magnum force fabrication?

[Rockatansky]

just wondering if any of you guys have dealt with these people before? i found them online when i was looking around at suspension parts. they're called magnum force race car fabrication. they sell suspension/frame parts and kits, headers and pulleys and things for engine swaps. seems like they deal with tti for exhaust.

just wondering if anyone has any experience buying from them or using their fabbed pieces like k members. they also sell custom bolt in rear ends for a bodies like 9 inch setups with whatever gear/diff combos you want.

seemed like the prices were reasonable too, but i never heard of them before.

this HTML class. Value is http://www.magnumfor

 

[Rockatansky]

dont know why the whole link wont paste. but you can google them if youre curious

 

[LS-300]

Try this link: Racing - Magnumforce Race Car Fabrication

 

[72bluNblu]

Magnumforce has somewhat of a checkered reputation, but they've been around for quite awhile (at least 9 years). I think most of it comes out of their customer service, or at least that's the complaint I've seen most often. There have also been a few "incidents" that have been widely circulated on the 'net about broken suspension parts, although, those were years ago and many of their designs have changed since then. And of course it's the 'net, so, you never get the whole story and there are always two sides.

That being said, I have done business with them in the past, and actually have a set of their non-adjustable bushed UCA's on my Duster. I haven't personally had any issues with their parts or their customer service actually. It wasn't gold star level, but it was better than a lot of places I've done business with. Better than my experience with YearOne, that's for sure. That's a company I would prefer to never do business with again, and won't as long as I have other options.

I'm sure other people will chime in. They're not the first place I would choose to take my business to, but they're far from the last place, and they do have products that I would buy again.

 

[pauly v.100]

I have those same uppers on my car with many miles on them, no complaints from me.

 

[lilcuda]

Personally, I would go with Firm Feel or Hotchkis before I would go with Magnum Force parts.

 

[72bluNblu]

Personally, I would go with Firm Feel or Hotchkis before I would go with Magnum Force parts.

No argument there, I would rather do business with Firm Feel, Hotchkis, Peter Bergman, PST or several others before Magnum Force.

 

[Rockatansky]

thats pretty much what i was asking thanks. i know there are several sources for suspension parts for a bodies. but as far as driveline parts go even though theres a good selection the price also shoots up really quick. these guys have a bolt in 9 inch rear for $2,800 which seems like a good deal to me. i would love to do an engine swap like a decent 360 in mine and i actually have a mild 440 that i've had for a while but its a tough swap and i cant see another way to get a decent rear in there for that engine for less than 3 thousand. i wouldn't cheap out and put junk under my car, but i also can't afford a $5,000 rear end right now either haha

 

[Louie70Dart]

Same place, but a different feel to it.
Magnum Force

 

[Furious65]

Hell, you can get a nice Strange S60 Dana 60 through Dr.Diff for under $2300.

 

[gregcon]

I think their K-frames and front suspensions are a joke. It looks great on a magazine to say you have one....but I have yet to see anyone substantiate why they are better. I think they're worse.

Several years back the brains at Popular Hot Rodding ran a story on a Duster with a Magnum Force K frame/suspension. Or maybe it was Alterkation. Either way, they made a bunch of unsupported claims on how much better it was than the junky stock setup.

One claim was it 'shaved 200lbs. from the stock setup'. Hmmm... that sure sounded impressive. But I started thinking it also sounded impossible. I happened to have a complete k frame from a 73 Duster out back, complete with PS box, control arms, and disc brakes. You know what I mean - basically the whole thing you'd drop out from a junkyard car. So I dragged it inside the shop and used my certified crane scale to lift it up. I took a photo of it - 233lbs.

So I got on the PHR website and posted the photo along with a very polite note suggesting that they must have made a typo in the article - there's of course no way the Magnum Force setup only weighs 33lbs. I bookmarked my post so it would be easy to find.

Their response? The next day they deleted my entire post! I guess the k frame maker spends more on advertising than I do....

