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-   -   This is the roll center, suspension pickup, and steering angle modification thread. (#/f/showthread.php?t=296725)

vipspoolz 01-16-2010 06:31 PM

best thread evaaar. srsly ive learned so much awesome shit thanks to you guys.

racepar1 01-16-2010 09:13 PM

Quote:

Originally Posted by Def (Post 3240908)
A front machined aluminum upright could potentially run into strength issues where it mounts to the strut. The dimensions are constrained by the strut mounting flanges, so you can make it a bit thicker, but that's it, so strength could be an issue.

The steel hub mounting bit will have to be machined separately and attached somehow, etc.

There's just a lot that would go into one, which is why I decided it wasn't worth the trouble given that you only need to get one adjustable arm to correct the roll center up there.

I guess I just don't understand the spindle thing... especially when no one talking about making them has even done a detailed look into our suspension geometry. I'm definitely not one to shy away from "hardcore parts," as I've definitely made/designed a few for the S chassis. I just think you guys are banging your head against a wall just for the sake of "another part to add to the car."

Now if you're looking at a new spindle for faster steering and bigger steering angles, that I can understand, but the geometry part is completely being glossed over and not understood by most other than "stock must be best, let's get it back there"...

IMO the main advantage to the aluminum spindles would be the weight savings. That's all I would really care about because like you said, one custom arm and you're done with the front suspension. I've seen aluminum spindles on other cars that are about the same dimensions near the strut mounting points as would be reasonable on a 240. I'm pretty sure that not all of them were forged. That would be the real proper solution, to have forgings made and do the final machining. That would be plenty strong, and plenty expensive to develop and produce.

PoorMans180SX 01-16-2010 09:33 PM

Can anyone comment on Battle Version front and rear LCA's? They supposedly use teflon lined heim joints (which definitely look more legit than most).

swiftmini 01-17-2010 05:03 AM

I have just read through this thread. Must say its all very interesting stuff.

I have been into the whole slamming an s-body, mega steering lock, decent handling for about a year now and iam really starting to get to grips with it, defo still learning though.

In terms of lowness, iam almost on the limit for a uk car. We have speed bumps over here that are sometimes over 100mm tall and also our roads are layed by under payed, half blind council workers (damn you peeps with sat nav tarmac laying equipment). Still not that low compared to you guys in us/jp/aus.

At the moment my basic spec is: on a s13 chassis

Rear
Godspeed arms all round
Godspeed arb
Apex gen1 coilover with 8kg spring
S14 subframe
Homemade risers bushes (offset hole for s14 subframe fitment) (rigid mounted flat too body)
Cusco two way diff solid mounted

Front
Godspeed tension rods
Stock lower control arm (I had to ditch the gashspeed lower arm because the rose joints and pillow ball were stuffed after on 2000 miles :wack:)
Home made psm knuckle mod (psm wanted too sell me full kit when I only wanted the weld on u shape parts)
Ikeya formula tie rods
Steering rack moved forward by 18mm, soon to be 24mm. ( I have many pics to show the crossmember fabrication)(its really simple and is legit).

When I made the psm styke knuckle mod I welded the part on, tracked up the toe by eye, and tested the lock either way. I then heated up the steering arms that they were welded to and bent them outwards to remove more ackerman.

When side ways my car feels amazing but its crap on the road and over bumps.

I think that because I have lowered the tie rod end by 50mm (2inch) that I also need 50mm of rollcentre correction on the outboard lower arm ball joint, to get the curves between the two back to normal.

If I put a trolley jack under my hub and jack it upwards from full droop to full bump, you can easily see that the hub bumpsteering a lot.

I'll come back and write more stuff later :D

redhatchy92 01-17-2010 06:55 AM

Have you guys ever heard of filling the chassis with filling foam to stiffen the chassis(like a roll cage). I have heard of it but just want to know if any one has done it so I can get some advice or pros an cons.

swiftmini 01-17-2010 08:08 AM

Quote:

Originally Posted by redhatchy92 (Post 3242031)
Have you guys ever heard of filling the chassis with filling foam to stiffen the chassis(like a roll cage). I have heard of it but just want to know if any one has done it so I can get some advice or pros an cons.

