whats needed for ultimate handling?

[TSiAWD666]

I know this is pretty necro, but i haven't found another thread like this in the forums. I picked up my 2G GSX in September for road race and the knuckle, i've found, is one of the major limiting factors in several suspension geometry problems. Specifically if the linkages could be moved around it could balance the effects of the anti-dive on lowering, as mentioned, but also the camber curve could be increased greatly (in conjunction with a shorter Upper arm) without many drawbacks at all.

it would literally optimize the suspension for shorter travel/stiffer operation while keeping most of the geometries oE

I know a guy who does CNC stuff and he is willing to machine me some new knuckles for way less than the 3k mentioned. literally just the cost of the chunks of aluminum it'd come from, so i've been working on a CAD modeling of what I think it should have been out of the factory.

any of you uber-experienced DSMers got any specific points other than the ones mentioned for correcting other connection points or steering angle stuff? (and obviously keeping the LCA at OE spec. Harder than it sounds, cause it DOES have to clear the front axles, )

Regarding re-creating knuckles out of aluminum, I don't recall where but Andrew Brilliant posted somewhere he'd considered it but tossed the idea as he said there wasn't a suitable aluminum material that was strong enough. Maybe it was a private email or a message on facebook... I can't remember. At least that's what I think he said. Wish I had the quote as my memory is fuzzy and I hate paraphrasing if I can help it.

Also, while designing your knuckles a modification you may want to consider is allowing a bit more inboard tire. That was a modification AB made to his knuckles by grinding out some metal and welding more material on the inside. No idea if this is possible with materials other than what we have oem.

 

[Bud92gsx]

The angle of your lower control arm should never aim "up" towards the ball joint. By overlowering the body will sit lower than the ball joint, making the control arm angle up. This defeats all anti-dive geometry and will upset the car. You want it as close to parallel with the ground as possible.

C..That wasnt so hard was it guys..

 

[Ludachris]

I've got a set of both at work. I'll break out the mic's and see what I can find out. Does the s13 use a c-clip like the 1g's do?

Can't remember for sure how it attaches. I just remember being so excited that the shank taper was the same.

 

[jtmcinder]

The angle of your lower control arm should never aim "up" towards the ball joint. By overlowering the body will sit lower than the ball joint, making the control arm angle up. This defeats all anti-dive geometry and will upset the car. You want it as close to parallel with the ground as possible.

Try to keep anti-dive and roll centers separate in your mind. They are, after all, rather different. And 2Gs have a completely separate piece for the anti-dive, as well.

 

[Tyeler18]

Try to keep anti-dive and roll centers separate in your mind. They are, after all, rather different. And 2Gs have a completely separate piece for the anti-dive, as well.

Sorry I was referencing a 1g since that's what bud drives. And I'm still quite new to suspension geometry. The chassis fab course I took at Wyotech covered suspension geometry fairly in-depth, but most of it was oriented around 4-links in RWD drag cars and 4 links in crawlers.

 

[greengoblin]

The start of something neat.

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[snowborder714]

Here's another setup that's in the works. Haven't really seen much of it, but it is actually developed and supposedly being tested.
Who wants custom aluminum lower control arms - Club DSM Canada

 

[Ludachris]

The start of something neat.

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Bummer, a 2g control arm. Would love to see a rear 1g lower control arm like that, with swaybar attachment threaded insert.

I need CAD software and some free time.

 

[lowell]

On the 1g, I found the an S13 240sx ball joint to have the same taper. Just don't know if the body of the ball joint is the same as a DSM to fit into a control arm. Unfortunately, it doesn't look like Whiteline makes roll center adjustment ball joints for the Nissans. Other companies do though. I just never pulled the trigger on a set for testing. Don't know that I'm the best person to do the R&D. Wish someone with more technical experience would try it though.

Not that this applies to the 2g, but I would bet there's a ball joint out there from another car that would do what we need while requiring little modification to make work.

