Been looking at these 2 options, and wondering if anyone has experience of these suspensions.
Both the B12 ‘fit & forget’ and the higher spec Tecna GT appeal, and if I’m honest I’m thinking of doing this for largely cosmetic reason, but happy to pay for either kit without lots of NVH, which seems to happen with higher spec kits.
What I have read on USA and German forums.
B12 kit -With Eibach pro kit 20% stiffer springs and proper Bilstein B8 dampers, not the Mazda factory Bilsteins (which many find harsh). 25mm lower approx, but will put you 10mm-ish from the start of the bump stops? Like the GT86, MX-5 clever use of bump stops to change spring rate works well at factory height, but with reduced travel? Compared to factory springs these shouldn’t feel too harsh, but I will be losing 25mm of travel? Will the spring rate compensate for the loss of travel?
Tecna GT - Bespoke made and tested monotube damper kits by 949 Racing, raved about in the US for damper control and comfort, but not seen anyone talk about them in the UK. 6K 3k spring rate which is double factory springs, how will this feel on poor broken UK B roads??
I know the 2 options are like apples and oranges, but 30mm lower is 30mm lower, just achieved in 2 different ways? I loved my GT86, but the B16 introduced a busy NVH feel that became tiresome after a while on long trips. Was that because Bilstein are a large company making a product to fit a car instead of designing a package correct for a car? Or just the GT86 NVH?
Any feedback or thoughts on these two would be great and how 6k 3k springs feel in the real world with good dampers?
Well, OK, you can, but it’s going to cost a lot more than that.
As soon as you start moving away from the work that dozens of engineers put in over years of development, in favour of finger-in-the-air guesswork and forum suggestions, you’re opening the door for all manner of unwanted outcomes.
Remember, your Toyota was also a tin-top with much better inherent stiffness, your suspension had less work to do and still it wasn’t to your liking.
Someone on here will invariably follow me up with “ah, but I use X with Y and it’s exactly like being stock”… I’d wager if they got back in a stock-suspension car they’d struggle to not concede on that.
Bottom line: You cant take 30mm of travel out of your struts and expect it to ride the same.
All very valid points, but I wonder if there is something that gives up little but offers the most, more sliding scale, than black or white?
which is the least worst option I guess, low spring rate and lose travel, vs increase spring rate but high quality dampers?
Like you say very few admit to buyers remorse, I’m the same sometimes, but many are happy with the compromise I guess.
The issue I have with more expensive suspension is that as the price goes up, so does the spring rate, as the suspension manufacturer assumes, often correctly, that to spend more you must be an avid track day user so spring rate increases. Or they have maintenance requirements because of low friction seals etc.
I don’t really want to do track days anymore, especially in the MX-5.
It’s true, the pricier ones do tend to go that way.
I think, if memory of the BOFI site serves, some of the manufacturers will give you options on spring rate on their higher-end kit.
Given the price of a replacement OEM Bilstein, we should be budgeting about £400 per corner to have any hope of being superior to what was already in place.
I speak from the position of someone who wanted a 25mm drop and now has to scan the road for every imperfection. Some people find that an acceptable part of the trade off though.
I know what you mean about scanning the road, even in our other car with uprated ARB, bushes and shocks B6 (so mild) I still look for the path of least resistance. lol.
I had a look at Bofi will have another scan on the site, thanks
We test drove the MX-5 with factory Bilstein dampers and didn’t enjoy it, (really harsh) and through google searching you can see the Mazda Bilstein dampers, look different, possibly outsourced to a price point?? The top cap where the piston shaft comes out differs between the two. The Bilstein B8 look nothing like the Mazda Bilstein dampers, wonder if they feel significantly different?
TBH when my wife and I are in the car (11 stone me and 8 stone her, so not heavy), it seems to drop about 20+mm so its likely only a visual thing when looking at the car with no one in it, Probably…??
