GTSBoy

Hypothetical hat on.... I think they want to make sure that it is no more than 8.2mm to ensure that the 14mm hex electrical isolator washer thing stays outboard of the hole, so the o-rig on it seals properly, and they want as much room as possible between the passthrough bolt and the plastic lid, so that it can't touch the plastic and heat it. Even assuming that the steel should run cold enough to not be an issue, they are probably applying additional paranoia in case of the sorts of crimp/terminal problems we're thinking might be at play in your situation.

Not more than 50°C. Anything you can't touch is putting up more of a fight than it should be.

Bah. That bit there can't be more than 0.5mm thick, and only about 6mm wide. That's only 3mm2 XS area**, which is a lot smaller than any other part of that circuit. (Although, granted, the wire inside the tank on that blue ring crimp looks a lot smaller than the wire outside!). The equivalent neck on the blue crimp has to be even smaller. **And yeah, I realise that 3mm2 should be able to carry ~30A. But something has to be the weak link here, and that is the narrowest part of the whole thing. So, unless the crimps are bad and causing high voltage drop, the next most likely suspect has to be the necks. The face area of the ring onto the passthrough's landing would have to be multiples of the neck's XS area. So long as they started out tight they (the ring contact face) never should have been the source of the heat. Same with the suspicion of the possible nyloc. If it started out tight, it shouldn't have ever gotten hot enough to melt the nylon, loosen and then cause the heat that melted the nylon. The circular argument has to start elsewhere. If it were me, I'd be thinking about some other sort of passthrough that doesn't require the nuts and ring terminals for conductivity. If there were passthroughs that had direct crimps on both sides, they'd be single use, but they would have metal to metal interfaces only at the crimps. Would be solid metal between the crimps.

I'd try the Jaycar one first. Don't even bother with replacing the passthroughs, as they will still work provided the melting is only minor and they still seal and insulate. You can always go back and replace those later. After you've put the new crimps on, you just have to make the pump work for a bit, then go back there and laser gun the terminals (or touch if you're brave enough) to see if they are sufficiently cool to relieve your concern. You might want to gather a data point with the old setup first, to see how hot they get now.

Yeah, see, I think I've worked out what is happening here. You (and other people) buy these massive "40 amp rated" pass throughs, and use fat wires, then make the connection between them using a ring crimp that has a much smaller cross section in that piece in the neck between the crimp and the ring terminal than any other part of the system. And it gets hot there. And because it is very well connected to the passthrough....that gets hot too. We probably need to be using more chunky wire terminations.

I'm thinking that if it is struggling to make boost....the turbo is damaged.

I don't know. Look at the wiring diagram?

You can't do a really convincing examination of either the valves or the pistons (through the plug hole) with an endoscope. You can have a look, but it is difficult to see everything.

Both the black plug (red/white/black wires) and the grey plug (yellow/green/brown wires) go to the location at the front of the plenum. I didn't recognise the wire colours in your first photo of the grey plug because they are so dirty.

What Josh was saying is that the stock gauge reads dead on centre across a really wide range of temperatures, from "not quite up to operating temperature" all the way to "you're just about to cook it". That means that if you ever see the gauge over the 50% mark it is actually very bloody hot, and yes, you might have done the gasket at that time. Or, you might not. Head gaskets can fail so that coolant enters the cylinder, exhaust gases enter the coolant, oil enters the coolant or water enters the coolant, or any of the possible combinations. Just not seeing emulsified oil in the radiator is not sufficient to rule out gasket failure. You also need to test the coolant pH, to look for dissolved combustion gases (CO2 -> carbonic acid when dissolved in water). A fluffy idle could be from a dying/dirty injector, dying coilpack (or perhaps damaged sparkplug), a vacuum leak on the inlet manifold gasket, broken piston/ringlands or burnt exhaust valve, and any of a number other things. You need to start working through the list.

