[Draco-REX]

I'm sorry for not finishing this yet.. I'll try to get to it today.

I don't have specific settings, this thread is more about my parts selection and my impressions of them. Right now I'm running 12 front, 14 rear from hard.

Fine tuning will wait for when I get the final rims/tires on.

[Draco-REX]

OK, final section is DONE!

I thnk this will "evolve" slightly as I finish the suspension and tune it, but the bulk of my impressions are here. I'm always happy to answer questions and discuss my choices if you disagree.

[williaty]

Originally Posted by Draco-REX

Camber plates are just a great addition to the front suspension. The biggest downside is that there is no compliance to them. Any energy that isn't absorbed by the strut will be transferred completely to the body of the car. They can make a suspension feel rougher than it is because the bumps will have more of a peak to them rather than being blunted by the rubber in the stock tophat. But when you watch the car, you can see that it's not moving as much as it seems.

I have almost the opposite take on this. Well, I totally agree that they're a great addition, and I totally agree that they drastically improve the steering. What I STRONGLY disagree with is the idea that they make the suspension feel rougher. They drastically change the feeling of hitting a bump, in my opinion, for the better. With both stock strut mounts and Group N strut mounts, after you hit a bump, you can feel some jiggle/wiggle in the front end as everything dissipates the energy and settles back to normal. This drives me nuts because it makes the car take forever to settle after a bump and as soon as it does, hey look, there's the next bump. With the camber plates, this totally disappeared. Now, hitting a bump is more of a "wham-done". It's a bump, you hit it, and you get on with your life. To me, it makes the car feel smoother due to the car having more "still time" in between bumps.


I will, however, say that they made the car much noisier, which you claim not to have experienced with your car. Running over rumble strips cracks me up now because the car rings like a bell.

[Draco-REX]

Originally Posted by williaty

I have almost the opposite take on this. Well, I totally agree that they're a great addition, and I totally agree that they drastically improve the steering. What I STRONGLY disagree with is the idea that they make the suspension feel rougher. They drastically change the feeling of hitting a bump, in my opinion, for the better. With both stock strut mounts and Group N strut mounts, after you hit a bump, you can feel some jiggle/wiggle in the front end as everything dissipates the energy and settles back to normal. This drives me nuts because it makes the car take forever to settle after a bump and as soon as it does, hey look, there's the next bump. With the camber plates, this totally disappeared. Now, hitting a bump is more of a "wham-done". It's a bump, you hit it, and you get on with your life. To me, it makes the car feel smoother due to the car having more "still time" in between bumps.

I should emphasize the word "feel" in that statement. The zero compliance of the spherical bearing is great for all the reasons mentions above and in the bushing section. My point was that there's an illusion of a rougher ride because more energy is being transferred to the body. If you could record the shocks of hitting a bump in a wave-like diagram, I think the stock tophats would have blunted or more curving peaks whereas the camber plates would have sharp, pointed peaks. More energy is being transferred into the body which makes for louder "whumps" but the actual difference in body movement is very small.

I think our difference in opinion is a matter of semantics, or context. I'm looking at the difference in ride quality whereas you are coming from a handling standpoint.

I will, however, say that they made the car much noisier, which you claim not to have experienced with your car. Running over rumble strips cracks me up now because the car rings like a bell.

I think there is definately more noise. As above, the energy being transmitted into the body is more and sharper. But I don't get the "ring" you do over rumble strips. I think that might be a resonnance thing with the wagon.

[boxtwo]

Draco- Excellent write-up! What you have done with your STi is right in-line with what I have been getting to with my own, minus the actual shocks.

Bookmarked for continued reference! Thanks for your work!

[stretch]

Draco, the web site you refer to in your damper section is this:
DGs Autocross Secrets aka Autocross to Win

I'm still not convinced that Ohlins struts make the ultimate street suspension, though, due to suspension travel issues. Even if the Ohlins added travel over stock, which I don't think they do, your front springs don't have nearly as much travel left in them as the typical coilover set. Coilovers can get you 3+ inches of bump travel versus about 1-1.5 inches on OE-replacement struts, and that travel is mostly bump-stop free.

That brings me to my second point. When you plugged the numbers into my suspension calculator, you probably weren't accounting for the jounce bumpers. (I don't know how you could, nobody has measured the Ohlins ones.) You have to be hitting the jounce bumpers on every bump with such limited travel even if you're not touching them already at your ride height. This pretty much invalidates the calculations in my spreadsheet because they assume a linear spring rate, not a progressive one. (Sorry, wait for revision 2!) Your real spring frequencies will be higher, especially up front.

That also means, going back to the coilovers, that your total spring rate is, at times, softer on a coilover with 400lb/in springs than it is on 275lb/in lowering springs w/ 275lb/in jounce bumpers. With coilovers, you'll always have 400lb/in (or 500lb/in, whatever you choose), but with lowering springs, your rate will vary between 275lb/in and 550lb/in.

