On the subject of the difference between ride height adjustable with threaded bottom section vs non threaded bottom section coilovers here's a great write up by Billy Johnson:

"The spring perch location does not shorten or lengthen the spring. The spring perch location will however affect how much the helper spring is compressed (preloading the helper spring -if you will) but it is not preloading the main spring and has no effect on handling.

IF you raise the spring perch location beyond KW's max setting, then you can completely compress the helper spring and start to compress (preload) the main spring. Since you are not adjusting the ride height to this level, you are not prealoading the spring.

KWs are designed with far more droop travel than most coilovers out there which have almost no droop travel. In order to have this droop travel and not have the spring loose and mis-align on the spring perches when full droop (jacking up the car or going over a big bump that launches the car), the helper spring maintains steady pressure on the main spring to keep everything aligned under all circumstances. Most racecars use shorter springs (which are lighter btw) and helper springs to keep the main spring aligned under full droop travel.

I would hardly call this a 'frequently touted drawback of the KW V3'. The V3 is designed to work in a certain operating range (which KW states in the owners manual) that will have sufficient compression and droop travel. Most people don't even know what preloading the spring even does (affects initial roll resistance which is so minute most people wont feel it anyway). Preloading the spring in any asian coilover greatly reduces droop travel. Cars that play with preloading the spring and have little to no droop travel are formula cars and prototype cars, with very little travel, perfect suspension geometry to work in that short range of travel, etc... For production cars and especially for street cars, you don't want this little of droop travel.

More droop travel will prevent the car from 'skipping' across bumps in the road, and especially after hitting apex curbing on the track. More droop travel will make the car feel much more planted and confidence inspiring, while keeping the tires on the ground to generate more grip. Too little droop travel (by prealoading the spring too much) can and will reduce overall grip if the droop limit is reached from bodyroll alone.

The whole threaded body with independent spring perch height and ride height (via lower body perch) is a great way for the manufacturers to use the same size shock internals for many applications as well as a great marketing gimmick to people who don't fully understand the so-called "benefits". Look at any production-based racecar out there; you wont see the asian coilover with "preload" design but rather a single spring perch, main spring, more often than not a helper spring, and more droop travel than most the street cars with 'coilovers' out there."
Billy
FX Motorsports Development
FXMDBilly@gmail.com

The quote is here:
https://www.s2ki.com/s2000/topic/384...t__p__17442400

The entire thread is good reading.

 

Sweetdill, I believe both VitaVenovatio and I will be at WSIR on 6/2. With 3 of us working on the car, swapping a set of shocks should be cake. Just be sure to have the heights set up before hand, and I'm sure we can get another S2k Challenge member to do the 4th corner.

We'll be able to get some solid testing/data

 

If it was me I'd install the eibach first as it has a remote resivoir. Much harder to route that around plus the shocks have to break in so you can't know height until its broken in. Only thing so far is that I am disappointed the rears are not shorter

 

I won't be swapping them just yet, esp. at a track I'm not familiar with. It will def. be a buttonwillow event.
I'll have Darrin even everything out for me.
And Boyguan, good point about mounting the reservoirs.
I still have the stock air box so there's very little room for those guys.

 

what do you guys think is the better coilover between the

evasive src vs. evasive eibach R2?

Seems the R2's are a bit more affordable, is the src worth the extra cost?

is a 1 inch drop (track drop) possible, without sacrificing too much on the R2's?


Thanks

 

I cant speak for the comparison between the two but I'm much lower than 1 inch on the R2's with no issues of bottoming out. I haven't measured but I can barely get a finger between the tire and fender.

 

So much good information on this thread, definitely learned a lot. But of course brings up many more questions. I am not saying anything below is right or wrong necessarily, I am just interested in learning. If there is a question mark behind a statement, it is just a legitimate question.

1. Overall damper length
I don't understand why people see OEM length shock body as a negative at all. If the overall length is shorter than OEM or this Eibach setup, aren't you already sacrificing that same amount of shock travel anyway? So the Eibach or OEM damper has more overall travel at stock ride height than a shorter damper at it's max (but lower) ride height. As the Eibach damper gets shortened (ride height goes lower) it just falls in line with the max amount of stroke of the already shorter damper? Isn't a longer shock body (within reason) better overall as you could still get optimal damping at more right heights? It seems like the longer the shock body length the longer the shaft, which allows for more overall travel? Isn't the optimal position of the bottom of the shaft in the middle of the shock body itself?

Edit: Ugh, I am bored and I made this and I may have answered the above questions for myself, so now the remaining question is.. Does this make any sense? (As oinojo mentioned, the shaft length is also shortened to match a shorter damper body:

(It of course isn't accurate in terms of sizes and I would imagine the piston length and positioning within the damper varies quite a lot from damper to damper, and this assumes the end of the piston is in the center of the damper under no load, but if all were identical..

Or is it not the bottom of the shaft that bottoms out (inside the damper) and instead the top of the shock body and upper mount coming into contact under load? Looking at that diagram again I am guessing the pistons are actually much shorter and the shock housings much larger.

2. Remote Reservoirs
How useful are remote reservoirs for most applications really? Is the main advantage of a remote reservoir just related to better heat dissipation, and therefore less fade, less time between rebuilds? Is the heat that builds up actually generated by the movement of the damper itself or other external components like the brakes? If it isn't generated by the damper, then wouldn't it take a substantial amount of heavy sustained driving (gran prix/endurance length racing) to really start negatively effecting the temperature of the damper oil? I don't see how autocross/time attack/track days would really see much of a benefit from remote reservoirs if the main reason is avoiding heat fade caused by long term exposure to other heat sources, so hopefully my assumption is just wrong in that regard.

Edit: It is wrong! I Was motivated to do more research and answered my own question. Dampers turn the kinetic energy of the spring oscillation into thermal energy (heat) and dissipate it. So I imagine most of the heat does directly come from the motion of the suspension itself, so more fluid to help dissipate that heat and putting it away from other sources of heat is never a bad thing. f@#k yeah remote reservoirs.

Sorry for so many questions and thinking out loud, but I feel like I am very close to getting a better complete understanding of these crazy dampers. So many people have no f@#king clue what they are talking about and I don't want to be that person.

 

The shaft length is shortened as well on shortened shocks. That is what you are missing.

 

Thanks, that makes perfect sense.

 

Back instock guys!