So, I'm probably just missing something totally obvious about how these go together. I look at these and think the springs are too short. If I understand correctly, the nut goes over the top hat (not in picture - still on car) and the upper spring perch comes to the bottom of the top hat. Isn't the spring supposed to be under tension once that's all assembled? Cause, these look like if the nut is all the way down and a top hat was under that then there would still be a gap between the upper spring perch and the bottom of the top hat. Or is the top hat thicker than I'm thinking? Or am I missing something else here? Also, it looks like I will have to cut off the spring perches. On the rear strut, there's only 5/8" of travel from the top the sleeve to the point where it hits the strut's srping perch. Over that range, the top the tapered part of the upper spring perch is 1&5/8" - 2&1/4" from the bottom of the threads for the nut. Is the top hat thicker than that, so that the spring will be under tension when its all together? Or does it not work that way? The front strut has less space at the top of the strut shaft. I hope the 315 lb/in 9" front springs aren't too long actually - some have suggested they may be. There is more travel on the sleeve, but there is still a lower point where it hits the strut's spring perch.
using a stiffer spring means it doesn't compress as much. which means that it doesn't have to be as long as the stock ones for the same ride height. so they won't need preload (which is when the spring is compressed a bit to assemble the strut). This is pretty normal. I'm not sure about the spring perches. I left the perches on my front struts (my rears are completely different...), and don't get anywhere near them, of course, I'm running 8" 250 lb/in springs, so it's a bit different.
Okay. Wasn't sure if that was normal. I had it in my head that you would always have preload. So then the stuff must all compress and seat in and tighten up and what not once it's under weight? Must have to finish tightening that top nut once it's loaded then, too, right?
Ever notice the dual spring setup on many coilovers? The small one is called a "tender spring" and its used to keep the main spring in place when under full droop travel.
Ooooh ... (light bulb goes on, maybe). That's what those "helper" springs are for?? I've been wondering that. Okay. So, I'm guessing I won't see full droop on this setup unless I unexpectedly go all Dukes of Hazard sometime. But if that ever changes that will be an issue. I think I get it now. Does that "tender spring" act like a low rate spring for small bumps too? Smooth out the ride? Or no?
Yup. My rears are actually almost fully compressed with the car jacked up do to the ridehieght I used to run at, which is still an inch low with my H&R coilovers. When I get everything in another shell I'll lower it a bit for a smoother ride and less stress on my dampers, as running them close to the top is really hard on dampers.
yea, compress the shock, by hand, the few inches extra. now, see how long it takes for it to extend the rest of the way on it's own. you don't expect to entirely unload the suspension for that long, while driving it, do you?
In the end, you don't want the spring to sit loose. When you put together the strut, you want at least a tiny bit of preload, i.e. just enough so the spring doesn't flop around and move where it shouldn't. On most aftermarket springs, you will find that the preload is almost nil, allowing you to install and remove springs without any spring compressors.:biggrin: With the type you have, you have to make sure they are long enough or that you take out enough slack with the thread adjuster to not have any play. If the spring can not do this itself (too short), you would need a helper spring to take up the rest of the slack. Any bump stops going on that strut? Does the dust boot even fit under that spring? Worried about excess wear of the seals from the shaft? Small note on D-Spec setting. You should be right around 2 full turns from full hard on that spring rate.
Well, as it is - it seems like there will definitely be slack between the top of the spring and the bottom of the top hat - even with the lower perch on the sleeve all the way to the top. If I need helper springs, is there somewhere locally I can pick them up quick - install's scheduled for Sunday. I am cutting the stock bump stops and putting them on at the time of install. Also, I will be picking up some bigger dust boots from NAPA that actually go over the spring. Part # provided by some guy on NASIOC who put GC sleeves on D-Specs last year. Also, there's some metal caps that go back over the seal - just had to hammer them off to put the sleeves on. Definitely want those nice struts protected from grime!! So, do we have a local shop that would have helper springs in stock and how much is something like that? Can anyone say if I would definitely need them? My initial thought was that the strut/sleeve/spring/top hat assembly should be kinda tight when all assembled and it definitely looks like I can't achieve that unless the top hat is quite a bit thicker than I think it is (never seen one just laying around ).
No, of course not. But will that slack be okay when assembling, or do I need to take it up with helper springs? Can I leave it loose, bolt it into the car, put the car on the ground causing the strut to compress and the spring to push up against the top hat, then tighten that top middle nut down?
Just tighten the top nut and then once its bolted on the car take the impact gun to the top center nut, mine just came loose today and made a horrid clunk, a quick tightening of the nut on the car took care of it. The shocks will compress and will take up the slack in teh shock stroke, don't worry about helper springs.
Eibach has tender springs, but they are spendy. Whiteline has them in their catalogue, but I cannot find them in any webstore, so you will have to talk to a Whiteline dealer.
yea, it's really not a problem. my old sleeves had like 3-4" of travel without the spring touching. it's not ideal, but for street use, you won't notice.
