2006 Mazda MX-5 NC 2.0 Sport

Well thanks to this thread I’m now the owner of a mx5.

Enjoy! Let me know when you make your pistonheads thread

Love this thread.
What Xenon bulbs do you have and would you recommend them? The existing headlights on my Sport Black are like candles and feel like I'd like to fix that before the next winter...

And as if by magic, one of my bulbs failed!

I've bought some replacement 6000k bulbs from the same company, so all is back to normal. But while I was shopping, I thought I'd try something a little different (for me).



3000k bulbs, yellow in colour. I've been inspired by watching the WEC lately, so forgive me if I've been 'that guy' and bought yellow bulbs.





I'll be honest, I quite like them. The good thing is that I have a spare set of 6000k's to go back to normal if I get sick of them, and these were only £9.99.

I've not had a chance to test them in the night as one of the bulbs had arrived faulty, flickering constantly. They're sending out a new set, but I suppose you get what you pay for.



Working on a nice flat driveway makes such a big difference from the gravel drive of our old house, that's for sure!

I'm now realising how little I've done to this car. The last post was mid-2022, and it's now March 2023!

In all honesty, I'm not sure if that's a good thing or a bad thing. It's great that I haven't needed to spend anything on it, but there's been little time or chance to do anything else. I still drive it every week though.

The yellow bulbs have been swapped out with the 5000k xenon's once again (I enjoyed pretending I was a WEC endurance racer for all of 2 weeks). I've also removed the stickers from the bumper so that it's back to a clean look again.

I spent the rest of the summer enjoying the car for what it was, went to the odd meet or two, but honestly 2022 has been a crazy busy year (for some amazing reasons), so there just hasn't been much time to work on the car.

A quick meet with Felix and his C6 last year made me realise how hilariously small my car is.





One modification I wanted to make were spacers. Unfortunately, there's a minimum width of 25mm that you have to use if you are to use the standard NC wheels. With no gaps in the back of the wheel for the original studs to protrude into, you'll need a spacer that creates a flush face for the wheel to sit on, hence the 25mm minimum width. Ideally I'd go for 15mm or 20mm, but I'll re-visit this in the future. For now, I was happy to try 25mm.

Ian (the blue MX-5 track car thread) was kind enough to sell me his Eibach 25mm spacers due to his wider tyres rubbing on the arches. I'm running the standard 205/45/17 tyres here, so shouldn't have an issue. I did worry about them on the track, but with the negative camber I'm running I've heard it would be fine. Time will tell...











It's worth noting that the suspension needed time to settle, so the camber and height are a little off. After a day or two, the car now sits like this:



I must admit, I think the look of that is great. It seems to suit the fenders of the NC that much better.

Now then. One of the biggest N/A performance modifications you can do to these cars is to replace the manifold. The NC has two catalytic converters, one in its usual place underneath the car, and another that's on the exhaust manifold itself. Not only is this additional cat quite restrictive, it's horrendously designed in regards to airflow.



You can clearly see from the photo how restrictive this is in regards to airflow, with all four pipes being pinched into the size of a postage stamp before they enter the catalytic converter.



De-cat manifolds for the NC can be quite expensive, so I spent months searching for a good used one, right up until I found a brand new one on Ebay for £250:




I messaged the seller to find out more information about this manifold. The seller was lovely and went out of his way to post the item, even to their own expense. They mentioned:

"They're British made, a company that was in Oxford/Bicester that used to make exhaust systems for all sort of race cars, F1, custom stuff etc. They've since ceased trading I learned. They're nicely made items, the welding is all tig. Its a 'Chris Tullet' unit. It seems they are now 'CTE advanced technologies'."

A brand new de-cat manifold for £250 by a company that's made exhaust systems for F1 in previous years... yup, looks like that's the find of the century.

It arrived a few days later, and the build quality is outstanding.







Replacing this with a de-cat manifold makes a huge difference. Coupled with a remap (needed to code out the O2 sensor), it brings the car from 157bhp to around 190bhp, which shows how restrictive that catalytic converter is. Regarding the MOT, it's technically illegal. Having spoke to my local garage, they mentioned that if a cat was present and it's now removed, it's a fail. However, the car still passes its emissions test without the manifold cat, and there's already one underneath the car where the tester would expect one. This means that, unless the tester is aware that there should be one on the manifold, it would pass. With the heat shields back in place it's almost invisible, so I have no concern of it passing an MOT.

I'm just waiting for warmer weather and longer days to fit this. I've heard it'll be a little tricky, so I'd rather take my time when it's warm. I also need a re-map shortly after as I won't be using one of the original O2 sensors (to check if the cat was working on the original unit), so that needs to be programmed out, as well as to re-tune the ECU with more airflow in mind. Very much looking forward to this.

Speaking of waiting for warmer weather; I haven't been using the car much flately or obvious reasons. These cars don't take kindly to road salt and water, and I'm not a huge fan of the swiss cheese approach to sub frames.



A day or two after the snow cleared, I took the car to the shops. A slow start naturally, but taking the long way to the store would help. Unfortunately, the battery decided to give up the ghost at a store car park with the freezing weather we've been having. No zoom zoom's anymore with this battery.



I picked up a Yuasa 5000 Silver battery that was in my local Halfords, dropped it in the next morning and all is well.



Ish. Since swapping the battery, whenever I come off the throttle and let the revs drop to idle, they drop a little too low, and the car feels like it wants to stall before it finds its natural idling RPM again. Aside from this, the car drives fine. I've driven it about a week now to see if it needed to re-learn air/fuel ratios, but it's no different.

Some investigation is needed...

I'll hopefully have it fitted in the next few weeks. It should make a notable difference by itself, but with the future remap it would hopefully release a lot more power out of it.

That's a fair shout with the coilovers. I'd have gone down the same route, but as all of my shocks were brand new when I bought the car, it seemed a shame to remove them. I loved the damping of the original shocks, but wanted a little less roll and a little less ride height. Hence, the springs and ARB's.

Thanks for the tip with the battery, I'll give it a long idle later today and I'll see how it goes!

4 into 1 manifold and a remap is always around 175-180hp crank on these.

Crucially you get full throttle opening in 1-3rd gear too. They feel substantially quicker than stock.

The manifold adds the character, the remap makes the power.