1996 Mazda Mx5 with ITBs - p16 video clip :)

[goldnrust]

In the spring & summer of 2010, I managed to shoehorn a 13b rotary engine from a 1989 Rx7 into my little red Mx5. It was my first big car project, and a steep learning curve but a lot of fun. When it was finished it made for a great little car but for various reasons including finances and me getting hold of a certain 1983 Rx7 in gold, I decided to sell it in spring 2011.

A couple of weeks ago I was looking back at old photos and thinking about my old Mx5. As far as I knew it was still with the mx5 parts/breakers company I sold it to (they bought it to take it to some shows and stuff as a point of Mx5 interest) so I dropped them an email just to say if they ever decided to sell let me know A few hours later I get an email saying 'well actually it split a fuel line and broke down about a year ago and has sat since if you want it back you can buy it from us'. I couldn't let this opportunity pass, I needed my 'red friend' back in my life.

Yesterday I paid, and tomorrow they are arranging transport for me, so hopefully it'll be home in just a couple of days The plan is to re-do the fuel lines (with safety in mind!), to remap the engine with the knowledge I've picked up in the years since I sold it, to improve on the exhaust design (quieter please, I feel too old for a car that sets off car alarms as it drives past due to sheer exhaust volume!), to make it corner better with chassis bracing and coil overs and finally to fit some cool new wheels

But while I wait on delivery….. lets start this story at the start. *cue the soft focus and harp to signify a flashback*

It's late spring 2008. I passed my driving test about 6 months ago, having done 2 years of all weather motorcycling I'd had enough, and I was driving a cheap Skoda Felicia. It's one of those spring days that hints at what's to come from summers warmth and sunshine, and there's a party to goto. A work colleague arrives to pick me up and take me to the party… in their MGB. I've never been in a soft top car before, wow. I've never sat so low in a car. I've never felt a car so raw and simple, almost motorcycle like compared to the modern bland stuff I'd driven at the time. I want one.

My dad patiently listen to me ramble on about how great it was, and how I liked the look of Triumph Spitfires, and how I could maybe even afford one. He even goes as far as to test drive some with me. I liked them, he said they were too rusty. And this is when he suggests an Mx5, I turn my nose up initially but warm to it when he explains how in many ways it encapsulates lots of the ethos of the old british sports cars but being 90s japanese it would be reliable and wouldn't fill up with water. He seemed pleased that he'd managed to put me off buying old rusty unreliable cars and back on the straight and narrow. His words of advice obviously didn't sink in really, see the Lancia and Rx7 threads! hahaha.

The second mx5 that we went to see was the right mx5. A 1996 1.6 in classic red. Being a '96 UK car it had the slowest mx5 engine, the 88hp reduced power for cheaper insurance special. Full poverty spec: no PAS, no central locking, no electric windows, no ABS, no airbags. But I didn't mind, it had no roof and I had motorbikes if I wanted to go fast!



My mum still goes on about how big the smile was on my face the day I drove it home, and how I didn't stop smiling for days. I was happy.

Then the inevitable happened, and I started spending more time on the mx5 forums, reading about various modifications. I caught the bug. No messing about with air filters and back boxes and Halfords wheels here, I went straight in for the kill with a bolt on turbo kit!



Which gave it a much needed boost of power. Over the next couple of years the car evolved bit by bit, eventually gaining a decent 4 point roll bar, Lotus Elise seats, lowering springs and replacement dampers, 15" Enkei wheels with 25mm spacers, a lip spoiler and much more power!




The basic bolt on turbo took me up to about 130hp, from the stock 88hp. Then with an intercooler, bigger injectors and a piggyback ECU I got it dynode at 193hp. After that a swap to the higher powered 1.6 mx5 cams, a switch to Megasquirt and some more boost for good measure took it on to an estimated 230-240hp. It moved pretty well by this stage!

