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10-04-2018, 08:30 PM | #23 |
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cool.
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10-06-2018, 04:44 PM | #24 |
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Ok, so, your mileage may vary yada.
My mission here was not to have a dual duty car or anything like that, it was to have stockish spring rates and much better damping, and still have nice long travel like stock and a cushy street ride like I had with my MCS doubles turned all the way down, but without the cost and hassle of a remote reservoir dumper, and with oem mounting for noise and comfort and compliance and simplicity. The stock shocks and strut have way too much “memory” after an impact. Too many oscillations before damping it out. I am not using the Sachs rear springs or adjusters which appear to be 120N/mm same Part as the f80 kit. I’m using ZCP “X5” code rears) I have a Dinan bar set on medium with dinan camber plates at -2/1.6 camber front/rear. Square 275/30-19 Michelin PS4S on 220m rears, with a 5mm rear spacer. I set the front at the same height as I was at the other ZCP springs and stock shocks. The rear ride height did not change with the shocks (had Bilstein B8 before). All that said, MISSION ACCOMPLISHED. I should have done this 2 years ago. The car is just plain better in every way. Ride over small expansion joints, better. Big hits and curb hops? Better. Frontend is way more pointy, rear still very compliant and controllable (did NOT want more rear spring, my street car doesn’t need to be any more lively than it already is). Memory is now very short. One place that was always disappointing for a performance car was how upset the car got in big displacement events like a dip followed by a bump. Totally unsettled the car. That’s gone. One impact and it’s ready for the next one within a tenth or so And there s a ton of adjustment range left. My biggest positive surprise is how nice it is over concrete slabs at neighborhood speeds. The MCs were always excellent there and the stock strust and shocks were harsh. Back to magic carpet ride. (Relatively, still has 30-aspect ratio 19’s on it) Anyway, yeah. Good stuff. If you want a nice riding street setup to replace your aging non edc car’s suspension for not muc. More than replacement stock dampers this is a great deal. It is not near enough front spring for r-compound track use imo because you’ll want more camber than is optimal to keep the outside shoulders happy. But they seem to have enough damping to “handle” much more than the spring I have on the car. They are turned down very close to all the way 5/20 and 6/20 front and rear. So, maybe. I probably will never know. Woop
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10-06-2018, 05:55 PM | #25 | |
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10-06-2018, 10:10 PM | #26 |
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I’m sure tires would be happier with the stiffer front spring and extra camber from lowering a bit. But I would not buy this kit with track use as even a secondary concern. The front springs are progressive and below 300lb/in when most people who do tRack setups land at 500+
I may one day use this car for One Lap but that’s about it. And cushy transits are just as important to me as Lap Times because old
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10-06-2018, 11:58 PM | #27 |
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Sounds like what I am looking for. Thx.
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10-07-2018, 12:12 PM | #28 |
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Another note: you have to find them on the Sachs website and download the instruction install pdf. One of the links is broken on the product page but it’s on there on the bottom. And it’s multilingual.
I derped my way to a few do-overs forgetting or deciding washers didn’t go where they go etc. long story short- you use the entire stock mount front and rear including washers/bump stop cups Fasteners which differ from stock: Upper strut mount bolt is 7/8” instead of 21mm Upper shock pin has two flats on it which means you need an adjustable wrench or a small combo wrench (my set goes to 7mm and it was too big) plus a ratcheting 16mm wrench for the top mount. Everything else is same fastener sizes as stock I didn’t need my spring compressors to install up front but I did (as usual) need them to get the stock springs to fit past the fenders on removal
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10-10-2018, 06:37 AM | #30 |
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Richbot: "All that said, MISSION ACCOMPLISHED. I should have done this 2 years ago. The car is just plain better in every way. Ride over small expansion joints, better. Big hits and curb hops? Better. Frontend is way more pointy, rear still very compliant and controllable (did NOT want more rear spring, my street car doesn’t need to be any more lively than it already is). Memory is now very short. One place that was always disappointing for a performance car was how upset the car got in big displacement events like a dip followed by a bump. Totally unsettled the car. That’s gone. One impact and it’s ready for the next one within a tenth or so"
Agreed. Had these installed a couple of weeks ago and sorry I didn't do it sooner. Better in every way says it all. Still adjusting front to get height where I want it. Dampers set at +12 front and +6 in the rear, similar to most advanced setting on edc but more compliant. I would swear that the springs are H&R by the way. Nice write up Rich. |
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10-11-2018, 09:35 AM | #31 |
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I have settled on +4 and +4 front and rear for mine. For performance driving I'd want a bit more, and if I still had the 17's on the car I'd probably want more too because those add a lot of flex, but with the 275/30-19's square, I want the extra compliance over small stuff.
Adjustment up front is easy, just turn the wheel all the way to the stop, make the adjustment, turn the other way, make the other adjustment. Rear requires you to reach around and find the lower shock mounting bolt blind and then move your hand up to find the adjuster. Not quite as easy-peasy, but still much more doable with the car on the ground than I was expecting. But again, keep in minnd I'm using the stock ZCP rear springs, ~550lb/in vs. the 685-ish springs the kit comes with, and I'm not lowered at all up front. If I'd lowered the car I might want a bit more. I have almost 1000 miles on these now and I don't think the front springs are going to settle any more, and it's still *slightly* by like 1/8" higher than it was before the front coilovers went on, so I may lower it a few more turns up front, which will mean I also have to move the swaybar mount...ugh, which means I probably need to shorten the endlinks, which probably are all seized from being used on the car 90,000+ miles (bimmerworld links). Now that I think it through I may just put it on my scales before that and see where I am cross weight wise and if it's close, not mess with it. On the stock ZCP springs and non-EDC dampers it was always right at 51% with me in it. Good for stability on ovals...lol I did manage to hit the bumpstop on the left front over a really bad concrete chuck/heave on the highway, and nothing broke, so, yay.
