Trackday Report – MX5OC Rockingham Weekender

MX5OC Rockingham Weekend – Track Review

 

This’ll be the first in a series, less about reviewing the track as a whole as that’s always a subjective experience – more of a diary about how we (BOFI) and our cars performed at the track with some discussion points.

Foreword;

This isn’t a post about track advise from experienced drivers, we’re just regular guys trying to take performance driving more seriously as much as our budgets allow – it might mean 3 track days this year, it might mean 10 – it’s all about seat time at this point, hopefully you can watch us grow and improve along the way.

Weekend Overview

The MX5 Owners Club Motorsport division does an awful lot with their limited budget, from running a sprint series aimed at regular folk, offering discounted track days and of course their annual track weekender, where its possible to wrack up near enough 12 hours of seat time and as we said above, it’s all about seat time.

Just taking a moment here to note how well organised the event was and how good the driving etiquette was on the track itself.

The OC is a varied community but at the end of the day, everyone there has at least one thing in common – a love for these silly impractical cars.

We luckily managed to avoid any rain during the day, a wet rockingham is a slippery one and frankly we didn’t want or need any more excuse to end up sideways.

Track Overview

 

Rockingham is (and I use the term lightly) fairly forgiving in the dry, certainly with R compound tyres (AD08R, 595RSR, NS2R) – the combination of high speed corners, elevation, camber change as well as bumps certainly makes it interesting – way more so than the layout design looks.

Taking it form the top, out of the gate you’re faced with the run down into deene – keeping close to the wall on your right hand side, learning where and how hard to brake is the most difficult part of track driving and this corner really shows – but, it does let you make mistakes with a straight run off around the rest of the oval if you come in too hot. A good rule of thumb is from 120MPH braking hard at the 100meter mark should put you in place to hit the second apex, take this corner wide ignoring the first as there’s a big dip and it puts you in a better place for the corner exit, in our cars this is a 3rd gear corner.

The next corner coming up is Yentwood, power into this, keeping left, braking into the cone to take the turn right, hitting the apex powering up the hill. Depending on your braking teqnique you might find yourself lacking brakes for this turn after Deene, so for your first few laps get the feel for how much speed you can carry through it – everyone’s car is different so we wont quote MPH in this, in our cars it’s a 3nd gear corner.

Chapman Curve is next up, the jurys out on the best way to take this (in our group), as you head up the hill from Yentwood you’ll be in 3rd by the top, a tap of the brakes at the cone to get the weight over the front and turn into the apex powering into Pif Paf.

A dab of brakes turning left hitting the apex, at Pif Paf you’ll be putting the power down through the next 2 sections Kirby and Steel Straight, in our cars we’ve managed it flat -but this completely depends on your setup and especially your tyres – if pushing, don’t upset the car with big changes in brake or throttle or you’ll spin.

Braking at the cone on your right into Gracelands – this is one of the more complicated corners, as you are going uphill into the corner and the apex is blind, brake and turn in at the cone keeping the power static – as the track falls away from you on the right and it heads downhill you’ll need to manage the car as it wants to push wide – but there is a lot of track there until the next apex on your right, hit that and move over to the left in time for Tarzan.

Tarzan is an aggressive hairpin, it’s possible to have a lot of sideways action on this corner and there are several ways to take it – but the general rule of thumb is take it tight and use all the track as you exit, just get over to the right on School Straight in time for Brook.

Brook Doubles as the pit entrance as well as being 2 sausage kerb equipped ‘S’ bends – brake at the orange paint you’ll see on the Armco on your right and turn in at the cone – keep the car as neutral as possible through these corners, if you’re slow in, stay slow, if you’re fast in – don’t make big corrections – if you’re really fast in, take an exit in the pit entrance.

As you enter onto the oval, you can take it multiple ways, hitting the apex and keeping the car neutral is a good plan – it’s possible to spin out here pretty easily if you apply the power too early as the track banks up and the cars weight shifts around.

Get up on the bank close to the wall, full throttle through the pit lane straight, taking the oval corner can be done flat but don’t make any drastic changes to power unsettling the car, stick with it – get the car down with the near side wheels touching the white lines at the pit lane exit where you started and push through until it straightens up – ready for your braking zone into deene.

Car Overview

So, the main question for us of the weekend was how would 4 recently rebuilt / built cars handle a track day – all of them turbo. With that being said, all of them running AD08R or similar and either 205/50/15 or 195/50/15 on 7J/8J wheels. Very comparable however you look at it – using similar or the same suspension (Meister R).