S13 and S14 front ball joint messurements? - Nissan Road Racing Forums

S13 Front
Taper low diameter 15.8mm
Taper High diameter 18mm
Taper length 19.5mm 20mm
Diameter where it presses in 41mm

S13 Rear
Taper low diameter 15mm
Taper High diameter 18.6mm
Taper length 23mm or 23.5
Diameter where it presses in 38mm

R32 front
Taper low diameter 15mm
Taper High diameter 18.6mm
Taper length 23mm
Diameter where it presses in 41mm

 

[jtmcinder]

Sorry I was referencing a 1g since that's what bud drives.

OK, then. On struts, the amount of anti-dive is determined (mostly) by the relative heights of the front and rear inboard pivot-points on the front LCA. If you have any way to alter these, without causing a ton of binding, then have at it. But, to be honest, since it's much less effective than a compression arm (because the compression arms have inboard pivots that are much further away from the lower LCA's pivot and the two heights can be altered without causing binding), most people just deal with what they have.

All of this, by the way, is why you see modified double-wishbone more often on road cars and struts on rally cars. Rally cars just don't brake hard enough for the extra weight and complication to be worth it. Add in that struts almost always have more available travel than any kind of double-wishbone and you get Evos and 1Gs on struts and 2Gs on wishbone.

 

[jtmcinder]

Here's another setup that's in the works. Haven't really seen much of it, but it is actually developed and supposedly being tested.
Who wants custom aluminum lower control arms - Club DSM Canada

Do you know this fabricator? If so, would he or she have any interest in creating new front LCAs for Evo X? We want more camber and caster from the LCA so we can keep the non-plate tops for full travel.

 

[snowborder714]

No, sorry, I don't know them. I was just made aware of that thread a while ago.

 

[Ludachris]

S13 and S14 front ball joint messurements? - Nissan Road Racing Forums

S13 Front
Taper low diameter 15.8mm
Taper High diameter 18mm
Taper length 19.5mm 20mm
Diameter where it presses in 41mm

S13 Rear
Taper low diameter 15mm
Taper High diameter 18.6mm
Taper length 23mm or 23.5
Diameter where it presses in 38mm

R32 front
Taper low diameter 15mm
Taper High diameter 18.6mm
Taper length 23mm
Diameter where it presses in 41mm

Very nice - wonder if anyone has come across the info for ours. I'll see if Moog might be able to supply the info.

 

[ACM]

If you take a handful of ball joints to your local machine shop they should be able to to give you all the pertinent dimensions, including the taper in degrees, at about 5 minutes per BJ, assuming they have a CMM. I used to get the cylinders off my RG500s measured to determine piston size/clearance, and they'd do one bike (4 cylinders) for a couple of 6-packs.

If you don't use the machine shop regularly they may want more than a few beers, but it shouldn't cost more than $50 to do them.

 

[eclipsegsx1736]

Here's another setup that's in the works. Haven't really seen much of it, but it is actually developed and supposedly being tested.
Who wants custom aluminum lower control arms - Club DSM Canada

Wow, this looks promising! Too bad there aren't any further updates. I tried to register for the board but it doesn't look like they're accepting new (or public) registrations. Bummer, I'd buy a set of these. It's a decent investment, but still a bargain for what you're getting.

Beau

 

[donk]

Racefab | Home has a lot of good parts for the evo i dont know how different the 2g and evo are in the suspention in the rear i know the front is totally different also i would love to have a pair of rear trailing arms like this for my 1g evo 2 gsr race car. - Page 18 - Evo123.net - The early Lancer Evo and DSM source

paired to a tube rear subframe =)

/A

 

[Ludachris]

S13 and S14 front ball joint messurements? - Nissan Road Racing Forums

S13 Front
Taper low diameter 15.8mm
Taper High diameter 18mm
Taper length 19.5mm 20mm
Diameter where it presses in 41mm

S13 Rear
Taper low diameter 15mm
Taper High diameter 18.6mm
Taper length 23mm or 23.5
Diameter where it presses in 38mm

