Sweet an innocent Stormy blue 1.8 NC gets a high powered 2.5…..

For sale now at: £7500.

Here at DuratecNC we love engines, engines is what we do best, engines are what people can’t do themselves as they don’t have the knowledge, nor the equipment. Some think they can, but then you drive past them on the straight, it blows up or it doesn’t meet expectations. We can do other things, but then hey, so can you, or at least, some of you can. You can scrape rust off bodyshells and paint them, fit roll over bars, coilovers, anti-roll bars, uprated brakes, wheels, polish bodywork etc. If you can’t, we’ll do that for you too, no problem.

So it made sense to me to put together a cheap car that had a highly modified, dyno proven great engine in it which you could buy, take it away and do what you wanted with it. The car could be test driven, bought, driven home. Developed further to make it into a proper track weapon or simply take the engine out and put it in your own car. Want just the engine? No problem, we’ll drop it out for you – take £1000 off the total price and it’s yours.

So here is such a car, it’s a bit more than a Star in a reasonably priced car.

It’s an 07 NC which originally had a 1.8 in it, 77600 on the clock. When the engine was changed the ECU and clocks were changed to those from a 2.0 and the mileage on those was 67200.

Underneath it’s solid, some surface rust here an there. The O/S cill and inner wheel arch area to the rear has been completely cut out and replaced (by me) so it’s been done properly. Painted and anti-stonechipped, wax injected in that area. Both cills were injected too. The rear and fronts of the cills had all surface rust ground off then coated with Rustbuster Epoxy (one of the best treatments around). It’ll be a few years before anything needs doing to the chassis.

Whilst the front subframe was off all the suspension bolts were removed, greased and put back in. Don’t underestimate the importance of this if it (the suspension) is to be overhauled at a later date as it’s a bugger of a job when the bolts are rusted in. It often includes the cutting off of suspension arms or complete removal of subframe and suspension. Not now, everything will come off like it did when new.

Rear sub is something else, never touched it so do with it what you will or pay us to sort it, but at least it’s easy to drop.

Exhaust is stock. It will need at least a manifold to bring the power back as it was mapped with an ILMotorsport one on. This is available by separate negotiation. A larger bore manifold (known as a 1.8″) is available elsewhere and would release a few more horses too.

Upper bodywork shows no rust apart from one rear arch which has a patch right at the top and a small part of the lip underneath has come off. Otherwise it’s what’s to be expected from a 2007 daily used car. Hood is fine, clean, no leaks.

Really the only bit of rust on the upper bodywork and an easy fix.

Suspension: Std dampers with H&R lowering springs.

Brakes work ok. Discs a bit worn, but calipers look they’ve had some attention or replacement recently, are all free and not seized.

Interior is stock, cloth seats, nothing much to report, but it does have some kind of Bluetooth fitted throughout. No leaks. Windblocker hinges have been snapped off, but if you want a replacement it’s no problem. Comes with a new and fully working oil pressure gauge, if you’re looking at that wondering what it means read the blog and the gauges for sale page.

So onto the exciting bit; the engine. It started off as a low mileage 2.5 which was stripped, cleaned and inspected and the following parts were thrown out: Pistons, conrods, bearings, balance shaft cartridge, sump.

Block bored with deckplate to suit new forged and lightened over-sized pistons, CR 12.5:1. New forged steel rods, DuratecNC St3 cams. Mild porting to head, valves and seats re-cut, lapped in. High lift, high RPM race valve springs.

All gaskets, seals, bearings replaced (including pulley bearings at front of engine) Crankshaft balanced and keyed, 550 injectors. Runs on 99 Ron, VVT is operational, fully and expertly remapped Mazda ECU.

Running bigger injectors gives you the headroom for other mods without finding bigger injectors. Putting both a bigger and completely different specification engine in with much larger injectors requires a calculation doing and applying to the ECU so it will run (this is in addition to the mapping which comes afterwards). This has been done which is why it drives at least as well as a standard road car.

A stock 1.8 makes 124 bhp and 123 ft/lbs. 2.0 produces 158bhp & 139 ft/lbs torque

This shows BHP @ the fly, WHP and torque in Nm

Output of this 2.5 is now at approx 100bhp and 82ft/lbs more than the car had originally at nearly 225bhp and 205 ft/lbs of torque:  Which is actually being held back by the original intake manifold. Stick some ITBs on to make approx 250 – 260 BHP (it’s dependent on how big the ITBs are) and you’ll have one of the quickest naturally aspirated NC in the UK. That’s more than a supercharged one! It’ll rev safely to 7500 and as it stands is devastatingly quick, 60 comes up in less than 6 seconds now yet it looks completely stock under the bonnet.

This is a bit odd as it shows BHP and torque @ the fly on the graph, but torque at the wheels is displayed top right. Red is power with the base map, green is after final mapping.

I built the engine with the intention of it being a full on track weapon which it is, but it’s also so easy to drive it would actually make a great road car. It’ll pootle along lazily at 1 – 2000 rpm in a high gear, but drop it down and it’ll pull hard until right off the end of the rev counter. It really does pull like a train, I really can’t say how much I am impressed with this engine and sure you will be too if you’re looking for a very capable N/A engine.

Comes with MOT until Dec 2021

Has not been declared to DVLA as an engine change as yet.

How the price breaks down:

Engine £6150

Car £1000

Removal and refitting of engines, mapping, development work, transport, welding, MOT: £2000

Total £9000

Total asking price £7500

Red trace is base map power, green trace is final WHP (187) the other two traces with dots are AFR Torque ATW top right (168)

So do with it what you will, improve the rest of the car to suit the engine or simply take the engine out and put it in another car, put your old engine back in this and sell it on. If you want the engine taking out and sending then there will be an extra charge for this.
This engine would benefit massively from ITBs as the original manifold is holding it back, estimate another 30 bhp on top of what it already has.

Because of our honesty don’t expect to turn up to haggle much as you’ll find you have no reason to, it is what it is.
Don’t just join in a track day to keep up with all the other MX-5s, set out to rub their noses into the tarmac and laugh like a lunatic 🙂

Want an engine to this exact spec supplied and built? £6150 including map. 

Associated Blog entries linked to this article:

More of a technical overview of what was done to the engine: http://www.duratecnc.co.uk/?p=823

Why an N/A?  http://www.duratecnc.co.uk/?p=214

Don’t know anything about the MX5 NC? http://www.duratecnc.co.uk/?p=52
Technical aspect of the 2.5: http://www.duratecnc.co.uk/?p=180
Cheap trackday car, why? http://www.duratecnc.co.uk/?p=369

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