[goldnrust]

It was around this stage that my love affair with 2 stroke motorbikes really began, and that a friend bought a certain gold Rx7 on a late night eBay session. This is the day we picked up my friends Rx7, which would in time become my Rx7. The Rx7 lined up with duckdown's Corrado (which he'd also be interested in finding back if anyone knows of it's whereabouts…), my friends mk3 Polo saloon that died after too much boost shattered a piston and too much rust shattered the sills, and my mx5



The result of the rx7 and 2 stroke influx was I began to get interested in rotary engines. In fact the rx7 had come with a spare 13b engine and gearbox from a 1987 Rx7. It seemed a waste not to make good use of it, so I gave it a good home



Jumping into the project head first, internet research had told me that the n/a 13b gearbox was internally the same as the mx5 albeit with different ratios. So it was simple enough to mix and match bell housings and tail sections till I had a gearbox that would match up to the mx5 prop and power plant frame/gearbox mount and also bolt upto the rotary engine.



I picked up a cheap hack to keep me mobile while I did the conversion, a mk1 Fiat Punto. The joys of head gasket failure and differentials coming apart, that's another story for another day though… Anyway, this meant the 1.6 block could come out of the mx5.



The new gearbox dropped in just fine, even the clutch slave flexi matched up to the end of the mx5 hard line perfectly!



And the engine drops in just nicely…



.. or so it seemed. The engine is sat on the steering rack, there's no sump fitted and it;s still not quite meeting the gearbox right.

So there was nothing for it but to break out the grinders, and make some room to lift the gearbox a bit.




This is a bit better Just enough room for the oil pick up with a sump that's shallow at the front.



At the time I'd not learnt to weld, so the next step was to get the car taken to my dad's work where one of his colleagues, Bill, would weld over my cut outs and tidy things up.




Having already decided that the 13b style engine mounts weren't gonna fit, Bill was good enough to make up a 12a style front mounting for the engine, that was welded right onto the standard mx5 subframe. At the time it went over my head a bit but now I realise just how I couldn't have ever considered doing this conversion without having him doing the fab work for me for beer money.



So The engine went in, and it fits, and this meant the interior could go back in too.

[goldnrust]

Bill next made up a lovely custom sump to my designs, and extended the oil pick up.




Now the real fun began, the sump caught on the subframe by just a couple of mm. And so the fun began, a couple of weeks of repeatedly fitting the engine and making adjustments and brackets; making clearance in the subframe for the sump, trimming down the intake manifold to clear the chassis rail, making sure the new larger radiator would fit, finding room for the oil cooler and making brackets for it, etc.



But finally it was starting to look like an engine in there!



So the next step was to send it off to the custom exhaust place that was making the exhaust. Looking back this is something I could have done for myself and saes a lot of money in the process, but at the time I'd not picked up a welder yet and the idea was quite daunting. On top of that the manifold was gonna be tough. There was very little room for the manifold because of the steering column. Life it much easier for guys in the US doing these conversions with the steering column on the comparatively empty left side of the engine bay!



I was so excited that this felt like it was nearing ready to drive, but the exhaust shop came back after a few hours and said there wasn't enough room. So back home it came, and thankfully Bill was able to remove the hump in the subframe that would have been for the old piston engine mounts, which gave us quite a bit more room.



Wahey! Exhaust




After that t was fairy plain sailing getting the rest of the engine bay loom built up, the intake manifold all fitted up, the radiator hoses fitted, and it was all ready to fire up At the time I was very much focused on getting the thing running, knowing tidiness could come later. Also as a slight rebellion to against all the colour coded neat engine bay world of my friends with VWs, so I pretty much used the most garish colour paint I could find for brackets and multicolours electrical tape to wrap the loom. In hindsight it looks a bit rubbish, haha.



On the same multi-coloured front, I did silly things with the boot lid. The boot lid was shot on my Mx5, about 6 weeks after I bought it I'd reversed into a fence in the dark and I'd bent the corner of it. I'd tried my hand at repairing it and repainting it but my bodywork skills weren't up to the job at the time. I've played with spray cans to do silly sort of absract things on my mountain bikes and stuff since my early teens, so it seemed the obvious choice to paint the boot lid in a stupid way. At the time I was building quite a pile of scrap engine and car parts in the garden (I'd later weigh it in to find I'd had a 1/4 ton of broken car bits in a pile in the garden!) so we grabbed a bunch of parts to use as stencils, grabbed a selection of old spray cans fro, the garage shelf and got wild!




So the only thing left was to get the car started and get driving it!

