Powertrix Coilovers: Quality Concerns and an Alternative

Powertrix enjoys quite a good reputation, particularly in the USDM scene. I was under the impression that they were a high quality bespoke coilover, a step up from the regular cheap China crap you see everywhere. After acquiring some, I'm not so sure.

Recently I disassembled my 16,000 kilometre old Powertrix Road/Tracks. The dust boots on three of the four were split in half completely, and I wanted to replace them. Once I disassembled the fronts, I found the bump stops smashed to smithereens. This of course was contributed to by the ride height they've been set to their whole life, but remembering that they were designed to incorporate this height, I'm not very impressed by the bump stops' condition after only two years.

The three step stop pictured below has most of the third step missing, what's left folded over and compressed. They are very very soft, made of rubber.





Looking over the rest of the coil, the bottom shock bushing is also completely FUBAR. I compared the bushing to an original on a spare OEM shock, and the Powertrix one is much much softer, the centre twisting/flexing by hand. The OEM bush, even at 20+ years of age, is much firmer. It could not be flexed by hand, but would with a tool placed through it for leverage. The Powertrix bushing appears to be already completely haggard.



All these components (boots, bump stops and bushings) will need to be replaced, at just two years/16000 kilometres of use. To top this off, the damper adjustment knob on one of the front coils has lost its "click" when twisting. Looking over the units as a whole, they do not appear to have been built to the standard I was under the impression they would have been. The term "cheap, generic rebranded China crap" was used by a an experienced colleague I was disassembling the coils with. Shortly before he mentioned, "they're identical to HSD's."

These are Powertrix coils:



HSD are an English parts supplier with their own range of coilovers. Here's a photo of a set:



The only difference between them is the lack of a top spring perch on the HSD's, a recommended Powertrix coil modification which takes 60 seconds tops per corner. Apart from that and the sticker, they appear to be identical. Are Powertrix coilovers generic items simply fitted up with branding stickers? You be the judge.

I have been led to believe that Powertrix coilovers are a superior option to other "cheap eBay crap" on the market such as Megan Racing, BC and CX racing, presumably due to assumed build quality. It is widely accepted that the latter are all mass Chinese manufactured and rebranded suspension. Now I'm of the opinion in the affordable coilover range it's mostly much of a muchness. Lending to this notion of genericness, the front Powertrix coils lack a bracket fitting near the lower mount to bolt the brake line to - a feature OEM shocks and both my previous sets of Tein coilovers had.

This isn't a complete write off of Powertrix coils. Despite the cheap accessories they're assembled with, in their favour they have a great adjustment range, the shock body is reliable (I have never heard of a Powertrix shock blowing out, even with 4+ years of daily usage) and they ride beautifully.

Would I still recommend Powertrix coils to people? Probably. Would I buy them again? Probably not. There has always been an excellent range of proven high quality coilovers on the market for those that can spend the money - HKS, Cusco, Tein, etc. If you're in the market to go very low, Tein Flex's look like they'll do the job. At around the 2k mark they're not cheap though, and the ride I've heard is at best described as "shit house".

If I was on the market again for an affordable coilover with very low ride height capability, I'd buy Powered By Max. PBM are a Japanese tuning company set up on multiple continents. They a large range of tuning components geared towards drifting and for a wide range of cars across multiple makes with all of their items designed for heavily lowered vehicles. Their coilovers are used in professional drift cars, their following significant across the American and Japanese S-chassis community and more recently Z33 owners have been using them as well. This is just to name a few. Google shows up plenty of threads created in an effort to crowd source opinions and I can't find a bad review. Not too long ago I helped a buddy of mine fit a set to his Soarer, and nearly a year later he only has good things to say about them. They appeared to be a quality manufactured bit of kit.

http://www.gtfactory.jp/cms/page.php?24

They're also cheap. Really cheap. $1000 cheap. For that price I'll be the first to admit there's no way they're manufactured in Japan. In fairness, this brings into question their quality as well but their extensive following, use in professional race cars and apparently excellent warranties inspires confidence. Realistically speaking there's a chance at that price the lesser components of the coils could be crappy too, but PBM list their Competition coilover as having a urethane bushing on the front rather than rubber which is good to know.