R32 front
Taper low diameter 15mm
Taper High diameter 18.6mm
Taper length 23mm
Diameter where it presses in 41mm

Just got off the phone with Moog - the diameter of our ball joints where it presses in is 1.571". Which is 39.9034mm

This means that the S13 ball joint is going to be wider, which is better than it being smaller. So we'd have to enlarge the hole in our control arms slightly to make it work. This should be pretty simple. The trick is finding the right aftermarket ball joint for the S13, one that actually has a longer stem and not just a longer body. I've found that there aren't many of them out there that do it right, and the ones that do are expensive.

On a side note, I'm checking with Howe to see if they have anything close to that as well, since we know they have a longer stud that works. If they have a housing that is similar size to the S13 that accepts their longer stud that would be the best and cheapest solution.

 

[PieEyedPiper]

Wow, this looks promising! Too bad there aren't any further updates. I tried to register for the board but it doesn't look like they're accepting new (or public) registrations. Bummer, I'd buy a set of these. It's a decent investment, but still a bargain for what you're getting.

Beau

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I know, right? I tried to register, too. I think I'm more excited about those arms than the suspension group buy.
I'm quite impressed by that joint-holding-block things or "yokes" he came up with. Looks like a fantastic design.

Makes one put into question the cost and trouble of a modded subframe vs. arms like those.

 

[jtmcinder]

If the inboard bushings on both the LCA and the compression are are stiff, that set-up is going to bind like mad. When you steer, the outer ends of both arms move fore or aft.

You can get away with stiff inboard bushings on one of the arms, although jumping straight to a spherical is better. When you do this, the other arm must be left soft or replaced with a spherical. Again, you can't use stiff, one-axis bushings on both arms.

 

[PieEyedPiper]

I was under the impression that both arms were going to use sphericals on the inboard side. I may have mis-read.

One thing I know I read correctly was that Mr. Bradley Woodward doesn't appreciate stink-bug mode as much as some of us, heck I even enjoy it in a street car.

 

[snowborder714]

FYI, you can't use any "free" e-mail address to register for that forum (Gmail, Yahoo, Hotmail, etc.). That's one problem I ran into when trying to register with my Gmail account. Now I just have to find a non-free account that I can use.

 

[jtmcinder]

I was under the impression that both arms were going to use sphericals on the inboard side. I may have mis-read.

Probably. I was just responding to that picture which has what looks to be an OE-style inboard end on the compression arm, maybe to keep the arm from flopping down.

 

[99redgst]

t.

Also, while designing your knuckles a modification you may want to consider is allowing a bit more inboard tire. That was a modification AB made to his knuckles by grinding out some metal and welding more material on the inside. No idea if this is possible with materials other than what we have oem.

I think custom knuckles would be one of the greatest things to happen to the 2g guys. You could build three positive gains into the design:
1. Lower ball joint mounts
2. Allow for more tire clearance
3. Make the brake caliper mounts for Evo Brembo calipers

I've been out of the dsm world for a little while, just as I was typing this I remembered the jdm knuckles guys were getting that fit the evo brembos. Were they from a galant? Do those have all the same measurements besides the caliper mounts?

Aluminum knuckles would be incredible considering how heavy the stock ones are. But even if the modified ones were a little heavier I would be all over them if it accomplished the three things listed above.

 

[ACM]

Yes, the JDM/Euro Galant knuckles are identical to 2G knuckles except for the caliper lugs, which are positioned for Brembos.

I'd be much more interested in adjustable Aluminium front lower arms.

The tyre already rubs on the inner fender wall if your offset has the tyre a few millimetres from the knuckle, so allowing more room in the knuckle to shift the wheel+tyre inboard would simply have it rubbing even harder.

 

[99redgst]

Good point about the tire rub. After you take that away, its easy enough to mount larger brakes and if lower control arms become an option there is no need for the custom knuckle. Which would be more expensive and less likely to happen than control arms anyway. So whats the update on those control arms?