[goldnrust]

Easier said than done. It took me and my friend Ross two 12 hour days of working on it to get it running. We had a number of electrical faults, basic things like sensors wired up back to front, but the sensor was buried under the intake manifold and it needed all stripping down to replace… along side a number of red herrings with the Megasquirt and then a wideband oxygen controller that took exception to being swimming in petrol in the exhaust of a car that was flooding heavily and to top it all off, a base map that seemed to be nowhere near!

But eventually it fired up. This is the second time it ran No wideband, just tuned by ear and feel, first ever drive of this engine up the road. It's a bit wobbly and as you can hear, stupidly loud!



A number of small detail items were sorted out on the Mx5 after this point but essentially the build was done. The biggest thing was getting it mapped as best I could. It made 175hp at the fly and 160hp at the rear wheels on a local rolling road. Not bad and a lot of fun in the nimble Mx5 chassis. While I was 40-50hp down on the turbo set-up I previous had, I didn't really miss it. The sharp response and revvy character of the rotary was more than worth the drop on outright power




After that I just drive it lots! I spent stupid amounts of money of fuel, 5-600 miles a week at 20mpg = £££.



I did get fairly excited when it popped up in a Speedhunters event coverage post! I've never had pictures of any of my cars get any media attention.



I did buy some new wheels, 14" Watanabes, which I think looked awesome, but they needed new tyres, and I ended up selling them to buy parts for the Rx7.



In the spring of 2011, I came to the conclusion that selling it, and concentrating on the Rx7 (build thread of that HERE btw) was the way forward. So I polished it up and got an advert up online.





A couple of guys came up from the south coast to buy it and away she went. I was a bit sad to see it go, but mostly just excited to get the Rx7 going!

[/flashback]

[goldnrust]

That brings us up to date with the car's story. I don't really know much about it's time with the new owners. I do know they fitted brakes from one of the newer mx5 model which are larger diameter disks, they also swapped the wheels for some Toms in 16", not my taste really, and fitted a normal red boot lid.

From there I only know the info from the emails of the past couple of weeks. A fuel line split under the car, and petrol caught fire when it hit the exhaust damaging some of the wiring loom but doing no other damage. After that they parked it up and left it. The MOT and tax ran out in February 2013.

Apparently they were going to re-shell it for an old Mx5 shell that doesn't need a catalytic convertor, but that seems naive seeing as the MOT emissions specs are done on the engines age, not the chassis age, so I was able to quite easily put the MX5 through as an '89 engined non cat test when I MOTed it myself. With that in mind they'd started breaking the car. They sold the clocks, drivers window winder mechanism, the steering wheel and took the Lotus seats for one of their other cars.

This is how she looks now, poor thing




She should be delivered home to me in the next couple of weeks, and I can start making her better than ever using all the skills and knowledge I've gained in the years since I sold her.

[luckyseven]

Barbarism Set fire to a car, leave it to rot and sell half the good bits off it. Grrrr

I'm sure with the skillz you've developed since you last owned it, the li'l MRX-5 will be up and running better than ever, Steve

[Clement]

Bookmarked! It's heartbreaking to see it decaying, good job on buying it back

I hope it's not too much of a hassle to get it back in shape, good luck!

[Mark]

This is going to be awesome! What's going to come to the gathering?!

[swampy76]

Nice story

Think it's bad that a so called specialist let it get in to that state

Looks like a fun project that could have a quick turnaround or take a while depending on how you go about it

[qwerty]

Looking forward to you getting stuck in!!

[grizz]

Great flashback.

Thanks for sharing.

I guess you know Oldones Racing??

[goldnrust]

Cheers guys

Swampy, the plan is to get it back on the road fairly quickly, replacing the missing parts and making just a couple of changes. Then the longer project sets in to make it kinda my perfect mx5. Since selling this MX5 I've actually had 2 more, both also mk1 in classic red, so I've got fairly clear idea about where I want it to go and what I want it to look and drive like.

Mark, chances are this will be coming to the gathering now, if the Fulvia hasn't sold by the time the gathering happens I might take that though as I know lots of people have been following its build. I think this might be more fun up tyne hill though if I get the chance

Grizz, yeah I met Era briefly at a show but mostly know him via the Exile forum, which I was relatively active on when I had my 1st gen Rx7.