The PBM's are also designed to supply stupid low ride height - they're renowned for it. On my buddy's Soarer, he were able to slam the hell out of the car without any spring droop. They had a lot more drop left in them, too. I wouldn't be surprised if they could wind all the way down to the point of dragging chassis rails.

Powertrix coilovers still managed to build a good reputation. Maintain them with new bump stops, bushings and boots and they should last you. I do not intend to change them unless I decide on going to a harder shock/spring combo, in which case I'll probably order some PBM's. I was simply shocked to learn what I have about my Powertrix's over the last week or two, and wanted to share my thoughts.

If any of the information I've listed about manufacturing, sources, etc please correct me. I would like to hear some solid information, rather than rely on my own speculation.

-A

 

Interesting read & info, Theo. I was going to buy a heap of Powertrix components such as upper control arms/tension rods etc... but not so sure now.

For the record, I wouldn't say the Tein Flex are sh!t house. The spring rates are not that harsh 8kg front, 6kg rear & 16 damper settings. I had them preloaded 10mm and damper setting set at 8 and I would head butt the roof on the highway if I hit a hard dip/bump lol. But since then I have removed preload and set the dampers to softest setting & I have no complaints

 

Nice write up mate, always good to know, was going to go with some powertrix also but I ended up going with some low (not super or ultra low, just bit lower than normal, legal) king springs with KYB Shocks, might sell them soon to get some really nice coilovers but they've done the job excellent for the past 6 months 12 months they've been on there, only really driven them 3 of those though lol

 

Tbh I'm not surprised. Afterall the invention of the shock absorber isn't new. Many other brands use the exact same parts as others but paint them differently and put a shiny sticker on them. And call them theirs. I looked at the trix coil overs and from the get go felt they resembled many other rebranded Chinese shocks. Now the only benefit I gave them is that trix test and customize the valving to accommodate their intended vehicle use.

However are the using what everything else has....? Who knows.

With all the raving reviews, your stern interest also, I gave them the benefit of the doubt assuming they're Chinese made, but customized to trix's pattent. Maybe not. But who can say yes or no for sure.

As for the compound of the stop and bushes. This is in line with it being made to a price.

Like I said I'm not surprised. But for the hype would have hoped they were a little better.

Also you're on the extreme side of use. Yes it fits the spot. But bottoming out the shock isn't ideal. Hence why your bushes are as flogged out as the are. Ran within its full range they'd prob last much longer.

 

Bump Stops and Bottom mount bushings

I'd like to address each issue one at a time.

BUMP STOPS:

The bump stops being destroyed and crushed is due to0 not setting up the coilovers properly. This is caused by bottoming out to frequently or by the looks of these destroyed bump stops, the coilover system had way too much spring droop to achieve an extremely lowered ride height that the entire car's weight was being supported by the bump stop. THIS IS THE ONLY WAY a bump stop gets destroyed in that manor. Proper ride height adjustment should always be done via the threaded bottom mounting cup. NOT THE SPRING.

These instructions/procedures are on the first page of our website:
http://www.powertrix.com/instructional.htm

IMPROPER SET UP CAN FURTHER CAUSE:

1. Compounded stress and increased wear on the lower mounts. A 1.5 inch rubber bump stop and a less that 1/2 inch rubber cup bushing can not be expected to hold the entire weight of a Z32 for very long.

2. Due to the inadequate amount of compression stroke in the strut shaft in which the dust boots protect, at rest, when the weigh of the car over compresses the damper shaft, it also binds/bunches up the dust boots making them more prone to getting caught in the spring during suspension actuation.

LOWER MOUNTING CUP BUSHINGS:

There is no doubt that the improper coilover set up helped accelerated the lower mounting cup bushing damage. However it seems in the last coilovers production run we may have had some inconsistent runs on bushing molds that resulted in a bushing that did not have the durometer strength/stiffness to our standard. We've only had a couple of reports of this and it is our policy to support our product.

