Confusion over rear suspension

Fastfatdude

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

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ChrisSlicks

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.

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Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms

Fastfatdude

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.

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ChrisSlicks

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.

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Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms

SPOHN

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.

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ChrisSlicks

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.

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Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms

Fastfatdude

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

how does that work out?

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Fastfatdude

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

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ChrisSlicks

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.

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Hotchkis ARB | Stillen CAI | Art Pipes | Berk CBE | Stillen AP Racing Brakes | AE Performance Oil Cooler | BC Racing ER Coilovers | Doran Control Arms

Fastfatdude

Great info.

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

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SPOHN

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.

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haitech

Helpful Thread

TopElement

"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.

SPOHN

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.

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fuct

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