Chux, you're running the GC sleeves on stock struts, right? Did the adjustable lower perch on the sleeve run into the spring perch on the strut? If so, did you cut them off or was it not a problem because you need to run them close to the top of the sleeve anyway? (IIRC, you had suggested the 9" because the 8" were kinda on the short side for you) I wasn't too keen on hacking up the strut bodies, but I guess cutting a perch off isn't a huge deal (unsprung weight savings FTW lol). I'd lose the ability to ever run some regular ol' big diameter springs, but that's why I have the sleeves in the first place.
yep, stock '92 FWD legacy front struts. left the perches as-is, and have zero problems. we'll see once I get the AGXs on there.
Ah yea, good luck with that... That does not look like a proper fit. Has this ever been done before on those struts?! The front will have preload and the rear will be loose and rattle (at best) whenever you have droop travel. Remember, struts travel in both directions from their 'resting point'. ...not to mention the loss in suspension travel. Christian (runnning D-Specs on the STi)
Definitely been done. There's a fairly thorough write-up on NASIOC and a less so thorough write-up on rs25. I am still confused by why there's such a difference in the gap for the fronts and the rears (rears having a much bigger gap). Wish I had a set of top hats laying around. I mean, if the rear hats are thicker proportionately then it would make sense - but I've never really seen top hats (besides web pics), so I'm just completely pulling guesses out of my rear at this point.
I just noticed your thread bro. Are these what you're referring to? http://forums.nasioc.com/forums/showthread.php?t=1597523&highlight=ground+control http://forums.nasioc.com/forums/showthread.php?t=1216901 When you come over sunday just arrive early enough so we can experiment with the rears.
I'm using the exact same strut/spring combo as InsatiableAmos on RS25, but without the helper srpings in the rear (which I forgot he used - makes me feel a little better seeing that now). He seemed to like that setup up an awful lot. I can't imagine how freaked I'd have been with the 8"s they recommend. Thanks to Chux and the others out there on the interwebz who helped me avoid that. Funny, though - I read in a couple different places just this week where people thought the 300+ lb/in 9" springs would be far too long for the fronts, at least. The NASIOC guy tried some really long, soft springs (like 10" front, 12" back - around 200 lb/in) and it didn't work very well for him. He had to reweld a spring perch on a couple inches lower to make it fly. I'm constantly plagued by utter lack of knowledge and experience when it comes to vehicles, but I'm guessing by the time the install's done on Sunday I'll have a lot better idea of how this stuff fits together!! Another question. If helper springs are so soft/compressible, do they end up fully compressed when loaded with the vehicle weight, basically turning into a solid chunk of metal? I see InsatiableAmos used 0.8kg/mm springs, which by quick (and therefore possibly entirely incorrect) calculation is roughly 90 lb/in. Not that it should really matter, I'm just curious. EDIT: Ahhhhh .... and rereading some of my bookmarks on this subject (man its hard to keep track of all the tidbits on the interwebz), "Finally, in regards to the stroke length of the D-Specs (and i imagine HTS002's), the fronts are about the same as the stock KYB subaru struts, while the rears are WAY longer. " (from IA) That would explain why the rear strut piston extends so much above the spring on the rears. Okay, I'm thinking now that I'm going to be just fine.
So here's the conclusion: I've got the perches on the GC sleeves down as far as they can go without hitting the perches on the D-Specs (which did not get cut off - yet). If the perches were cut off the D-Specs I could get a couple more turns downward on the sleeves. There was a small bit of preload on the fronts created when the top washer was tightened down. The rears, however, were loose and had a good sized gap. They bolted in fine and did not pop or clunk or rattle at all. Appears to be working perfectly. As it sits now it is about stock height, maybe a bit lower and possibly still sinking in a bit. So, the 9" springs at those rates (315 lb/in F, 280 lb/in R) could've gone 8" and been okay too, I'd guess. Might not be able to go maximum low with the 9" springs. Could certainly go higher than stock, though! Also, the car is pretty much unshakeable. That thing is planted. As a side benefit, it absolutely skis over snow. Breaks lose on snow in 2nd and even 3rd like wrexinators taxi did when the turbo hit hard. Can't exactly say that's safer, but it is funner. It is pretty bouncy, though, especially under 25mph. I'm not sure I'm finding the right damper adjustment spot yet, but that's been slightly confounded by snow pack in the wheels on the highway (wobble, wobble, wobble). I've been ranging from 1&1/4 turns from full hard to 3 turns from full hard. Seems like the softer settings were really prone to continuous bouncing - especially on the highway. I think that means its underdamped - it felt kinda like uncontrolled spring oscillations - but I could be wrong. Higher settings felt less bouncy, but way up at 1&1/4 it was stiff enough to be hopping off bigger bumps. It's at 1&3/4 front and 2 rear right now, but that was feeling bouncy too. Oh - and it appears scooby921 spacers would've fit perfectly in the rear top hat, but we used a couple 16mm inner diameter washers from Home Depot. They were needed to fill a gap between the washer going on the threaded top of the strut piston and the top hat.
Turn them softer (4.5 turns I think) until they break in....then go from there. For reference, I am running Swift R-Spec springs on the STi and I run about 4 turns from hard in the back and 4.25 in the front...
^ Do you know the spring rates for those Swift R-Specs off hand? Also, I remember reading online about the break-in setting for the D-Specs, but it wasn't mentioned in any of the instructions actually included with the struts. Nevertheless, I dialed them down to 4.5 turns from hard and it felt much, much better on city streets. Will have to wait until later to see how that play out on the highway.
