Dale FZ1

You really need to know what is the turbine spec. Is it a TDO6SL2, or a TDO6H? The difference between those two is roughly equivalent to the difference between GT30 and GT35 in Garrett product so fairly significant. And is the turbine 10cm or something else?

Looking forward to this build story. Laughing at the ratio of preparation time vs race time. How true but also makes it worthwhile

Fingers crossed, this will produce the results you've wanted from the start. 3 weeks to workshop time and tune won't take long to pass. Will it??

Handling doesn't look too wayward, perhaps a little bit of oversteer on exit. Is that likely body roll with camber change on the track transitions? Even that clubman track permits quite a long time at 100% throttle.

Daniel you'll probably find the T67 is not as good as TDO6H turbine spec for your engine and application, if you chose that route. Why not try the Holset, especially if the price and terms are right. If it doesn't perform to expectations, it should be relatively straightforward to rejig the inlet and dump pipe plumbing to take a different turbo. Got any ideas on what you'll use for an exhaust manifold? That's a lot of mumbo to be trying to put to the ground in an R31 chassis... ??

Since they are used in diesel applications it's a fair bet that the compressor will be engineered to be efficient at higher PR. And at the targeted output, it will be running up around 20psi

There is very little information available on Holset gear, since they are not sold into the performance aftermarket. You have done well to find out that much info on the specs, but obviously there are more details that will dictate what it can flow, and how it will perform with regards to spool/response. Those impeller dimensions aren't radically different to a GT3576, or a budget Kinugawa TDO6H-25G. Either of those will support 320rwkW plus/minus 10kW depending on setup and tuning. But you'd expect them to perform differently from each other, and the Holset. What is drawing you to the Holset?

400km competitive in high ambients is a lot to ask from a single set of tyres when you're running a GTR with their weight bias strongly to the front. How did the rear tyres hold up by comparison? What camber/toe settings were you using on the front? Tyre wear will be compromised if you've got it setup to turn in and hold a line. A good navvy is worth their weight in gold. The whole event can be so much easier when things click together.

Deleting VCT on a non-Neo head will not cause oil starvation to the cam bearings. VCT on a road-only engine is probably a good thing to achieve broadest torque spread. On other applications, it is open to debate. If you disassemble lifters, yes they have to be bled before installation. It is as simple as collapsing them so that they will pump full of oil without any air pockets. Try using a piece of hose as a stethoscope to identify which one(s) are noisy. Could be a weekend spent lifting the cams and lifters to give them some attention.

^ shows an LS fits but how much is it extended past straight lining? Credit to the owner, and a good looking unit should be fun but would struggle to match an Evo or MX5 anywhere there's bends. Warps also makes valid points about the Honda platforms. An R chassis / LS combination would be a hoot to drive and a real talking point, but I figure the others easier to set up due to collective knowledge on the things. All that said, if I was to re-power my 33, it would get an LS...

F*ck yeah!!

Go for a 4.363 or 4.375 diff gears, they will be better than 4.111 without making things too busy on cruise.

There is undeniably some merit in the idea. With some thought and attention to detail, an LS / R chassis marriage could work, with better weight distribution and the same sort of power output (if different delivery) as something with the RB engine. If you don't care what people who don't know any better have to say, then an MX5 is top of the tree. And if you want to go fast, then an Evo is the pick.

All interesting to muse over, but what are the results 6 months after from fitting the small trim 3076 to your RB?

Good to know it seems to be handling better. Heavier front springs? High temps are like a monkey on your back, decent ducting makes a world of difference. Running W7/W3 combination front/rear, I found things only settled down with a lot of effort to getting heat into the brakes on warm up lap. Otherwise it seemed to have rear-bias and tendency to lock the rears. Once things were nice and warm, trail braking was no problem and very effective.

Ok Adrian, 6 months later have you got the 33 tuned and run up on the dyno? Also interested to hear comment on overall satisfaction with this specification.

I used cardboard sheeting to get the shape right and then used composite aluminium signboard. That stuff is more rigid than ally, and cuts easily with a circular saw. Undertray only, currently no forward projection to make it a splitter. Pics can be found in my thread in motorsports builds. Mounting takes a bit of creative thinking and used a few aluminium tabs and nut-serts to make it work. But it can be done by someone prepared to take the time.