Therefore even though the premature damage could possibly be to user error, we would not rule our that you possibly received a set of lower mounts with the inconsistent bushings and would like to replace the lower mounting cups with our new design and upgrades:

Our new mounting cups feature the following New UpGrades:
These will also come with all new coilovers orders.

1. Longer mounting cup to provide more mount to shock thread contact for increased structure abliity
2. Brake line brace for direct bolt on mount to secure the OEM brake lines.
3. Upgraded Bushing durometer for increased suspension performance and durability yet still maintaining comfort.



We have been manufacturing coilovers since 2002 (over 10 years) and there is a reason why our products particularity our Coilovers have such great reviews of quality and service. We still to this day have customers with our coilovers currently on their cars with 60,000 - 100,000 miles on them.

Please contact me So we can replace the lower mounts and help you with proper set up of the coilovers so this does not happen again.

 

You'll never get him to setup the coilovers properly

 

Great writeup Theo & I'm sure this will help others in the future.

Charles glad to see you post publicly & offering assitance. Just got a question...any truth in what Theo mentioned about rebranding the HSD coilovers? Are the HSD & powertrix coilovers made in the same factory?

Abraham

 

Manufactuing

OUR COILOVERS ARE NOT MADE IN CHINA.
Our Manufacturing Facility is in Korea with R&D taking place in the USA at our San Diego R&D Facility and several local road course tracks.

We have many customers over 10 years on our dampers/shocks with them still going strong. And our original prototypes produced in 2002 are still being used on daily driven cars today.

Anyone can make shock mounts to bolt up to any car on the market, where the technology and innovation is in the damper or shock itself.

POWERTRIX is a Nissan/Infiniti specialist and we go through a much more stringent R&D process in designing our coilovers specifically for the different Nissan/Infinity chassis.

This includes extensive measurement of compression and rebound stroke to determine shock and piston length and specific valving to define damper adjustment. Also spring rates are determined by the calculating the vehicles distribution weight and characteristics of each model.

Most coilovers companies marketing strategies is to bring a coilover model to every new car available as fast as possible so they do not take the time and efforts including R&D and actual road and track testing that we take pride in. Every Nissan/infiniti coilovers system goes through these R&D steps and every model of coilovers has anywhere between 6 months - a years' worth of road & track testing before we release them for sale.

So the biggest difference in our coilovers systems and others is the most important part of the coilover, the damper or shock.
On a shock dyno test, you can see just how much a shock is actually working and how much the adjustments actually make a difference.
Our struts have some of the widest range of true adjustment and you can physically feel the difference with a single click.

Others may state that they have the same amount of adjustments or boast that they have even more (as much as 30 way) but in reality there is little or no difference in 1-10, 11-20, 21-30 so in reality there is only 3 damper adjustments that do not even cover the same range as our dampers do.

The issue with the OP is not the Quality of our products but the particular suspension set up and multiple other issues of his partiular set up and riding too low.

 

Thank you for the reply Charles, I am interested to hear the lower bushing failure may be the result of a production error.

In the case of spring drooping, the lower cup mount was already wound all the way in before the spring mount wound down. This was necessary to achieve the ride height I was after. If this isn't recommended, why do the coils incorporate the additional thread to do so? I didn't modify the coils, simply installed them, adjusted them within their manufactured limits, and drove.

Are Powertrix coils simply not suitable for my application? Would you recommend removing the upper spring perch?

I would happily like to send back my lower cups for replacements. I'll e-mail you. A longer lower shock mount however would only exacerbate the problem occurring at the front end in regards to the lowered height - the spring will have to be drooped even more to have the same ride height.

 

There are a couple of scenarios that can help with your particular set up.

Yes, remove the top spring seat and this will further help with achieving more ride height adjustment. In fact it is required to do so with the new longer lower mounting cup. Do not droop the spring any more. This will help prevent the need to do so. (See dirrections below)

1. Measure the shock housing (removed from the mounting cup) from top to bottom and let us know the length. It may be possible to run a shorter shock to help achieve the lower ride height without sacrificing too much compression stroke.

