Hi, this is an article I wrote for MR2only on track preparing your MR2, its just the text but hope it will be of some use, if you want the full article buy the mag--lol
With
safety cameras in abundance and ever increasing traffic driving on the road for pleasure is becoming harder and harder, hence the rise in popularity if the trackday.
The MR2 is a natural choice for taking to the track, with its mid-engined layout and excellent dynamics it represents a good challenge for any enthusiast, and with prices of Mk1 and Mk2s being very low many people are using them solely for track work.
In this issue of MR2only we will look at preparing your MR2 for the rigours of the track, from simple choices for the odd outing to a preparing a full on stripped out track weapon!
The first decision when modifying your car for track work is to decide how much time it will spend on track, if your car is your daily driver and you plan on only venturing on track once or twice the approach is very different to a dedicated track machine, as its a rule of thumb that the better a car becomes on track the worse it is on the road.
First of all this guide will not take into account the biggest factor on going faster around a track, the driver, if you are a novice track driver a few hours tuition will see your lap times drop by much more than a fancy set of coilovers or some huge brakes, so always be aware of your own limitations.
Before going on any trackday there are several
(fairly obvious) things you should check, regardless of the state of tune of your car.
Remember the track, while a very safe environment, is a harsh one, and any weaknesses in your car will make themselves more obvious than on the road:
Tyres
in good condition with no damage and at the required pressure.
Brakes
make sure you have a good amount of pad and discs are not very worn or thin, a set of good road pads will be scrap at the end of a hard day on track.
Check brake fluid level and condition.
Oil
make sure you have checked the level and the quality, the elevated temperatures of track work will destroy oil much quicker than road driving, be aware of this if you have old oil.
Under bonnet check
make sure there are no loose hoses or cables that could cause a problem, water temperatures will also be much higher than on the road so the cooling system will be working harder, ensure all hose clips are done tightly and there are no obvious cracks in the water system.
Ensure all wheel bearings, ball joints etc are in good condition, a bearing with play in it may be hardly noticeable on the road but be very obvious when your car is on the limit of grip.
Ensure there are no lose objects in the cabin, a small heavy object can become a killer in an accident.
If you are a novice driver I would suggest doing a trackday in your standard car before splashing out on expensive modifications, this will give you a taster of what to expect before parting with any hard earned money and before you have ruined your perfectly good road car, once you have done that first trackday and got
the bug there are many things that can be done to make your car more suitable for the track.
Brakes
The standard brakes are the first thing that should be upgraded, this can be done cost effectively and with little detriment to road use through replacement pads, unless a specialist race type pad compound is used such as EBC yellow stuff or Carbotechs its unlikely you will notice any difference at all, and even then they should be more than acceptable.
Upgrading discs is the next step and there is a large choice of drilled/grooved discs on the market, this was covered in some more detail in Issue 6 of MR2only.
Going to larger discs is a huge step in the MR2 and should only really be considered after significant chassis and tyre upgrades, this again was covered in a previous MR2only issue.
Up-sizing front discs only or going to 4 piston callipers has huge consequences with brake balance and pedal feel and should be carefully considered.
That said, when the tyres and chassis are up to it, it is possible to stop your MR2 much quicker than you can with standard brakes and with very little in the way of fade.
Another good upgrade is braided brake hose, especially if you are using track pads, these will replace the standard
(probably badly fatigued) rubber hoses and will decrease pedal travel and increase feel.
Suspension
It is with modifications to the chassis that you can seriously destroy a road car, it is a very common misconception that your car will be faster if its lower and stiffer.
For a track set-up lower and stiffer is a good place to start, but the lower and stiffer you go the worse the car will be on the road.
Not only will the car tramline and bump-steer much more significantly but it will bounce over bumps rather than absorb them, it doesnt matter how big your tyres are if there not in contact with the ground they are not gripping!
It is likely if you have a Mk1 or Mk2 with standard dampers they are very worn, a good place to start would be slightly lower springs with replacement dampers such as Bilsteins.
If your car is mainly used on the road I would not recommend a coilover set-up, many people that do use then do so for
bling, but in reality there are not appropriate for road use.
