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I swapped to Flex Z coilovers for anyone wondering if I stuck with the Basis Z. The Flex Z is a night and day better product for only a couple hundred more $$$. No strange noises, and it isn't too rough (dampening set to 12 out of 16, 16 being stiffest) but feels much more planted with even less body roll and handles bumps and dips amazingly. No rubbing issues anymore even with my 10.5" +23 rears with 275/35 tires.
If you are considering either, get the Flex Z - it is a much, much better system that is fully adjustable and made in Japan, not China (not saying the Tein products from China aren't quality, but you get my point). The welds and quality look much more solid. Mine came correctly preloaded and tightened from the factory, so all I had to do was adjust the dampening and also the rear spring height before the install. The rears are a bit of a PIA to adjust properly thanks to the divorced rear suspension design of the G/Z but once adjusted properly they ride like a dream. It should have come this way from the factory- I wouldn't call it jarring at all (maybe if you've driven plush sedans and SUV's for years?) and in my opinion feels very close to the OEM suspension on my BMW 328i (f30) with sport suspension.
Curious to see how the Flex Z will handle a few track days soon enough.
Updated with pictures of how my car currently sits.
I finally got my Tein Street Basis Z coilovers installed on my coupe about a month ago now, with the help of a friend. The install was very straightforward and really wasn't too difficult once we had an impact wrench. I'll try to list out all of the tools we used below to help anyone else looking to install these, but will probably miss something so let me know if you have any q's at all about the install or the coils/ how they ride. I ordered them from ImportPartsPro (part # GSP92-8UAS2), along with some SPC Xaxis rear camber arms (Part #72262) that we installed at the same time; the pricing was fantastic and they did a great job with shipping it out ASAP w/ 2 day shipping. Great customer service even when I was a PIA and thought about returning them for the Street Advance Z, which I'm glad I didn't do at least for now bc of the roads here.
Install- I followed Tein's instructions and a couple DIY's here on the forum for the install. Started in the rears with a floor jack on the pumpkin, then used 2 jack stands also for safety and got everything loose with just a breaker bar, and it ended up taking maybe 3 hours for both sides with no power tools. We used your basic metric open ended and deep sockets, a ratchet, a torque wrench and a rubber mallet. Tein included some pretty good instructions for what they were, with plenty of reference information regarding proper heights, torque specs, and adjustments. The top nuts on the dampers were probably the most difficult to tighten properly, until I ordered a part for $25 from a Mustang website (Steeda, I'll attach a link below). That tool allows you to hold the damper rod with a vise grip (in the notches at the top of the threads) while you tighten the top nut down with a torque wrench. It made things much much easier for the new Tein dampers after we swapped out the OEM top hats. I also went ahead and eyeballed the settings of the factory camber arms and then matched them as close as I could to my new SPC arms. Once I got it buttoned up, we dropped the car and took in the amazing reverse raked look
On to the fronts and the finishing touches, the install was again very straightforward and simple, and this time we had an impact wrench so it took half the time. Jack stands are a must for safety for the fronts, please don't try this using the emergency stand that is in the trunk, all though we did use that as a backup jack in addition to my floor jack with the stands. One of the biggest takeaways I learned during the install was that you absolutely do NOT need a spring compressor for the OEM springs when you go to remove the top hats. I had read one or two mentions on the forum about not needing a spring compressor for the OEM top hat removal, so I decided to give it a shot without using the strut/spring compressor that I'd rented for free from autozone. It barely jumped an inch- perfectly safe. Keep in mind I was on the OEM Sport suspension though - if you are coming from aftermarket springs that won't be true or safe to attempt. We finished installing the new front Tein coils, dropped it and took it for quick spin. The difference was immediately noticeable for me- such improved steering response and it goes exactly where you point it now with no understeer. It really should have come like this from the factory. It did settle out a good bit over the next hour of driving and sitting, and it was so insanely out of spec it was very squirrely to drive. I let it settle a slight bit more over the next day, made some final height adjustments, corner balanced it, and then had an alignment done w/ one of the nicer Hunter alignment machines in town and got everything right at 2.1 in the front and 2.3 in the rear. I set it almost to the max of Tein's low recommendations, and will try to measure floor to fender again tonight if anyone is interested in those measurements. I'll try to find the alignment spec sheet also when I get home and upload that too, but the alignment fixed all of my issues and I even had no problem w/toe at all which is what I was mainly concerned about.
I was heavily considering the Street Advance Z model vs the Street Basis Z, but am really happy with the Basis Z especially at the insane price people have been getting them for. I do want to say that I think the Basis Z is made in Tein's China factory now- I had read otherwise on the forum but found a news post from Tein somewhere (I'll try to find it) that said their springs and basis Z models would be made there, not in the Japanese plant. Don't quote me though lol, the accuracy of that could be quite off. I still stuck with Tein regardless bc I used their springs in the past on my G35 coupe and have only heard great things about the quality of their products and their quality control. For rough roads, I definitely think it holds up over all the bumps, cracks and potholes. It definitely feels a little bit more firm than the OEM sport suspension and you will feel every crack a little more, but it seems like Tein did a pretty good job matching the dampening to the springs on these for not having the ability to adjust it. I think that had I gotten the Advance Z, I'd have to set the dampers to almost the softest settings and it would still be too rough/firm or bouncy for the crap roads here in Wilmington NC. The rears do seem to get bouncy on bumpy roads, but no worse than stock or in any other lowered car. Very happy with my decision and until I can afford to risk breaking my car at the track, these are fantastic coilovers for the street and spirited driving. I can't wait to see how they do once I get some Hotckis sways in a couple months also. I have some Z1 extended studs and 20mm hubcentric spacers that I've been meaning to install also to fix the even worse fender gap after the drop now, so I'll post more pictures once I get those installed also, I just haven't had much time lately. Cheers.