 

[Bill Crowell]

I bought their A-body forward strut brace kit a few months ago:

Magnum Force Engine Compartment Forward Strut Chassis Braces

It was shipped out right away, and I was happy with it. At first I thought it was expensive ($299), but the body person who installed the kit pointed out that it had tubes and plates of different wall thicknesses (the braces themselves are 1/4"!), which you could never really obtain and duplicate on your own for the same price. So Magnumforce is OK in my book. Maybe they got their act more together recently?

 

[gregcon]

I should be clear that my gripe is with the aftermarket K-frames and their use of generally weaker-than-stock components. I have a set of Magnum Force A-arms which are generally decently made parts.

Which brings me to another example of how the aftermarket often provides lesser performance....tubular A-arms are a good example. Tubular arms have a lot of 'cool' factor as they look like race car stuff. But...I'd be willing to bet are less strong than the OEM stamped arms. Why do race cars use tubular arms? Because the average fab shop making race parts can't afford the multi-million dollar investment it takes to make a stamped arm. The amount of engineering, R&D, and tooling needed to make a stamped arm far exceeds anything a tubular arm sees. A tubular arm has steel in places it doesn't need it, and doesn't have steel in places it does. A stamped arm is a wonderful assortment of bends, radii, and 'elegance in engineering'.

 

[pishta]

stamped arms also cost about $3 after all the tooling is in place. When you need about 600,000, stamping is the way to go. Welded tubular arms require about 15 different manufacturing steps and at least 30 minutes per arm to assemble unless they are automated which would not work financially. they probably used something very similar to tubular during R&D of the suspension, then found what worked and sent it to design for the stamping pattern.

 

[gregcon]

stamped arms also cost about $3 after all the tooling is in place. When you need about 600,000, stamping is the way to go. Welded tubular arms require about 15 different manufacturing steps and at least 30 minutes per arm to assemble unless they are automated which would not work financially. they probably used something very similar to tubular during R&D of the suspension, then found what worked and sent it to design for the stamping pattern.

That is correct. But it doesn't change the fact that the tubular arm is a lesser part. It's an example of where mass production benefits both cost and performance.

 

[72bluNblu]

Tubular arms are not a lesser part if they're designed and built correctly. The tubes are far stronger than the stamped arms as long as the welds are good, even with fairly thin wall tubing. And they're MUCH stiffer than the stamped arms. Obviously the stamped arms are more than strong enough, and the flex is small enough that most people would never even notice. Tubular arms are overkill for most folks, but to get the right alignment with the stock arms you need offset bushings. And the stock arms are 40+ years old, many are damaged, the threads are worn, and the stamped reproductions are not as good as the originals. Now, the stock arms are more likely to bend in failure than break in any way because of their stamped construction. Because of the welded joints of the tubular arms there are fracture points introduced, but, as long as the welds are quality and the tubing is sufficient they won't fracture at anywhere near the strength it takes to bend the stockers.

The problem with your mass production argument is that the goal is the cheapest parts that will do the job, not the best parts. The reason the factory has stamped arms has nothing to do with strength, beauty in engineering, or anything even resembling performance. It's because stamped arms can be mass produced for a tiny fraction of the cost, and the factory already had the tooling and the engineers to do it. The only goals were strong enough not to break and price per unit. It's true in reverse too, most racing applications use tubular not because a stamped arm wouldn't be strong enough, it's because tubular arms easier to construct. Tooling and stamping equipment costs a fortune, and engineering analysis on a stamped part is much more complicated (especially if you don't have solid modeling software). Welding equipment (even really good welding equipment) is far less expensive and a skilled welder can fabricate a set of tubular arms that are bulletproof in short order. The engineering analysis on tubular arms is much simpler to model, just a couple of straight tubes in many cases and that can be worked out by hand (although that's not much fun still).