The next step would be a set of coilovers such as Tein Superstreetss, these are reasonably priced at around
£600 and can be set quite soft
(relatively of course), but are more than capable of tightening the MR2 chassis up nicely.
The Tein Superstreets would be a good compromise for a hardcore road car, something you do use on the road but maybe not 10s of 1000s of miles per year, or a car that you do several trackdays in a year.
You can buy coilover suspension much cheaper than that but always remember, you get what you pay for.
A set of coilovers for around the
£1000 mark should be more than enough for most trackday warriors, usually having adjustable ride height and damping and adjustable top mounts
(at least on the front).
A good quality set of coilovers are a good investment for serious trackday enthusiasts, as they offer adjustability to tune the cars handling and can be rebuilt when they wear, so a good set of coilover suspension should last the lifetime of the car.
It is possible to go further still, paying anything up to
£2500 for off the shelf MR2 coilovers, it is unlikely however most drivers will be able to tell the difference between these and a set less than half the price, so while you get what you pay for the money you save would be much better spent elsewhere.
They will also offer much adjustment, such as compression and rebound damping
(maybe low and high speed), camber adjustment via top mounts and lower bolts
(which change roll centres differently), so do nothing but confuse the owner and making it difficult to get a decent set-up.
To offer even more adjustability
(which may be necessary if your car is very low and you are serious about handling) the next step would be roll adjuster blocks and adjustable camber bolts or top mounts.
The consequences of using these have been discussed in previous MR2only issues, but are essential
(and reasonably cheap) to maintain good wheel geometry.
The suspension geometry will now need setting up from scratch, it is relatively pointless setting the car to factory settings and a better bet to use a specialist such as WIM
(
http://www.wheels-inmotion.co.uk/) who will set-up your car to your requirements.
This should be treated as a start point however that can always be tweaked with you new adjustable suspension!
Chassis
Due to the mid engined layout the chassis structure on the MR2 is very stiff, with the import only coupe being the preferred choice for the hardcore enthusiast, being stiffer and lighter than the moonroof model and T-bar.
While the T-bar model will hold its own on the track you are always fighting a losing battle with both chassis stiffness and weight, sure you can make the chassis stiffer and lighter, but it will always be heavier than an equivalent coupe, if your setting out from scratch to buy a track only MR2, make sure its a coupe!
First on the shopping list to improve the taughtness of the chassis would be a bush kit, as with most things the original ones
(especially on Mk1s and Mk2s) will be worn and fatigued.
Any movement due to worn bushes will be amplified if you have stiff suspension and low profile tyres, as these items will absorb less movement.
A full polybush kit for a Mk2 is around
£100, it will not overly detract from road manners and help tighten up the chassis responses.
The next step would be uprated front and rear strut bars, some MR2s have these as standard but they can easily be improved upon, especially at the front, the rear section of the MR2 doesnt benefit massively from upgraded strut braces as it is reasonably stiff around the rear.
The strut brace ties together the tops of the suspension towers a little better, essentially making the chassis stiffer, the benefit of doing this is you will let the suspension work more effectively, as the body shell will flex less, and as such any loads through the wheels are controlled by the suspension rather than absorbed in an uncontrolled manner by the chassis twisting.
Its worth noting that the chassis flex on a T-bar will be concentrated around the centre of the car, as losing sections of the roof will reduce the rigidity of the body shell considerably, tying the strut towers together wont help this and in all likely hood make the situation worse, as the twisting of the body shell will now be more concentrated in the centre of the chassis, rather than absorbed by the whole body shell.
There are a number of options available on the market place for strut braces so choice isnt an issue.
Going a stage further it is possible to purchase under body bracing from companies in Japan, although these will offer very minor
(if any) improvement in chassis responses.
It is also possible to fully prepare you shell by seam welding major spot welded chassis joints, again this is for hardcore race cars and it is unlikely most people would notice any difference at all.
Wheels and Tyres
The same rules apply to tyres as we have already mentioned with other aspects of your track car, in that a hardcore track tyres will in all likely hood be a poor choice for road mileage.