The box was in decent shape but not packaged too well by Tein as others have also said. Everything arrived in good shape though. After the install without making any height adjustments yet.
Post install pictures, sorry they're awful. Better ones are below. Current height. 26.25" ftg front, 26" ftg rear. Current height. 26.25" ftg front, 26" ftg rear.
Hi I’m very new to coilovers and I’m looking into getting tein basis or flex. My concern is that I don’t want to go too low since my driveway is steep. According to Tein’s website, the initial drop before adjustments is -1.8” front and -1.4” rear. I measured my stock height at roughly about 28.75” FTG front and 27.5” FTG rear. I only really want 1”-1.5” drop from stock height which isn’t really possible in the front at least because the initial drop is -1.8”. In the pictures you took with height of 26.25” were your height adjustments at the max high setting? I’m assuming you got that ≈2.6” drop in the front through initial drop -1.8” plus max high setting of -0.8” adding to 2.6”. But, how did you get the rear to be 26” if the initial drop of -1.4” and max high setting of -.6” would be a -2” drop which would put you at shout 25.5 FTG in the rear? Or am I understanding all of this incorrectly?
Hi I’m very new to coilovers and I’m looking into getting tein basis or flex. My concern is that I don’t want to go too low since my driveway is steep. According to Tein’s website, the initial drop before adjustments is -1.8” front and -1.4” rear. I measured my stock height at roughly about 28.75” FTG front and 27.5” FTG rear. I only really want 1”-1.5” drop from stock height which isn’t really possible in the front at least because the initial drop is -1.8”. In the pictures you took with height of 26.25” were your height adjustments at the max high setting? I’m assuming you got that ≈2.6” drop in the front through initial drop -1.8” plus max high setting of -0.8” adding to 2.6”. But, how did you get the rear to be 26” if the initial drop of -1.4” and max high setting of -.6” would be a -2” drop which would put you at shout 25.5 FTG in the rear? Or am I understanding all of this incorrectly?
Also, nice write up. Very informative.
You can actually go higher than the recommended settings, it just might decrease the ride quality slightly or decrease the life of the dampers, especially depending on which coilovers you go with (ie the Basis Z). You also have to be careful with the Basis Z when you raise it to not decompress the spring too much- there always needs to be 5-10mm of preload on the springs otherwise they will rattle and eventually fail/blow the dampers since the spring would essentially be floating until a big enough bump is hit to compress it- hope that makes sense. I honestly adjusted it so many times after the first install I couldn't remember what heights it ended up at but I want to say I was around 25.5 or 25.75" ftg in the front and rear when they were removed, which was too low for the Basis Z. It caused a lot of bounciness and rubbing in the rears when I installed my rear 19x10.5 +23 work wheels- had I raised it half an inch to an inch it would have made a big improvement in ride quality. I have my old set of Basis Z with 10k miles on them boxed up I was about to list for sale if you're interested, but totally understand if not after reading my thread and comments about switching to the Flex Z, lol.
The Basis Z is only height adjustable and when you adjust the height you also change the preload and dampening characteristics, so I'd only recommend the Basis Z for a small drop, somewhere in the middle or higher side of the Tein recommended heights. Some are fully independent adjustable (dampening, height, and preload like the Flex Z I have now and others like BC racing, Fortune Auto, Stance), but the way the OEM rear suspension is engineered on the G/Z it uses a divorced setup (spring sits separate from the damper in a spring bucket behind the damper) so if you go with a fully adjustable setup you always have to adjust the length of the rear damper to match the height of the spring after you adjust it. Only Stance, HKS, Fortune Auto and a few other companies make "true-style" rear coilovers for the G that eliminate the spring bucket and cost anywhere from $1,300 to $4,000, so it's a slight PIA to correctly adjust the rears of the Flex Z and most other fully adjustable coilovers for the G unless you really pay up - but if you don't need to adjust height often after you get it where you want it just set it and forget it, like a lot of people on coils do including myself. Those recommended settings are just the general drop Tein recommends for the install before making any adjustments later, but you definitely don't have to stick to what they set it to/recommend. It does give you a good starting point though to raise or lower it from their settings. The Tein Basis Z are considered a mild drop solution if setup correctly, and aren't really meant to be slammed or raised too far past the recommended settings. The KW V1 is a better solution for a small drop (Front: 0.6" to 2.0"; Rear: 0.4" to 1.7") but are significantly more expensive. If you don't have a ton of mileage on your OEM suspension I would consider a set of Swift, Eibach, or Tein lowering springs also, since that's a little cheaper and sounds like it could get you the heights you're going for, but coilovers are worth it if you're eyeing them. I had Tein lowering springs on my old G35 coupe and loved them while I had them, and the Basis Z was great for city driving and cruising. The Flex Z is a different league though and allows you to really fine tune everything. I'll eventually swap from the Flex Z to a true-style rear coilover from either Stance or Fortune Auto with Swift springs, maybe HKS, but for the price IMO the Flex Z is the best option. I don't trust BC still and have been reading about them for a decade, but that's just me personally- some people say great things about them.
10-12-2020, 01:42 PM