Probably best to start a new thread about expanding foam filling, or have a search cose it bound to have beenm covered on here before.

The japs love it but it soaks up moisture and makes it impossible to weld the sills properly if needed.

mmdb 01-18-2010 05:14 PM

Quote:

Originally Posted by redhatchy92 (Post 3242031)
Have you guys ever heard of filling the chassis with filling foam to stiffen the chassis(like a roll cage). I have heard of it but just want to know if any one has done it so I can get some advice or pros an cons.

Check Freshalloy.com. Someone did a bit of analysis bout it. My friend who's done it swears it adds significant stiffness.

Back to roll center talk. I got off the phone with Driftworks. I hope my phone bill doesn't kill me. Anyway, I ordered the hubs from them. I know some folks here have been debating about the design and what not, but I figured, what the hell. I'll give it a try. If anyone wants to do some analysis on them then I'd be more than happy to take my car, once they're installed, and spend a few hours plotting dynamic suspension changes (ie toe, camber, steering ackerman, etc).

I'm anticipating that I will most likely remove the rear sway bar with the increase in roll center and maybe decrease the rear spring rate from 7kg down to 6kg or lower to compensate for the added roll resistance. I'm basing this on my previous modification when I installed moonface roll center adjusters in the rear which added ~15mm of height to the rear spindle. Doing so definitely did add to the rear roll resistance, which felt excellent during corner entry. I'll follow up with my opinion once I get these installed.

GripTerror 01-18-2010 05:30 PM

cant wait to hear your review/analysis

codyace 01-18-2010 05:45 PM

Quote:

Originally Posted by mmdb (Post 3244788)
Check Freshalloy.com. Someone did a bit of analysis bout it. My friend who's done it swears it adds significant stiffness.

Back to roll center talk. I got off the phone with Driftworks. I hope my phone bill doesn't kill me. Anyway, I ordered the hubs from them. I know some folks here have been debating about the design and what not, but I figured, what the hell. I'll give it a try. If anyone wants to do some analysis on them then I'd be more than happy to take my car, once they're installed, and spend a few hours plotting dynamic suspension changes (ie toe, camber, steering ackerman, etc).

I'm anticipating that I will most likely remove the rear sway bar with the increase in roll center and maybe decrease the rear spring rate from 7kg down to 6kg or lower to compensate for the added roll resistance. I'm basing this on my previous modification when I installed moonface roll center adjusters in the rear which added ~15mm of height to the rear spindle. Doing so definitely did add to the rear roll resistance, which felt excellent during corner entry. I'll follow up with my opinion once I get these installed.

I took my rear sway bar off for an entire morning once at a track session, and absolutley hated the way the car reacted.

GripTerror 01-18-2010 05:48 PM

ive run swaybarless and will never do so again. It felt like garbage. I run the stock HICAS swaybar now in the rear.. was contemplating a stiffer rear (progress or tanabe). The car felt all over the place, it felt crappier turn in, lazier, rolled a hell of a lot and understeered too much on track.

Try it both ways and let us know

longfellow 01-18-2010 05:51 PM

Quote:

Originally Posted by redhatchy92 (Post 3242031)
Have you guys ever heard of filling the chassis with filling foam to stiffen the chassis(like a roll cage). I have heard of it but just want to know if any one has done it so I can get some advice or pros an cons.

I just did it to my subframe. Needless to say its worth it and would suggest it to anyone who wants to really help an aged unibody car. There is a thread on Freshalloy about it. They used 2lb foam, I just used 8lb foam which I find to be a better solution.