I've assisted in the design, and did all of the construction, on a few sets of tubular UCA's for a Formula SAE team I was on back in college. I actually had to increase the thickness of the tubing used in our UCA's for welding purposes. They were strong enough to meet design criteria when the tubing was still too thin to reliably weld to the much thicker wall threaded plugs. Now, that was a really light car and you wouldn't have that issue designing and building tubular UCA's for cars that weigh 3,000+ lbs, but even standard wall thickness tubing and proper design will give you more strength than is necessary as long as the welds are good.

 

[gregcon]

Yes, original arms are getting old and harder to find good ones. And the aftermarket pieces are poor quality. That's actually why I have a some Magnum arms...it was easier to buy those than go scrounging.

Another problem I have with 'race bred' parts is they often don't need to be as strong as OEM parts. They're often used in cars that are lighter than stock cars, don't have a 5 people or luggage loaded up, and don't see potholes or curbs or all the other stuff a street driven car sees.

There's also the benefit seen in a stamped arm in that it can be made into a much more complex shape - one that conforms to the vehicle's body requirements. A stamped arm is practically 'molded' to fit and has no trouble with clearances or with providing a good flat bumper surface.

I'd like to see actual calculations of strength and rigidity between a stock arm and a tubular arm.

Of course....most tubular arms also use the infamous polyurethane bushing which is another slop-mess.

 

[72bluNblu]

There is nothing wrong with poly bushings on the UCA's. And for that matter, there's nothing wrong with using poly bushings for the LCA's either, as long as you make the appropriate modifications and make sure everything fits properly on installation. That last bit is not trivial, because the poly LCA bushings use old bushing shells you must confirm the proper fit. They are not perfect and there are now better options, but installed properly they work fine. I run both poly upper and lower control arm bushings and have for tens of thousands of miles on the street, potholes and inclement weather and all.

There is no benefit to a more complex shaped UCA if you're not the one designing it. The shape of the stock stamped UCA's on these cars does limit rim width and backspacing. I ran stock UCA's on my Duster with offset bushings until I bought my new rims and tires, when I found that an 18x9" rim with 6.1" of backspace would not clear the stock UCA's at steering lock and with the suspension at full travel . Not a problem if you're running narrower rims and tires because you don't need that kind of backspacing or width, but the stock UCA's absolutely limit what is possible on these cars before the frame and fenders do. So, yes, there can be problems with clearance when using the stock arms if your plan is to run anything other than a stock suspension and wheel configuration.

Also, remember that when the UCA's for these cars were designed they were intended for use with bias ply tires, which are not capable of transferring the suspension loads that radial tires can in general, and certainly aren't capable of transferring the same loads as modern tires and compounds can. Unless you're running bias ply's, you're outside the original design parameters. Same goes for upgrading torsion bars, brakes, etc. The OEM parts of the 70's where not intended to see the same loads as a car modified with the aftermarket parts of today, their design parameters were completely different. If I buy a set of tubular UCA's, they should have been designed with all of those considerations in mind.

As far as strength goes, I'm not going to argue with you. I've done the engineering before. Really, it comes down to how strong a particular control arm was designed to be, tubular vs stamped has nothing to do with it. Tubular arms are used in everything from street cars to trophy trucks, you can design them for anything from tractor-trailers to yugo's. Their strength depends entirely on the application and construction. The stock arms were designed to handle a set of bias ply tires and 10" drum brakes, you can't change that. Yes, you can absolutely design stamped arms to handle a lot more than that, but the factory control arms you're talking about were not. So I have no idea why you would think that OEM stamped arms designed for 1970's performance levels and mass production would be stronger than aftermarket tubular UCA's intended for modified cars and greatly improved performance. If you really want to find out if the OEM stamped arm is stronger than a particular aftermarket tubular UCA (because they're all a little different), you'll have to break out a stress/strain gauge and do some destructive testing, because that's truly the only way to know. Even the calculations and models aren't as good as that.