mx5trackdayproject.co.uk

Category: Suspension

  • Thoughts on Development Direction

    Thoughts on Development Direction

    Introduction

    So the recent mods (see previous posts) are all in the car and have been tested at a shakedown at Thruxton Circuit in blisteringly hot conditions. In this post I review the work this far and how this has shaped future thinking for the car going forward. There’s some YouTube links below which show full runs at Thruxton.

    IL Motorsport Chasis Bracing

    In my New Bracing Goes In post I said that I was hoping to improve the rigidity of the chassis having notice some kick when changing gear under load having installed stiffer suspension.

    I can honestly say I didn’t notice any kick on the drive in (though this was pretty gentle) and not on the track so I’m going to say that adding the IL Motorsport Cross Brace and Rear Suspension Brace have improved the handling of the car.

    I was definitely pushing my limits further than before and my pace improved over my previous outings.

    BC Racing DS Coilovers

    I love these, they are a definite improvement over the old worn out Bilsteins. That is not to say I would not have loved new Bilsteins, which I did in my younger days on a different more rally-orientated car; or any other make of coilovers for that matter.

    When I drive on the road with softer settings they are comfortable in that role and when I set them much harder on the track there is less roll than before and there seems to be tighter control at higher speeds. On this occasion I drove in with them set at 1 click off softest, then started the sessions at 5 clicks from hardest in the morning and 1 click from hardest in the afternoon. I accidentally drove home with them set at track hardness and frankly it was not pleasant so note to self – change them back before loading the boot; and a learn from the experience.

    My spring rates are the 6 front and 4 rears which is the BC Racing recommendation for MX5 NC’s. I noticed at Thruxton that where I was pushing the car much more than on previous runs I was getting more roll than I had anticipated in the harsher corners like Campbell, Cobb and Segrave, which made me start thinking about anti-roll bars as a future option.

    The car was splendid through the chicane at Club so as I’ve already said above, I’m really happy with this choice.

    I’m not drawn to the idea of upping the spring rates yet (c.£200) as the ride for road use is pretty good at the settings described above. I don’t really want to add harshness given my Grand Tourer objective, though this would change if the car was to become a track-only tool but I’d still need to upgrade the ARB’s anyway.

    Thruxton 2026 07 07 i

    Yokohama AD08RS

    These are the newer road legal spec and sometimes get battered for not being as good as the old spec. I’d pretty much decided that I wanted AD08’s as the start point for my track-focussed tyre choice.

    Since I’ve got them I really like them. My standard road tyre is Dunlop Sport Max which is a pretty good track day tyre for wet conditions. The Yokohamas were part of a tyre & wheel package from Wheelbase last year.

    On my last trip to Thruxton I did notice that the tyres protested the treatment they were being given by squealing pretty regularly on the tighter corners but the handling remained strong and I was doing 12 lap runs. I did trip the DSP once or twice when pushing harder than normal. I’d have no problem getting them again but I have not yet tried them against anything else.

    If I could afford them when the time comes and if they were available in my wheel size then I’ll try the Avon ZZR’s recommended to me by a very fast MX5 owner I met in June who raved about them, though at c.£260 each for the Avons and half that for the Yokohamas that’s a couple of Track days so we’ll have to see what the budget will allow.

    Fox FX004 Wheels

    These Black 17 x 7.5’s are shod with Yokohama AD08 RS215/45/R17 came from wheelbase as a package and frankly I think they look fab .

    I don’t think they were a weight saving choice (Budget wouldn’t allow), but they look mean and that’s got to be wort 1-2 mph. EBC Yellow Stuff Brake Pads on standard discs and calipers

    Parked up at Silverstone Old Pits Paddock

    I love them they work well for me, though for the first time I noticed that they get better with a bit of heat in them. With good braking point selection they hauled the car down to

    BBR GTI Catted Manifold, Centre Pipe and GT Rear Box

    Again I love it it burbles nicely, makes a good noise when up and running and the car either is faster or feels faster. I added a Versatune standard NCU package ECU flash as a stop gap until I can get it on aRolling Road. Again Ive not been disappointed despite the cost.

    I fabricated a heat shield for the rear of the alternator until I can be sure the heat generated by an unshielded manifold won’t damage the black plastic ?? vent to channel cooling air into the alternator.

    Thruxton 20260707

    So Where Next…

    As the car does not over heat despite 30+C at a fast track where the car is up near maximum revs for a lot of the lap I’m not thinking an Oil Cooler is necessary at this time and have removed that from my development plan for the time being.

    I’ve been thinking that I’ll start getting together the parts for a clutch swap. With over 80+k miles on the clock I’m expecting the clutch to need replacing in the not too distant future. I’m also convinced that this car has been tracked at some point by previous owners again increasing the likelihood of increased wear. The car itself is not showing signs as yet. Its going well an is eager to go faster when the load button is pressed.

