It’s been niggling me in the back of my mind that I hadn’t started a project thread for the car, and I’ve had a couple of people ask if I had done a write up….so here it is.
Every car I have owned seems to get “modified” in some way, I always intend to keep them stock then inevitably I end up going down the rabbit hole of spending far too much moneyon parts I don’t really need. I like to make them my own but more than that I enjoy refining the dynamic aspects of the car to suit my own preferences, I am very particular and hard to please.
I have owned far too many cars over the years from a Honda s2000, Lotus Exige and a modified mk3 (NC) mx5 to most renaultsport models made, but enough about me and onto the car.
I purchased a 30th anniversary Nd2 towards the back end of last year. I knew I wanted an ND2 for the engine but just wanted the best condition car I could find for the price, initially I wasn’t keen on the you’ve been tango’d colour of the 30th cars but the recaros, brembos, rays wheels and interior uplifts certainly appealed. Now I’ve owned it a while I am a big fan of the colour but also the car in general.
Few pictures of the car at different stages of development:
The Mx5 is such a good base platform it really is, great out the box but also seems to respond really well to upgrades and chassis tuning. Initially I found the ND (MK4) lacked “feel” both through the steering and the chassis to inform you what the car is doing when loaded up going into a corner. The ride was great but there wasn’t enough information coming my way to fully enjoy and exploit the car.
I have tried to complete each upgrade I have done in stages so I could get a feel for the difference it made and draw direct comparisons. The first thing I did was fit a set of eibach lowering springs to the car and in hindsight I wish I had gone straight to a decent coilover (more on that later) as the process to change the damper and spring is much more involved. One of the lower rear damper bolts was also seized (fairly common I believe) but fortunately the trusty Dewalt impact gun managed to free it off after repeated attempts. Anyhow, springs on and straight away the car just looked right rather than the Dakar rally setup that comes from the factory. Objectively even after getting the alignment done, I didn’t notice a significant difference to stock springs in terms of roadholding, maybe a slight reduction in role.
I wanted a more connected feel so based on feedback from others and stock availability in the UK I purchased a set of eibach anti rolls bars. I was expecting the fitment of the front bar to be a nightmare so asked my dad to come over and help for moral support more than anything. I needn’t have bothered as in reality it’s a straightforward install especially if you use the Flyin Miata guide which is superb. I cut one of the arms off the stock OEM bar using an angle grinder which sped up the process and made the whole job a lot easier. Rear bar is a formality and a 10-minute job. I used adjustable drop links on the front to neutralise pre-load and standard on the rear (as you can’t get adjustable ones short enough). On the road, big improvement car felt tauter, tighter, and offered more cornering load feedback. The eibach springs and anti-roll bars are a nice on road balance with the stock Bilstein dampers.
The next stage was to get the car to sound more “sporting” and enjoyable to rev out with the top down. I wouldn’t say the OEM exhaust was bad, but the engine/gearbox transmits so much resonance it sounds a little thrashy at times. I did a lot of research and ended up purchasing a Goodwin Racing (GWR) Super Street (single tip) exhaust from the US. The difference was profound and exactly what I was looking for, such a good sound! The backbox uses a Helmholtz chamber to capture drone and it really works, it’s like a music instrument based on throttle load.
I still wasn’t fully satisfied with the handling dynamics of the car and had a feeling the chassis had more potential. I managed to pick up a new set of Mesiter R GT1 dampers (double digressively valved) at a very fairly acceptable (with man maths applied) price. Install was a doddle in comparison to the springs, one set of damper body’s out and new ones in probably 1 ½ hours max. I double checked the spring pre load applied from Meister R and played around with the ride height which took more time. At a later stage I also added an additional spacer to the top of each damper above the top hat bushing, this effectively increases the pre load on the bushing. This was an improvement I found on the US forum which really does make a big difference to damper response. Lots of talk about pre-load, but another critical task to do when conducting a suspension change is to loosen all the bolts that connect the rubber bushes within the front wishbone and rear hub (lots of them!) and retorque at ride height with the suspension loaded. The best way I found to do this with access was to measure the distance from the centre of the wheel to the top of the arch and repeat this measurement with the wheels off the car, using a jack to lift the hub to the correct height, then tighten all the bolts. The GT1’s made a big difference for me much tighter responses from the car and it actually deals with smaller imperfections in the road much better than you would expect. It’s definitely stiffer than the standard bilsteins but you can tell the quality of the damping is much better. I have much more control and confidence in the front and rear of the car now, very impressive.
Something I have played around with extensively on the ND is chassis balance, I find the rear is far more sensitive than it ever was on my NC with similar modifications/alignment. The ND has some clever suspension/hub design to limit bump steer and keep toe angles more consistent through suspension travel. I don’t know if it’s due to bush deflection or just the nature of the chassis but it’s been far more challenging to “dial in”. It’s certainly a much more responsive and playful chassis than the NC though which is nice. Something I noticed is that that the Meister R GT1’s have a 6kg front and 4.5kg rear spring rate which is quite a close ratio front to rear and I found that with the 16mm eibach rear anti roll bar the car is too rear biased and “loose” particularly during high speed transitions. The first thing I did was to fit 8kg front springs (the damper valving is fine up to 10kg), I anticipated a harsher ride but in reality, all I felt was a better feeling front end and more settled rear, but the change was relatively subtle. At a later stage I switched back to the OEM rear anti roll bar (which in hindsight I maybe should have done first) which made a dramatic difference with a less sharp end rear making the car very confidence inspiring on the road. Jumping forward quite dramatically I have also tested a 14mm cusco rear bar and US mx5 cup car rear drop links which feels like a very nice balance particularly on track where you want the rear to be a little more mobile. So, my recommendation would be OEM rear bar for roads use, the 16mm rear bar that seems to be included with most bar “sets” is just too stiff for the ND unless you are running very high front spring rates and it doesn’t match well with their front bar.
