Rear trailing/toe arm fab work for 1G AWD?

[Ludachris]

This might be a little extreme, but I had been thinking about the possibility of chopping off the rear toe arm, separating it from the rear hub, and welding on a tubular piece in it's place.

Why? Lighter weight and more space for wheels/tires. Imagine a bended tubular piece similar to this welded to the rear hub:

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I'd be concerned about strength and durability, as the design would have to be good. But it could be a cool project.

Thoughts?

 

[Ludachris]

I wonder if connecting the swaybar to the trailing arm would hinder handling at all. Came across this in my Google searches - done by a drag racer over on Talk:

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Not sure it would be idea for road racing, but since we're talking about trailing arms, might as well discuss the possibility.

 

[underradar92]

If one were to fab a trailarm, it'd be nice to use the bearings hub design that is on a 3s, for caliper options and for the more robust bearings. Building in brake duct fittings would be nice to see too. Why go through all that work for a somewhat lateral result? The adjustable radius arms would comp for any track width differences. Win-win.

In case the question is in anyone's mind, the casting portion of the arms are steel, not iron so welding is no problem.

Tim Zimmer (Twicks69) had 3s rear hubs/axle shafts fabbed for his 2g so, this can be made to work somehow, for 1g's also.

As for the swaybar, looking at the rear crossmember in my backyard, it looks like the pivot C/L's for the trail arms are pretty close to that of the swaybar pivot. One would optimally still want some sort of link, in my opinion, for preload adjustments and if one has the (awesome) adjustable Whiteline GVR4 rear swaybar.

 

[pagosa dsm]

If you lift up a trailing arm,you will notice most of the wieght is in the spindle.The trailing arm is thin steel.You can not have a 2 link arm because of toe adjustment.I think the only way to have smaller and lighter control arms is install a complete new suspenion.I built heim joint trailing arms and tubular upper and lower control arms.I think that is the best we can do. You can see photos of my suspenion in my gallery.
Rick

 

[ramsack]

The 3si trailing arm uses the same bearings. The only difference is that the hub is different to accommodate the drum e-brake. You'd be adding more weight.

 

[pagosa dsm]

The 3si trailing arm uses the same bearings. The only difference is that the hub is different to accommodate the drum e-brake. You'd be adding more weight.

Are the 3si and the 1st gen trailing are interchangable? Can you get any photos?
Rick

 

[ramsack]

http://www.dsmtuners.com/forums/handling-tech/376722-1g-rear-brake-upgrade.html

There are some links in there. Napa lists the same part numbers for the rear bearings between the 1g DSM/GVR4 and the 3si. The arms look identical. I don't have measurements because I only own a DSM.

 

[dsmmack]

Those pic's look familiar

I've always wanted to make an aluminum rear trailing arm.
The main issue is the fact that the knuckle/hub assembly is all part of the trailing arm.

 

[Ludachris]

Just to be clear, I'm not suggesting chopping the trailing arm off from the hub and making it two piece. I'm suggesting chopping it off and welding a tubular piece in its place that adds some benefits (lighter, more wheel clearance, better toe adjustment, etc). A 3si assembly can definitely be used for this type of project. The photo I posted above was only meant to show a curved tubular bar with a solid bushing. The connection point at the hub would be welded, not bolted.

 

[MidShipCivic]

3000GT have the samewheel base as a 1G AWD different track width though that can't hurt reduces weight transfer. That's a good enough upgrade.

In my opinion, the subframe isn't suitable for high power, and the rear suspension can be improved with double wishbone it'd be much easier than the arm being redone.

 

[underradar92]

http://www.dsmtuners.com/forums/handling-tech/376722-1g-rear-brake-upgrade.html

There are some links in there. Napa lists the same part numbers for the rear bearings between the 1g DSM/GVR4 and the 3si. The arms look identical. I don't have measurements because I only own a DSM.

I like the sound of this^^^. Means no half shaft mods needed. Just slide a DSM hub in and go, yes?

I read in another thread that the 3s trail arm, if used with a stock length lower radius arm, will widen the track either 10 or 20 mm. I'm kind of cool with that since the added thickness of my front brake hats has widened the front a bit. I also saw, in the same thread that the 3s parking brake may be adaptable to DSM cable ends with little to no fabrication. It's apparently been done on a GVR4 or two.

So, it would seem that chopping up a 3s arm, fabbing a new arm section wouldn't be out of the realm of possible. The problem with all this to me is, the last place we need to be looking to shave weight on these things is below and behind the CG. Not to mention that we are looking at retaining the hub section intact, which is the lions share of the unsprung weight in this part.