    I’m thinking I’ll be going for the Bofi Stage 2+ kit on the premise that it will cope well with heavy track use and a lightened flywheel to make it a little more eager.

    The other possible development direction might be Aero with a splitter at the front, some underbody air flow smoothing and wing at the back and probably done in that order. But that’s a cerebral exercise for now as the car is going well and I’m probably still less competent in my driving than the car’s capability.

    Finally there could well be the option of doubling down on my BBR GTI upgrades and going for the Cam upgrade to take the car to 200 BHP.

    I’m back at Thruxton next month so if you see me come over and say hello.

  • Set the controls for the heart of Thruxton

    Introduction

    So this week I’ll be popping over to Thruxton Circuit for some fun in the sun. I’ve done the driver briefing and filled in the wavers so I’m good to go.

    Car Preparation

    As usual the weather guru’s have been consulted and predict hot and sunny with 20c to 29c during the core day. So it looks like it’ll be a top down kind of day.

    The Yokohama’s (AD08’s) will be the tyres of choice resplendent on their black rims.

    Tyre pressures have been checked (1.9 Bar), wheels torqued up to spec (100Nm) oil level has been is checked, ditto the coolant level. It’ll all get checked again when I get there.

    Super Unleaded will go into the tank and extra in the can on the morning of departure and I’ll get sandwiches, pop & crisps for the day at the same time.

    A tool box, work mat, fuel can, a picnic chair, tow-bar, tyre inflator, pressure gauge, a puncture kit and umbrella (as a mini sunshade) will go in the boot.

    Sandwiches, pop and crisps; helmet, HANS and anything else will go in the passenger seat or footwell. I’m on my own for this one, no support car for me.

    I’ve charged up the batteries on the GoPro so I can have a go at recording some video this time.

    I’ve noticed the air-con might be a bit feeble so the journey back might be a trifle warm, we’ll see.

    Mods since last time

    On this occasion I’ve added some chasis bracing to the frame so it will be interesting to see what effect this will have on handling. I’ll write it up next week.

    I’m not sure that the new rain light will have much effect on a sunny day though it also adds an extra brake light repeater function which may help those overtaking me, know wha I’m up to!

    As above I’ll be running on the Yokohama’s rather than the Dunlop’s.

    Can’t wait…

  • New Bracing Goes In

    New Bracing Goes In

    In this post

    My MX5 NC already has some chassis bracing both on the front struts (see the images in my previous posts)and on the chasis rails underneath the car (see below), in this post new upgraded bracing goes it to try an improve already excellent handling.

    The why of it

    From the start the aim has been to create a grand touring track day car and in my post on the new BC Racing Coilovers, I mentioned that the car had acquired a kick when changing gear under load and whilst this was not a track day problem it was a put off when driving on the street.

    The forums suggest that this can be chasis kick caused by the relative softness of the previous suspension no longer soaking up the chasis twist from the rotation of driveline.

    It may also be a contributing factor that I Polybushed the rear suspension and the diff bushes where replaced with even harder poly bushes.

    Sites like Flying Miata suggest that it is difficult to overdo chasis rigidity and forums have suggested improved feel in the driving experience.

    For all these reasons and because they are hidden underneath the car I pushed the go button the IL Motorsport X-Brace and Rear Suspension Lower Brace as a first step in bolstering chassis rigidity.

    Why IL Motorsport?

    Only because I liked the look of the parts (they’re red) and in comparison to others they seemed pretty good value. I didn’t buy the full kit because I’d heard that the OEM front suspension tower brace is pretty good anyway and doesn’t really need replacing and the OE front bar (before the X brace) could be upgraded later as it is still pretty substantial.

    Instalation

    So you need to have confidence that the suspension won’t collapse when you start loosening bolts, and you’ll need to take a moment to search google for the installation instructions which didn’t arrive in the box and then a further moment to get your head around the instructions before you start any of this.

    I lacked the confidence to pull the bolts without chocking the subframe but it was either overkill or additional body stabilisation for the whole operation.

    I found that you need to pull the bolts out first, then instal from the back forward as the suspension brace sits under the cross brace. The hex bolts supplied replace the originals from the cross brace (I wasted 10 mins trying to work out why the wouldn’t bite on the suspension bars).

    The instructions also give torque settings for all the bolts, but these are pretty low. I triple checked them all with a torque wrench.

    Impressions

    They are both light and strong, the OEM x-brace could be flexed with my hands but the new one could not. Once I worked out what went where and how, it all went on pretty easily.

    As the rear module sits on top of the existing subframe rails it does hang down below the chassis and lower suspension arms rails a little (~1 – 1.5cm), the X brace less so as it is a replacement for the original. So if you have clearance issues you’ll need to work around these when driving over an obstacle or like me when pulling off the drive.