On topic, the Front upright idea was just an idea and something I'd like to see if I could make in the mill as practice or something. As for right now I'm just going to modify godspeed flca's and figure out a simple solution for the RLCAs because they're not far off as is.

mmdb 01-18-2010 05:54 PM

Quote:

Originally Posted by codyace (Post 3244847)
I took my rear sway bar off for an entire morning once at a track session, and absolutley hated the way the car reacted.

I hear ya on that. Did you have any roll center adjustment? Essentially increasing roll center height is similar to increasing spring rate or sway bar stiffness. It could be that you didn't have much of either, or the balance between your front and rear suspension was significantly off causing a ill-balanced chassis. OR! It could also be your throttle points are off (you're gassing it too early or too hard - move your throttle point back).

Quote:

Originally Posted by GripTerror (Post 3244852)
ive run swaybarless and will never do so again. It felt like garbage. I run the stock HICAS swaybar now in the rear.. was contemplating a stiffer rear (progress or tanabe). The car felt all over the place, it felt crappier turn in, lazier, rolled a hell of a lot and understeered too much on track.

Try it both ways and let us know

Yeap will do.

codyace 01-18-2010 05:57 PM

Quote:

Originally Posted by mmdb (Post 3244863)
I hear ya on that. Did you have any roll center adjustment? Essentially increasing roll center height is similar to increasing spring rate or sway bar stiffness. It could be that you didn't have much of either, or the balance between your front and rear suspension was significantly off causing a ill-balanced chassis. OR! It could also be your throttle points are off (you're gassing it too early or too hard - move your throttle point back).

I'm not going to disagree that I may be a bit hard on the fun pedal, but when going back to a bar, it certainly put the car 'back in control'. To me (and I drove around on the street with it unhooked) it just felt so disconnected from the front that it wasn't very confidence inspiring. It really felt as if the entire car was pushing instead of persay the front or the rear. I also couldn't use the diff to correct the car either with it off...it just seemed all over the place compared to with the bar on.

No roll correction at the point in time, but also not slammed to the ground either. Everythign but Control arms and rear traction arms upgraded at the point and time too.

racepar1 01-18-2010 06:01 PM

Quote:

Originally Posted by PoorMans180SX (Post 3241605)
Can anyone comment on Battle Version front and rear LCA's? They supposedly use teflon lined heim joints (which definitely look more legit than most).

Battle Version does not make lower control arms. Alex re-sold some china arms a while ago and everyone mistakenly thinks that they are actual battle version parts, which they are not.

Quote:

Originally Posted by redhatchy92 (Post 3242031)
Have you guys ever heard of filling the chassis with filling foam to stiffen the chassis(like a roll cage). I have heard of it but just want to know if any one has done it so I can get some advice or pros an cons.

Foam filling will certainly increase chasis rigidity greatly. I am actually likely going to go that route with my next build, which will be an actual street car. The downside is that it can trap moisture and promote rust. I wouldn't imagine that it would be much of a problem in the southwestern states, but elsewhere it could be a real issue. I would also imagine that there are certain foams out there that would be better or worse for water absorbtion, but I have not gotten that far into researching it yet.

Quote:

Originally Posted by codyace (Post 3244847)
I took my rear sway bar off for an entire morning once at a track session, and absolutley hated the way the car reacted.

Quote:

Originally Posted by GripTerror (Post 3244852)
ive run swaybarless and will never do so again. It felt like garbage. I run the stock HICAS swaybar now in the rear.. was contemplating a stiffer rear (progress or tanabe). The car felt all over the place, it felt crappier turn in, lazier, rolled a hell of a lot and understeered too much on track.

Try it both ways and let us know

I liked the feel of my s-13 without the rear sway for the most part. The only thing that I noticed was the car seemed a bit more "sluggish" on turn-in. I was willing to deal with the "sluggishness" since it increased center-off rear grip so much. When I do install my s-14 rear subframe I am going to try the 21mm hollow JDM rear bar though as IMO running without a rear sway is only a band-aid and should be applied as such.

