This is the roll center, suspension pickup, and steering angle modification thread.

[TTnickdizzle]

Why dont we see anyone modding the upper pickup ponts on the rear subframe?

Im planning on modding my rear subframe by bringing up the rear pick up point on the RLCA like 50 mm or so but im contemplating raising the pick up points on the RUCA, Toe rods, and the traction rod as well. But after reading thru this thread it was mentioned that raising them may not be worth the hassle it takes because you need to cut into the body making space where they were extended and what not.

The way i see it which may be incorrect but lifting the RUCA pickup will help decrease the negative camber gain that occurs during squat vs. the stock position which is good thing right?

[swiftmini]

Originally Posted by PoorMans180SX

You are correct sir, above post edited.

sorry if my post came across in a harsh manor. I just re read and i was a bit blunt

[swiftmini]

Originally Posted by TTnickdizzle

Why dont we see anyone modding the upper pickup ponts on the rear subframe?

Im planning on modding my rear subframe by bringing up the rear pick up point on the RLCA like 50 mm or so but im contemplating raising the pick up points on the RUCA, Toe rods, and the traction rod as well. But after reading thru this thread it was mentioned that raising them may not be worth the hassle it takes because you need to cut into the body making space where they were extended and what not.

The way i see it which may be incorrect but lifting the RUCA pickup will help decrease the negative camber gain that occurs during squat vs. the stock position which is good thing right?

It is a lot of trouble to go too. if you do go ahead, either lower the front lca mount and the traction rod. Or raise the toe rod and the rear lca mount. Its easier too build a subframe that raises and tilts a little bit in my opinion. i have just done a frame the is tilted and raised.

also i personally think that 50mm is far too much. ive spoken to people that have lowered the front lca 15mm and the traction rod 10mm with a standard style solid subframe bush.

[swiftmini]

couple pics of my new rear setup on my r32.

s14 subframe with the rear mountings cut down by 10mm. i machined the bushes in the lathe and then cut the frame. i welded it all back up with filler plates but didnt get any pics it would appear :/


Fits nice and gives a bit of tilt too reduce anti squat geometry a little bit. The front is just flush mounted as per norm.


Geomasters and really rubbish godspeed arms. I will be adding second handbrake caliper brackets and my own lower arms soon.

[brainfood]

Originally Posted by TTnickdizzle

Why dont we see anyone modding the upper pickup ponts on the rear subframe?

Im planning on modding my rear subframe by bringing up the rear pick up point on the RLCA like 50 mm or so but im contemplating raising the pick up points on the RUCA, Toe rods, and the traction rod as well. But after reading thru this thread it was mentioned that raising them may not be worth the hassle it takes because you need to cut into the body making space where they were extended and what not.

The way i see it which may be incorrect but lifting the RUCA pickup will help decrease the negative camber gain that occurs during squat vs. the stock position which is good thing right?

I've done it a couple of times for time attack cars and would offer the service if anyone wanted it but its labor $ and most people can just bolt on rear knuckles and subframe risers.

[TTnickdizzle]

^ Im down to do the labor, and have a welder... but im just curious to see if i notch into the body at those points; is it going to be any weaker structurally? I was knocking around down there, where i would notch into and it seems like a very strong point. I am just worried that its a main structural "frame rail" in the unibody and i may weaken it by cutting a box out of it and rewelding it.

Do i have anything to worry about? its a unibody right, what can happen?

[Motary]

Originally Posted by TTnickdizzle

Why dont we see anyone modding the upper pickup ponts on the rear subframe?

Im planning on modding my rear subframe by bringing up the rear pick up point on the RLCA like 50 mm or so but im contemplating raising the pick up points on the RUCA, Toe rods, and the traction rod as well. But after reading thru this thread it was mentioned that raising them may not be worth the hassle it takes because you need to cut into the body making space where they were extended and what not.

The way i see it which may be incorrect but lifting the RUCA pickup will help decrease the negative camber gain that occurs during squat vs. the stock position which is good thing right?

What are you trying to achieve? People don't generally modify positions because they are very close to the chassis

[TTnickdizzle]

I have a pretty low Z32 and i had way more foward bite before going this low and im trying to get that bite back. I feel like my RUCAs and/or toe rods are angled too much and im getting some pretty significant camber/toe change under compression killing the traction. I just dont feel comfortable modifying my cast aluminum knuckles and them be safe afterward. But i think rasing the pick up points on the subframe is pretty straight forward.

[Firestorm]

...or simply raise the car so it doesn't ride like shit anymore. doesn't get more straightforward.

[PoorMans180SX]

Originally Posted by TTnickdizzle

I have a pretty low Z32 and i had way more foward bite before going this low and im trying to get that bite back. I feel like my RUCAs and/or toe rods are angled too much and im getting some pretty significant camber/toe change under compression killing the traction. I just dont feel comfortable modifying my cast aluminum knuckles and them be safe afterward. But i think rasing the pick up points on the subframe is pretty straight forward.

Buy PSM knuckles, extend traction rod, fabricate e-brake, buy subframe risers, buy s-chassis lowers for coilovers, install everything, done.

[TTnickdizzle]

Originally Posted by Firestorm

...or simply raise the car so it doesn't ride like shit anymore. doesn't get more straightforward.

lol not happening. Im over 4x4ing

Originally Posted by PoorMans180SX

Buy PSM knuckles, extend traction rod, fabricate e-brake, buy subframe risers, buy s-chassis lowers for coilovers, install everything, done.

I was thinking about that aswell that but before i invest the cash, i wanted to see if this is a viable option.


Brainfood: Since youve done this already what have you done after you notched the body to strengthen it or keep rust out?