    It does not seem to foul the BBR exhaust that I can see, but it gets a thorough shake-down test next week at Thruxton.

    How the mod affects handling is something I’ll find out next week when I’m back on track.

  • Wet One at Silverstone Track Day

    Wet One at Silverstone Track Day

    Last June (2025), Silverstone was hot and sunny, we took a support car loaded with tools, tyres, gazebo and picnic table; and iit was glorious.

    This year the June track day was cold, breezy and rainy, though to be fair it settled down after 14.00 and the sun made an appearance, but what ever the weather a track day at Silverstone is such fun.

    It’s an expensive venue so it’s a once a year treat for me. This year the weather forecast was bad enough for me to cancel the support car because sitting in a car for much of the day gazing at the rain and being bored while I was out on track having fun was not something I wanted to inflict on anyone.

    Tyre Choice

    My Yokohama AD08’s were swapped for my SportMax road tyres in the rain the day before as they’d be no use in the expected heavy thundery rain.

    An early morning start on the motorway saw mixed conditions and I stopped at the services on the A43 at Brackley and took the opportunity to top up the petrol can with Super Unleaded and then a short final leg to the track and registration at the old pit lane.

    Setting Up

    The rest of the pit area
    My Pit

    I arrived at the track at about 7.30 and the gate and parked near the Cafe. I registered and got all the info want back to my car and pulled all the gear I’d crammed into it out.

    Two tool boxes, torque wrench, and a dry box for my food and drinks. I pulled my tow bar out of the boot and packed by helmet and HANS bags into the waterproof box.

    I placed the gear in front of the car so my Pit Box was clear to anyone who might be tempted to block it when I’m out on track. This has happened to me before at Castle Combe and is particularly irritating especially when your gear is in full view of them. I now reverse park and go no further back than the line for this reason.

    The Paddock
    The Padock, Drive up to the big truck and turn left into the pit lane.

    Some cars pulled in beside me and they arranged their cars specifically for this reason, telling me they have had similar experiences.

    Car Prepration

    Having experienced a bit of torque twitchiness on the motorway I backed the rebound on the suspension to +5 (five clicks from softest) with a plan to adjust as I went along and then also reduced tyre pressures to 1.8 bar (cold-ish)all round ready for the rain.

    suspension adjustment made easy with extenders all round
    Dial to max soft then +5 clicks

    Once round all the wheel nuts with a torque to check they were all firmly at 100nm and I was ready for the briefing and sighting laps.

    Briefing

    The Briefing was well attended with an explanation of the format of the day, the flags in use, when we stop for lunch, rules for overtaking, then it was back to the car to kill time until the sighting laps.

    Game On

    A wet track

    The sighting laps started at the usual pace and speeded up. After that the track opens and we’re on our own.

    Silverstone in the rain paddock side is bleak, track side however is much more entertaining.

    I followed the usual pattern of trying to get some heat into the brakes and tyres and building up speed as the laps tick by. I managed to get between 80 and 90 mph down the Hamilton straight, 90 to 106 down Hanger and 80 to 100 depending on the intensity of the rain and whether I was giving way to faster cars or not. Never once did the car feel like it was aquaplaning on the straights or braking in straight lines.

    Turning however was another matter several times I underbaked and the Traction control pulled it all back together.Appart from the trying the tarmac run-off between ?? Maggotts and Becketts, and going all wheels over the line at The Loop which is very slow and for which the car was off line due to the traction control being unhappy that I was pushing the cornering forces much harder.

    Given the weather I elected to put in more laps each time I was out (uptown blocks of 10 laps) and this help build a better picture of the conditions and the available grip.

    There were some really nice episodes where I had an open track to play with. On others I was forced to pull over on the right side of the track to let faster cars past. In the rain this can create a worry effect where there is vision at the sides of the track but a grey hole in your vision where you know the cars should be but you can see nothing but grey water as they speed past you (especially at the end of the Hanger straight).

    After the lunch break things began to dry out and I was able to get the roof down on occasion.

    Thoughts on the Day

    Despite the weather I found nothing to put me off Silverstone in the rain though I prefer the dry conditions for grip.

    I used the petrol pumps at the circuit rather than drive to Brackley on this occasion as I was shocked to find at the lunch break to find I had been racking up the laps and was down to less than a quarter of a tank. MPG for the car had dropped from 37 to 22 with enthusiastic driving on the track and across he whole day (including travelling to and from the circuit) I used nearly two tanks of Super Unleaded.

    In the wet conditions the tyres remained pretty intact with none of the heavy wear and melted rubber from the previous year evident.

    The brakes (EBC Yellow Stuff on normal discs) were again superb.

    The new suspension was excellent and I ended up settling at +7 clicks.

    Given the rain and some visibility issues Ive decided to buy a flashing rain light as a safety measure for similar conditions.

