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Practical to Mod Tube K-member for Street?

1K views 22 replies 11 participants last post by  cosmoracer 
#1 ·
After spending all day looking at the K-member posts and realizing the car I purchased for street usage (road racing) is set up for drag racing with a QA1, I'm at a lose for words. Options are to sale and start over, get another K-member, or modify the QA1 (has coilovers & tube control arms as well). Apparently, they are made from mild steel so welding won't be an issue. Has anyone attempted this or have an idea of the weak areas on these? How practical would it be to weld gussets or reinforcement tubes for additional strenght? Car is 1990 LX Coupe with SC running 450rwhp...

Comments or suggestions?

Thanks
 
#7 ·
It probably makes the most sense to swap it out for a MM or a stock unit but is there that much of a difference structurally between the QA1 and the MM unit? Seems like they are very similar with a little bracing in the right places... understanding that the k-member isn't designed for the street out of the box but I read where D&D?? made a plate kit at one time to change their kit to street usage. May have to run a finite element model on the QA1 to see where the weak points are and look into adding plates before giving up... I guess I was hoping someone already looked into this. I have some kind of lower control arms, look like the GMS with Sway bar mounts and their coil over system so possibly all is not lost.
 
#9 ·
I had a QA1 k-member in my car and i added some bracing to it and got MM A-arms (I was tired of busting QA1's bushings). I open tracked my car for 3 years with it around 8 times a year. My car doesn't see street driving.. almost at all but I was always afraid of running r-compounds at the track, so i always ran street tires. The rest of the car was always really strong and well balanced, so i got to lap really good times for running street tires. Today, I got the Agent-47 front end.... then I realized what i was missing... :D
 
#16 ·
As did anyone who purchased a MM unit, I did a lot of research before my purchase. The fanboy internet jargon is absolutely right in this case... do the sensible thing and sell the QA1. You'll have absolutely zero problems selling it in the classifieds for near what you paid for it.

I'll tell you one thing, I would not want anything in the back of my mind during a fast sweeper doing 100mph. You have a weld give out and the car unsettles, could get ugly quick!
 
#19 ·
I have never seen any tubular K member other than Maximum Motorsports, or Griggs, so I can't say for sure that the QA-1 is junk, but if I ever bought suspension parts for a Mustang, I'd be calling a shop in San Luis Obispo. I have built more road race Mustangs than most people here, and my cars have won a lot of races. When you're trying to find a welding shop on a Saturday night, the dollar difference won't seem so much. How much is your car worth to you? So why worry about a few hundred bucks.
 
#20 ·
Well its not the money as much as the application and time to swap it out. It will see occasional street usage for fun and drag, but not autocross so probably be ok with the way it is...

I don't think I'll be doing any autocross with 4" tires up front and 12" in back.
 
#22 ·
It was initially, but my post just prior to yours says...

"I'm doing a 180 after sleeping on it. I'm going to keep the QA1 but modify it for street usage. My flop but going to try it anyway..."

Decided to leave it a drag car but may beef up the QA1. The MM k-member has a few extra braces that I can duplicate to give me a little more margin. I know it will not be anything like the MM but it will add a little insurance. Car is set up for bracket racing and would be very expensive to convert back to full time street usage or autocross.

Thanks for the help.
 
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