OK, so after a closer look at your first photo I realise that while the body of the TCS throttle is present, the motor isn't really there and it looks like the TCS TPS is not present on the back. So you should not have any wiring coming out of the three bolt cover on the front, or on that block of alloy on the back. That leaves just the main throttle body (the part closest to the plenum). To the best of my knowledge, the main throttle body and its TPS is the same between TCS cars and non TCS cars. What do you mean by "the throttle body has two plugs"? The main throttle body TPS in your photo clearly has one bunch of wires coming out the TPS on the front, and these should go to a loom plug at the front end of the plenum, as I described above. You show that grey plug with 3 wires, but you do not say where those wires come from, apart from "out of the throttle body". But where on the throttle body? Are you sure? As to the driving behaviour. Are you running >10 psi? The stock ECU will chuck the shits at you based on the inputs from a number of sensors (the AFM and the boost sensor primarily) if it thinks you're pushing it harder than Nissan wanted, which is not very hard at all. If you are, you should really have Nistune in the ECU.

FWIW, I got about 20 out of the RS4s. I liked them....until I didn't.

The pictures are a little confusing. 1. I was under the impression that GT4s did not have traction control. So why do you have a traction control throttle body on your crossover pipe? 2. Ditto, Stageas, even turbo Stageas, do not have TCS either. 3. What engine loom are you using? The original car's, or the one that came with the engine? Are you sure the one that came with the engine is actually from that engine? See question 2.... There are 2x grey loom plugs on that part of the engine. One is on the loom and clicks onto the Neo's boost sensor at the rear of the cam/coil covers. The other hangs off the traction control motor (front side of the crossover pipe, down low) and runs left and forward to a bank of 3x loom plugs located at the front end of the plenum. But depending on the provenance of your loom and the engine and that crossover pipe, you might not have everything. You certainly have things you shouldn't.

235/45-17 were 320ea fitted 14 months ago. It hurt, but not what I would call eye watering. And I could certainly not get RS4s for half that, even had I wanted to go back to them and their painful road noise in the last 50% of tread depth.

My vote is for my current tyre. AD09. I'm at about 10k in and they're gong to last another.....5. I've killed a set of tyres at 8k before.

Boost leak or exhaust leak. Boost could be from anywhere, including manifold/plenum gaskets. Exhaust is frequently head to manifold gasket or from manifold to turbo gasket. Often caused by missing nuts or broken studs.

Check for spacers on the front, in case they've been pushed out a little to try to match he rears better.

Meh, maybe the JSAI ones are FG not CF. But, given that I'm not convinced any of these look any good, it hardly matters.

JustJap sell CF underskirts like that.

When stationary/slow....yes. When going fast, no. High pressure builds at the base of the windscreen and will either inhibit or reverse the flow.

I have S15 helical too. It is a bit worn. I think the drive behaviour you describe is related to this wear. Wear of helicals is something that no-one seems to have paid a lot of attention to, but now that they (as in original Nissan ones) are all a bit old - we're starting to see the consequences. The ends of the helical spurs wear into the casing. That's where they perform the braking that diverts torque. Some of the more modern helical designs have proper wear surfaces introduced there, but the Nissan ones are just steel on steel (or iron).

You should Nistune the ECU, so you have freedom to use modern injectors instead of replacing with the same old shit. This is also required if you want to boost it up above ~200rwkW, where the stock injectors will be running out of capacity. Having said that, it is unlikely that the injectors need replacing just 'coz. If you imported it from Japan, the fuel should have been pretty good quality for the whole life of the car.

The pedal and pedal box (everything inside the car) will be the same for all manual R32s. There might be a caveat for the GTR pedal in that the rod that pokes through the firewall is supposed to connect to the input side of a vacuum booster, not direct into the clutch master cylinder. Therefore, your safest bet is a clutch pedal from a GTSt. Good luck finding on these days though. All the manual conversions were done 20 years ago.

I think he meant Haltech meant that the Haltech PDM doesn't like driving loads with PWM. Not that the pumps don't like it. Think about the heatsinks that we strap onto SSRs for just handling a single PWM load. Then picture how much heatsinking is visible on a Haltech ECU or PDM. None, right? So it's no surprise that they don't want to run PWM loads directly.

I think the PDM outputs (the ones that can actually output big power) are not intended to be driven like that. They're either on or off, switched only at a low rate. To do PWM you need to use an ECU output that is PWM friendly (ie, able to be run at high frequency) and drive a separate SSR, instead of trying to thrash the (presumably) SSRs in the PDM.