I built the R32 purely as everyone liked to say RB20s are shit, don't make power, etc etc, plus the fact everyone thinks a 600bhp turbo won't spool well at all on a 2ltr; especially not on a super short stroke engine like a RB20.
I did it to prove a point really, and I did, making a dyno proven 470bhp on a standard head and cams, making some boost below 3k, full boost by 4k, and making big power to 8k+. The mapper said with mild cams and more boost, 550bhp was highly likely even on pump fuel. The thing was a fucking weapon and reliable too, in fact it's still running the same engine and turbo to this day, about 4 years later. There's a couple of pics below, and a fair few vids on my YouTube channel...
Fast forward to now, and one of my current projects is a Renault 5 GT Turbo Raider.
I fucking love them, they were my 1st n 2nd cars when I passed my driving test, and despite all the mental cars I've owned, they're still one of my fave cars as they're mad fun.
For the last year or so I've been helping a mate spec/build his one, and the result is fucking awesome. 230bhp, revving to 7.5k, totally reliable on standard internals, and as it weighs nothing it's plenty faster than stuff like E46 M3s etc etc.
But the main thing I like about them is the driving experience- Being a tiny light thing it feels 10 times faster and more fun than similar performance in a 'normal' car, and that's why I do cars- TO BE FUN TO DRIVE.
Anyhow, despite shit tuners and retarded owners over the years giving them a bad rep for being unreliable, in reality the GTT C1J engines are strong as fuck when done right. Honestly. I promise! So the other week, despite having a totally different plan until then, I decided it's time to fit a man size turbo to one.
I happened to have a pretty big spec GTT engine sitting in the shed waiting to be used, and like history repeating itself, Compressor Racing just brought out another new turbo, a Holset HX32 based turbo, which ticked the box as ideal for the big turbo I wanted (it's about Garrett GT30 size- 500bhp max).
This time it was me making him an offer, and we agreed, considering all the good exposure my RS341 exploits got him, that I'd buy a turbo off him for a good price in exchange for a no-bullshit writeup on what I'm doing, plus some fitting/tuning info on Holset stuff in general (I get asked on an almost daily basis stuff on Holsets on tuned cars, I seem to have ended up with some kind of 'Holset guru' rep), so here it is...
They come in a variety of specs, but what got me deciding I was gonna use one on my GTT is the fact this one has a 7cm (about A/R 0.50) T2 (T25, T28, whatever) turbine housing, which, in my experienced guestimation, I think won't spool up much/any worse than the 0.63 A/R GT28R on my friends GTT, but a whole shitload more power potential.
Yesterday, the first thing I did once I had it, was do a mock up on my original/standard engine to see what needed doing, and once it's all laid out I'll take this engine out, put the fancy one in, and make some serious boost...
I'm gonna make a 3in (probably) custom side exit for the thing, but it's a shame it's not a drag car (and we live in a country that rains a lot), or I'd fit this straight out the bonnet, as it fits perfectly, and is fucking mega- An Inconel exhaust from a Cosworth engine Indy Car!
Refitting it is a bit of a bastard though, but here's how...
Instead, attach a 2nd molegrip tightly to the adjuster, and use that to (carefully!) wind the circlips closed with that (you've got no hope by hand unless you've a massive adjuster knob on yours), and THEN when you close them up, the circlip is fully compressed, and hey presto, job done.
Oh, here's a mini-tip for you too- Keep the bloody plastic dust covers that come on the turbo, don't just bin them- They're fucking mega handy to stop shit getting in your turbo when you're mocking stuff up etc...
Just like pretty much every Holset I've ever seen, the internal wastegate isn't that big, even Compressor Racing state they'd highly recommend external gate if using on a spark ignition engine, and considering the amount of people running Garrett GT2871s and GT30s with internal gates and serious boost creep issues, I wasn't taking the risk of trying it, and an external gate is a better design from a performance point of view anyhow.
So, how do you do it? Well I've seen some people run a solid bar instead of the actuator, locking the wastegate arm shut, but I don't really see the point of that, so I do what 99% of people seem to do- Turn the MIG welder up to full blast, and BZZZZZZZZZZT.
You could cut/grind the arm down too to make it look prettier, but I've left it for now as might use it as part of a turbo hanger to support the weight of the turbo when fitted.
FINALLY, and another question I'm always asked about HX35s, HY35s, HX32s, HX40s, and everything else (think even HX55s are the same? I forget now), the bloody compressor outlet flange!
Rather than a normal slip-on, it's a fancy v-band on most Holsets, so your options are, find what the fuck fits to it, or the most common solutions of grinding it down a little and using a normal hose on it, or TIG welding your own chosen fitting to it instead.
Both of those solutions are easy enough, but you could make something fit, or indeed fit the proper thing. While the ID of the flange is 2in, it's bigger than a typical 2in v-band, and you need a 2.25in v-band and clamp to fit to it, but they do, nicely.
BUT the ideal thing to do is just buy the right thing like they had from the factory, and that's this...
Oh yeah, here's another thing I'm always asked- Holset oil feed and returns.
Feed is 12x1.5 thread, don't need a restrictor unless you got mental high oil pressure, but use a -3 line rather than bigger.
Return is IMPORTANT! Almost anyone who cries about their Holset smoking has usually fitted some pissy small return. It needs to be like 19mm ID bare MINIMUM, ie huge. Even most so called 'huge -12 fittings' on eBay have ID of about 12mm, so nowhere near enough. Fuck the fancy fittings, a plain, but large bore pipe is all you need.