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Discussion Starter · #1 ·
If you look to some other platforms with similar rear suspension setups (350z, e46), the general consensus is that the rear shock mounts weren't designed to hold the weight of the car, and it's dangerous to run true rear coilovers without reinforcing the mount points.

http://my350z.com/forum/brakes-and-suspension/356556-true-coilover-rear-damper-or-not.html

true rear coilover conversion

I searched, and there's been almost no discussion of this rather important little quirk in our suspensions, even though PBM and Fortune (maybe others) use this design.

I'm kinda hoping that this will evolve into one of those engineer debates that go way over my head... Now GO!
 

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| Boost Addict |
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The only problem I see is that our car wasn't designed for a proper coil mount and like it was mentioned on your first link, if a true coil is installed then theres a chance the upper mount will need to be reinforced to be able to handle the load the strut will transfer to the mount. This is something I'd be very interested in learning more about and makes me wonder what Rhys Millen used on his GC.
 

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that guy
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Off topic a bit- Are you sure the Fortune Auto coilovers are a true rear coilover? I did not know that!
 

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Hammer lane Hero
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This has been my main concern on pulling the trigger on PBM coils. I want a true coil setup for the track this year.

That being said, apparently 1320 has been thrashing his coupe both on road and the drift track for like 15-20k miles with no ill effects (If I'm remembering correctly)

P.S. Strykr, Rhys used true coils in the rear, but I'm not sure of re-enforcements though.
 

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Lord Stig
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I've had my PoweredbyMax coils on for a good 3 months with maybe 5k miles. Its seen the harsh conditions of LA. And bumpy road of chino hills. They're fine. No need for reinforcement. The coilover is built n designed for the stress. [email protected] doesn't mess around, they engineered this to be top notch quality for an amazing price. Even ARKs formula d car is running PoweredbyMax.
 

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Jedi Master
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i think it's ok.

mustangs have been going from struts to coilvoers for decades and they work fine
 

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Hammer lane Hero
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I've had my PoweredbyMax coils on for a good 3 months with maybe 5k miles. Its seen the harsh conditions of LA. And bumpy road of chino hills. They're fine. No need for reinforcement. The coilover is built n designed for the stress. [email protected] doesn't mess around, they engineered this to be top notch quality for an amazing price. Even ARKs formula d car is running PoweredbyMax.
Oh I know the coils are built to go the distance. I'm just worried the OEM strut MOUNTS can't take the punishment.

sent from my not-so-smartphone
 

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제네시스 쿠페
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they can
 

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Discussion Starter · #9 · (Edited)
See, this is why I envy the other communities. While it's great that some people have had no problems so far with true coilovers, no one is offering any actual arguments with physical evidence/research as to why it's safe in general. (As opposed to just "mine hasn't exploded: therefore it's fine!") Cris90 probably came the closest, but the counter-example is that e36's just plain RIP through the mounts with true coilovers.

Even at just my uber-noob level of knowledge, I would say that the kind of forces encountered by a grip racer's suspension going through tight slaloms is probably pretty different from the kind of forces encountered by a drift guy's suspension sliding around at high speed.

If we have any engineers here, this is a perfect opening for you...
 

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Hammer lane Hero
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This is a job for Ibnzmonkey
 

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I drive a V6
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i agree. The shock mounts werent designed for the force of a spring, no idea if they will hold up.

I still dont understand why people want this conversion, I dont see a benefit really...other than being able to say they have a coilovers in the rear.
 

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Hammer lane Hero
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i agree. The shock mounts werent designed for the force of a spring, no idea if they will hold up.

I still dont understand why people want this conversion, I dont see a benefit really...other than being able to say they have a coilovers in the rear.
The further outboard you move the springs, the better lateral stability you have. It's a more direct control of suspension travel vs. A sort of lever system that the springs have in their stock location

sent from my not-so-smartphone
 

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I drive a V6
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The further outboard you move the springs, the better lateral stability you have. It's a more direct control of suspension travel vs. A sort of lever system that the springs have in their stock location

sent from my not-so-smartphone

Yes, but is there a quantifiable benefit? Many race teams use the standard set up in their vehicles (not drift...I dont follow that so I have no idea)
 

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that guy
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The quantifiable benefits are reduced unsprung weight due to a significantly smaller and lighter spring. There are also the benefits of ease of adjustment.

