usa1racing

Has anyone tried to replicate an aftermarket torque arm at home, specifically those offerings from BMR? I’m switching to an LS1 T56 trans. and Ford 9” rear, and I’d like to build an arm that locates somewhere other than the transmission tailshaft. What are the advantages to running a shorter torque arm, such as BMR’s? If anyone has built their own, what are some of your material specs? I would run an SSM setup if I could find one, and didn’t have to section the floor.

Shagwell

first off, the SSM set-up sucks for a street car. It's like ladder bars, only non-adjustable.

As for a homemade motorsports tq arm, it all comes down to your skill level and fabrication abilities. Some guys can't change there own oil, some guys can build a complete tube chassis and drivetrain for their car. Yes, it can be done, it has been done. I like 1" .120 wall DOM steel tubing for a street tq arm. I've gone 1.66 60' on an arm made from Lowes' 3/4" black iron pipe.

Length depends on power level and the height of the front mount. Shorter arms react faster, therefore work better for lower power levels. Longer arms react slower, thus are better suited for higher power levels. If memory serves me correct the BMR arm is roughly 48" and the factory is something like 54-56". Mine was 52, but the car would have been better suited to a shorter arm, as I had to run an excessive pinion angle to make it react fast enough to provide the needed traction. The BMR and Jegster short units are good for around 500hp, past that they become harder and harder to tune and become less tolerant to changing track/surface conditions.

If you wish to build your own, you should really consider reading come chassis and suspension design books first so that you have some insight as to how changing something will affect how it works/reacts.

xpndbl3

iTrader: (5)

no problems with the jegster arm here and for how cheap it is, I wouldn't bother fabricating your own, once you add up materials, etc you're not really saving anything.

Sonix

iTrader: (1)

Can you give info on how you made yours shagwell? I was going to do that this winter myself.
I was thinking a spherical rod end at the front, and maybe solid rod ends at the back (non bearing style), bottom being a female.
Then a double adjuster on the back bottom mount, to easily adjust the angle.
I'm not sure what I could use to measure pinion angle very accurately though?

Mikz86TA

iTrader: (4)

I have thought about using round tubing welded to the inside under the lips of a stock arm and some 1/4 steel plates near the ends as a cheaper way to strengthen the stock one. Also by using the stock clamshell bracket at the tranny, cutting off the mounting bolts that go trough the tailhousing and fabing up a vertical plate to weld the clamshell mount to from the stock trans crossmember. These were ideas and not really thought completely through yet since Ive been working on other projects. Stiffening the trans crossmeber was a part of it to. This method would basically keep the tq arm accessible for removal easily, have bushing options still availible, and mount it off the tailhousing. Any other ideas constructive criticism and opinions are welcome.

92droptopws6

iTrader: (10)

jegster is a great unit,especially for the money....they also have the best fitting SFC for thirdgens(imho).
you cn also try this set up i am doing this on my 95
www.g-forcesuspension.com their website is down for recon.but hold on to it and check it out

dennisbernal91z

iTrader: (2)

xpndbl3: I didn't know you had a jegster arm. I have a spohn and it sucks cuz the tranny x-member is huge and very hard to get around with 3" pipe. The place where my pipes go around the member is where I scrape sometimes. I was thinking to try and fix this once and for all by going with a jegster, new-non hacked up Y (or fixed up) and Skule or other tranny x-member for my T-56.

Kinda think it would be a lot of $ for fixing my scraping. My other option is to just notch the member and run oval pipe by it. Think that would be better.