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10-18-2018, 11:30 AM | #32 |
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Just a bit more info:
Lowered the front a bit more, My initial setting was about 3mm higher than it was with the stock struts. dinan plates and ZCP X6 front springs, now 6mm lower than it was (so, basically, stock no-plates ZCP height because the Dinan plates add about 6mm to the stack height). Rear height is identical to stock ZCP, as it should be with just a shock change The perch could go about 18mm lower. It's got plenty of room to the tire (275/30-19 front Michelin PS4S on square 220M rear 9.5 et23). But like the KW's et al, would need to convert to a shorter spring to keep the perch up high out of the way if one wanted to run a shload of front wheel with these. If you're doing that with these, you're probably missing the point of them. I think your basic ET25 10" wheel should work with most street tire 275's, and certainly with a spacer. There's room for my finger in between the sidewall and spring perch TIGHTEN THE SET SCREW ON THE SWAYBAR ENDLINK BRACKETS If you don't get it all the way tight (using a standard 4mm allen, so not like you're torquing to a million ft-lbs) it will clunk and you will think the car is about to fall apart. I thought I had it tight but I didn't after lowering the car and drove it and was ready to burn the whole car to the ground until I found the loose set screw SACHS docs also show the lower perch shnugged up tight against the swaybar mount, so that's what I did. The install instructions are terrible.
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10-25-2018, 09:15 AM | #33 |
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Finally took it over one of the on-ramp yumps that would completely unsettle the stock suspended car in 2nd gear.
The butt didnt fly into the air like it did with the stock shocks and with the B8’s. It Didn’t even break traction, WOT at 6500rpm in 2nd. In the past it would just spin up the tires and then bog as it caught trAction again going 2-3mph slower than it was before it hit the yump. With traction control on the car would just fall on its face on the old setup because it was such a severe loss of traction, now it’s just a flash or two. I almost hit the limiter because I was so surprised it was still accelerating. And it’s 48 degrees out. That was my final “was this a dumb expense or not” test and it was not dumb. Yay! But, caveat, stock ZCP rear springs. Not using the 20% stiffer springs that come with the kit. I would think it would be a bit more skatey over bumps with a stiffer rear spring. |
11-05-2018, 07:05 PM | #35 |
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I wonder how much different it will be using the Sachs rear spring... I have gotten rid a lot of my toys so this car needs to be acceptable on the street, have fun at hpde and while not caring about breaking track records. I have Ohlins DV and they are terrible at low city speeds, ride good at highway speeds though
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11-05-2018, 07:55 PM | #36 |
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48 n/mm is the best (in german) I could find for the front, it's progressive who knows if it's even accurate, and the rear rate looks like it's 120
Edit : nope that’s F8x, see below or correct E9x M3/1M ra
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12-03-2018, 04:42 PM | #37 |
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Sachs/ZF engineer just got back to me
The correct spring rate for the E9xM/E82M’s (linear front and rear according to the docs) 54 n/mm front (about 308 lb/in) 120 n/mm rear (about 685 lb/in) Also sent me a shock dyno which is very interesting I’m askig permission to post. The adjustment range mostly changes the shape of the curve in small displacement rebound on the rears and the front adjuster has more impact PUN INTENDED on both rebound and bump So, front spring is 10% softer than the next “softest” springs in a kit I know of, the Ohlins R&T, which is 60n/mm front 120 rear Still digging these. Pretty damn awesome dampers. |
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12-04-2018, 09:13 AM | #38 |
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Here's the data sheet for the Sachs coilovers, with damper dyno plots, posted with ZFNA's permission. DOn't know why they don't send this for all the vendors to put right out front on the website, or maybe they did and the vendors just don't bother, who knows. I think there is a link to this paper on Sachs' website but it's broken. Anyway, enjoy. They use 0 clicks as the reference point for full stiff obviously. I'm checking with them what convention they are using for the dyno plot (is negative for bump or rebound force (EDIT: Yep, uses the typical convention) but typically, negative is rebound. Rebound and compression are progressive at full soft up front, and go stiffer and digressive as you adjust. The rear doesn't seem to change rebound much at all, only compression. The "knee" is about where it is on most dampers, around 1-2 in/sec which is the unit used on most domestic dynos you'll see
I'll have to double check my setup sheets but if I remember right, I ran my MCS setup pretty close to my street rebound settings and jacked the compression damping way up on the track/autocross, but without same-day dyno plots who knows. I do know I like how these behave, in general, on the street at lower (4-5 clicks from full soft) settings. IIRC on the Ohlins plots I've seen, they are never all that progressive even at their softest settings and this may be why some have reported low-speed ride complaints on the R&T
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12-04-2018, 03:02 PM | #39 | |
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03-24-2019, 09:38 PM | #42 |
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I assume the answer must be yes, but did you cross-shop these against the more common coilovers for our platform such as Ohlins, KW, etc.?
What were the deciding factors in favor of the Sachs set-up? |
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03-25-2019, 11:05 AM | #43 |
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- Rubber lower shock bush, stock mounts front and rear
- Not too much front spring - Fewer moving parts (single damping adjuster, no strut length adjustment) - 25%+ cheaper than the other options (because a simpler design see above) - OEM supplier of the E9x suspension Believe the KW3 uses a progressive front spring which means the rate is a bit of a black box
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