True coilover "supporting" mods

k67p67

If you intend on using the KWs, you just need to decide whether you want to use the KW springs (in which case you'll need toe bolts) or ditch the KW springs and go with some 2.5" ID springs and the SPL mid links. Make sure to select springs with appropriate spring rates to work with the KW dampers if that's the route you choose. The second option is considerably more expensive.

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redondoaveb

I did read what you wrote but then I got conflicting info from another poster, that's why I was trying to clarify it. Now I know that you are correct. I didn't understand the difference between what a true coilover and what the KW's are.

redondoaveb

Yeah, I'll just go toe bolts. It's too bad the SPL mid links don't work with the KW springs (or should I say it's too bad the KW springs don't work with the SPL mid links).

MaysEffect

My apologies for the confusion, i thought you were talking about the toe arm "traction arm" as the adjuster linkage to replace.

It seemed pretty self explanatory you can't use the aftermarket "toe arm" with the oem style divorced spring combination. In that optionzero recommendations is what you need with a divorced spring coilover if you want to change camber and toe. But to be clear, the "toe arm" subsequently changes camber and toe simultaneously (more toe than camber), certainly if you are still using the oem traction arm in the front.

The odd thing i don't understand about the aftermarket kits, is why isn't there adjustable upper control arms. This would be extremely better for changing camber and using the lower arm to fine tune toe. Changing the lower control arm geometry effectively changes the wheel base and SR.

MaysEffect

Just to be clear 2.5inch i.d springs and 60mm i.d springs are not the same. A 2.5inch however can be used on some 60mm perches, not vice versa.

Last note- if you do decide to get new springs, i highly recommend http://performanceshock.com/index.php?main_page=index or http://pitstopusa.com/

The guys at PSI are extremely helpful.

OptionZero

You are correct, 2.5 inches is actually 63.5 mm

SPL's own product listing says their mid links are made to accept 2.5 inch ID springs

the easiest way to do it is simply to order the springs from SPL at the same time.

Mike at SPL is a very knowledgeable and helpful guy, call him with any questions at the time of your order. He got my sorted when i realized my aragosta springs wouldn't fit. (Bulletproof actually didn't help me much . . . i even asked them specifically if the springs would fit the SPL arms)

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AARONHL

I am concerned about the upper strut mount area on my g37 sedan with the true coilovers. Should I be worried? I know my Maxima back in the day had true coilovers in the rear so I don't see why this car couldn't?

Also what benefit does an aftermarket traction arm have (the rod in the frontward bottom part of the rear hubs)?

MaysEffect

It keeps the tire from changing static toe under load. Toe-out on the outside wheel being the primary problem with decreased ride height and increased spring load. It also reduces yaw which generally comes from for/aft movements. The oem rubber bushings will probably absorb up to 2degrees alignment change. Downside is you will actually induce more will spin and faster more accurate sliding in the rear with the solid arms.

NOTE - adjusting traction arm length is an even more complex adjustment that will effectively change the wheel base as well as weight jack the car if unevenly set. This change in geometry can change front wheel caster which can lead to an assortment of other steering change.

The arguments you may see about "bumpsteer" is a lose one. The bumpsteer in the rear is independent to each wheel unlike bumpsteer on the steering wheels. So the overall impact of toe change with the oem arms will not suddenly change the steering load on the car. However the solid traction arms will change the amount of load transferred across the car and act more like a solid axle and increase bumpsteer, not reducing it. In most cases this isn't a good thing but will give you much faster and accurate steering feel, something the g37 can benefit from.

The g37 actually has a better ability to handle strut tower load than the 370z as it has an upper rear deck and backseat surround to absorb deformation. But i'm not saying its a good idea in either case. For those who've actually changed to a true coilover setup can speak on wether it works better and the amount of wear.

Rusty

Some people who went with a true coil-over in the rear of the Z have not reported any problems that I know of. A couple have reinforced the upper mount area by finish welding the plate that was spot welded. most of these guys track.

To add on to what MaysEffect said. The stock rubber bushings have a lot of friction and deflection in them. By changing out to SPL parts. The suspension moves freer. There is no binding.

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MaysEffect

Not sure what you mean by freer, but in all cases the solid traction arm will reduce the amount of suspension change which would make things stiffer.

Rusty

If you remove the spring and shock, disconnect the sway bar. There is enough friction in the stock bushings that they will hold the knuckle in place. And it's hard to move it by hand. If you replace the bushings with SPL parts. The knuckle will drop. And you can move it through it's arc by hand. Something that you can't do with the stock bushings.

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MaysEffect

gotcha. I'm not sure this means much though when you are taking into consideration 3000ibs of weight forced down on the wheels. The amount of friction is probably still less that the un-sprung weight of the wheel and spindle.

But of course, free floating bearings will have less static friction than rubber to rubber.

Rusty

Spherical bearings took alot of the numbest out of the handling. The car feels alot tighter. You can feel it more.

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AARONHL

Good information about the traction rod, so if you have toe rods on the car should you adjust toe and then adjust the adjustable traction rod? That way toe can be where it needs to be before you lock it into place with the traction rod?

MaysEffect

I think the most comprehensive adjustment (when changing out all the arms) should be to set the alignment fully inward (reset to full positive), then adjust the rods front to rear.

So traction arm first > camber arm > toe rod.

OR

remove the oem rods, match the length of the new rod to the old rod, then adjust the alignment accordingly using the same format as above.