modifications to custom irs rear trailing arms to lower car
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thanks Mike
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I see that Dave Folts makes the IRS transmission yokes to use Corvette U joints, could someone make a stub axle or adaptor to run Corvette stub axles and axles? You can have the Corvette axles shortened to fit at any driveline shop for under 100 dollars.
This would be a bullet proof setup for drag race use since we don't have that much wheel travel.
This would be a bullet proof setup for drag race use since we don't have that much wheel travel.
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5,711 Posts
I got my 12" long axles for the Fiat through Carcraft in Riverside CA and they worked well and they weren't anywhere near $600
Jim -- keep that swing arm you built -- you only need to change the end where it hiem is attached === I'll draw something up for you -- this is done all the time and works in this situation
Jim -- keep that swing arm you built -- you only need to change the end where it hiem is attached === I'll draw something up for you -- this is done all the time and works in this situation
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544 Posts
If you don't go "too narrow" you can use off the shelf narrow axles that are close to the correct length, then machine off material from each end to end up where you need to be. This style of car doesn't need all the spline length that the axles come with.
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170 Posts
Why would you do that?shag55 said:
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The difference in the amount of flex between the two designs will be very very little -- I used only 2 bars (see reply #15) and there was very little flex and I did some SOLO stuff with the Fiat. You can over design this stuff very quickly. Go down to the local off road shop and look at the arms they use to control the rear ends in 4000# trucks, V8's and launching them 10' in the air, we don't need anything close to that. KISS baby, KISS
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288 Posts
been awhile ,hope everyone had a great Xmas and newyears .
sorry i don't have a lot of photos of all the steps but the images will show you where its at .
Since the last post in early Dec , before removing that arm i had a good look at it and came up with a few changes that will allow for all the adjustability i"m looking for.
caster , camber and toe as well as in/out for tire clearance issues.more on those later .
Yes i did need to go back to the more original setup on the inner heim joint as i thought , due to not being able to remove the bolt .
quick walk through went like this .
bolt the bearing assembly 3/4" above centre line to the 3/8" plate .by bolting the bearing assembly to the plate instead of welding it allows for replacement if required or even shimming out if needed .as well the bolts will stick out enough to allow the outer bearingcap to be attached with a washer and nut .
i was going to mount the caliper directly to the 3/8" plate but decided in using the supplied caliper mounts that sandwich between the bearing housing and outer bearing cap .figuring if there is some form of distorsion on the trailing arm the caliper and disc will always be true.
taking the plate/bearing assemble back to the car it was bolted to the torsion arm and the process of using the angle iron mentioned earlier on to square the assembly to the torsion tube was used .i was able to now place the inner heim joint back to the inner position as before and with the stub axle installed in the bearing housing locate the best position for the lower diagonal arm .special attention was used to make sure the shock clearance was not a issue with that arm .
removing those components it was time to mount them all back to the jig , lower plate with bearing assemble was mounted as well as the inner heim joint with a short piece of tubing attached .also a jig was fabricated to allow easy setup in my drill press for notching the 1 1/4" tubing .instead of using tubing for all trial and error i used wooden
1 1/4"dowel which cuts way easier , way cheaper and allows for easy changes .once the final angles were completed i would then install the steel tube and make the final pieces for both sides before changing setup in the drill press ,
I figured if i allowed the diagonal arms to pass through the plate it would be way stronger than flat welding the tubing to one side only of the 3/8 plate . a easy solution for figuring out the compond angle was to use a pipe with a I.D of 1 1/4" angle cut at one end and 2 inches up cut at 90 deg .i slid this up the wooden dowel test diagonal arm and slid it down the dowel until it rested squarely on the 3/8 plate .tacking it in place with the mig left me with a perfect guide for the hole saw .
once removed from the jig i set it up on the drill press and bored the compound angle through the plate .
back to the jig and what you see is were I'm at .
what happens is after welding is completed the 3/8 plate will be cut to size/shape .you can also see a test wooden dowel being used for the upper diagonal arm .but before i finalise that i will tack the lower arm together and test fit once more and make sure of the upper arms position as its close with the new shock placement .will get some images of that later and how the rest of the modifications to the stock trailing arms come into play .
good to be back at it and it looks like it will all come together as planned
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sorry i don't have a lot of photos of all the steps but the images will show you where its at .
Since the last post in early Dec , before removing that arm i had a good look at it and came up with a few changes that will allow for all the adjustability i"m looking for.
caster , camber and toe as well as in/out for tire clearance issues.more on those later .