[johnny_b]

Originally Posted by PoorMans180SX

Buy PSM knuckles, extend traction rod, fabricate e-brake, buy subframe risers, buy s-chassis lowers for coilovers, install everything, done.

i have this exact setup in my s13, im just wondering how much people extend their traction rod by? i know it probably depends on ride height etc,
(which for me is around 5-10mm rim to guard on an 18")

i did a bit of reading and guys local to me used 15mm as the general rule, however I'm not sure if the pbm subframe risers and pbm drop knuckles will have an affect on this.

I'm looking at for now just cutting and shutting my traction arms to desired length, and hopefully be able to adjust the toe to zero with the standard eccentric bush, if not ill buy pbm toe arms as well.
(ill be changing both these arms, and the lca's down the track just not on my list of priorities atm)

[PoorMans180SX]

EDIT:

http://nissanroadracing.com/showthre...ion+arm+length


An 8.5in total length is a good place to start.

[az_240]

Originally Posted by PoorMans180SX

An 8.5cm length is a good place to start.

I hope you mean mm

[swiftmini]

Don't even bother! Wait until you have access to bump steer gauges you will pronbably make it worse if you try guessing.

[swiftmini]

Ride height and angle of arms



Front end now

Motary: can you give some advice on working out my rear rc? The multi link is confusing me a little. Shouldi just lca and camber arms as my double wishbone layout in cad? And anti squat needs calculating with my new tilted frame

[GSpot_s14]

does anybody know the part #s for the parts needs for front roll center correction? i called pitstop usa and the guy wasnt too sure if he was finding the correct parts and wants part numbers instead which is fine with me bc i dont wanna buy wrong shit

[GSpot_s14]

does anybody know the part #s for the parts needs for front roll center correction? i called pitstop usa and the guy wasnt too sure if he was finding the correct parts and wants part numbers instead which is fine with me bc i dont wanna buy wrong shit

[PoorMans180SX]

Originally Posted by GSpot_s14

does anybody know the part #s for the parts needs for front roll center correction? i called pitstop usa and the guy wasnt too sure if he was finding the correct parts and wants part numbers instead which is fine with me bc i dont wanna buy wrong shit

Can't buy this stuff at Pitstop USA man. You're going to want to do a lot of reading.

[My$800S14]

Has anyone used this? Integral Ball Joints for Lower Control Arms

[My$800S14]

Also I'm sure this has already been covered so I'm sorry if I'm beeing redundant, but, I was doing some research on some other web pages, and I was looking into roll couple, and I wondered how bad it is to adjust your front roll center without adjusting the rear, because your roll couple would be off, and you would have so much more rear body roll, and obviously so much less in the front, aswell as the amount of grip front and how little in the rear

[Motary]

For racing, use this as a basic guide:

Arb, spring, rc +etc for calculating weight redistribution

Swiftmini, maybe these help:





if not, download susprog trial version and use these to look yourself:

susprog files for s13

Use display>control to move the image in 3d

[SomeoneWhoIsntMe]

almost done with the front end of this stupid cressida.

[brainfood]

Originally Posted by TTnickdizzle

Brainfood: Since youve done this already what have you done after you notched the body to strengthen it or keep rust out?

I just boxed the frame rails after notching them. I'm sure they are a weak point in a rear end accident now but the subframe also helps stiffen that area when bolted in. I wouldn't worry about them at all during normal or track driving only I there was a crash. Even then I don't think they are unsafe but I think the chassis is more likely to bend now.

[swiftmini]

Originally Posted by Motary

For racing, use this as a basic guide:

Arb, spring, rc +etc for calculating weight redistribution

Swiftmini, maybe these help:





if not, download susprog trial version and use these to look yourself:

susprog files for s13

Use display>control to move the image in 3d

Thanks mate I've been away for a few days but ill have a proper look tonight.

The top pic is confusing but the second one makes sense ill download susprog and see how i get on with it!

Iam currently researching roll axis, anti dive and anti squat geometry. Trying to figure out what to test first

When i raise my front crossmember iam not sure whether to raise front tension rod mount the same, or leave it! I'll probably make it so i can test both

[Motary]

If you going deep into it, try getting Milliken & Milliken book called "Race car vehicle dynamics"

you can also find a pdf on the internet

[swiftmini]

We had that book at uni but at the time it was way above my level. It's the only book i dont own, shame. its so expensive

Ill buy myself a copy as a present

[swiftmini]

ok I read small print

[My$800S14]

What method of welding are you guys using on these cast knuckles? I was thinking preheat the metal to 500* and then nickel stick weld? But a friend was saying he was mig welding them with great success preheating with a torch then, using a deep bevel, and then a root pass and a couple cover passes I would think that a mig weld wouldn't be stron enough, and that he would need some heat passes before the cover passes, and that a torch might cause to rapid of a heat application, and an uneven aplication of heat, what are the thoughts from yo guys that have been modding knuckles?

Missile Media™2011

[RHDphil]

Originally Posted by My$800S14

What method of welding are you guys using on these cast knuckles? I was thinking preheat the metal to 500* and then nickel stick weld? But a friend was saying he was mig welding them with great success preheating with a torch then, using a deep bevel, and then a root pass and a couple cover passes I would think that a mig weld wouldn't be stron enough, and that he would need some heat passes before the cover passes, and that a torch might cause to rapid of a heat application, and an uneven aplication of heat, what are the thoughts from yo guys that have been modding knuckles?

Missile Media™2011

There not cast, they are forged, tig is best, thats how i do them, no preheat needed, mig is possible, id prob preheat if Mig welding