Dale FZ1

Running a auto-spec diff 4.363 ratio will claw back a large proportion of any drop in low-speed response when driving in built up areas in the higher gears. Make the car a better thing in most ways except possibly a steady 110km/h motorway cruise. No need or desire to run the thing in 2nd gear.

Wait until he does, and has first hand experience how well it works, and over how wide a range. Previous post suggests its a slow process of expanding the rpm/load envelope but he's getting the picture...

Which variety of TDO6 do FP use though? TBH I'd like to see a few results for the TDO6SL2-20G (throwing in the HG variant with 20.5G upgrade), and the TDO6H-25G.

That would be before they are all varnished up and making noises. Provided OP gets a proper, reliable diagnosis, the solution is clear. Cams out, lifters out, disassemble and scrub clean with suitable solvent. Reassemble and enjoy a silent top end with zero lash. Unfortunately that costs money for anyone unable/unwilling to do it themselves.

Making sure that the car's cabin is well sealed against exhaust fumes and fuel vapours is really important, also decent ventilation into the cabin works wonders. Fuel lines running through the cab can be a source of fumes simply because of incorrect spec. Teflon lined is the only reliable way of ensuring no degradation over time. Either in the pits or between stages, step away from the car and any fuel containers to avoid fumes. I've only ever felt or been sick in 4wd cars. An Evo with antilag on gravel can stop, turn, and accelerate faster than any 2wd car I've experienced on tarmac. But I haven't been in a 4wd on tarmac yet. Not being dehydrated or hung over is a great start, as is not eating great big difficult to digest breakfast. Fatigue is always an issue due to leadup preparations, but rest and a clear mind helps with focus on the job at hand rather than thinking about being sick. The only other thing you could try is Kwell or equivalent sea-sickness tablets. Natural stuff like Ginger helps some people.

I'd think the TDO6H gives way more flow than necessary for a 20G compressor. Weight would be a factor inhibiting response too. Go for an EW setup and don't look back. Makes for far easier spec changes if you're using essentially the same housings with different internal profiles to suit the rotating bits.

Better yet, take it to your engine builder as you indicated you planned to do, and get his diagnosis. Were the lifters disassembled and cleaned during this build? If they weren't, and are the cause of the noise, it's clear what needs to happen to cure the problem.

What is the current specs of your powertrain? R32 spec RB25? What turbo now? The TDO6SL2 20G 10cm? What's it making? RB20 spec gearbox holding up with the torque ok? Diff centre?

Show us some more pics of your trailer. Car sure sounds angry, with traction questionable...

A bit of hunting through the Kinugawa catalogue shows the SL2 turbine is available with either 9 or 11 bladed options. Fewer blades would give higher flow efficiency but maybe a bit less drive (response) at lower turbine speeds. The 20G compressor is available as a billet item with extended tip and presumably higher flow capability/efficiency than the standard cast item. I can picture that combination punching pretty hard and making decent numbers at higher boost levels. It's only a matter of what cost for that spec, and whether they will warrant their units without the BS shipping costs borne by the customer.

I've never "got" the reasons why people have tried to achieve the absolute maximum flow output of their particular turbocharger(s). Screwing 24-26psi out of what you'd have to call a hybrid match of Mitsubishi copy bits is going to have to highlight any spec mismatch (compressor:turbine rotor) or spec deficiencies (thrust bearing, centre bearing or shaft) and bring about short service life. Those who were around in the Group A days might remember early Sierra RS500s having ugly smoky failures on track as the racers tried to screw big numbers out of the T3/4 hybrid turbos. Look at the Mitsubishi trends with what they fit to their own engines and it's pretty clear that they put a lot of focus on turbine flow, whether the various Evo specs, or light diesels, or trucks. Achievements with the TDO5-16G on Lithium's mate's S14 proves that combo works with a 2 litre 4 cyl engine. For someone wanting to use the Kinugawa gear on an RB25 chasing the 300-320 rwkW target running pump 98 I think the TDO6SL2 20G would do a particularly good job without wanting to destroy itself in short order. I think the reason Garrett products seem to use impellers with comparatively big dimension differences to their turbine rotors is because the ball bearing design can deal with high thrust loads much more effectively. But ask around and see how their nylon cages for those bearings deal with heat when pushed hard and it's not a happy scene there either. Bottom line for me is that if you want to run a biggish compressor and push a lot of boost into the engine, you've got to uncork the hot side a bit to let it all out.