PoorMans180SX 01-18-2010 06:02 PM

Quote:

Originally Posted by mmdb (Post 3244788)

I'm anticipating that I will most likely remove the rear sway bar with the increase in roll center and maybe decrease the rear spring rate from 7kg down to 6kg or lower to compensate for the added roll resistance. I'm basing this on my previous modification when I installed moonface roll center adjusters in the rear which added ~15mm of height to the rear spindle. Doing so definitely did add to the rear roll resistance, which felt excellent during corner entry. I'll follow up with my opinion once I get these installed.

I think you might be overestimating the effect of raising your roll center. You might be able to reduce your spring rate, or take off your bar, but I doubt both. Did you get the front ones too? Because you'll have to make equal compensation for the front.

longfellow 01-18-2010 07:17 PM

Quote:

Originally Posted by racepar1 (Post 3244875)
Foam filling will certainly increase chasis rigidity greatly. I am actually likely going to go that route with my next build, which will be an actual street car. The downside is that it can trap moisture and promote rust. I wouldn't imagine that it would be much of a problem in the southwestern states, but elsewhere it could be a real issue. I would also imagine that there are certain foams out there that would be better or worse for water absorbtion, but I have not gotten that far into researching it yet.

Marine grade pour foam is water proof. The only think you have to worry about is if you leave something half filled or pockets that can trap air. Other than that if you cap off or silicone shut any foam filled area so its water tight you shouldnt ever have an issue.

Check US Composites. I used their 8lb pour foam with great results.

mmdb 01-18-2010 07:34 PM

Quote:

Originally Posted by PoorMans180SX (Post 3244877)
I think you might be overestimating the effect of raising your roll center. You might be able to reduce your spring rate, or take off your bar, but I doubt both. Did you get the front ones too? Because you'll have to make equal compensation for the front.

Yeap yeap I got both front and rear as a set. When I played with my rear suspension I was running GP Sports knuckles with ~35mm of adjustment PLUS a moonface roll center adjuster with a total of ~45-50mm of adjustment in the front; and 15mm moonface roll center adjuster in the rear. I dropped the rear sway bar from a progress (forgot the diameter) to a whiteline 22mm rear on the softest setting. It helped a lot with oversteering issues while rolling on the throttle. I definitely felt a significant change in my car's handling with a change in roll stiffness as 20mm to 15mm was added and removed. I hope the knuckles' height offers a balanced setup. Otherwise I'm glad I have coilovers to raise/lower the car. Time will tell :X

Otto347 01-18-2010 08:52 PM

Another option for the guys wanting to lower the toe mount on the iron uprights. Im going to give this a shot and ill let you guys know how it works.

If anyone here knows a little hot rod history they used to make jigs for front axles and use a bottle jack and a torch to lower the car. Heating the axle and using the jack to move the spindle mount point up, basically making a home made drop axle. Im going to try and setup a jig that will hold the upright and the bottle jack will keep the toe mount in a straight line. Im pretty sure it should work and I would trust that better than cut and welding cast iron.

racepar1 01-18-2010 11:05 PM

Quote:

Originally Posted by longfellow (Post 3245025)
Marine grade pour foam is water proof. The only think you have to worry about is if you leave something half filled or pockets that can trap air. Other than that if you cap off or silicone shut any foam filled area so its water tight you shouldnt ever have an issue.

Check US Composites. I used their 8lb pour foam with great results.

Yeah, that's about what I figured. I'm actually thinking of foam filling a few key places on my fastback after I get the full cage in. I'm not sure what density I would want though.

GripTerror 01-19-2010 06:42 AM

^Let me know how you plan to do that and how you execute it (where/how/density/etc...) as I'm in the same boat. Even after I cage I'm considering using foam to stiffen up some more... considering I run heavy spring rates and want to try some race slicks not just R comps :D mmm used race slicks lol

longfellow 01-19-2010 08:10 AM

4lb or 8lb foam from US Composites is your best bet. I'm going with 8lb foam for my chassis.