[adam73bgt]

Got this bookmarked I'll be interested to watch how the recommissioning goes, I've always kinda wondered why there aren't more rotary MX5's about

[goldnrust]

Theres a simple reason: £ per HP.

I liked the MX5 scene when I was more involved in it, but with some distance it's easy to see that with such a following it's easy for the scene to be quite introvert. It's really surprisingly cheap to buy a bolt on turn kit for an Mx5, fit some aftermarket management and hit 250hp. To spend double the cost of that, with a relatively large amount of fab work needed and end up 70hp down with a car that only does 20mpg isn't for most sane people Any kind of engine swap is rare in the mx5 work really, everyone now and then someone swaps in an SR20DET or tried to fit some sort of japanese straight 6, only to find they could have got the standard mx5 engine with a built short block capable of taking huge boost levels and making big power for considerably less.

Coventry isn't far away really, you should pop down someday if you're still keen on the rotary swap for the MGB, we can talk all about petrol powered spyrogrph/spinning dorito engines

[luckyseven]

Uncle Era of Old One Racing; genuine legend in his own lifetime and font of all rotary wisdom, lol Genius with a carbide burr

As to rotary MX-5s, what Steve said really. Upgrade kits for the standard MX twin cam are so cheap and easily available (such as the excellent BBR turbo kit) that why would you bother with all the faff of an engine transplant unless you a) really need to scratch your fabrication itch and b) really need a rotary in your life


...although I think everyone needs a rotary in their life, clearly, they just might not know it yet

[adam73bgt]

Jun 22, 2014 22:24:31 GMT goldnrust said:

Theres a simple reason: £ per HP.

I liked the MX5 scene when I was more involved in it, but with some distance it's easy to see that with such a following it's easy for the scene to be quite introvert. It's really surprisingly cheap to buy a bolt on turn kit for an Mx5, fit some aftermarket management and hit 250hp. To spend double the cost of that, with a relatively large amount of fab work needed and end up 70hp down with a car that only does 20mpg isn't for most sane people Any kind of engine swap is rare in the mx5 work really, everyone now and then someone swaps in an SR20DET or tried to fit some sort of japanese straight 6, only to find they could have got the standard mx5 engine with a built short block capable of taking huge boost levels and making big power for considerably less.

Coventry isn't far away really, you should pop down someday if you're still keen on the rotary swap for the MGB, we can talk all about petrol powered spyrogrph/spinning dorito engines

Aye thats a fair point, also I guess the rotary and piston Mazda fans keep themselves apart to some degree

I may have to take you up on that sometime, I'm still considering my options engine wise, to be honest its been a while since I was last in a rotary engined car (passenger in an RX8 round thruxton) so I should really remind myself what they're like

[goldnrust]

There's pretty much two type of people on the mx5 forums in my experience, those who'd have a Lotus Elise if they had more money and those who'd buy an rx7! Another point to make is that for most Mx5s are cheap thrills and rotary engined Mazdas are thought of as expensive cars to run, that puts people off.

In many ways an rx8 Renesis engine feels just as different to its predecessors as the engine in the new MG6 does to your B series. The Rx8 is still a rotor, and has a certain character that can't be suppressed, but is much more refined. The older 13bs are so much more raw, more pops and bangs, more flames, more punch you in the back mechanic throttle response. Very different!

[georgeb]

Excellent start, and bookmarked. I shall look forward to evolution.

This also must be the first time I've ever read a coherent explanation for dropping HP!

[adam73bgt]

Jun 22, 2014 22:49:42 GMT goldnrust said:

There's pretty much two type of people on the mx5 forums in my experience, those who'd have a Lotus Elise if they had more money and those who'd buy an rx7! Another point to make is that for most Mx5s are cheap thrills and rotary engined Mazdas are thought of as expensive cars to run, that puts people off.

In many ways an rx8 Renesis engine feels just as different to its predecessors as the engine in the new MG6 does to your B series. The Rx8 is still a rotor, and has a certain character that can't be suppressed, but is much more refined. The older 13bs are so much more raw, more pops and bangs, more flames, more punch you in the back mechanic throttle response. Very different!

Hmm sounds like an excuse to get out in more rotor powered cars for me I do like pops, bangs and flames... (but then who doesn't!)

[Deleted]

it is a shame to see all your good work get trashed :/ but tlc will bring her back to life