Hopefully the pics and stories are enough motivation to get things together and have it running again. Lesson for the kids about what it takes to keep a GTR running fast and reliably

I think Simon's suggestion at post #2 made the most sense given the OP is in the UK and not running E85. Looking at this thread, if the OP's setup consists of bolt-on airflow modifications only (inlet pipes, turbo, FMIC, poncams and exhaust), I'd suggest his dyno might be happier than the typical Australian spec. 260rwkW from 13psi on an RB25 is not something generally seen.

Have you got any comments from your tuner? ie are you looking for a "problem" that might not exist, purely because a certain number did not appear on a piece of paper? Previous posts indicate that all the bits are well made and there are no leaks, so if compression is right, AFR is right, and it's taking a decent whack of timing then perhaps it's time to run it down the strip and see what trap speed it can pull as the best indicator of power.

Soakingdisassembled lifters in solvent or thinners works wonders, then scrub them with a toothbrush to remove all oil varnish. Make sure they are fully collapsed when reassembling. Seems to let them fill with oil much easier when you have the first startup. OP you will know easily enough the difference between lifters and injectors by the noise they make.

Agreed. Speak to Jez, he tuned it and should know what to expect. This is a GTR so the awkW figure is going to be lower than the rwkW figure due to parasitic losses. Not a whole lot of point throwing stuff around on a forum when you can get an opinion from the person who's actually produced the tune.

Pressure test the inlet system for leaks. Any idea if it likes ignition advance, or has it hit a plateau where more timing doesn't make more power? How is the fit of manifold to head, and turbo to manifold? Any sharp ledges that will affect flow? How is the pipework for both I/C and exhaust? Well designed and made, nice bends, minimum of protruding welds into the air/gas paths to upset flow? Spec and condition of cat? Spec and condition of filter?

Going away from the OEM CAS? Wondering if going with a chopper wheel on the harmonic balancer would offer any advantages. Give us a bit more info on this one.

For track use, I'd suggest that a 1.06 turbine housing on the GT30 is a reasonable way to go, with more efficient turbine flow and reduced backpressure for better scavenging and reduced retained heat. And the 60-1 compressor while not ultimately as efficient still isn't a bad thing. Arguably the best thing about using the GT35 turbo is that you've achieved more efficient turbine flow and would consider using less boost to achieve the power target but not smack into traction/driveability issues that Scott is alluding to. And if you're thinking of trying to use 500rwhp in a 2wd chassis and effectively get it to the ground on short/tight tracks then good luck.

Mick how does your system go for noise suppression? It would have plenty of flow capacity, be good to see pics for how it looks and fits.

Checking stated aims, I'd question why you'd want to max either the AFM or injectors. Decide on the airflow (ie power) target, and gear both the fuel system and ECU capability (thinking peak measuring ability of the AFM) to suit.

There are technical and practical reasons why the 6 bladed BCI-18 compressor is a better thing. The maps point the way forward, but GTSBoy makes a valid comment. I suspect Discopotato03 will wade into this. Meanwhile why not run the unit you have and see how it performs on the 30DET.

If you have a post-turbine restriction then with reduced pressure drop across the turbine you will end up with less efficient scavenging of the combustion chambers and retained heat. From there, agreed that the thing shouldn't/won't take as much ignition advance as you have it running closer to the knock threshold. Your compressor discharge temps shouldn't be any higher, it simply pulls in mass flow of x, squeezes that mass to a pressure ratio y (boost pressure + atmospheric pressure), at an efficiency rate z as shown on maps (if they are published) and then that is ducted to the inlet. Compressor efficiency simply describes how much heat is added to the air mass while it is being squeezed. Backpressure across the combustion chamber can mean that the turbo is working against itself to a certain degree. It's good to know that your ECT is not going through the roof.

If it is going back onto the rollers on Monday for a quick run, I see good merit in Scott's suggestion. Firstly, drop the exhaust and see what result that gives. You'd want to at least eliminate both mufflers and the restriction they offer. Unigroup may want the cat dropped too, so rely on their opinion. Secondly, have a spare good CAS handy and be prepared to slip that on. Neither step is going to take much time and you will soon know what sort of changes are needed to get the best from your setup. The overheating issue is concerning - before Monday can you install a new thermostat and/or check the fan belt for tension so the fan is getting good drive? One is fairly cheap to do, the other only takes 5-10 mins.

Ron your pics on post 31 pretty clearly show the neck-down restriction, pics 3 and 4. If pic 4 is the rear muffler, the guts of that thing must be somewhere around 2.25". There's the source of your problem Unigroup identified. Adrian the best/biggest mufflers may well have to be made, but there are decent off the shelf units around provided you look. There's not much bling factor with Hurricane or Mercury products, but they offer sizes and shapes that can fit and provide decent flow and muffling ability.