Welcome to my full-fat, no-nonsense 1.8 k-series VVC turbo build.
I wanted an awesome car so decided to build a forged 1.8 k-series turbo with up to 300bhp to slot into my Rover 200 BRM.
Basic spec of engine:
- 1.8 k-series turbo block
- Wossner low comp (9:1) 80mm forged pistons
- Maxspeeding steel rods (standard 1.8 nasp length)
- Westwood Ductile liners
- Ported VVC head (keeping VVC)
- Wilky-spec rebuilt T28R ball-bearing turbo (from a 200SX S15) with billet comp wheel
- Emerald management
And some other tweaks to keep it all under control: Brembo 4-pots on front, ZR 160 rear beam and brakes, X-power springs on ZR struts and full poly bush.
Long intro (skip if easily bored and go straight to the pretty pictures):
A couple of years ago it became apparent that the 1.8VVC in my BRM was badly in need of attention – Even as a recon unit it had sprung oil leaks in several places (so bad you couldn’t tell where it was coming from). So I decided to take it off the road and upgrade. The basic brief I gave myself was to make the BRM what I think it would have been if the designers’ brief had been “make something special and don’t worry about production costs”. It’s already a great car and the 1.8 VVC suits it well. The handling is great and whilst the styling isn’t everyone’s cup of tea, I love it. I considered all the options and for reasons I’ll not go into I eventually decided to go with a 1.8 turbo k-series.
So began my project. I did my research and the plan unfolded over the course of several months. I didn’t want to just bung a ZT lump in and get a remap. Like I said, I want something special. I want to make it a project and learn from it.
The weaknesses of the k-series are well known and it obviously has a reputation for eating head gaskets. The problem I had initially was that there are lots of unknowns. So few people have turbo or supercharged the k-series (and even fewer have documented their results in detail) that I was working blind for the most part. It was clear that much more than 200bhp would probably require stronger liners, pistons and rods to be reliable long term. More than 300bhp would probably be unusable/unnecessary in a front wheel drive road car and I’d be placing other parts under stress that are difficult and/or expensive to upgrade (Crankshaft for example). Revs will be kept at a sensible 7,200rpm. So 300bhp became my upper limit, with a rough target of 250-270bhp. Not ground-breaking but the extra torque from the forced induction combined with relatively lightweight chassis and a turbo choice giving very little lag, should make for a very fun car to drive every day.
My first hurdle was to find suitable forged pistons and steel rods, as without viable upgrades the build was going nowhere. This is really where the project actually started around 18 months ago – As I write this I have literally only just taken delivery of the pistons! I needed a low compression ratio for forced induction. The stock 1.8T uses 2mm shorter rods to lower the CR to 9.2:1. My upgrade options were few and far between but eventually settled on Wossner pistons custom designed by Jonathan at JDM Dyno (well-known up north for tuning Elises). Unfortunately there was a bit of a wait. More on this later…
Anyway, here's "The Lady" as pictured at POL 2013:
December 2012 I took delivery of the donor lump – a 1.8t from an MG ZT. This was much easier for a number of reasons – it came with a few bits I would need (exhaust manifold, oil filter housing, etc) and the crank ladder already has the turbo drain (I didn’t fancy drilling a non-turbo one). Additionally, being relatively low mileage, there was less chance of it having previously overheated and softened (annealed), causing the liners to drop to below or flush with the deck and giving me head gasket issues later.
Got it up on the engine stand and started stripping it.
All stripped and cleaned (not using this head):
Naturally, a splash of orange
(this IS a BRM!)
Back on the engine stand
Essential for a reliable tuned k-series: Uprated liners. A few options but I went for the most robust - Westwood ductile iron liners
Trial fitting and measuring the stand-proud. Happily have a universal 0.004" above the deck. Bang on!
This project couldn't really get going until I got the pistons. As I said earlier there were a few options. In the end I opted for JDM Dyno designed Wossner pistons. Jon at JDM has the rights to these pistons so you can only order through him. Annoyingly, an order couldn't go through until there were several confirmed orders. I waited over a year for this to happen and in the end just ordered two sets to get it through. that was a couple of months ago. They are finally here!
They are basically a dished piston which reduce the compression ratio to about 9:1. Big boost would require less than that (8:1) but these are designed for moderate boost (12psi) to retain good off-boost driveability. That's the idea anyway! They also retain the 18mm pin (floating).
I ordered the rods some time ago. I went for Maxspeeding rods in the end. I believe that they will be more than adequate for my purposes. I was very impressed with the build quality. I've included some side-by-side pics with the standard turbo rod and piston
That's it for now. This lot has to go off for balancing before I put it all together!