Yes i did need to go back to the more original setup on the inner heim joint as i thought , due to not being able to remove the bolt .
quick walk through went like this .
bolt the bearing assembly 3/4" above centre line to the 3/8" plate .by bolting the bearing assembly to the plate instead of welding it allows for replacement if required or even shimming out if needed .as well the bolts will stick out enough to allow the outer bearingcap to be attached with a washer and nut .
i was going to mount the caliper directly to the 3/8" plate but decided in using the supplied caliper mounts that sandwich between the bearing housing and outer bearing cap .figuring if there is some form of distorsion on the trailing arm the caliper and disc will always be true.
taking the plate/bearing assemble back to the car it was bolted to the torsion arm and the process of using the angle iron mentioned earlier on to square the assembly to the torsion tube was used .i was able to now place the inner heim joint back to the inner position as before and with the stub axle installed in the bearing housing locate the best position for the lower diagonal arm .special attention was used to make sure the shock clearance was not a issue with that arm .
removing those components it was time to mount them all back to the jig , lower plate with bearing assemble was mounted as well as the inner heim joint with a short piece of tubing attached .also a jig was fabricated to allow easy setup in my drill press for notching the 1 1/4" tubing .instead of using tubing for all trial and error i used wooden
1 1/4"dowel which cuts way easier , way cheaper and allows for easy changes .once the final angles were completed i would then install the steel tube and make the final pieces for both sides before changing setup in the drill press ,
I figured if i allowed the diagonal arms to pass through the plate it would be way stronger than flat welding the tubing to one side only of the 3/8 plate . a easy solution for figuring out the compond angle was to use a pipe with a I.D of 1 1/4" angle cut at one end and 2 inches up cut at 90 deg .i slid this up the wooden dowel test diagonal arm and slid it down the dowel until it rested squarely on the 3/8 plate .tacking it in place with the mig left me with a perfect guide for the hole saw .
once removed from the jig i set it up on the drill press and bored the compound angle through the plate .
back to the jig and what you see is were I'm at .
what happens is after welding is completed the 3/8 plate will be cut to size/shape .you can also see a test wooden dowel being used for the upper diagonal arm .but before i finalise that i will tack the lower arm together and test fit once more and make sure of the upper arms position as its close with the new shock placement .will get some images of that later and how the rest of the modifications to the stock trailing arms come into play .
good to be back at it and it looks like it will all come together as planned
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288 Posts
finally got a chance to weld it all up and give it a quick trim .
still more to trim and weld on the shock mount .
for fun put a stock irs control arm on the scale ,14 lbs and this arm plus the bearing housing and material for shock mount came in at 13 lbs .
not bad 1 lb lighter and there is still more material to come off .
next week will finnish modifications to the spring plates and mount the inner piviot bracket .
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still more to trim and weld on the shock mount .
for fun put a stock irs control arm on the scale ,14 lbs and this arm plus the bearing housing and material for shock mount came in at 13 lbs .
not bad 1 lb lighter and there is still more material to come off .
next week will finnish modifications to the spring plates and mount the inner piviot bracket .
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288 Posts
well it all seams to fit , thank god.
quick thanks to Mike for taking time to answer my e-mails and talk on the phone !!!
i cant tell you how nice it is to bounce ideas of someone who has recently done something you are working on , again thanks ,and thanks to
everyone that e-mailed me thoughts or posted information .
i have 1 last thing to fab up which is the lower shock mount , i have a few thoughts but figured i would post up some pictures and see if anyone has any input .
was originaly thinking on the trans side of the lower diag tube to weld on another tube straight down with a bushing on the end for the lower shock bolt to pass through see photo with 1 yellow line or use two steel 3/16 plates on each side of the lower shock see 2 yellow line photo .
just woried about flex and stength as well as keeping the lower shock vey stable.
let me know
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[img= width=600 height=800]http://www.dialedinperformance.com/images/busbox/PICT0613.jpg[/img]
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quick thanks to Mike for taking time to answer my e-mails and talk on the phone !!!
i cant tell you how nice it is to bounce ideas of someone who has recently done something you are working on , again thanks ,and thanks to
everyone that e-mailed me thoughts or posted information .
i have 1 last thing to fab up which is the lower shock mount , i have a few thoughts but figured i would post up some pictures and see if anyone has any input .
was originaly thinking on the trans side of the lower diag tube to weld on another tube straight down with a bushing on the end for the lower shock bolt to pass through see photo with 1 yellow line or use two steel 3/16 plates on each side of the lower shock see 2 yellow line photo .
just woried about flex and stength as well as keeping the lower shock vey stable.
let me know
[img= width=600 height=800]http://www.dialedinperformance.com/images/busbox/PICT0613.jpg[/img]
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2,342 Posts
Jim, I think you should put a wheel & Tire on before welding this up. Looks like you already have a custom upper mount. From the pictures, the shock looks pretty low. Something to consider would be raising the upper mount so the lower mount doesn't drop down so low. I ran into the same problem. I ended up raising my shock mounts, as I also needed clearance for coil springs. You probably won't need to go that high. Maybe just as high as the body will allow.
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