looked beefed up enough as the other tubular cross members weve seen before. And I do believe they were actually designed by engineers. And like eclipsh said before, this piece is something that could cause a major accident while racing if something went wrong.

But seriously, it is a nice piece, hes got some skills.

1fastlaser · 10-22-2007, 07:04 AM

Quote:

Originally Posted by absolute_DSM

I dont think anyone is doubting the man. Anyone that has done any type of fabrication can appreciate the time it takes to do something like that. ( BTW that truck frame is sick, and Im not even into that kind of low.

THAT kind of project really shows he knows what hes doing. )

I think the good members here are trying to help with the positive critizism. We are more thinking of racing, not just driving it on the streets.

With the lateral Gs of road racing and the body twisting of drag racing, it just doesnt looked beefed up enough as the other tubular cross members weve seen before. And I do believe they were actually designed by engineers. And like eclipsh said before, this piece is something that could cause a major accident while racing if something went wrong.

But seriously, it is a nice piece, hes got some skills.

completly understand. Yes its in testing. Gotta find what issues could go wrong. I put about 150 miles on it, racing it driving it 0 issues so far. Im friends with alex at dogboxracing so we are gonna be devolping alot more stuff including these. I will keep everyone posted

laserspeeddemon · 10-22-2007, 01:55 PM

The welds look good. The design, well thought out. I can tell that this craftmanship isn't trail and error. The bends look like it was well planned. But I wouldn't take this on the street. Anything breaks and you wreck into someone, prepared to be sued and sued hard.

InfiniteGSX · 10-22-2007, 02:05 PM

1fastlaser, I'm sorry to say... Look at that K Member... and then put it next to that truck frame. Very Different! Looks like the K Member was a quickie! That Truck frame has all the nessecary support comming from all angles. That K Member doesn't. It isn't that were doubting the mans previous jobs. But If you look at how suspensions get damaged, before you build something like that... you will know that peice looks very brittle. It looks very flimsy on the bottom side... which is why I mentioned a VBrace, and a X Brace, which in the end, would look like that truck suspension, and probably wouldn't break or bend if you dropped the car off of a plane.

Its exactly like LSD Said, If it does break... your not going to have much time to react before total destruction... and you, or someone else could get hurt. I'd feel safer knowing that I spent some extra time adding a little more brace to it. It doesn't take very long to pull the motor out of these cars, I say pull the motor on a friday night, spend all of saturday building around the steering box and I'm sure you guys have some tools you could put pressure on the bar itself, to see how it reacts.

BTW, don't take this post as me putting you or your guy down. Just would rather be safe then sorry. We really dont want to see anyone get hurt.

bmoha2 · 10-22-2007, 03:50 PM

Wow that lowrider was incredible. I would like to see some more pics of the k member. And did you say it is going to be produced as in being able to purchase it? Especially in cro moly that would be cool.

1fastlaser · 10-22-2007, 09:01 PM

Quote:

Originally Posted by InfiniteGSX

1fastlaser, I'm sorry to say... Look at that K Member... and then put it next to that truck frame. Very Different! Looks like the K Member was a quickie! That Truck frame has all the nessecary support comming from all angles. That K Member doesn't. It isn't that were doubting the mans previous jobs. But If you look at how suspensions get damaged, before you build something like that... you will know that peice looks very brittle. It looks very flimsy on the bottom side... which is why I mentioned a VBrace, and a X Brace, which in the end, would look like that truck suspension, and probably wouldn't break or bend if you dropped the car off of a plane.

Its exactly like LSD Said, If it does break... your not going to have much time to react before total destruction... and you, or someone else could get hurt. I'd feel safer knowing that I spent some extra time adding a little more brace to it. It doesn't take very long to pull the motor out of these cars, I say pull the motor on a friday night, spend all of saturday building around the steering box and I'm sure you guys have some tools you could put pressure on the bar itself, to see how it reacts.

BTW, don't take this post as me putting you or your guy down. Just would rather be safe then sorry. We really dont want to see anyone get hurt.

Well im not gonna argue, all is understood. It wasnt a quickie by any means. Look at his work, he knows his stuff and has built ple