Someday i will be a full build on this car again. Then I will fix it right. Think my second plan sounds OK?

usa1racing

The G-Force suspension looks a lot like the bars built by Pete Z and Ed Quay for Stock class cars. I'm going to build something similar, but I wasn't aware that you could do away with the torque arm. I planned on retaining the torque arm with this type of bar, but I'm not sure how much of a purpose it'll serve, and I'll ditch it if it's going to bind the suspension. Joe Russell also builds a similar bar, with the link on the bottom, I believe.

xpndbl3

iTrader: (5)

yup I have the adjustable one, and I'm really pleased with its performance on the street even I hook up a lot better. That spohn crossmember is usually cut up and the lower tabs removed then some gussets welded in to allow for true dual exhaust. I don't really mess with y-pipes on these cars, although a buddy was running the 1 3/4 hooker long tubes, with some y-pipe and a mufflex 4" and running very respectable numbers with the same mph and similar ET with removing the exhaust so it wasn't a restriction at all.

dennisbernal91z

iTrader: (2)

Nice to hear. Maybe I will have the dyno shop chop the x-member a little and re-tuck the pipes. I can't imagine the 4" having restriction. It is HUGE. haha. Well thanks for the heads up. Maybe someday I will swap over to the jegster to see how it is. For now, the Spohn is just too new. Thanks again.

-Dennis

BMmonteSS

Any type of suspension like the one in the picture above should NOT be used with a torque arm. The upper link controls axle wrap, which is the job of the stock torque arm. This type of setup is just like the lakewood "traction" bars, and will cause the suspension to bind tighter than a 30 year old aluminum bolt when used with a torque arm. The second and more serious complication of this setup is that it mimics a ladder bar style suspension. When the upper link mounts to the lower control arm instead of it's own chassis mounting point you basically remove any ability of the rear end to rotate in roll. This works ok for a drag car as the whole rearend acts like one gigantic sway bar. To better visualize what I'm talking about, in your mind remove the rear end from the car with the control arm still attached to the rear end. In order for the suspension to allow roll one control arm must move up while the other moves down, with the upper and lower control arms bolted to each other this just isn't possible. You basically have a suspension setup like an ATV, and if you have ever rode an ATV you know it tight turns the inside rear tire likes to come off the ground....not the best idea on a street car.

usa1racing

Actually, that sounds like just what I'm looking for, as my car is mostly a drag car with a little street driving. However, I'd mount the links on the bottom (different variations of these bars do) to put force on the links in compression, not tension, but only if I wouldn't lose a ton of ground clearance. I think I can build them and have the bottom lip of the axle bracket be no lower than the bottom of the rim. Plus, not having a torque arm would free up a ton of room for exhaust, which is where my ground clearance issue is now. The price is pretty much a wash, as I'm building a Ford 9", so I'd either have to buy the torque arm bracket, or buy the materials to build the traction bars. Buying the bars outright from someone who builds them would at least double the price.

Shagwell

The problem with this is that you will now have very short, non-adjustable ladder bars. The only suspension adjustment you have is pinion angle, atleast with ladder bars you have a few front mount holes to vary the instant center hiehgt. Your IC is now only 20ish inches forward of the rear-end housing, thus the rear suspension has very little leverage to transfer weight/the car has very little leverage to control the rear-end. Also, the factory control arm mount was not designed to handle twist/rotation from the rear axle.

All in all, this is a horrible suspension design. It will work ok for a very mildly powered car, but won't even out perform factory components(unless factory is worn out). I learned the hard way not to run ladder bars in a high-horse car, I wouldn't run them in a street car being non-adjustable and way too short.

usa1racing

Perhaps this is a bad setup for a street car. I've just been basing my observations on what I've seen on several thirdgen and fourthgen Stockers. Since I'm building primarily a drag car, I thought this would be good path to follow. I had planned on building up the control arm mounting points on both the car, tying them into the subframe connectors, and on the rear, fortifying the CA mounting brackets on the rear. If I did build a torque arm similar to BMR's with a frame-mounted crossmember, then I'd look into flipping the crossmember over, bent to the contour of the trans tunnel, to free up some more room for an exhaust.

BMmonteSS

You should do a little research on instant centers and anti-squat as where the pickup points are will drastically alter the way the car launches. An inch in the wrong direction can mean the difference between worse than stock performance and a perfect wheels up launch.