    Hopefully I’ll be back next year.

  • MX5 Suspension & Exhaust Upgrades Begin

    MX5 Suspension & Exhaust Upgrades Begin

    Introduction

    May and June saw the process of preparing the car gathering pace ahead of planned trips to Silverstone and Thruxton circuits.

    Planned works included BC Racing DS coilovers in the corners, a sound-pipe delete and a new catted BBR GTI Exhaust System. Also plans included installation of adjustable seat runners on the passenger side and new EBC yellow stuff pads for the season ahead.

    BC Racing Coilovers

    Choosing the suspension has been the most stressful decision about the car so far. I wasn’t sure I even needed to upgrade and it was pretty good already with the Bilsteins which were standard on this spec of car.

    The choices I thought about were – should I stay with the Bilsteins’ or try something else; and if something else then what; should I run with the pack and fit Meisters or try something else like Yellow Speed Racing, Ohlins, or similar.

    At Thruxton I’d hit the bump stops at Campbell on more than one occasion last year when trying to conserve speed so this had made up my mind to try something new. I was looking for something firmer, and with 88k on the clock I thought the Bilsteins’ were probably past their peak.

    In the end, after much humming and harring I chose the BC Racing DS range as I wanted something that might be more plush for the road bumps and stiffer for the track day undulations. I elected to stay with the softer 6Kg/mm front 4 Kg/mm rear springs as BC racing had strongly suggested this starting point so I elected to run with it and upgrading springs if necessary in the future would not be that expensive.

    Installation

    I measured the ride height of the car (hub centre to top of wheel arch) prior to starting and decided that my target would be 245mm for the front and 250mm for the rear once the new suspension was installed.. This would give a little rake for loading and acceleration squat and I gambled that the stiffer springs would not squat so much with fuel and passengers on board, It will be easy to adjust the height once the car had settled onto its new suspension should this not be enough.

    I having jacked up the car. I removed the wheels then the bolts on the suspension upper mounts and also removed the turret brace bars. These bolts are not torqued up very much and were easy to remove.

    The front left was the first to succumb to change and took me a little longer than I had anticipated. I ended up accidentally disassembling the whole original shocker on the car having misunderstood what I was looking at when I was looking down at the top mount as the top of the Bilstein mount which had a black shiny metal cap was nearly the same colour as my car and looked like a permanent part of the car. having understood the issue the remaining mounts proved much easier to remove.

    I also removed suspension upper wish bone bolts, brake line fasteners, anti-roll bar and drop-links to allow for the necessary wiggle room and it all came out nicely. The only pig was the strut bottom nut and bolt which was super stiff and took plenty of work with a breaker bar to get out.

    To be fair the new struts are pretty boring to look at but are super clean and have no rust (unlike my rusty Bilsteins which had definitely seen better days).

    When refitting the top suspension mount brace to the BC’s I took the opportunity to drill the brace top and fit 11cm extenders to the front suspension adjusters and 25cm extenders to the rear. these facilitate rapid adjustment of rebound on track days. I wound it all up to 5 clicks off max hardness all round for the test period

    The sound pipe has been deleted and a Mk3.1 air pipe replaced the original. Also the suspension adjustment is blocked by strut brace
    Sound Pipe Delete and new suspension fitted

    New Exhaust System

    Whilst the car was up on the jacks I took the opportunity to instal a new exhaust. This was a the BBR GTI catted manifold, mid section and Grand Touring exhaust. Removing the old manifold was the most trickiest operation with rusted in bolts catching on the body work despite angling the engine over on one side as seen in the Turbo installation YouTube video from Flying Miata.

    The purchase of some swan neck ring spanners proved very useful in both the removal and installation phases for managing the manifold bolts.

    I also gave some thought to he absence of heat shields on the BBR manifold and fitted some gold reflective tape to the pipes and cam cover and existing engine bay shield and fabricated a shield for the back of the alternator where there appears to be a black plastic air duct.

    Heat shielding over new exhaust, also suspension adjustment extenders fix the problem of fouling caused by strut brace.
    Heat shielding and suspension adjustment extenders.

    Versatune

    Also while I was at it I opted to remap the ECU by flashing it with a vesatune basic upgrade.

    Impression

    So the weird thing is that the suspension feels a little stiffer but not massively different at urban speeds. The engine note is exactly what I wanted with a little burble and more open bark under acceleration and is not any more intrusive at motorway speeds than OEM.

    I had dialled the suspension up to five clicks from hardest all round and have noticed that under hard acceleration there is now some kick in the straight line direction upon gear change and I think this may be because as yet I have not had the tracking re-set. though it may also be chasis flex, but tracking will be the first step.

    Anyway despite this anomaly it was more or less ready for Silvestone and Thruxton and the seat runners would have to wait for another day…..

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