Budget MX5 tarck hack advice

[Onetrackmind]

Hi everyone.

I’m considering building a cheap track day MX5. My plans are to pick up a 1.6 Eunos and fit the brakes and Torsen diff from the 1.8 Eunos. I think I will go for the 1.6 as they’re generally cheaper and I’ve heard that there is more scope for FI in the future. Does this sound logical?

My plans would then be to fit coilover suspension and get this aligned properly. I’ll fit a rollover bar, track day brake pads, fluid and braided hoses. I’ll also fit some budget bucket seats.

Is there anything else I should consider for a budget MX5 track hack? Are up rated ARB’s or poly bushes a necessity?

In the future I will hopefully fit lighter alloys with track day tyres. I’ll also consider a cheap turbo (HKS) or supercharger (M45) kit when funds become available.

Thanks

[worldwidewebs]

I can't help on the FI side of things I'm afraid - the best people to ask are usually to be found on MX5Nutz.

Just over a year ago I bought myself a standard but solid Mk1 1.6. The following is what I've done to the car:

- Gaz Gold Pro coilovers. Used and proven in the Ma5da racing series. If I was buying again I would still get these and they'd be my first mod to the car

- Brakes. Standard discs and calipers are fine (at least with non-FI levels of power) but you'll need to replace the pads. I used Yellowstuff initially which were shockingly bad but have since put on Carbotech XP8 which are sensational. I wouldn't bother with changing the calipers or disks until you've experienced these pads

- Fluid. Any decent DOT 4. I use Millers 300 Racing (£13 from Opie Oils)

- Brake lines. Fitted a set of braided hoses but tbh never felt any difference. I'd wait until they need doing

- Bushes. Never bothered as my OEM ones are in good condition. Can't say the car feels bad

- Rollover bar. Fitted a TR Lane TD bar and harness bar. Good for the money but, as with pretty much all similar items, it will restrict rearward seat travel

- Seats. Sparco Sprint 5. Not bad for the money but am about to swap for a pair of JK Composites seats (if they can pull their finger out). Drivers seat is mounted to the floor (rear seat humps removed) for better legroom

- Wheels/Tyres. 15" Team Dynamics with Hankook Ventus V12 K110 tyres (35 quid a corner). I only changed to 15" from 14" due to the tyre choice available as the car handles better on 14" wheels but the grip available for the power I have is a good balance. Not a fan of sticky tyres on relatively low powered cars as you might as well drive a train on rails

- Geo. Whatever floats your boat, but get a good one!

As above, the car was superb but I decided I wanted a bit more power without going FI so I fitted a head from Blink Motorsport. The car feels a lot perkier now and has a lot more low/mid-range grunt. Not compatible with FI (as the head is skimmed) but well worth it if you're staying N/A.

That's about it really. Personally, I'd go for changes in the following order (assuming everything else is safe and ok for track)
brake fluid
pads
dampers
roll-bar, harness bar, seats and harness (do one, do them all!)
wheels and tyres
engine

[Onetrackmind]

Great, thanks for that. Seems pretty simple to get the car to decent track spec.

How's the diff in your 1.8? I read that they tend to fail and become 'open'.

Do you find you are able to keep up with other track users easily?

[piefacemate]

Onetrackmind said:

Hi everyone.

I’m considering building a cheap track day MX5. My plans are to pick up a 1.6 Eunos and fit the brakes and Torsen diff from the 1.8 Eunos. I think I will go for the 1.6 as they’re generally cheaper and I’ve heard that there is more scope for FI in the future. Does this sound logical?

Opting for a 1.6 on the basis of cost, but then retrofitting 1.8 components at your own expense sounds rather illogical to me; you'd be better off just purchasing the 1.8 to begin with.

From a FI perspective there isn't a difference. A 1.8 will have ultimately more capacity for power as it's a larger capacity, plus if you wish to look at built engines in the future you general start with a 1.8 as the base.

An automatic car would be a better starting point for FI due to the lower compression ratio the auto offers, but of course you'd have to them fit a manual gearbox.

Bear in mind the cost of building a FI car yourself, particularly for track work. If you've got / will have the funds available you might want to consider one thats fully or partly built to save on the expense. And unless you're a particularly gifted amateur it's a fair bit to attempt on your own.

The viscous coupling and torsen differentials were available on both 1.6 and 1.8 models are optional extras (or standard on some special editions); a torsen diff makes sense for you to upgrade to, but make sure you're purchasing a torsen and not a non-LSD 1.8 diff as they do exist.

Otherwise, worldwideweb's above advice looks pretty much spot on and comprehensive. The only thing I'd emphasise is the TR Lane rollbar, or similar. If you're uncertain about the necessity, youtube MX5 roll-overs, you'll soon change your mind!

And sign up to mazdaontrack for discounted trackdays... hope to see you on a few!

[skinny]

yeah as above, it's worth keeping the early (94-95) 1.8 in mind - these are the lightest of the 1.8's but will come with the bigger brakes and a stronger diff - which will likely be an LSD if it's an import. the 1.6 is perhaps a little more eager to rev than the 1.8 but the 1.8 is obviously a little more torquey, and whilst FI is maybe more common on the 1.6, you won't struggle to charge a 1.8.