2. Currently the coilovers come with 200mm length springs. We are switching to 175mm springs on the front our new coilovers to compensate for the longer botom mount and to allow for some droop if necessary however we do not recommend drooping the spring more than 3/4 -1 inch with out using helper springs to safely take up the droop gap. This is also an option we can try.

Unfortunately with the other control arm clearance issues you are having, the issue is not simply finding something else that works, its sound more about limiting the suspension travel to prevent the control arms from hitting the shock towers. That would be going against all suspension dynamics by using high spring rates and less suspension stroke. It is not conducive to proper suspension set up and handling but it may be what you are limited to do to have that particular look. Unfortunately for what you want to do with the car, there may be some severe sacrifices in suspension performance.

But this is very common with the "Hella Flush" crowd here in the USA where as they have there cars slammed so low and use a ridiculously high spring rate to limit suspension travel so that way the wheels and tires do not rub.

REPLACING FRONT BOTTOM COILOVER MOUNTING CUPS ON (RT) and (UL) COILOVERS
​

When switching lower mounting cups (on RT and UL coilovers), to the new design, the top green spring seat will need to be removed. This can be done by following the steps below:

1. Using an impact gun to loosen and remove the top 14mm or 17mm shaft nut.
2. The top pillow ball can now be removed.
3. Remove the 1 or 2 washers
4. Remove the Green upper spring seat
5. Replace the washer(s) and Replace the top pillow ball mount
6. Tighten the shaft nut with the impact gun but do not use excessive force as once tightened, it will just spin the shock shaft.
7. Repeat with other front coilover.

After the green upper spring seat is removed and shaft nut is back in place and tightened, the spring will be loose in the assembly will need to be re-positioned so that the top of the spring rests against the bottom of the top pillow ball mount. This is achieved by threading the bottom green spring seat and lock nut up in the assembly until the spring is in place.

​

 

Likewise I also have the Flex's with no complaints damper is on the softest front and rear.

How do you adjust the preload? Is this done by winding up the lower spring perch to compress the spring? Also how does the preload affect handling?

 

Anti PBM is not a Japanese company mate, they've just chucked some Japanese characters on their logo. Their made in Taiwan with d2, ksport, etc.

Plenty of people run bc, megan, etc but that doesn't mean they're not a budget base level coilover. It just means plenty of people are cheap.

 

Correct. I thought I would give it a go and see what difference it would make. Once the slack was taken out of the spring I wound it another 10mm, preloading the spring. Wouldn't recommend it, was bumpy as hell haha.

 

Wow, you smashed on those bumpstops. You're as low as me, and not even I have hit my bump stops. Something is seriously off with your coilover set up. I told you to remove that upper perch if you wanted to go lower. By drooping the spring, you're reducing the travel of the shock, therefore making it a higher possibility that you will ride on the bump stops and ultimately destroy them as you currently have. That drooped height probably led to the boot failures as well, as mine are still intact after 4 years!

And the extra threading is there because the whole shock body is threaded. You can't leave part of the shock unthreaded. Just because the threaded portion is there, doesn't mean you should droop the spring there. You're ultimately going to blow the shocks because you're placing the piston of the damper in a place where it shouldn't be, and ultimately end up damaging the shock. I run at my height with nearly zero preload, meaning minimal, and I mean maybe 1-2mm of droop, to run at my ride height. I'm not sure why you're having so much trouble breaking things at your height.
Improper set up almost seems like the reason for everything failing. You're setting up the damper and it's components for failure with so much spring droop.

What you need to do is get a replacement bump stop, remove one of the 3 sections (as I have), remove that top collar, raise the spring back up to where it should be, and you should be able to attain the ride height you desire.

I'm sure you've seen my write up on 3ZC with regards to remove the top collar. I think I've even linked you to it, so you wouldn't have to run so much droop, as it is just unnecessary.

