Aluminium K Frame?

Malicious · Apr 13, 2017

Just going to throw this out to the group to discuss.

I see a lot of custom fabbed K frames and all use good thick steel but a lot of new cars are using a lot of aluminium in structural components such as the rio bar and front & rear K frames. There's obvious benefits in weight, but how realistic is it to be able to fabricate something that can handle the loads of the K frame out of aluminium? What are the main forces that the K fram is going to see in this aged body?

I honestly feel like it is entirely viable using the correct thickness for a coil over application but I wonder if a K-frame that uses the stock style suspension such as the Q-a1 K, would be achievable?

Would you need steel sleeves for the lower control arm pivots? Maybe captured bearings? I would think that heim joint / hinged and dampened strut rods (such as PST's) would be necessary. But the lower control arm pivots remains point of concern for me.

Yeah I am contemplating building one, but its more long term for the moment. I'm mulling over improvements for 'Stage 2'.... And I enjoy fabricating & design challenges.

HEMI-ITIS · Apr 13, 2017

If you slice and dice the stock "K",the weight diff would be mininal.

Kern Dog · Apr 13, 2017

XV Motorsports offered an aluminum K member with one of their front end packages. I don't know of anyone that bought one though.

dieseldazzle · Apr 13, 2017

This ones pretty light

Malicious · Apr 13, 2017

Actually looks like the standard K from them is Aluminium:
https://xvengineering.com/collections/frontpage/products/xv-level-ii-front-suspension-e-and-b-body

I like the idea they have, but I have to say I feel like it looks a little flimsy...

Malicious · Apr 13, 2017

Yeah the Qa1 is nice, but I have a nice swaybar that I don't think works with that set up. I have their upper control arms, pretty good quality stuff.

Torkmnstr · Apr 13, 2017

I talked to a guy who got all the xv stuff and he said his alum setup was all out of whack. Had to cut it all up and reengineer. I like the idea of have a little beef up from with steel for the fact that it handles a lot of work and alum is overall pretty soft...

HEMI-ITIS · Apr 13, 2017

Some of those front end kit are very nice.But then your changing to a rack and coilovers.By the time your done there is 6 to 7 grand missing outta yer wallet!

69 GTX · Apr 13, 2017

In my mind there are better place to lose weight than the K member. I wouldn't even consider it with out a front & rear engine plate. Just me. In this case more HP may be cheaper than less weight.

gkent · Apr 13, 2017

Modern vehicle aluminum K frames are designed in conjunction with the rest of the car using CAD CAM programs. Other portions of the car would be strengthened to compliment the K frame and maintain strength. Designing an aluminum K frame for an older car without CAD CAM would likely yield an inferior piece. Using CAD CAM you'd likely have to add support elsewhere in the car and there likely wouldn't be any overall weight savings. FWIW, you don't see anyone cranking out aluminum Mustang II front ends - probably for a very good reason.

BobJ · Apr 13, 2017

Hell I made my K frame heaver when I welded all the seams and installed Firm Feels bracing kit with skid plate. I wanted to take out as much flex possible.

HEMI-ITIS · Apr 13, 2017

The stock "K" is not all that heavy,this notch might weigh 3 or 4 lbs

Kern Dog · Apr 13, 2017

I think when the Sales department/Ad department writes ads for these aftermarket setups, their "math" for weight savings is based on a power steering stock setup versus theirs with a NON power rack to make the weight difference seem greater.

streetwedg · Apr 14, 2017

I have seen factory aluminum k frames before. Not sure but I think they came on the altered wheelbase cars. I have a friend with a 64 Hemi car and he's always looking at rare SS parts. K member couldn't have weighted more than 5 or 6 pounds.

Mike67 · Apr 14, 2017

I agree with Stanton, those are all engineered as an integral piece of the whole car.
My other thought is how many modern cars are running cast iron big blocks that even come close to the stock torque output of a big block.
I would think you would have to have some really thick aluminum to make it reliable for a driver. May even be the same weight as a stock k by the time you engineered it for durability...

glassman · Nov 30, 2018

streetwedg said:
I have seen factory aluminum k frames before. Not sure but I think they came on the altered wheelbase cars. I have a friend with a 64 Hemi car and he's always looking at rare SS parts. K member couldn't have weighted more than 5 or 6 pounds.

The light weight k members that Mopar built were Magnesium and they cracked and were deemed unsafe. I run "John Holt Racecars" light weight k members in 3 of my cars. He modifies the stock unit and after he is done, it is half the weight. A lot of the SS/AH cars on the circuit today use his k members.

Badvert65 · Nov 30, 2018

glassman said:
I run "John Holt Racecars" light weight k members in 3 of my cars. He modifies the stock unit and after he is done, it is half the weight. A lot of the SS/AH cars on the circuit today use his k members.

Any chance you have pics of one of these K frames? I checked his website but they weren't mentioned.
The k frame on my 65 Belvedere started out at 43 lbs, when I finished cleaning and modifying it, it was down to 35 lbs. Was a heck of a lot of work for 8 pounds.

biomedtechguy · Nov 30, 2018

dieseldazzle said:
This ones pretty light

I haven't lifted my stock K-member, but I lifted my new QA1 K-member and it's seems light...and...pretty!

glassman · Nov 30, 2018

Badvert65 said:
Any chance you have pics of one of these K frames? I checked his website but they weren't mentioned.
The k frame on my 65 Belvedere started out at 43 lbs, when I finished cleaning and modifying it, it was down to 35 lbs. Was a heck of a lot of work for 8 pounds.

Sorry, cars are put away for winter. He uses chrome molly round tubing and there is no part of the original k member left in the center and all of the 5/8" tab around the edge is gone and then welded. stock steering box still mounts to k frame. Hold downs and tow strap mountings are optional. $750

HEMI-ITIS · Dec 1, 2018

I do not know if this has changed,but several guys I know that went to a rack lost considerable turning radius............
I have a steering box brace because the motor mount was totally removed as I have a front engine plate and a mid plate.Also ran braces to both sides of the modified "K"
Also added "J" bars to stiffen the front chassis.

Aluminium K Frame?

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