BMo

EVO EDGE,
I woulde assume you've been reading https://www.evolutionm.net/forums/sh...d.php?t=141153

Mattsteg45

iTrader: (2)

So guys, say i'm buying springs tomorrow, who can honestly tell me they were happy with their springs, and which ones did you use?

Michael Adair

Personally, I did plenty of research. The Eibach sport springs were "supposed" to be the best, lowest spring rate springs for the Evo. I say they are junk....On my '03 (the KYB strut's) they made an already poorly damped car even worse. In other words the spring rates do not match the damping characteristics of the shock. Unless you can find an aftermarket spring that is softer than stock(which I don't believe exists)I would wait an do coilovers. There is NO comparison in ride quality. By the time you buy the springs and add labor you are over halfway to coils. Unles you can stand a lowered car the looks good and knocks your fillings out on every bump..........

Kayaalp

iTrader: (1)

I agree that dampers need to be matched to your spring rates. However, the Evo is massively overdamped with stock springs. Using even softer springs, as you suggest, would make things even worse.

Personally, I have a stong tendency to think that the Ralliart springs are probably the way to go. After all, these are essentially factory parts that are designed to work with stock dampers. 5kg/mm front and 5.5kg/mm rear sounds about right to me. Plus, the ride-height is only changed minimally. All in all, this sounds like a good package.

Emre

Mattsteg45

iTrader: (2)

Thanks two both of you. I really wish I could justify coilovers right now, but I just spent money on the wheels and tires.

So far the only springs people seem to be happy with are the hotchkis. I think I'm going to install the springs myself, and that way, if i don't like them I can switch back easier, and I didn't waste money on the install.

Michael Adair

I have no experience with Hotchkis. As Kaaylap stated it is hard to make the set match. I may have not stated it correctly but what my car does is upon going through rough sections of roads at speed is the shock compresses loads up and then "springs the car back up too fast" actually causing loss of traction if the road is too bumpy. I have driven perfectly setup coilovers and they absorb the hit better than release the shocker slower therefore holding the car to the road. You may be ok with how the Hotchkis feel, just don't drive an Evo that is setup perfect because you will be bummed out................

redevo8driver

iTrader: (1)

does anyone know the spring rates for the hotchkiss springs? i like the lowering but I just didnt know how stiff or not stiff they were I tried googling for hotchkiss because evostore.com and lancershop.com dont have the spring rates listed thanks

point&shoot

iTrader: (3)

Can you back up this statement that the Evo is massively overdamped? I find it hard to believe that a performance car builder would not match the shocks to the springs. This is a really basic thing to get right. On the other hand, I've experienced the fact that the car seems to loose traction over really rough pavement, as if the tires aren't staying in contact with the road, so maybe you're right, but I'd like to know the basis for your claim.

Kayaalp

iTrader: (1)

Back up the statement? Just drive the car over a challenging road and you'll see for yourself. The springs are too soft for the dampers. This isn't rocket science.


This is not so strange as you might think. Lots of Japanese performance cars are overdamped. It makes the car feel lively and darty at low speeds...which most buyers mistake for "great handling." On the track it all falls apart.


The basis for my claim is a bunch of years of track driving and instructing plus setting up a bunch of racecars. This is my personal experience with a stock 2003 Evo 8. The MR's are supposed to be much better. Maybe the 2005's are better...but I have no experience with them.

Emre

JT-KGY

iTrader: (3)

Exactly... Autoxers lift rear inside tires all the time at corner entry due to front
springs being too soft.

point&shoot

iTrader: (3)

Interesting. Are you saying that the overdamping causes the shock not to let the
unloaded front wheel fall down quickly enough to keep it in contact, and that a
stiffer spring would push it down faster? If so, I haven't noticed this in my
autocrossing (2 1/2 seasons). But I haven't gone to racing tires yet, and I'm
sure you get more suspension travel with the higher traction.

I *have* noticed on the track that the inside front tire will break loose on
exit from an uphill, tight corner. But this is a steady state condition, i.e. the
tire keeps spinning as long as you are under full throttle and turning sharply
enough, so it has nothing to do with the shocks. I don't really mind it, because
with my open front diff (03 Evo), this shifts all the power to the rear wheels,
where you want it coming out of such corners. In any case, this could be
addressed by a stronger front sway bay.

point&shoot

iTrader: (3)

From everything I've heard, including reviews by drivers who took both cars
on the track (regular Evo vs. the MR), the Bilstein shocks in the MR are somewhat
more comfortable, and probably better at keeping the tires stuck to a rough
road, but the suspension in the standard Evo gives slightly better lap times
on the track. This makes sense to me, under the assumption that a track is
almost always a better road surface than the typical street, especially the
streets here in the North East.

Question for anyone: does the MR have stiffer springs or softer damping or
both?

Question 2: What's the formula for ideal spring rate vs. damping? I don't
even know the units of damping force, but my physics background tells me
it should be force / rate of motion, i.e. lbs/(in/sec) or something like that.

djh

If there were such a thing a lot of engineers would be out of business! But see any physics text for a discussion of the damped harmonic oscillator. There is a value that gives what's called "critical damping" which has no overshoot. By that criteria passenger cars are almost always underdamped.

Yup, force divided by velocity, or mass divided by time. In practice the damping rate is not constant over the full range of velocities. The rate can also be different for compression and rebound.

Dave

point&shoot

iTrader: (3)

Yes, I'm aware of the concept of critical damping. And I've noticed that with
most street cars, if you push down on a fender and let go, it pops back up
slightly above the rest position, then returns to rest, i.e. it's underdamped,
compared to critical. So I agree with you there.

Are people claiming that the damping of the stock Evo is super-critical (i.e.
that the suspension, when compressed, returns to rest position more
slowly than for critical damping? This can't actually be tested by the "push
on the fender" method, since that can only detect overshoot. Moreover,
the suspension of the Evo is so stiff that if you push on the fender hard
enough to move it significantly, you're in danger of denting the fender!

I would have thought there is agreement about the best damping ratio
to maximum the pressure of the wheel on the road over time, given at least
some expectation about the roughness of the surface. Critical damping
sounds intuitively like a good thing to strive for, but I can't justify that
mathematically.

machron1

iTrader: (1)

Apexi ExV Coilovers and Megan Racing Street Coilovers,
both Spring Rates: 8kg Front and 6kg Rear