I forgot about that option but if I remember I kind of ruled it out sometime ago, because when I did speak to BBR I didn’t feel the info was very in-depth about the revalving damper information. Not that I wanted specs, but what did they try to achieve with the revalve etc. but didn’t get anywhere. I have read on USA forums that most seem to run the koni dampers at nearly full soft, and the adjustments was therefore largely redundant?
Good to hear someone likes them, do you run the BBR at nearly full soft too?
As far as I understand it, the Koni option BBR offers isn’t adjustable?
The BBR Koni option sprang to my mind as a suggestion for you as well, but I think you’d have to have a journey out in an equipped car to see for yourself. Given different suspension options, for different people, on different surfaces, is entirely subjective.
I’ve run B12 kits on other cars previously, but I haven’t seen much, if any mention that I can recall, on an MX-5 (ND or otherwise). However, just changing to Eibach ProKit springs for that 30mm lower ride height is a popular option. You may be able to sample that in a local member’s car if you’re lucky, before committing. And just changing your spring setup would also allow you to evaluate if you’re happy with any change to the ride compliance and to NVH, before considering any change to the damping.
Not a bad idea about the springs first (apart from cost)
I wonder if the B12 kit is perfectly good enough with a slight drop? But because of the Bilstein supplied from the Factory onto the MX-5 many may be put off, even though I’m sure the dampers are worlds apart.
I’m always reluctant to change just springs, apart from in my youth when I had little knowledge and budget (I even cut them ) Although I understand knowledge is a dangerous thing too! But would prefer to fit a package.
I’m not in a rush, mainly as I’m reluctant to mess up something that took years to fine tune as Goodj says. But appreciate that what engineers and testers want often differs from bean counters want, so everything is a compromise.
I have been waiting for the Germany forums to get TUV for the Tecna GT kits as they seem to be more into modifying (one topic on lowering is 200 pages long, and an Ohlins thread is 69pages).
I think no one has yet asked the most important question. What are you trying to achieve with this update?
What are the things in handling specifically what you are looking to improve and what are the compromises you are willing to make to achieve it?
Or do you just want an upgrade, which is perfectly ok in my books at least. Car is our pride and joy and we want to leave our mark on it.
As a disclaimer, I have not yet accumulated any hands on experience on car suspensions, but I have fiddled with motorcycle suspensions quite a lot. Also I’ve been learning a lot of theory about the car suspensions lately on my quest for removing some body roll without sacrificing too much comfort.
All the theory I’ve learned recently seems to align with what I already know about bikes. Superior handling and comfort are mutually exclusive. Ok I’m oversimplifying here a bit, but I make an assumption you are not planning to buy fully adjustable suspension with custom springs done to your specific needs.
One thing that also always annoys me is calling shocks harsh without specifying on what conditions. Is it harsh driving in city, on b-roads, on track?
All of these need different kind of things from shocks. On a race track harshness can be because there is not enough slow compression and the harshness is because travel runs out. On the b-road it can be because you have too much slow compression and suspension can’t settle enough. And I’m talking ONLY shocks here, springs, travel, ARBs, control arms, tyres etc. adds a whole new level of complexity to the mix.
So asking is A better than B without understanding what better actually means to you, is very difficult thing to answer.
If it helps, I have 949 Racing’s Xida fitted to my ND with GT spring rate (6k/3k). They supposedly have similar handling characteristics to Tecna’s which weren’t available at the time I bought the coilovers directly from them.
The car is lowered approximately 25mm compared to standard and the following were my initial impressions:
Noticeably smoother over minor road imperfections
Added sense of floatiness while remaining firm and more compliant
Good question, I feel sometimes difficult to answer.
If I change to reduce arch gap I would like a higher quality damper with the lowest spring rate to allow it to work on broken UK roads but won’t bottom out. However higher price tends to force you into 8k 4k or 10k 6k plus spring rates, and sometimes force you to service the units too which I don’t want. JRZ, Ohlins, Nitron Xidas were all excluded because I don’t need something that high end for road use really if I’m honest. But also don’t want cheap £800 coilovers which will likely have poor internal components.