The adhesive composite sheet is good stuff. Concept probably not far removed from the gold stuff, but considerably cheaper. Downside is that because it's not paper thin (more like 1mm), it doesn't conform to the join between bonnet stiffening frame - bonnet skin. Easy fix, just run a blade along the join and then use silver refrigerant tape over the top. After a run, the section of bonnet where the sheet is applied is much cooler (less hot) than the areas directly adjacent. Should be problem solved there, so thumbs up. The slip on sheath for the loom is thicker, probably 4mm. Easy to apply, and nothing appears to have been heat affected. Thumbs up there too. Ceramic coating is not IMO an effective stand-alone solution to control radiant heat. It does work, but I reckon the lagged (but non ceramic coated) dump pipe contains more heat than does the turbine and manifold that have only ceramic coat. Physical barriers (ie some sort of heat shielding) can be very useful, dependent on what (if anything) actually needs protection from heat. At this point I think my setup is working and things aren't being fried. Short run event formats should/might mean it is easier to deal with radiating temps simply because the length of exposure is shorter. I'd imagine a 20 lap race format would throw up more challenges.

Looks like a variation on a proven theme from the MCA car at least from the front end. Just added weight, probably hp, and mechanical grip for power down off the slower corners/turns. Wonder how much weight it carries over the front end for balance, and what the underside looks like?

Quick plug if anyone is looking at buying a HTA 3076. There is a brand new unused unit in my shed, needing a new home.

Selling brand new unused HTA 3076 turbo. Surplus to needs. No turbine housing with this unit. Runs the 0.7 A/R compressor housing as supplied. $1750. Any serious responses please PM.

Geometry changes? That's going to be dealt with in your suspension setup, not related to wheel diameter. Price and availability of the sizes you want are probably the biggest deciding factors - if you can't readily get them, or they are ridiculously priced then you'd be looking elsewhere. Competing to win, vs entering to have a run are also far different things that means you might just have to deal with the price difference. Assuming you're looking only at the Yoko A050, 245 section width. Are there different nominal aspect ratios, or tyre heights for a given rim diameter? Big call to make any definitive statement about durability/reliability of the tyre based on its rim diameter, although a taller tyre is going to have more rubber to play with for a given distance travelled. I'd think the manufacturer would vary carcass construction and rubber compound for the different sizes and rated load capacity. There might be some merit in targeting specific tyre sizes because the sidewall height (or aspect ratio) is going to impact general stiffness/compliance levels and tyre response. Formula 1 vs other open wheel categories highlights this, in my mind at least. Definitely a mind bender, there's probably going to be a bit of trial and error in finding what you prefer.

~$2k AUD landed is pretty steep for that turbo kit, when you look it's not really a bolt on kit with just a selection of pipe bends that it states you will have to do some fabrication to make it all go together. The turbo and gate are both pretty average spec when you consider what else is available as Asian knock-offs and their prices. When I mentioned fuel and ignition changes, I'm talking about reflashing the ECU as a tune to suit your particular setup, not one of those generic plug in interceptors or whatever seems to still be popular in the US or UK. Poor or inappropriate tuning will kill a VW as easily as a Nissan even on 6psi. If there is a flash tuner available then you'd probably go with that, otherwise look for a decent plug-in ECU. Maybe look at Link, and check whether Adaptronic can engineer something for a respectable price. I like Plattsy's suggestion about injectors, quite a good budget conscious idea. Suggest having a good look at Rotrex supercharger and mounting kit. Boost delivery on one of those won't provide the bigger mid range hit of a turbo but the overall delivery is friendly, and packaging easier when you factor in heat shielding etc for the turbo setup.

If there are concerns about funds before embarking on forced induction, then it can't end well especially without changes to fuelling and ignition. There are going to be changes necessary regardless of how extra air is forced down its throat. An old ceramic turbo? Forget it. Turbine failures on RB25 setups simply from bumping up the boost and running them harder are well documented. I've had a run in two cars running centrifugal superchargers and came away impressed with the linear delivery in each. Torque did not seem to fall away, due to rising boost curve. The downside seemed to be cost/time/effort involved in mounting the supercharger and getting an effective belt wrap to prevent slippage as rpm and drive requirements rise. Possibly a different perspective, but I'd spend some of the $5k on suitable brake pads, rubber, and adjustable suspension links to give the thing max traction once aligned correctly. The rest stays in the bank for entries, fuel and incidentals. It would rail around corners and you'd be capitalising on the strengths of the platform without placing ridiculous stresses on a well used engine.

I'd expect more efficient cooling. Not so sure about the goals of drag/lift, but it should reduce underbody airflow by venting up over the screen so perhaps it will as a side benefit. Definitely a well worn path, with roots back to 60s vintage sports/racing cars so it can't be a bad thing. Templates look pretty good, reckon you'd need foam or race tape to get a good seal and encourage the air to flow how you want it without leakage.