ive worked with a few sets of D2's on various cars, i fitted some last week in fact and set the car up, so ive got some thoughts on them
heres the problems i have with them, considering i build dampers day in day out for my job.
my opinions on road car dampers are a little skewed as im used to working on Ohlins, which are one of
(if not THE) best damper manufacturers in the world, and so most other stuff looks worse to me.
but still, ive got real-world perspective and can judge the lower end stuff on its merits.
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1.
they look pretty, but the anodizing is really poor.
it chips off at the slightest contact.
especially on the adjustable top mounts, as soon as you adjust the camber it scrapes the anodizing off
2.
they are clearly made in China or a Chinese territory, and are made to the cheapest price possible, at the expense of quality.
whilst this isnt a specific problem with the damper, it never stands a product in good stead
3.
the damper design itself is a generic monotube setup, which can work very well.
but the internal design just isnt very good, theres more to mono dampers than just shims on a piston, and its the specific details that set apart the likes of Ohlins and Sachs from crap like Gaz, Leda, D2, etc
4.
the people who design the damper, clearly dont look at the car they are intended for.
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a) lengths are often too short.
this might be done on purpose to lower the car, but its always by too much.
so in order to keep the car from being sat on the floor you have to wind the ride height adjustment all the way down.
which then means it cant be used for height adjustment any more, except to go lower
(and youre already too low)
b) they have adjustable drop link brackets on some of them.
but they can never wind into the right place to fit the standard drop links.
so you need adjustable ones
(which all cars should have anyway if theyre being fitted with proper suspension, so that roll bar preload can be removed)
c) they dont have brake line brackets, etc on them, but they do come with universal ones.
except the universal ones never fit as is.
ive had to cut, bend and drill them every time to get them to fit how they need to.
Tein make shítty dampers, but they do at least have the correct brackets on them!
d) the top mounts often dont sit in the correct orientation for pure camber adjustment.
if they dont sit perfectly perpendicular to the car then adjustments will significantly affect castor and toe as well.
5.
their user manual recommends tightening spring platform lock rings with a screwdriver and a hammer.
anyone who says a screwdrivers use is to be hit with a hammer is a moron.
its something you do if youre lazy, uneducated, or have no other choice.
but in an official user manual, they should at least recommend using a drift
(aka punch).
aside from the fact that using c-spanners and pulling them against each other is how race dampers have been working for years, and if done tightly they simply dont come undone! unless D2's spring platforms are poorly toleranced and/or made from crap materials
6.
they are sprung WAY too stiff
7.
the dampers have WAY too much rebound, and no bump damping.
which makes the car feel like a go kart and the driver
(assuming they are an average punter whos never driven a properly setup car, or a race car) feel like a hero.
but its not genuinely fast, and theres a lot more fun to be had from a properly setup car
8.
this kinda relates to point 4, but the dampers often lack droop.
this isnt just to the detriment of performance, but on a road car is quite dangerous.
not having droop on a bumpy road will result in wheels losing contact with the road completely.
which on the driven wheels can lead to the car pulling around side to side.
ive seen D2's which when fitted with the supplied springs have less than 5mm of droop travel on the front wheels of a FWD car.
which is insane on a road car
just a few things i have observed.
the indepedant ride height and spring preload adjustment is a cool idea and reasonably well executed, just with poor quality materials, and on dampers that cant necessarily use it.
it also means that drop link, brake line, etc brackets cant be properly mounted to the strut cases.
as dampers though, they are horrific.
they would work well on a drift car, il say that for them.
but for road use or track use they just arent worth the money.
a set of Koni's in standard strut cases, with ground control
(or similar) coilover sleeves, running 2.25" or 2.5" universal springs would be FAR better.
youve got camber adjustment as standard
(and can buy aftermarket camber bolts to give more adjustment if required), and ride height adjustment can still be done just by winding the platforms up or down on the ground control kit.
D2's are worthless IMO