Hence my thoughts about a Bilstein B12 which ‘should’ at least be matched. Or perhaps the BBR package. But then the Tecna GT which is designed for road use could be a good option and likely the highest end damper with the lowest spring rates at that price point.
Smallish drop, quality matched setup, 99% road use. Capable of European road trips without getting out feeling rough due to NVH. (Slight exaggeration )
Answer: is just keep it standard
Will contact 949 in the USA and have a chat with them just to clear up that option I think.
The Koni kit was on my car when I got it. I ran it for six months without adjusting it, and was perfectly happy. Before a big alps trip where I knew some of the roads I’d be driving quickly on would be unforgiving, I dialled it down to full soft. I didnt notice any downsides on the road, and have left it there ever since. I just don’t think about it, which to me indicates that it must be pretty good. The plus side too is that if you do a track day you can tighten it right up in a couple of minutes.
So it’s more on the “I want best for my baby” -kind of case. Understandable.
In general what I’ve gathered, stiffer springs are not usually the culprit for harshness. And usually sportier shocks might need stiffer springs (or vice versa). So if you increase rebound damping you also need to increase spring rates. If spring rates and shock rebound dampening isn’t a match suspension will start “packing” because spring is not strong enough to overcome rebound dampening. Over a series of bumps (like a washboard road), the suspension stays compressed and “jacks down” until you are riding on the bump stops and the the ride will be harsh, because there is no travel left in the suspension. So when looking at the coil overs, spring rate usually tells you also something about the overall stiffness of the dampener.
Of course you can’t take this like a gospel. For example what I’ve understood Bilstein B6 (which are basically the “OEM” bilsteins) and B8s have basically the same internals. Main difference is that B6 is longer (so it can be fitted to stock springs). B8 is designed to work with lower springs, and B12s are just B8s with lowering springs matched by Bilstein. I’m guessing that’s actually one of the reasons why NDs with Bilstein shocks have stronger OEM rear springs. To overcome higher damping of shock. Front spring are not so under sprung on ND, rear springs on the other hand are.
Also when discussing “the better internals on quality shocks”, it’s good to keep in mind that one thing that is usually superior in premium shocks is their temperature control. In the end shock is just a piston with valves and shim stacks. When talking about superior internals we are talking on better materials to control the temperature inside the shock and how prone shock is to temperature changes when driving hard. This isn’t usually that’s much of an issue on the street. Other thing of course is the piston and it’s valving but also how adjustments work. Adjustment is effectively a way to control how much oil gets pass shim stack. Problem is that this affects how suspension works in general. Traditional needle valve is no way optimal and this is why ie. Öhlins has quite complex bleeding valve constructions on their shocks. So if you don’t need adjustments (= need to make it to work on race track and street) I’d look for non-adjustable shocks.
My impression why cheap coilovers are particularly bad on MX-5 is because of relatively long travel on suspension. Cheap coilovers usually have quite short travel, which isn’t that big of deal on McPhearson struts where travel is much shorter in general and camber control is poor on extremities anyway. It’s not about that their internals are particularly bad, but they just don’t have the travel double wishbone + multilink could benefit from. But this is just me thinking out loud. If someone has actual facts, please correct me.
It’s interesting that the first post the objective was to improve the look of the car by lowering it. Hence all the discussion on suspension travel and damping in trying to obtain the original NVH. I personally don’t worry about the fit of the wheels in the wheel arches. I am more concerned about ride comfort on our terrible minor roads and have learnt to accept the body roll on my 1.5 ND when cornering hard which isn’t very often on open roads. I probably corner hard only at roundabouts. If I used the car regularly on track days then I might want to alter the suspension.
Previously I had a NB on standard suspension and my son had a NA with lowered suspension, adjustable shocks and stiffer antiroll bars. It might have been good on the track but on the road it leapt from bump to bump and my NB with its compliant suspension was quicker in the bends and more comfortable.
) Although I understand knowledge is a dangerous thing too! But would prefer to fit a package.
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