Dale FZ1

Firstly, that plumb back merge does look good. But, I agree with your assessment on the WG angle. Gas has mass. And if it's highly energised pressure pulses trying to change direction rapidly, not going to happen easily. Workmanship on the 6boob manifold is no problem, but that WG design doesn't look right (to me) with a short hard 90 straight off the collector, not going generally with the direction of flow first. Reckon I would be doing some re-engineering there. Does it currently have a divider right up to the WG valve? Twin scroll, needs completely separate gas flow paths. Is there an inline restrictor for the MAC plumbing? This is where you make the thing really sensitive to duty cycle changes. I have used a 1.2mm MIG tip to great effect many times in plumbing MAC valves, cheap too. A novice error I have made twice is to have the ports connected to the wrong nipples. Worth knowing. From comments, there's a historical problem showing even with a different turbine/WG setup. Presuming you've used the same tuner, and approach to tuning. Could be a basic error there, require a second set of eyes over the tune file to see if things are all good there. (Suggestion is directed towards problem identification, not blaming or flaming individuals)

I've seen 3 and 4 port valves, but 5 is a new one to me. Was there a tech or performance advantage to 5 port as the reason for choosing one? If it's a Haltech product, I can't see anything on their site (or anywhere else online with a 1 minute search) for how a 5 port valve plumbing is configured. Maybe get onto them for tech help to at least confirm. Some pics on the WG placement and pipe angles would be a big help for people to understand what's the problem. Bench testing the gate for correct function and all intact would also be a good idea. Pretty sure most of us are guilty of failing to review/check ALL the basics when something doesn't seem to work as it should.

So effectively it does the same thing, whether the boost controller is activated or not? Just that the boost levels (static, and rapid throttle change to spike) are higher? Is this setup being operated in open or closed loop? Possibly the gate setup/design has some deficiency, as per Roy's suggestion. Got any decent pics to upload?

But no problems maintaining the 12psi if you went WOT from low rpm eg 2000rpm? And holds that through to max rpm (whatever that is for you, presuming around 7500)?

If it holds 12psi without the boost controller in play, the hardware is probably ok (ie the manifold and gate setup). Sounds like the boost control solenoid is either hooked up incorrectly, or the ECU settings aren't in the ballpark. Whoever set it up, get onto them and have another go.

Change the grade of oil you're using first. eg. if you're using a 25w60, go to a 10w40. There's a lot of effort to remove/refit an engine, an oil change won't cost much as an experiment.

Road use, the 3076 0.8A/R combination is damn hard to beat. They pull down around 2000, and run up to 7000 without falling over. They're not magical, but it's tried and proven. If it's track, go to a 3576 0.8A/R. Provided you're wearing blinkers and only want Garrett. As per Piggy's comment, you need to let it breathe out.

This ^^ +1 There's a fair bit of effort to pull the box, and you wouldn't put in a lighter flywheel without correspondingly more serious clutch setup. And if it's a daily driver in heavy traffic then forget it. Actually, still do it, but buy an automatic Hyundai for the heavy traffic grind.

When I made the change, it required a slight change to the way I walked off the clutch. Button clutch, so it slightly increased the chances of a stall. So use another couple hundred rpm at the engagement point. Otherwise it was all positive. Engine felt more responsive to throttle changes (but not by a huge amount - you get used to it so quickly it becomes the new normal). Made a relatively sporty car feel a little more sporty, IMO.

If this is what you had in mind, completely agree. It's an incredibly tight fit though - VK is wide and high because of those DOHC heads

The most obvious comparisons are with Paul's and Peter's RB28 and RB32. Fair call IMO to suggest this thing is lagging behind them both especially in the mid range, but it's hardly a weakling. This is still pretty strong! As above^^ the restrictions should be investigated if the absolute best from the engine is being sought. The old adage of "boost being a measure of resistance to flow" always holds true, so measuring/assessing turbine inlet pressure is probably worthwhile, similar with turbo speed. ie. my thoughts are that potentially camshaft specs, and turbine A/R might be working against you. High output has got to require good scavenging/cylinder thoughput, but not to the extent that bulk turbocharger shaft power is wasted by poor charge trapment in the cylinder. And maybe the 8374 is actually undersized for whatever you're chasing out of the engine? The VE characteristics of your engine may well require a bigger turbine capacity, and use the compressor to push air through if you want more hp. How that affects torque and throttle response down low/mid rpm is a different issue IMO (or not, if you're an EFR convert ) Playing at this output level is going to take time/effort/$$ and at some stage enough is enough. There are no silver bullets, and identifying the "best" combination for this engine beyond the exhaust and cooler might not be easy. I know I'd be ecstatic with something this strong.