A road legal semi-slick tyre such as Toyos ubiquitous R888 or Kumhos V70a will be extremely good on a dry race track but take time to warm up on the road and will have much reduced wet weather performance, is this what you want on your drive to work so you can have a bit of extra performance on the odd trackday you do?
A road tyre on the other hand may overheat on a dry track, performance dropping off significantly, how much we are hoping to find out in the near future, conducting a full tyre test with the help of Jon at
www.tyrereviews.co.uk, hopefully bringing you the results in the next issue of MR2only.
From a personal point of view I tend to stick to good quality worn road tyres, purely for cost and fun reasons, a worn road tyre will slide predictably and will not move around on its tread blocks
(as there mostly worn away!) so is not so prone to overheating, grip will improve slightly too over a newer tyre but still not as much as a dedicated road legal track tyre, this allows me to slide the car much more often than perhaps I could with very sticky tyres, after all a trackday is not a race, its meant to be fun! They can also be bought at a very low cost from supplier of second hand tyres.
As we have discussed in previous issues having lightweight wheels offers huge improvements to performance and handling.
If buying wheels purely for trackwork then steer clear of cast wheels at all costs.
They are heavy and not particularly strong, a much better option would be standard wheels with good quality tyres, if replacing the wheels to offer more tyre sizes forged wheels are the only way to go.
This is also one of the few things that will improve things both on road and track, a light wheel will help handling, grip, ride comfort, straight line performance and aesthetics.
Its also worth noting if your a novice to track driving it is worth sticking to road tyres, as they will slide more progressively and give you a much better chance of staying on the black stuff!
If you are a more experienced track enthusiast it is always possible to step up to slick tyres, obviously these are not road legal and will be pretty useless in the wet, they will need a few laps to get some heat into them and be less predictable, but, they will offer much more grip than even a trackday tyre.
Most trackday companies will insist on a roll hoop/cage of some description if you are running slick tyres, so at this point you will likely have a fairly serious track car.
Transmission
The forced induction MR2s usually came with some form of Limited Slip Differential
(LSD) to give better traction out of corners, these can be replaced with much more aggressive items which stop the inside wheel from spinning much sooner.
They will offer more traction but also make the car more prone to oversteer and might feel a little bit weird on the road, the inside wheel seeming to skip across the tarmac.
The clutch could also be replaced for a more aggressive item, although in reality the clutch doesnt have that much of a hard life on track when compared to that of a drag car, or even a road car whose owner is a traffic light junkie, my own track MR2 Turbo has been using the standard clutch for 5 years!
Interior
Seats
The standard seats are very good in an MR2, especially some of the optional seats to be found on the Mk2, they are however quite heavy and do not offer the support for hard track work.
There are 100s of seats available to replace these, from
£100 fixed back bucket seats to very expensive carbon fibre jobbies, how much you want to save that last Kg is up to the size of your wallet, but a good fixed back race seat can be had for a couple of hundred pounds.
Make sure the seat has enough holes for harnesses
(if you can see yourself going that route) and it is fairly pointless having a seat with a reclining backrest, as these are just as heavy as a standard reclining seat.
It is unlikely a fixed back seat will be as comfortable as a standard seat, but it will offer more protection in an accident and significantly more support during cornering, the headrest part of the seat will also be further back to allow comfortable use of a crash helmet.
It is advisable to try the seats too before ordering, ensuring you have the right size
(good seats come in various widths), this is important as you dont want a tight uncomfortable fit or a big wide seat that allows you to slide around.
Aftermarket seats can be fixed in a number of ways, side mounts, custom subframes or home-made subframes.
Sidemounts are not especially easy to fit in the MR2, with the floor being very uneven and requiring additional plates welded in to make the floor flat enough to mount the side mounts.
The other option is to use your old seats and fabricate runners, this enables you to mount the seat low and still keep some form of adjustment, although some skill is required to fabricate them.
Custom subframes can be bought from the seat manufacturers that allow you mount the seat directly onto the standard fixings in the car, these are quite expensive however and not all seat manufacturers make these, so worth checking how you will mount the seat before parting with your cash.
Harnesses
Before fitting harnesses to your car you must seriously consider its usage, a correctly fitted and tightened harness will seriously restrict your movement, making road driving much more difficult, visibility at junctions is difficult as you cannot move forward and you have similar problems while reversing.