All this coupled with the seeming inability for anyone to even make a decent front control arm that anyone will/is able to buy. Just saying.

 

[MidShipCivic]

I read in another thread that the 3s trail arm, if used with a stock length lower radius arm, will widen the track either 10 or 20 mm. I'm kind of cool with that since the added thickness of my front brake hats has widened the front a bit. I also saw, in the same thread that the 3s parking brake may be adaptable to DSM cable ends with little to no fabrication. It's apparently been done on a GVR4 or two.

Galant VR4 rear track 57.1''

TSI awd rear track 57.2''

3000gt / GTO rear track 62.2''

4.9'' / 124.46mm difference in rear track width respectively tsi vs 3s/gto.

 

[ramsack]

Track is the distance between the CENTER of both wheels. The 3si has a much wider wheel stock, so it's not going to be almost 5 inches. Notice how the Galant track is smaller, but they use ENTIRELY IDENTICAL rears. Their wheels are slightly skinnier. 10-20 mm per side sounds right.

 

[MidShipCivic]

Track is the distance between the CENTER of both wheels. The 3si has a much wider wheel stock, so it's not going to be almost 5 inches.

Where did you see I said that? That is a reference.

 

[Ludachris]

I like the sound of this^^^. Means no half shaft mods needed. Just slide a DSM hub in and go, yes?

I read in another thread that the 3s trail arm, if used with a stock length lower radius arm, will widen the track either 10 or 20 mm. I'm kind of cool with that since the added thickness of my front brake hats has widened the front a bit. I also saw, in the same thread that the 3s parking brake may be adaptable to DSM cable ends with little to no fabrication. It's apparently been done on a GVR4 or two.

So, it would seem that chopping up a 3s arm, fabbing a new arm section wouldn't be out of the realm of possible. The problem with all this to me is, the last place we need to be looking to shave weight on these things is below and behind the CG. Not to mention that we are looking at retaining the hub section intact, which is the lions share of the unsprung weight in this part.

All this coupled with the seeming inability for anyone to even make a decent front control arm that anyone will/is able to buy. Just saying.

I thought about that too... seems the focus should really be on the front subframe and control arms for weight savings. I know. But we've already discussed that and we know there likely won't be anyone producing a tubular front subframe for us, at least nothing more than a one-off piece. I'm still hoping we can get BMR to produce some control arms, but chances are they'll cost somewhere around $500, which is more than most DSMers will pay, even if they are quality pieces that we haven't seen before.

In the end, these mods are mainly to reduce weight for road racing, and it'd be really expensive. And it doesn't really make much sense to take it this far with these cars. But in the end, I just want to try stuff that others haven't. It makes more sense to sell it and start over with an E30 M3, just like it would be easier to get power out of a V8, but what fun would that be? I'm just partial to these cars for whatever reason, even if it doesn't make much sense. If nothing else I'd just like to see more innovation with these cars, just for the hell of it.

 

[Ludachris]

3000GT have the samewheel base as a 1G AWD different track width though that can't hurt reduces weight transfer. That's a good enough upgrade.

In my opinion, the subframe isn't suitable for high power, and the rear suspension can be improved with double wishbone it'd be much easier than the arm being redone.

Hey David, I'm not worried about the subframe handling high power, this would mainly be for handling, not drag racing. I'd be more worried about flex. So, there are two options, tubular replacement or welding metal reinforcement pieces to the stock subframe. That's probably the direction I'd go until I had money to spend on a tubular subframe. As for double wishbone, I don't know about redesigning the suspension, I just want to swap in tubular pieces where possible.

 

[underradar92]

Galant VR4 rear track 57.1''

TSI awd rear track 57.2''

3000gt / GTO rear track 62.2''

4.9'' / 124.46mm difference in rear track width respectively tsi vs 3s/gto.

Ahhh, maybe the 3s subframe is 104.46/114.46mm wider? Like I've mentioned, GVR4 guys have already done this swap.

This thread describes it: http://www.galantvr4.org/ubbthreads/showflat.php?Number=872101&page=&view=&sb=5&o=&fpart=2&vc=1

 

[MidShipCivic]

Ahhh, maybe the 3s subframe is 104.46/114.46mm wider? Like I've mentioned, GVR4 guys have already done this swap.

This thread describes it: TH3 Lazy arse Australian / New Zealand Picture build thread Page 2 | Galant VR-4 > General VR4 Discussions | GalantVR-4.org Mitsubishi Galant VR4 Forum

I just see that one guy has done it no record of any other.

Ramsack posted the thread where that was first pointed out, I'm in that thread too.