Pretty strong result there Boost taper to control turbine speed? Would you put up the torque curve too please?

If you're completely satisfied with the GT3076 (and there's still a lot to like about that turbo on a RB25), then stay T3 high mount and be happy. Bear in mind there's a fair bit of fab work to get the piping right and even the gate in correct position. So it'd be good if future turbo changes allow for direct bolt in spec changes (eg move to a GT35 or something within reason). I'd suggest you do the homework on alternative brands in the same price or performance range too. You "might" move away from the Honeywell gear given what the cost of a bare housing is and the funds you could recoup on sale of existing gear. Besides the higher priced options (EFR, PTE), you'd be mad not to look at BW S256/257, Masterpower/Borghetti MPR54/59, and the Kinugawa range. There are T4 options amongst those, and the dimensions of a T4 hole may allow for a nicer transition in the collector area of a high mount. I don't think T3 single vs T4 single will make much difference to overall performance given your current turbo is going to top out around the 300rwkW mark. A proper split pulse setup probably will make a difference, at a cost. Bottom line for me, you've got to price up the alternative setups and gauge what's most attractive and within your budget. They are all going to perform differently but no dogs there. Garrett preferred? - T3 single scroll, single gate. Easy move to a GTX3071 or GTX3576 in future. Don't look back. Bigger budget? - T4 split pulse, EFR 7670 IW. Bigger again? - T4 split pulse, EFR or PTE twin external gates. Smaller budget? - T4 split pulse, BW S257SXE twin external gates Smaller again and open mind? - T4 single scroll, BW S257SXE or Masterpower MPR545, single gate. Smallest budget, still open minded? T3 single scroll, Kinugawa TDO6-25G, single gate.

Depending on your ride height, it could be worth installing a set of camber arms and traction arms in the rear. Objective being to have the tyres running at an appropriate camber, and minimise/eliminate bump steer as the suspension goes through its range of motion.

No. Get an Evo. Most of the awd thrills with a fraction of the costs. They all flatter to deceive.

Change to the V band. Effort is worthwhile. 30mm flares might get you out of trouble for now but wider set would have given you room for future changes. You're going to need to use tin snips on the guards anyway, and good clearance helps when the fronts move up/down and lock to lock. Hint - flares to suit 240Z are remarkably close to what's required on these things. All steps forward though, looking good.

Buy in a complete water injection kit. Will save a LOT of hunting around for the right bits. Yes the benefits are there to be had, and they're worth taking. HANS should probably have taken a higher priority in the purchases stakes, but there's nothing to stop you getting a setup before taking this thing for its next run.

Matchbot also makes it easy to understand the value of efficient intake/piping/cooler/exhaust system to making target hp at the lowest boost level.

As a matter of interest Josh, what have you done for solid mounts?

Wiggins style clamps = cool Hope there's some flex in the system for when the engine torques over? It's looking good for sure.

Post mortem review - what caused that failure?

The flow graph says you have lots more flow capability with that pump being fed 13.5v. Going off your sums, those flow numbers say you hit an equilibrium point roughly at targeted max injector flow. Is there any chance you'll be staying at that point for more than a few seconds at a time? Run the GSS342 at 13.5v, peace of mind.

So you are getting float, or don't know and are just chasing info? Probably a bit hard to contemplate playing with the tune without at least giving it a squirt on the rollers to validate what's going on. You can achieve plenty with road tuning, but an hour of dyno time isn't that expensive and will tell you heaps.

^^ Highly relevant. Consistent with observations about turbine spec etc. I'm not suggesting 20psi is where it all goes downhill, but below that point we don't hear much talk about valve float.

The answer is a bit rubbery, will depend a little on how big/small spec your turbine and exhaust system is. The original springs aren't that heavy, and if they've seen a bit of work it's probably time to replace/upgrade. Setups will vary, and some will experience float earlier than others if the springs in that car are on the softer end of production tolerances or otherwise tired. If I was looking to run up over 20psi, springs would be on the shopping list.