joshuaho96

The basic concept is fine but I've seen people mention issues with things like cylinder distribution especially because most manifolds are designed to split air evenly but not liquid. That and issues like injectors clogging, how to avoid damaging the system if you leave the car outdoors in freezing conditions with 100% water in the lines, valve stem/cylinder bore wear from water washing away engine oil, etc. I still think a lot about adding an Aquamist setup to the RB26. Water injection to me is a great idea but it definitely requires a lot of thought, as much as any fuel system. Being able to replace boost enrichment with water injection instead is something I'd really love to do.

I would go for Aquamist if you're going to do this. And integrate the control of the injectors into a standalone ECU. Just from reading SAE journal papers it is scary IMO how much can go wrong with WMI even when you have proper control over the injectors and full integration into the rest of the ECU.

Yes, there is a washer. PN for the bolt is 14053-42L0A, if you look up pictures it clearly shows a washer on it:

I don't think you can actually buy one separately as OEM. In theory you could get the whole unit sent off to Nismo for rebuild but the cost is hilarious: https://www.nismo.co.jp/heritage_parts/repair.html If you are confident it's just the pressure switch and not anything else FPG sells the pressure switch by itself, not a direct fit but close enough: https://frenchysperformancegarage.com/products/fpg-nissan-gt-r-attessa-pressure-switch-replacement

I also don't recommend torquing the crap out of it. It's a thin screw going into cast aluminum. If it leaks it's almost certainly the washer or the surface it's sealing against is no good.

The name of the game when it comes to stuff like E85 is thermal efficiency, not mpg. Of course mpg will be worse, the volumetric energy density of ethanol is less than gasoline. I'm willing to bet with most if not all turbo RBs going to E85 is a net benefit for thermal efficiency.

It's really unfortunate IMO that billet means it's no longer really streetable. I want an engine that you can count 10 seconds and start driving as long as ambient temps are over 5C. I'm also not super wedded to 8mm thick liners or anything like that, my power requirements are comically low and covered by stock block but it's really everything else that keeps me up at night.

By better shock loading do you mean it transmits more shock loads? Pretty sure it's more torsionally rigid no?

Try goo gone which is a citrus oil.

You can try but I have a feeling the answer is maybe not. The hoses and pipes that hold it to the vacuum box under the plenum are a really tight fit.

The A-LSD controller modifies the slope of the LSD lock pressure vs TPS curve depending on how much lateral g you pull. The more lateral g you pull the harder it locks up: https://sci-hub.se/10.1016/0389-4304(94)90219-4 Seems kind of suboptimal to have an open diff any time you let off the throttle but someone at Nissan thought that was a good idea.

Would love to get a link, I keep using a chinesium harbor freight one and the image is horrifyingly blurry. It was useful for getting that paper towel out of my intake manifold but anything smaller than that and I had a hard time spotting anything.

Those things are so low res as to be useless for spotting leaks unless it's super obvious. It really shouldn't be that hard to figure out the source of the leak. If the actual photo wasn't out of focus it would be pretty easy to see what's going on.

The balance tube has coolant flowing through it. There are a bunch of o-rings that seal up the balance tube to the intake manifold. That can be one leak path. The other is the intake manifold up against the cylinder head. The throttles themselves don't get coolant flow to my knowledge but the intake manifold does. I recommend undoing the harness on the balance tube so you can get a better look at where the leak is coming from. Certainly a lot easier than getting eyes on the back of the intake manifold up against the firewall.

The AWD or A-LSD system uses it to determine lateral g of the car and adjust the transfer case lockup or A-LSD lock pressure accordingly.

The reason isn't that complicated. You just have an early version of the transfer case: https://nissan.epc-data.com/skyline/bnr32/3884-rb26dtt/trans/331/32103M/ 1989-1991 R32 GTRs call for two drain plugs. This was later cost-reduced to one. The transfer case housing was also revised to suit. So you could drain it to get it extra empty of fluid before refilling. Evidently though Nissan engineers decided it wasn't actually that useful to do so.

If you want a knob or a switch/button/etc to adjust the boost any standalone ECU can do that too.

Possible it's calcium additive from Shockproof gear oil.

If the engine is hydrolocked I don't know why you're still trying to start it. The more revolutions the engine turns the more damage you're doing with bent conrods.

I still have no clue how the RB26 TPS closed switch works. As far as I can tell it has one but when adjusting it for the factory ECU you go purely off of the voltage and then unplug the TPS to reset the voltage the ECU decides is the magic number.

I've driven a week on 4 lugs no problem. Probably don't push your luck much longer than that.

-5s generally speaking can do 500 whp. If you push them hard with enough octane and supporting modifications 550 whp should be doable. Solid state relays are the same basic idea as a mechanical relay. You apply a voltage to turn them on and off. The difference is that unlike mechanical relays they can be switched at relatively high frequencies like 60 hz. PWM a normal mechanical relay that quickly and it will die in something like 10 minutes. The idea is pretty simple. You would buy a relay like this one and make sure to put a heatsink or something on it: https://www.haltech.com/product/ht-030202-solid-state-relay-100-amp/ Then you follow the directions for ground switching the pump. In the ECU you would set up a table for your auxiliary digital output that would be PWM percentage with respect to say TPS percentage and RPM. To just get the car running you would just say 30% duty cycle at idle regions, 50% at cruise, then 100% at WOT. It doesn't need to be super precise like injector fuel delivery so just getting it close enough is fine. I recommend looking at this to get an idea for what kind of PWM frequency you need to achieve to keep the pump relatively consistent in flow instead of changing wildly as the relay turns on and off: https://www.portescap.com/en/newsroom/2022/03/controlling-brushed-dc-motors-using-pwm The OEM fuel pump control module is doing the same kind of idea, except unlike this solid state relay it is just switching between resistors on the ground path which means most of the fuel pump power at idle is being wasted as heat in a resistor. Solid state relays do waste some power but far less.

I'd be interested in a new cast block that is primarily interested in fixing the more obvious issues with the RB26 design. Core shift and thin walls is a big one. Another is oil control. Improving the oil returns and feeds is one thing but what would really make me be willing to drop 8k USD would be a lot of engineering/validation devoted to the block/oil pan to integrate internal scavenge pumps and make the engine capable of surviving 1.3g continuous. Being able to confidently push hard on tracks without being afraid of oil surge/excessive blowby would be amazing for peace of mind. Also not having to drill and route even more hoses and all that fun stuff for crankcase ventilation so it retains a relatively factory look and feel would be great. I would also want this block to be first and foremost street-oriented. It needs to just work with low p2w clearance pistons.

Agreed, once you start doing your own work you realize just how cheaping out is actually more expensive in the long run.

-5 turbos are going to be sized for like 600 crank hp. So yes you will need injectors, you will need a fuel pump. If your tuner is using a standalone ECU it will be pretty trivial to wire up either a brushless controller with a flow control signal or a simple PWM with a solid state relay as mentioned earlier. I strongly recommend PWM control because for some effort invested in your ECU and wiring you can keep more things stock and makes more room in what is already a pretty cramped engine bay. If you control the fuel pump well enough the stock FPR is sufficient or a similar Nismo adjustable FPR. Hard wired to the ignition switch/main EFI relay at 100% duty cycle you're going to have to have enough return fuel capacity to absorb over 300 lph of fuel delivery at idle. This depends on your comfort with electronics though. Personally I have no problem wasting my life on code/staring at documentation if it means less mechanical complication but your opinion may differ.