I have also gone all out and fitted chassis braces to the car which I was initially hesitant to do with the ND due to the limited information/feedback available, but I noticed such animprovement with them on my NC I decided to go ahead. So Initially I fitted a rear strut brace which is essentially a goodwin racing copy, didn’t notice a huge difference in fairness but there was a slight change in response. I then fitted a dave fab front brace and noticed a more immediate change in steering response and connectedness. I then purchased the hardrace front, side and rear brace packages which are far more extensive that the IL motorsport items available on mx5 parts etc that just replace the OEM aluminium items. These have made a very dramatic difference to the feel of the car once again, very happy with these. The car just feels more cohesive and connected much more like I remember my lotus being.
I then begun to explore different ways to wake the engine up but very few options seemed to be on the table other than going to BBR. I was originally looking at getting the BBR 220 conversion completed, which with the cams and higher rpm seemed very appealing but the costs of the full package it seemed prohibitive. When I dug deeper there where severalowners reporting drivability issues, so I decided to just focus on ecu tuning and making the engine breath as best it could. This is when Adam Read at CleaR Motorsport got in touch after I had posted on the forums regarding a recent purchase of Versatuner software from Fab9 in the US. He had used the Versatuner software to great effect with his 1.5 ND and wanted to continue to develop what he had learned on a ND2 2.0 car. Over the subsequent weeks and months Adam has worked some magic refining every element of the map to something that I believe is far beyond anything you would get from any other tuner. I have been really impressed by the time and effort Adam has put into this refining every detail and continuing to develop the map and provide updates as time goes on, he is a genuine credit to the mx5 fraternity and we are lucky to have him. Whilst power has increased, with naturally aspirated tuning the gains are never huge, however the car feels so much more alive and visceral, throttle response is so much better and the car just feels generally better to drive in all scenarios.
I have gone through various iterations of exhaust setup on the car, as mentioned previously I fitted a GWR super street backbox which sounded superb, but I was keen to experiment and throw more money at the car unnecessarily. I started with a 4-2-1 decat manifold again supplied by GWR as Adam had seen good gains on the 1.5, the removal of the pre cat shouldincrease gas flow significantly. This provided a welcome bump in mid-range power and torque and there was also a positive increase in engine response. A negative side effect was the increase in noise, with the GWR super street it was just slightly to loud at full throttle which was a shame as it sounded just right with the standard manifold. So, I decided to get the GWR Super Q exhaust which is designed to be fitted with an aftermarket manifold and at the same time fit theirmid pipe section with a high flow cat. The car now sounds just right and feels a more complete system, mapping work is still ongoing but there is a nice linear spread of power and torque, the mid pipe seems to have added a little more all-round which is nice.
Arguably the best thing I have done to the car is fit a second hand differential from the fiat 124 abarth which has a 3.45 final drive as opposed to the 2.86 in the standard diff. This results in better acceleration, better gear connection and more punch out of corners as the gear ratios are shortened. Again I have Adam to thank for this as he not only managed to source a diff but helped me fit it as well.
The main aim for me has been to get to a stage where the car works for fast road use (with 3 days a week to the office) and on track. This is a tricky balance which is always a compromise and I usually end up sacrificing some on track performance which is fine by me and in reality road manners/feedback are key. I certain seem to be able to accept a more raw car the most on the road but the car works really well on both road and track its probably the best all rounder I have owned.
I have put this write up together to help anyone else with the same interests or desire to get more from the car. Appreciate its not for everyone and most will go their own way but if you have any questions, please feel free to fire away.
I have not detailed everything I have installed on the car, so I have put together a list below:
Oils: Engine Motul 300v 5w30, Gearbox Motul 300 gear 75w90, Diff Motul gear 300 ls 75w90, Brake Fluid Motul RBF660
Meister R GT1 Coilovers 8kg f/ 4.5kg r (6kg front as supplied)
Eibach Front Anti Roll Bar (27mm solid) and rear oem bar (11mm) or Cusco for track (14mm)
IL Motorsport front adjustable drop links
Paco Motorsport front anti roll bar reinforcement
Powerflex lower control arm inserts
Powerflex Diff bushes (black)
Fiat 124 Abarth rear differential (3.45 final drive)
AWR engine mounts (62a)
Paco Motorsport seat lowering frames
Hardrace front, mid and rear chassis braces
Dave Fab front strut brace
Gravity Performance rear shock tower brace
Guardian Designs Corsa steering wheel
Endless Me20 Brake pads
Mazda OE Aero Kit
Verus rear diffuser
Goodwin Racing Max torque 4-2-1 manifold, mid pipe with 5” sports cat and Super Q header edition backbox.
Verus throttle pedal spacer
CleaR Motorsport ecu custom tuning
ClearR Motorsport clutch stopper
Konig Hypergram 17X8 ET45 alloys with Michelin cup 2 connects in 215/45/17
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