If the harnesses are loose enough to allow you to see at junctions its highly unlikely they will be any safer that the standard belts in an accident, if not more dangerous.
They are also awkward when getting in an out often, please consider these facts before deciding to fit some!
Harnesses come in various specifications, 2 inch wide, 3 inch wide, 3, 4, 5 and 6 point with various buckle types and mountings.
A 3 inch wide 5 or 6 point harness with an aircraft type buckle and a snap fixing
(rather than a plate with a hole) is the preferred option, with a 4 point 2 inch wide as a bare minimum.
The 3 inch width of the shoulder straps makes the harness much more comfortable to wear, and offers better protection in a crash.
A 3 point harness is a non-starter in an MR2 as it is very difficult to mount safely, also all the load during an impact is carried through a single bolt point.
A 5 or 6 point harness includes a crotch strap, the purpose of which is to stop the shoulder and lap straps riding up during use, ensuring they will be in the correct place in a crash and to stop you
submarining, which is a condition where the body is squashed into the seat during a crash, this can cause massive internal injuries.
Stopping the harness riding up your body also allows the harness to hold you securely in place during very heavy braking.
The crotch strap is not especially comfortable for road use or long journeys but offers a big advantage during track use, so once again it is important to decide what you will be doing with your car.
Mounting the harness is perhaps the area where most people fail to see the importance of doing something correctly, I have seen time and time again incorrectly fitted
(and hence dangerous) harnesses where the owners refuse to acknowledge there error, please ensure they are fitted absolutely correctly or they may offer significantly less protection than a standard belt.
The harness shoulder straps should leave your shoulders as close to horizontal as possible, in an MR2 this means bolting them directly to the firewall behind the driver or on a cross bar on a roll hoop thats at the correct height.
WARNING
:- do not, under any circumstances mount harnesses to the floor of the car behind the seat, the harness will do virtually nothing in an accident, the harness will not stop you being flung forward in a serious accident.
I would recommend mounting the harness to the firewall
(this is also a very strong part of the car, being 3 layers of steel), as this allows you to fine tune the mounting position to your shoulder height, this does however mean you have to drill holes in your firewall, which may not be ideal if you have a fully carpeted interior, but it is the safest place.
Using FIA approved eyebolts and spreader plates mounted in the engine bay side of the firewall, the harness can be simply clicked into place
(never use just nuts without spreader plates, as these may pull through the firewall in an accident), the excess harness pulled through the buckles and simply left to hang behind the drivers seat or trimmed off.
The lap straps can be mounted on the standard seat belt mounting holes which are very strong.
If you have a crotch strap this can be mounted onto the floor underneath the front of the seat by drilling a hole in the floor, and again using an eyebolt and spreader plate.
The floor is only a single steel sheet but in the event of an accident the crotch strap does not take any load, so this is more than adequate.
It is worth noting also that an aircraft type quick release buckle is actually illegal for road use and should fail an MOT, although I have never heard of this happening, so its always worth keeping you standard 3 point seat belts, just in case!
Weight saving.
Saving weight is mostly free and can endow you car with terrific performance, weight saving is also felt everywhere, acceleration, braking, corner speeds and turn-in, it does however come with a penalty.
Most of the weight you can easily remove from an MR2 is there to add refinement, to make the car quieter and a nicer place to be, if you decide to go down the route of removing weight you need to consider very carefully where you will do your driving, and if you are prepared to accept the compromises saving weight will bring, especially as for much of it theres no going back!
As most of this additional weight is to add refinement most of it is to be found on the interior of the car, so thats where we will start.
Removing 1 or 2 single pieces of interior trim or carpet will make little or no difference, if you go down this route you need to commit fully, removing every bit of interior trim including: Carpet, firewall carpet, glove box, headlining, plastic trim panels, door cards, centre tunnel padding, cubby box, radio and speakers.
It is also worthwhile removing the bonded on sound deadening on the floor, centre tunnel and firewall, the best method of removing this is with a hammer and chisel, then rubbing down with a wire brush drill attachment, the surfaces can then be primed and painted.
