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spending too much money
1,187 Posts
Discussion Starter · #1 ·
Hi all,

I thought I would share my new project with you on Nutz - it's not an mx5 but it does run the mx5 drivetrain :)

The car is a roadrunner sr2 which will be running a mk1 1.8 mx5 engine, 5 speed gearbox and rear LSD diff.

This car originally started off as one the Mazda on track hire car which was one of the first ever built sr2's. After many years of abuse the car was then sold back to roadrunner and here's where I come in!

I had been speaking to mike at roadrunner regarding a new kit I wanted to order then came the proposition that I would buy the old Mazda on track car, it would then be stripped back down to bare metal and remade to the 2015 roadrunner sr2 specification (the main obvious change being going from outboard to inboard front suspension)

So after discussions and a great package of works agreed I paid my money and the journey began..... It was then swiftly halted by a major fire to the body shop unit next to roadrunner's which nigh on destroyed roadrunner's unit and the equipment inside (rolling road / lathe / tube notcher etc etc)

Luckily for myself, the car I had purchased/waiting to be worked on was at another premises and survived to ordeal

This clearly meant delays to the project thankfully Mike is starting to get back up and running again so the project continued!

Here's a few pictures in various stages of the build:


The next one's show the new front inboard suspension mounts:



My new seats on purpose built runners:



The last picture also shows a new addition which is the removal rear stays, here's another picture:


Makes rear diff maintenance easy! The roll cage is pretty intense, but is well proven and tested (can see the stress testing video on YouTube)


The plan is to go for a John player special theme which means gloss black bodywork and gold powdercoated chassis/roll cage/wheels etc

I am planning to keep the car fairly standard to get it shaken down / through IVA etc then I will be progressing with my TD04 turbo build :)

So overall the project is progressing nicely, I just need to confirm my shade of gold powdercoat this coming week as it will be going in for coating Thursday!

I have the engine and gearbox will me at home to prepare/clean up before sending it back to be fitted into the car (I will be receiving the car as a rolling chassis with many bits already fitted by roadrunner)

So far I have dismantled the engine to the point where I just need to remove the flywheel/crank pulley and water pump before painting and assembly begins - the engine will be getting a cambelt/water pump service before heading back.

The engine bay colour scheme is going to be aluminium silver block/head/inlet manifold and the cam cover will be shaved then painted wrinkle red :) can't decide whether or not to expose the cam gears yet - difficult decision!

I will try to keep this updated as I go along, I will post my current progress with the cam cover shortly!

Thanks for looking and any comments welcome :)

spending too much money
1,187 Posts
Discussion Starter · #2 ·
Ok first update post!

The engine cam cover is pretty mundane at the best of times so I took some inspiration from many places including this website, and various historical pictures of JPS/lotus cars.

It started off like this:


I removed all the internal baffles then took it to work for shot blasting:


Looked in good condition but I wanted the 'shaved' look so off came the lettering:



I did a bit of blending around the PCV? valve hole as well because it was a bit untidy.

It's now ready to be cleaned in the parts wash and then etch primed (will be done at work when I can as I have everything I need including an industrial oven)

spending too much money
1,187 Posts
While I'm on a roll... Third update!

So with having the opportunity to freshen the engine/gearbox I wanted to future proof my drivetrain.

I am planning a turbo conversion in the future using a TD04 so I needed to ensure my clutch and flywheel were going to be up for the task.

So the first purchase was the clutch:



I managed to source an ACT xtreme clutch for a 1.8 mx5, apparently rated to approximately 315ftlb which is more than enough but I can maintain a full face organic clutch as well which was the main thing for me.

Second purchase was the flywheel:


It's an RPC 1.8 flywheel from Tegiwa imports. It is a gorgeous piece of engineering, just looking at it makes me smile (yes I am sad like that!)



And a final check to confirm that the street disc does indeed fit the flywheel:


Happy days, can't wait to get this setup on the road. It will definitely be overkill for when I'm driving the car NA but it will be better to break the clutch in without boost first :)

spending too much money
1,187 Posts
Discussion Starter · #4 ·
Long overdue update!

Firstly I had to decide the correct gold powdercoat for the chassis.... This turned out to be very difficult in the end - at first I thought RAL 1036 (Pearl Gold) but that basically looks more brown than gold. I then settled for sun gold which is made by Tiger coatings. It was fairly expensive ordeal changing the powdercoat colour but it's definitely worth it!