Truthfully, you aren't altering the suspension geometry in any meaningful way by changing the location of the spring. The suspension is a lever system, and none of the properties of the lever ( arm length, fulcrum position, etc ) are being altered at all when simply changing the spring location. You aren't making the shock tower take any additional abuse, because in either spring configuration, the only purpose of the spring is to control the shock piston movement, NOT to control the control arm movement. Whether you like the difference in feel you may or may not get by moving the spring location around, is totally subjective
 

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Hammer lane Hero
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You've got it backwards. The purpose of the spring is to hold the car up, while the damper stops it from feeling like you're riding a rodeo bull.

Moving the spring to the shock location now makes the shock mount support the weight of the vehicle instead of the spring perch. Hyundai didn't plan for the rear shocks to hold up the car, so we're nervous the upper mount can't take the strain

sent from my not-so-smartphone
 

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I drive a V6
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indeed.

Try pressing down a shock...the average guy can compress one easily...Now try a spring.

The spring seats are much more substantial than the shock mounting points.

The weight of the car is on the springs...not the shocks
 

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that guy
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You've got it backwards. The purpose of the spring is to hold the car up, while the damper stops it from feeling like you're riding a rodeo bull.

Moving the spring to the shock location now makes the shock mount support the weight of the vehicle instead of the spring perch. Hyundai didn't plan for the rear shocks to hold up the car, so we're nervous the upper mount can't take the strain

sent from my not-so-smartphone
In either case ( true coilover or separates ) the spring is still holding the car up, and the spring also controls the motion of the dampers. You aren't altering the lever. Changing the spring location makes next to no difference. The spring can change how the car's weight shifts around, but it can't actually change the weight of the car. The weight support comes from the spring mounted to the shock body and the upper spring hardware which is mounted to the chassis , just like the front suspension. Many cars use a two point upper mounting for the rear coilover, and get by just fine. In either case, all weight is still coming down on that upper shock mount, regardless of the location of the spring. This is the simplest physics imaginable, the inner part of the rear lower control arm ( where the OEM spring is ) barely moves at all, the outer part of the control arm moves a lot. The shock is mounted near to the outer end of the control arm, and that is the end that sees all of the violent up/down movement in either case. So no matter where the spring is located, all of the abuse still happens at the shock mounts.

This topic is the first time I heard of anyone being worried about the strength of the upper rear shock mount. The better question here, should be why do YOU think there is a problem? Has there ever been a reported issue or failure? Do you have any quantifiable evidence to show that there is actually a problem that needs addressing? If I were you I would wait for reports of failures to come in, before you go worrying about a problem that doesn't exist yet.

Just my .02
 

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that guy
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indeed.



The weight of the car is on the springs...not the shocks
You're absolutely right, and in either scenario, the weight of the car is still on the springs, and all of the abuse happens at the shock mounts.
 

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Hammer lane Hero
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Alright, since the basics of gravity and physics seem to be escaping your grasp, I'll make a rough analogy.

You have a 50lb backpack slung on your shoulders, all is good an you can walk all day like that.

Now, take the backpack, and sling it over your forearms. It's still on your body, the weight of the bag hasn't changed, but your elbows don't have the same reinforcements that your shoulders do. You could carry it a while like that, but you'll drop the bag off your forearms long before your shoulders.

Why? Because even though your arms see all the violent movement (shock mounts), your shoulders (spring perches) are designed to take the sustained load.

That's my .02

sent from my not-so-smartphone
 

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meh. these coilovers were night and day difference for me compared to my megans.

the moment I installed them I couldn't even feel the difference between them and my OEM struts.. that's all that mattered to me.
 
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