SoSideways 01-19-2010 08:37 AM

If you guys read gunluvs14's analysis for the chassis foam stiffening experiment that he did (he's the guy that did the analysis and made a huge thread on Fresh Alloy about it), he said that the reason why he went with the foam that he did was because of the weight to stiffness ratio.

He went with what he did (can't remember what he used, as I'm typing this from memory) because he said if you used the next higher up weight foam, that there was a point of diminishing results.

He also used the 2lb foam for the A-pillars I think, due to the fact that you have to spray it like upwards and stuff, and the 4lb or 8lb foam wouldn't work there.

As for the moisture issue that you guys keep bringing up, you know what? If it can get in, it can get out. The same openings that will allow for the moisture to get in, will allow for the moisture to evaporate.

longfellow 01-19-2010 09:00 AM

The difference with foam is alot of the holes in the bottom where standing water would escape through become blocked so if water gets in its just going to sit there. So it is important to take that in to consideration. Especially with the subframe. Moisture isnt an issue since these foams are water tight.

The foam I used is the type where you mix it in a bucket and pour it down a funnel. It wouldnt work for the a-pillars. But you can always use the Handi-foam 2lb kit if you want to do those later.

jholman05 01-19-2010 09:12 AM

Just a little food for thought, I like actual numbers as opposed to 5-8lbs. So I thought I would weigh s13 and z32 knuckles. s13 has oem bushings, and the z32 has energy suspension bushings with tiny grease fittings. So they are similarly equipped.

http://i159.photobucket.com/albums/t...02_3960918.jpg

http://i159.photobucket.com/albums/t...02_3960918.jpg

I know this is a couple pages late, oh well.

GripTerror 01-19-2010 09:20 AM

So 4.8lbs per corner that's still awesome. I have mine sawed off in the rear for arizonazcar's wilwood rear bbk kit.. so mine is even lighter ;) Now we need mmdb to do the same for the driftworks version. Any news from PBM? The ziptied thread is dead... (they dont talk about it) and their website says nothing.

SoSideways 01-19-2010 10:21 AM

Quote:

Originally Posted by longfellow (Post 3245968)
The difference with foam is alot of the holes in the bottom where standing water would escape through become blocked so if water gets in its just going to sit there. So it is important to take that in to consideration. Especially with the subframe. Moisture isnt an issue since these foams are water tight.

Well, if the water can get into the foam, it can get out of the foam, thus the "blocked passages" created by the foam will still be a way out for the moisture.

Gunluv has had the foam in his car for at least a year now, might be longer (I don't even remember when he did the foam... long time ago, I do know that, just can't remember specifically now... maybe 2007?)... so far, I haven't heard him report any detrimental side effects caused by the foam on his car yet, like rust, etc.

The only things he mentioned to me was that it understeered a bit more after the foam, but he has since tuned the understeer out, and that his brakes worked slightly differently too, since the chassis is stiffer now and the weight transfer is more pronounced.

I will ask him if he has seen any pronounced rust spots or anything like that on his chassis, especially around the rocker part.

longfellow 01-19-2010 10:30 AM

It cant get into the foam thats the point, its water proof meaning water is not going to seep through it. So if you foam your subframe like I did and there is a small gap in the top or its not filled up completely water will get trapped there and rot out the structure. Same goes with rocker panels.

The A/B/C pillars you dont need to worry about since water dosnt get anywhere near that area.

SoSideways 01-19-2010 10:53 AM

Well I told gunluv to check in on this thread, but his computers at work are setup to where he can't browse forums, so hopefully he will chime in after he gets off of work.

KA24DESOneThree 01-19-2010 10:55 AM

Too OT. Make new thread, find old thread, or PM please.

Let's try and keep this fairly pure, not like the Maximum rubber thread's stupidity.

GripTerror 01-19-2010 10:57 AM

SoSideways: That's where a proxy comes in play, ;)


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