First is the chassis in a special primer (can't remember exactly what is was):



Then the gold powdercoat was shot and the result:


Happy days :)

Then it was back with Mike and the black aluminium panels were fitted, giving the contrast against the chassis I was looking for:




And the wheels have been refurbished and shot in the same powder:


Next overdue update is the engine/gearbox!

spending too much money
1,187 Posts
Discussion Starter · #5 ·
Ok so engine/gearbox update!

I've been working on this for a few days each weekend making sure it's ready for when it's needed. My colour scheme is going for aluminium silver block/head and a wrinkle red can cover, shaved and chopped. Any engine ancillaries are gloss black or silver depending on how much colour in an area.

So firstly I had a very greasy engine/gearbox, done approximately 80k from an 1.8 import mk1.


So the strip down began, which meant everything came off the engine although I did not remove the head (not needed)

I took many parts to work for shot blasting which included the inlet manifold/water pump pulley/throttle body.

Everything got etch primed and then painted in Simoniz Matt aluminium engine enamel or gloss black - should be good for the temperatures the engine sees on a good run!

Sadly I didn't take many pictures of the progress (too busy doing it!) but here's one of the block prior to rebuild (the block recieved 2 coats of etch primer and 2 coats of paint) -




So then the rebuild commenced, which included a new water pump/cambelt kit. It went pleasantly well with no major concerns.

The finished product ended up like this:





And finally my favourite one:


So the engine/gearbox are pretty much ready to go bar from a few sundries/additional service bits which I'll do once it's in (oil changes/spark plugs)

Looking forward to making further progress/getting the engine in to see how it looks in the car.

I have the calipers/discs to tidy up next - maybe next weekend!

spending too much money
1,187 Posts
The toyo R1R are meant to be very soft (main reason for buying them!) which I would guess on anything heavier than a kit car means they will get chewed up :(

The car itself is booked at around 550-560kg, although weight saving will be done where possible, for example the OZ ultraleggera wheels are 5.2kg without tyres and approximately 11.5-12kg with tyres which as light as I could afford in 15" without going forged/magnesium wheels :)

I'm initially hoping for sub 600kg and then I will change materials/lighten where possible in the future.

Those seats are actually roadrunner's own mould, although they look similar to tillets :) they are fibreglass and weigh very little too!

Looking forward to stoneleigh kit car show, hopefully attending on Monday :)

Thank you for the kind comments all :)

spending too much money
1,187 Posts
Quick update again!

Engine/gearbox/calipers back with Mike at the roadrunner garage ready for installation - going to get busy very quickly I think!

It's looking lovely with its black bodywork going on well and the rear arches look great, credit to Mike and his team doing a great job:





And a quick sneaky peak at a possible winter upgrade that I'm contemplating before the turbo conversion:





They are AT power throttle bodies, from a custom hayabusa build which are 50mm inlet diameter and a taper to 45mm (same ID as jenveys) , they are also 'shaft less' butterflies which is quite fancy :)

spending too much money
1,187 Posts
Discussion Starter · #17 ·
Ok well I have really slacked with updates so I'm just going to pop a few pictures then do an update in the future but long story short, all road legal and just waiting for plates to arrive!







And the last update, had a dyno session to dial in the ecu settings (thanks to Canems ECU)


And the result, 145bhp on a stock engine with the only mod being 5.6kg flywheel!


Watch this space!

Sent from my iPhone using Tapatalk

2,700 Posts
Excellent piece of kit, got me thinking now...

spending too much money
1,187 Posts
Discussion Starter · #20 ·
I nearly forgot about this thread!


She's home, road legal and ready for tinkering :)

The car is simply excellent to drive, so much so that I have decided against going FI and instead I'm going to focus on a stock block NA/ITB build - shooting for 160-170 flywheel horsepower.

The reason? After driving the car with just 145bhp it was enough to make me realise what I actually wanted this car to do - provide a raw driving experience.

The turbo kit would have been great fun/excessive BHP for the car but I just don't think it would have the same experience that I was looking for.

The current modification plans (engine wise):

- BP4W ported/skimmed cylinder head (covered in separate thread on here)
- jenvey throttle bodies (just ordered yay!)
- upgraded camshafts
- 2.25" exhaust with new exhaust manifold

I will update this thread with none engine updates as well when I remember!

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