Confusion over rear suspension
 

Hi,

Sorry if i am asking dumb qns.

If i see correctly, the rear sus setup is such that the spring and shock is mounted separately from each other, almost side by side. Therefore i assume that if changing to aftermarket, they will be mounted separately as well.

But i keep reading about this "true coilover". Does this mean that this type of aftermarket has the shock sitting inside the spring just like the stock front sus? In such case, it means that where the original rear spring is sitting will be empty space? And will there be additional mods to the whole sus setup to accommodate such "true coilovers?

Finally for example, Zeal sells 2 types of each model. One that is separate (more expensive) and the other that is true-sus (cheaper). Can anyone explain where the price disparity comes from since material used is likely the same right?

Thanks for any help in clearing up my confusion.
Ffd

Correct, the Z does not have a rear "coilover" however for all practical reasons it acts like one except when it comes to calculating spring rates (lever arm effect).

Some racers prefer the "true coilover" because they can swap out shock and spring as one unit if they have multiple sets (configured for different rates). However this can potentially effect car classing for certain racing clubs. The downside to the coilover is that it will reduce the clearance between the wheel and the strut so it might make it difficult to run large wheels. The strut is somewhat inset so it probably isn't that bad.

Most of the OEM replacement suspension leaves the rear spring separate, however they still refer to it as coilovers generically.

As for the price difference in the Zeal, not really sure why the true coilover is cheaper. Could just be the quantity in which each unit is produced.

so does it mean that running as a single unit has more downsides than upsides?

any idea what the limits to wheel/tire/camber if i run the single unit coil overs?
And any additional modifications needed?

thanks.

It comes down to personal preference I guess and also what your intentions with the car are.

I'll check the clearances when I have the wheels off next (should be soon). With an 11" wheel and tire I rubbed the chassis before I rubbed the shock (with separate spring) so there should be a little room to maneuver.

I run a true style setup and I love it. There's no difference in feel that I can tell. But it might be because I've been riding on them for a year now. They feel great, especially on the track. I'm really blown away on how good my Stance coilovers turned out to be.

But no additional mods are needed if you went that route.

True coilover vs inboard spring will feel the same (i.e. the 2 zeal kits mentioned will feel identical) as the shock and the spring are in the same plane in either case, but any quality coilover set (whether true or not) will feel like a huge upgrade over stock.

so, where there used to be a spring is now just empty space?

how does that work out?

Hmm, will find some chance to hoist up the car and have a look clearly on how either systems will work.

It remains vacant. With the factory design the spring sits in a seat formed into the rear lower control arm, after market will either simply replace that spring or vacate it in favor of a spring on the strut.

Great info.

So when i buy coilovers, i will therefore need to check beforehand if it separate or as a single unit...

Far as I know Stance and JRZ are the only coilover companies that make a true design for our cars. And of course JRZ's are costly. But stance are great coilovers. At first I thought I was just getting away with cost. Boy did they surprise me. I love the spring rates as well, being there stiffer than most.

When it comes to the spring seat you can purchase a bar that replaces it but not sure where. I know some of the G35 guys had a replacement. It's a very simply design.

Helpful Thread

"Coilover" simply means the spring goes over the damper. The Z just needs an adjustable spring seat, and adjustable dampers are preffered.

Technically, keeping the spring and damper separate is better since that's the original design. Combining them into a single unit (without getting technical) affects vehicle dynamics and possibly chassis wear.

It might effect the dynamics for DD but very minimal. Especially with a proper alignment. But a true setup is proven to be better for performance base handling. That's what we here are looking for anyways. I personally really feel no difference in control with this setup. I also have a hard time believing there would be any additional wear.

you need these SPL PRO SUSPENSION | 09+ Nissan 370Z Z34

1. Shock mounts on chassis and upright were not meant to support the weight of the car.

2. Spring loads are originally inline with vertical wheel loads. With a spring moved rearwards, there is a twisting force on the upright and suspension links.

3. With the spring removed from the center suspension link, there is a a twisting force on the upright when the wheel tries to move it vertically but the damper provides resistance on the rear of the upright.

Not saying any of this is going to cause a failure, but definitely something to think about.

I can see that being very true to a point. But do you think having higher springs weights help with this a little?

So I am totally new to all of this talk and want to ask an even more simple question. Can I just leave the spring there or maybe put a lowering spring in place of the oem spring AND put my coils on. I got the Stance GR+ and I read a couple places that I should take the spring out. I am thinking that it will not affect the coil and possibly provide some added support on the frame itself. is this wrong of me to think that double damper is not better than single coil damper? insight?

I'm thoroughly confused by what you said.

My guess is you wanna run 2 springs (oem location plus the coil springs over the dampers) and 1 damper on each side...?

I think theoretically, sure, but have fun figuring out the right combination of spring rates needed. Both springs will have to be significantly softer, and the rates cannot be directly compared to each other due to the different locations.

2 springs won't yield added chassis support, at least not that I can see here. I think your concept is that it's better to spread the weight load to 2 spots instead of 1. Well technically speaking, the shock mount was never designed to take on car's weight.

I guess thats what I was thinking... distribute the damening acriss 2 springs... I figure why not. But I could be totally off on that thought. Call me crazy. Lol

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Rear springs
 

I just bought Bc racing coilovers and i’m trying to install the rear coil right now. Got it on no problem however the oem spring is too big to get the control arm back on the strut. I tried jacking up the control arm to get it up to it but it couldn’t get high up enough. Do i need new springs or is there a solution to this?

Post pictures to show us what the problem is and give hs more info


Do you have OEM arms or aftermarket

By “too big” do you mean too tall or too wide?

The OEM spring bucket is around…3.5 inches i think? And BC should have supplied springs that easily fit in there


OTOH, the spl midlinks require a spring thats 65mm ID which is smaller than an oem spring