We have 16x6 stock +46mm offset and 2nd gen 3000gt are 18x8 +46mm.


VR4 cable ends 3kgt

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DSM E-brake mechanism

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The wheel base is the same between VR4 3S and DSM so I really doubt that the cables will be an issue.

 

[underradar92]

Cool, now to locate people parting out some turbo 3s's. I'd guess there isn't a lot of demand for these arms so they should prove affordable, hopefully. < (DSM cheapness showing)

 

[tsi87889095]

Why wouldn't you bolt the arm to the hub? You could do a double shear and then you could remove it when ever you need to easily. I work in a fab shop at a nascar team and have been kicking around ideas for making jigs for lower control arms for the front and making tubular sub frames for the front and rear. For the front i was thinking of raising the points on the sub frame wear the control arm bolts in or making two points for it to bolt in so that if the car was lowered a lot you could still have a stock ride and would not have a lot of negative camber and you would still have the correct angle on the control arm. On our race cars we have three points wear the control arm bolts to the chassis so we have a lot of adjustablty depending on what track we go to. So we could use this same concept on our sub frames. For the lower control arms i would like to use a common ball joint like a GM one that is easy to purchase but this requires the spindle to be reamed to fit the new ball joint. These are some ideas i have and would like some input. Thanks guys.

 

[Ludachris]

Why wouldn't you bolt the arm to the hub? You could do a double shear and then you could remove it when ever you need to easily. I work in a fab shop at a nascar team and have been kicking around ideas for making jigs for lower control arms for the front and making tubular sub frames for the front and rear. For the front i was thinking of raising the points on the sub frame wear the control arm bolts in or making two points for it to bolt in so that if the car was lowered a lot you could still have a stock ride and would not have a lot of negative camber and you would still have the correct angle on the control arm. On our race cars we have three points wear the control arm bolts to the chassis so we have a lot of adjustablty depending on what track we go to. So we could use this same concept on our sub frames. For the lower control arms i would like to use a common ball joint like a GM one that is easy to purchase but this requires the spindle to be reamed to fit the new ball joint. These are some ideas i have and would like some input. Thanks guys.

In regards to your ideas about control arms and using different ball joints, it's been found that a particular Chrysler ball joint has the same taper, no need to ream out the spindle. I'm not sure if the thread where this was found is here or in the Handling or Road Racing forums - do a quick search for "Howe ball joint" and you'll almost certainly find it. Might make sense to create a thread in this forum to start spec'ing things out if you're going to get started on in though. I think any control arms that are made for our cars should resemble the ones made by BMR (BMR Fabrication Inc.)

Back on topic, there isn't a reason why the rear trailing arm couldn't be bolted to the rear hub if it was done right.

 

[tsi87889095]

Thanks for the info. I did not know about the Chrysler ball joint. That's great one less thing to figure out. Do those work for the rears? I could not get your link to come up on the lower control arms. I think i know what ones you are talking about they look very similar to stock but have more bracing and are powder coated black. I would like to build them so you still could use stock bushings and would look some what stock but be stronger and maybe lighter but its hard to achieve both . I think it would be good to start on these first and then once i have a jig for them move on to the sub frames. I have all the resources as far as material and tig welder and so on. I have been wanting to do this for a while but was not for sure if there would be much of a market. I originally was going to do it for my dd and for my rally car i want to build one day. Let me know what you think.

 

[underradar92]

Thanks for the info. I did not know about the Chrysler ball joint. That's great one less thing to figure out. Do those work for the rears?

The taper is the same on all of the ball joint receivers on 1g's so, yes. In fact all of the ball joints are the same so, one could use the Howe ball joint all around the car. Some one, in fact is doing just that. http://www.dsmtuners.com/forums/roa...further-refining-rear-lower-control-arms.html

Progress is stalled at the moment but should resume as the weather cools.

 

[Ludachris]

Thanks for the info. I did not know about the Chrysler ball joint. That's great one less thing to figure out. Do those work for the rears? I could not get your link to come up on the lower control arms. I think i know what ones you are talking about they look very similar to stock but have more bracing and are powder coated black. I would like to build them so you still could use stock bushings and would look some what stock but be stronger and maybe lighter but its hard to achieve both . I think it would be good to start on these first and then once i have a jig for them move on to the sub frames. I have all the resources as far as material and tig welder and so on. I have been wanting to do this for a while but was not for sure if there would be much of a market. I originally was going to do it for my dd and for my rally car i want to build one day. Let me know what you think.

I edited my post above to fix the BMR link... they chose the day I post this link to relaunch their site.