It is at this point you will likely need earplugs for motorway driving, so please be aware what you are doing to your car.
It is also possible to remove the air-conditioning system, which includes a very heavy compressor in the engine bay, a radiator, associated pipe-work and a heat exchanger in the cabin behind the glove-box.
Perspex windows can also be added but replacing the glass itself saves little weight, and can cause problems due to the frameless window design of the MR2, a good solution is to remove the winder mechanism which is especially heavy on the electric windows and prop the glass window in place.
This will save a few more Kg.
Other areas to save are removing the spare wheel and trim in the
frunk, the carpet and boards in the boot and the sound deadening from the engine bay.
The forged steel engine hoist brackets can also be removed
(but not discarded
you might need these one day!), along with the EVAP system.
The electric ariel can be removed as can the heavy boot spring and the steel trim piece found on the underside of the engine bay lid on Mk2s.
By now you have removed pretty much all the non-essential items and saved up to 100Kg, which is significant and should be felt during even road driving, to go much further requires spending some cash, and as I have mentioned I would recommend lightweight wheels as a first option, after that the choices are plentiful, from carbon fibre and fibreglass panels to less obvious choices like downpipes on turbos
(an XS power downpipe saves 12 Kg over a standard cast item), its also worth considering weight if replacing parts for aftermarket options, an XS-Power turbo exhaust for example is much lighter than the equivalent HKS or Departure item.
An aftermarket air-filter or induction kit will also be much lighter than a standard airbox assembly.
Roll cages
A roll cage is not a bad idea for a track only MR2, especially once you are accustomed to fast track work or are running very sticky tyres, there are, as ever downsides.
A roll cage will add some weight but this can be partially recouped by removing door bars and door skins, but more importantly safety.
Fitting a roll cage to predominantly a road car means you suddenly have a 2 inch diameter steel pipe right next to your head, where as before you had some rounded plastic 6 inches away, so a minor spill or bump on the road which would have you head flinging to one side in free space now has your head flinging onto a steel bar, with the potential to cause injury where before there was none, its for this reason I wouldnt recommend a roll cage in anything other than the most hardcore track cars.
It is also more difficult to get insurance with a roll cage fitted for this reason.
A
round the dash cage, think very carefully before putting any cage in a road car
Roll cages can be bolted in or welded in, and either go round or through the dashboard.
The ones that go around the dash make entry and exit a little tougher but obviously mean you do not have to destroy the dash.
By now you will have quite a track beast, a noisy, hot, uncomfortable place in which to have lots of fun and scare other track users who expect a little MR2 to get in the way, not go round the outside down the Craner Curves!
Out on track
As we have mentioned at the beginning of this article it is advisable to check some aspects your car before venturing out on track.
It is also worth considering some others bits and pieces to make your day more enjoyable.
Take some tools, a simple socket set, screwdrivers, spanners, pliers, duct tape and cable ties could save you from going home early on a trackday, for example if a water hose pops off of a bit of body trim becomes lose, a trackday is still an expensive hobby, so it would be a shame to waste a day for something as simple as that.
A jerry can or petrol container is also not a bad idea, my own turbo will do just over 7 mpg on a dry trackday, and it is not especially highly tuned, so using a tank in a morning is a real possibility.
Any on-site petrol stations are likely to be very expensive assuming they have one at all, driving 15 miles to find a petrol station between sessions is always an annoyance!
Venue, depending on your car you may get very different experiences from one trackday to the next.
If it is your first day it is worth considering the venue, as an incorrect one may put you off for life! For example, if you have a pretty standard Mk1 a big track like Silverstone may make the car feel underpowered, likewise a highly tuned Turbo may be quite scary around a wet Cadwell Park, with is minimal run-off and car crushing concrete barriers.
Airfield days are good for novices as they chance of damaging your car are virtually none, for the more experienced person though the challenge of an airfield is much less than that of a proper circuit.
Finally, it is always good to go with a group to exchange banter, tips on cars and driving and its a good social gathering, there are many trackdays organised through MR2 owners forums on the internet, some of which will be attended by our good selves, so hope to see you there and drive safely!
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