The RCE replacement jounce bumpers are very soft initially but get extremely stiff after the first inch, even stiffer than stock, to resist the repeated bottoming out (this is why I prefer them to softer bump stops). I don't know what the Ohlins ones look like. The stock jounce bumpers are about 300lb/in, IIRC, for the first inch- getting stiffer thereafter. RCE springs are roughly 275lb/in, so you can safely assume your spring rate more than doubles when you hit a bump. This actually can ride pretty nicely (if the suspension doesn't bottom out too hard) because the suspension becomes very underdamped and rebounds quickly, but it does have performance ramifications. That's a hugely progressive spring rate.

If someone in your area has a set of quality coilovers, do a back-to-back comparison over varied roads and report back, please. Make sure the both of you have backed off on the valving to make it fair; when I sampled the Ohlins the adjusters were too stiff, skewing my opinion.

One more thing, if it's not too late- I'd recommend sticking with 17" diameter wheels and instead going wider.

[Draco-REX]

Originally Posted by stretch

Draco, the web site you refer to in your damper section is this:
DGs Autocross Secrets aka Autocross to Win

Yup, that's it. Lots of good info there.

I'm still not convinced that Ohlins struts make the ultimate street suspension, though, due to suspension travel issues. Even if the Ohlins added travel over stock, which I don't think they do, your front springs don't have nearly as much travel left in them as the typical coilover set. Coilovers can get you 3+ inches of bump travel versus about 1-1.5 inches on OE-replacement struts, and that travel is mostly bump-stop free.

Possibly true, however at the time I was ordering parts all of the coil over options were just plain overkill for the street. Now there's the TiC SST coil overs which are a great solution.

That brings me to my second point. When you plugged the numbers into my suspension calculator, you probably weren't accounting for the jounce bumpers. (I don't know how you could, nobody has measured the Ohlins ones.) You have to be hitting the jounce bumpers on every bump with such limited travel even if you're not touching them already at your ride height. This pretty much invalidates the calculations in my spreadsheet because they assume a linear spring rate, not a progressive one. (Sorry, wait for revision 2!) Your real spring frequencies will be higher, especially up front.

That also means, going back to the coilovers, that your total spring rate is, at times, softer on a coilover with 400lb/in springs than it is on 275lb/in lowering springs w/ 275lb/in jounce bumpers. With coilovers, you'll always have 400lb/in (or 500lb/in, whatever you choose), but with lowering springs, your rate will vary between 275lb/in and 550lb/in.

The RCE replacement jounce bumpers are very soft initially but get extremely stiff after the first inch, even stiffer than stock, to resist the repeated bottoming out (this is why I prefer them to softer bump stops). I don't know what the Ohlins ones look like. The stock jounce bumpers are about 300lb/in, IIRC, for the first inch- getting stiffer thereafter. RCE springs are roughly 275lb/in, so you can safely assume your spring rate more than doubles when you hit a bump. This actually can ride pretty nicely (if the suspension doesn't bottom out too hard) because the suspension becomes very underdamped and rebounds quickly, but it does have performance ramifications. That's a hugely progressive spring rate.

If someone in your area has a set of quality coilovers, do a back-to-back comparison over varied roads and report back, please. Make sure the both of you have backed off on the valving to make it fair; when I sampled the Ohlins the adjusters were too stiff, skewing my opinion.

Well, I worked with what I got. I'm hoping the Ohlins bumpstops or jounce bumpers allow for more travel than stock. But I don't think I need that much travel in general. Granted a large amount of travel would be helpful for the occaisional pothole, or if I rally-crossed. But the only time I would get into the bumpstops would be uder heavy braking. And so far, I haven't had any issues in braking zones. I've also driven hard over miles of really undulating tarmac without the car feeling upset. So overall I think this combo is acceptable.

There are some compromises in my suspension, but it was put together with an eye towards a car for DD purposes that would once in a while see a track or AutoX. If I were AutoXing as often as I RallyX the other car, I would have made different choices.

One more thing, if it's not too late- I'd recommend sticking with 17" diameter wheels and instead going wider.

Too late.





I agree that 17s would be better in general, but I like my form and function in equal amounts.

[mckman]

D-Rex,

Great write-up.

I think this is the shock dyno article you are looking for.

DGs Autocross Secrets aka Autocross to Win

[midnit]

Originally Posted by Draco-REX

I agree that 17s would be better in general, but I like my form and function in equal amounts.

Nice pickup, TE37s look sweet on STIs, imo. Check out mine

http://i127.photobucket.com/albums/p...en1_h_crop.jpg

[St-ill]

awesome write up.

[Saabaru STI]

nice setup!

I have Ohlins Sportlines instead of the struts, but everything else is similar.

I REALLY liked the subframe replacement. Let us know how that made a difference on your car.

[williaty]

Keep in mind, I didn't pull any HDR bull**** with Photomatix. The car is just that damned shiny right now.

[Draco-REX]

LOL.. I posted some pics of it in the Exterior forum.

Anyways, the RCAs went on today. Already, there's noticeably less body roll. Tomorrow I'll get the car aligned and then I'll update the RCA section.

[antonch]

Looking good, I am trying to decide what to do with my OBP exterior wise as well...I think I am liking the no-sticker look.

What ride hight are you set at?

[Draco-REX]

Originally Posted by antonch

Looking good, I am trying to decide what to do with my OBP exterior wise as well...I think I am liking the no-sticker look.

What ride hight are you set at?

The Ohlins are a fixed perch design, like the stock strut. So ride height is pretty much set.