BTW, bump stops are there to protect the damper from having the piston travel into a spot of no return. They are not there to constantly stop the travel of your suspension. That's what your springs are for. With so much abuse that your bump stops saw, I'm surprised you haven't blown any of the dampers. At that point, might as well just weld metal rods in place of the shocks, LOL

BTW, about 96000km on my coilovers, with monthly track abuse for 3 out of the 4 past years and they're still fine. Bushings, boots, and bump stops

 

Preloading does make the ride a bit bumpier. It adds tension to the springs, causing the spring to be in a constant state of wanting to expand, causing that bit of bumpiness. Usually I leave any spring preload at zero, and leave whomever is corner-balancing the car in charge of adjusting that.

 

In an ideal world it wont affect it one way or other.

The further you wind up a spring perch, the higher the car will go. The spring length will remain the same and so the spring rate (in Kg) will remain the same until such time as the shock extends to its limit (tops out) and THEN the resting spring rate will increase as the shock is "topped out" and cannot extend further so winding up the spring further com presses the spring and increases its rate.
This hould NEVER be done and results in a sharp increase in wear of the shock shaft, upper and lower sliding bearings due to excessive side loads over a much smaller distance between the top and bottom shock bearings.

So what this also does is limits suspension "droop" when the wheel needs to drop away from the car such as when an inside wheel in hard cornering and the roadway drops away.

The shock extends onto its extension stops and the wheel lifts off the ground. Front wheels dont contribute to grip and stability if they are off the ground!!! The ride becomes really uncomfortable on "whoop-de-doo" kind of road bumps

For a give car setup, there is an ideal amount of shock compression AND extension travel which is determined by the shock manufacturer and is ultimately maintained by spring setting alone.

The spring perch is adjustable to account for differing length springs and different rate springs which will settle to a lower, or higher static height for a given weight of car. NOT primarily for ride height adjustment.
Adjusting spring perches as the primary method of rideheight is extremely ghetto and compromises the entire suspension setup and operation as Anti has so obviously found out.
Is why better setups include a threaded lower shock body with an adjustable lower mount.
This way, the spring height can be adjusted for ideal resting shock extension depending on the length/rate of the spring fitted and then the lower mount is adjusted up and down to achieve correct corner weights and/or rideheight.

Grossly drooping, or winding up the spring perch alone puts the whole relationship out of whack.
Just as does fitting grossly lowered springs to a non-adjustable spring perch shock.

In Anti's case, results in the shock running hard against the bump stops in normal driving. No rubber compound or duro will last any length of time and its no wonder the lower mount is buggered as it went out in sympathy, possibly dodgey rubber duro or not. The rubber mounts are not designed to take repeated hard impact loadings!!!
If rose joints were fitted to the shock along with solid pillowballs on top then theres a good chance of suspension component failure due to repeated heavy impacts onto full bump.

Hes running the shock completely out of their ideal range of movement for the given spring/damper rate, chasing a "look" and he either needs to go down the, as Charles mentions, the "Hella Flush" road of stupendously heavy spring and damper rates to severely limit/control suspension travel or look towards a custom shock/spring setup, OR fit drop spindles that will maintain sufficient suspension travel and comfort at the ride height he wishes to use.

/rant

E

 

Thanks for the reply Eggar. Like I said when we talked, the top perches are going. The car's been off the road since we spoke, so I haven't been in a rush to do it ASAP. Good post.

I'm at about the same height as Articdragon192. I the spring was drooped two centimeters or so to get that height with the top hat in place. It's not like I'm dragging rails everywhere, looking to throw sparks on the way to the shops. My set up isn't really out of the ordinary as far as I'm concerned. I can see how the lower bushing would be taking the brunt of a hard knock once the bump stop has fully compressed, and it wasn't designed to do that of course.

The new cups - are they longer only in the "cup" section? As in, bushing to base-of-cup is the same length? In situations like Articdragon192 and I's, if the bushing was closer to the base of the cup no droop at all would be necessary (assuming the top perch is removed) to achieve the ride height. Meaning super slammed height with suspension travel as long as any height. Assuming it wouldn't foul on the knuckle anywhere?

Quick photochop done, it looks like an inch of travel could be obtained here.

Before, after



If the new cups are longer beyond the base of the cup, I'd be better off with my current ones.