dave12285

iTrader: (2)

Update!

I called the race shop to get them dyno tested and they said they may not have a mount for them as they deal with eyelet mounts generally. They could fab one for $90/hr. I didn't have the money or time for that so i got the new springs from Fortune that probably should have come with the original purchase.

Fortune has sent me new springs in Swift boxes but they have no markings on them other than some alphanumeric code probably representing the rate "SLC_045_150080". I requested 8k springs all around. I thought it was interesting that the springs are a different design and they're shorter. So far i've swapped out the springs on the front end and the ride is much improved. When i get another free couple of hours i'll do the rear and get it aligned. I would still not recommend these coilovers by any means.




I need to select a spring rate for these shocks. Are there any knowledgeable suspension people that could chime in? Thanks in advance.

Iowa999

iTrader: (1)

8 kg might work well. You'll be way over 65% down low, but it should ride nicely and not skitter, if those plots are to be believed. You could also go as high as 10, but then it won't be as over-damped down low and the ride would suffer on rough surfaces. Your call.

dave12285

iTrader: (2)

So you think 8k all around? It's currently 9k, 10k and i'm not very happy with the ride quality over rough surfaces. These shocks are supposed to be matched to 9k, 10k springs. It seems to go through multiple cycles over large bumps on the freeway. For example, traveling at speed and hitting a bump will compress, rebound, compress, rebound. This gives it a "bouncy" feel. Just for information sake, the preload is 0 front and rear. Ride height is about 1 finger all around.

For some more feel type information, my last set of coilovers for my old IX were Zeal Function XS on 10k/10k and i was very happy with the ride.

Thanks for the help Iowa.

Iowa999

iTrader: (1)

Can I be honest?

Yes?

Thanks.

That plot is what Fortune claims the curves to be, but I don't really believe them. Search around and see if you can find any independent tests of 510s. Maybe even find a place that will dyno yours. I'd love to see an unaveraged, raw plot.

Note that preload and ride-height is irrelevant to what you're describing, which is plain, old under-damping. Now, those curves are a tad low for 9/10, but not by enough to cause what you described. I suppose you could just drop back to 8/8 and see how that is. But I'd still want to see curves I could trust before playing trial-and-error, especially since it's a new alignment each time.

ps. I'm assuming you've tried cranking them up a bit, yes? They are adjustable, yes?

dave12285

iTrader: (2)

If I can be honest... I was the told by them to run them at full stiff. They also said that the valving matches my rates. Those seem mutually exclusive to me. Why would you match rates to have a choice of only the highest setting on the shocks?

Anyway, I have run them full stiff and the bouncy feel gets better but is still obviously present and accompanied by harshness. I would rather have them 5 clicks stiffer than the current full stiff and feel every bump than deal with the bouncy character.

In their sort of defense, they've been very helpful with trying to help me solve the problem. The issue came to a head when they offered to send me new springs and I realized I couldn't ask them what rates I should use because they already think the shocks match the rates I have. Interesting dilemma, especially with your thoughts of the dynos being inaccurate.

dave12285

iTrader: (2)

A side note on the adjustability, the shocks are 24-way adjustable theoretically however, in reality, the last 8 is the real adjustment area per them.

Exyia

iTrader: (6)

this is why I like you Iowa (and many others here on EvoM suspension section)

never afraid to be brutally honest. leads to real discussion and the only reason I visit EvoM

Iowa999

iTrader: (1)

Dave -

I would be delighted if you took your car to Thyssen Krupp (in Poway) to see if they would dyno your shocks. Yes, this will cost money, but you'd be doing everyone who has looked at the curves that FA has put out, seen how digressive they are supposed to, along with the 2:1 rebound to bump, and been tempted to buy them. Those guys normally work on Bilsteins, but a shock dyno is a shock dyno. As long as they have brackets to mount your shocks on their dyno, they could do this and it's part of what they do. With real curves, they and others could give good advice. If the curves are whacky, then ... well, let's not think about that unless and until we have to.

dave12285

iTrader: (2)

I actually already have a call in to a race prep shop with a shock dyno in town. I wonder if we could put together a small fundraiser after I find out the price. I'm still interested in doing the dyno regardless.

Iowa999

iTrader: (1)

Prediction: no-one will chip in, but lots of people - including me - will express interest in the results. But this isn't as bad as it seems. In some cases, they won't chip in because it's merely curiosity. (This is where I'd fall; I have no intention of getting anything from FA at any point in the future, no matter what the dyno shows.) In other cases, they won't chip in because these things often vary by a lot across specific shocks, even when they are supposed to be the same; so your data won't help them very much.

But I'd, at least, say thanks and then help, as much as I can, with choosing the right springs.

dave12285

iTrader: (2)

Fair enough. I'll update the thread when I hear back from the shop.

Iowa999

iTrader: (1)

Thanks.

I'll do whatever I can to help when you have the data.

You also have my respect for doing this right.

Iowa999

iTrader: (1)

One more thing, which might be useful to have in mind when you go to the shop. Most people set up a car by first choosing the natural frequencies (front and rear) for the suspension, calculating the springrates needed to get these values, then valving the shocks to the springs. What you're doing is a little bit backwards, but you're kind of stuck, since getting new springs is possible, but revalving FAs would be a total PITA (if it's possible at all). In any event, be ready for them to ask you such things as what frequencies you were after. But don't feel obligated to have answers. Most good shops are used to drivers who aren't into the math. The only thing that really annoys such places is a person like me - a person who knows the math, but isn't a very good driver and seldom listens to anyone. [tee hee] Just tell them what you plan to do with the car and listen carefully, if you're not into the math. This is often the best part of going to a good shop: what you learn in the casual conversation while they do the work.

In case they don't know Evo Xs, knowing that our front motion ratio is about .96 and our rear motion ratio is about .84 might be useful. Each front corner weighs around 950 of which around 120 is unsprung. Each rear corner weighs around 750 of which around 100 is unsprung. That's all they need to plug in the values to a standard spreadsheet for doing the math.

They might ask some other questions, such as whether you're using the "2/3 & 3/2" rule, where you want the knee, and whether you want 65%, 75%, or whatever critical damping; if you haven't heard of these things, just say that. People sometimes get defensive when the shop gets technical. Don't. Just be honest. A good shop will talk TO you and not AT you.

ps. if you're a 40- or 50-something like me and didn't need the above, just move on and treat it as me talking to the lurkers

dave12285

iTrader: (2)

I'm not 40-50 something but the above advice goes along with my way of living in a way. I try to speak with people who are very knowledgeable about a certain subject and i just shutup and listen. I was actually going to build a sheet of corner weights and motion ratios as i thought they might ask that stuff. Thanks for taking all the work out of it for me. Thanks again for all your help and i'll be sure to update this thread when i hear back on Tuesday. Cheers!

jyamona

iTrader: (8)

sub'd for actual shock dyno results. curious to see how close they are to the manufacturers published results