The biggest consideration is cooling when turbocharging these cars, we have 4 cars running slightly different setups.

MK2.5 – Gail (TD04 1.8VVT) – Suffered Overheating issues, running an ALU Radiator, no coolant re-route but with the factory air dam and undertray. No other exterior modifications.

Mk1 – Mecal (T25 1.8) – Suffered the most overheating issues, it has an ALU Rad and a coolant re-route but it also has a very forward fitting intercooler that basically fills the whole mouth of the bumper and has no air dam or undertray so whatever air was there, was just going under the car.

Mk1 – Winston (EFR 1.8VVT) – Suffered no over heating issues, has a coolant re-route, an ALU rad and full ducting.

MK1 – Leaf (T25 GT2554R 1.6) – Suffered some coolant leaking issues, due to a poorly sealing radiator cap and a lower rad hose that needed tightening – other than that, it was rock solid all day which we believe was due to the GV Lip and the air dam and undertray, making better use of the air that was available.

The next consideration is oil pressure and temps, not all the cars have oil temps logged but Gail was managing 130c oil temps – we want that far closer to 100c for longevity and the route we’re taking in the development of the cars is creating a fairly standard oil cooler kit (thermostatic) , frankly, it’s a must for any turbo application that’s getting used on track.

From a pressure standpoint, 1.6s are especially picky with their oil, many NA cars in the pack were tapping their lifters off after a hot lap with whatever their choice of oil simply not being able to cope with the heat – with the lifters being hydraulic, it certainly doesn’t help power.

The Fuchs 15w50 Race oil used in the leaf didn’t let us down on that front, even if we assume it was up at 120c or so, no lifter tick on idle and up where it needed to be hot running the track.

With that being said, we ran Mobile 2000 fully synth in Gail and Mobile 2000 Semi Synth in Mecal without any pressure issues – with the right cooling its film strength should suffice – for peace of mind we like the 15w-50 more race spec like Fuchs or Gulf Competition.

Tyres & Suspension

Overall, the cars setups all performed very well with the takeaways being…

AD08rs and Federal 595s are excellent – The 595s performed well at cadwell last year, we could see them getting very hot and can see on a 25c day that it’d be worth moving to something even more racey like NS2Rs or R888rs.

Managing tyre pressure fluctuations was interesting, we had them filled with nitrogen (for free, mind) and had to adjust the hot pressures 3 times which frankly tells us unless you can fully purge the tyre of all air using dual valves nitro is pretty pointless – it felt that the tyres were getting several psi higher on track – meaning a cold pressure of 23 psi would have been needed. We stuck with 25 psi cold all around to get 28-30psi hot.

On Suspension it feels like even with the 10kg front and 7kg rear springs on Leaf it could use some adjustable anti roll bars, it’s certainly not a must but Gracelands really showed how much the car wants to lean over as the track falls away from you, we’ll continue testing before making any hard changes or spending some cash. The main issue was front left tyre rub with the ride height, it just needs to be dialled in a but with maybe a turn of preload set – ideally, it needs to be corner balanced.

Cardboard List

Ah the proverbial cardboard list, the main focus for all of the cars is going to be;

  1. Cooling
    1. Ducting
    2. Venting
    3. Oil Coolers
    4. Coolant Flush
  2. Brake Fluid

That’s the main list, unfortunately for Matt (Mecal) – it’s going to need a rear main seal and potentially a clutch – depending on how contaminated it is as during the weekend it was slipping at anything over 60% throttle – a function of the oil mist in the gearbox housing from the leaking rear main.

Franky, it’s a much smaller list than it could have been and we’re quite pleased, no one managed to fall off the track even while pushing hard, granted a couple of ‘squeeky bum time’ moments were had by all but hey, that’s what you want out of a track day.

Where Next

Depending on availability we may be at the Mighty 5s track weekend at Llandow but that may be too close, we want to go back to Cadwell Park soon – we’ll put an update out on what we decide for anyone who wants to attend alongside us.

With the cardboard list in hand, expect a few updates from us surrounding the development of the cars – the main aim for all of them is reliability to enable us to get some consistent seat time and the answer to that is cooling.

Hopefully this was helpful, we managed to give a handful of passenger rides to the friendly folk who came and said hello – sorry about the standard passenger seats! People were having to hold on tight! If the coffers can support it, we’ll put in buckets and harnesses for passengers next time round.

 

 

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