joshuaho96

I mean the other day I had to walk someone through diagnosing why their timing belt was walking off the cam gears. At least one of the issues was a bent tensioner stud. Local mechanics have found runout on the CAS mechanism causing weird failures. I'm also no saint here I've documented some of the things I've had to learn the hard way. Something I discovered recently is that my CA emissions catalytic converters weren't even welded correctly to align the downpipe to the main cat and they tossed the support bracket that goes from the transfer case to the downpipe to support everything there. I spend a lot of time chasing down these decidedly unsexy problems and the net effect is it feels like I never actually get to the original objective (flex fuel, VCAM, oil control, cooling, etc).

I think this is just a product of how the US market works for this stuff. Shops are expensive and there's no real way of knowing what kind of results you're going to get, people don't really have the institutional knowledge. I have heard too much at this point to really put faith in anybody "full service" except maybe DSport and they aren't really a full service kind of shop. If you go to the right place I have no doubt they'll get it right for you. Some locals have set it up right but the cost really is nuts and even now they're still fighting issues. And you know I'm a crazy person who thinks things like twin scroll, relatively short low-mount cast headers, PCV recirc to intake, recirculating BOV, right-sized for ~400 whp, MAF load, validating all of that to a standard comparable to OEM test programs, etc are relevant. For what it's worth, multiple local owners at this point have been stuck in a perpetual cycle of blowing a motor -> getting someone to rebuild it -> some missed detail causes the bearings to wipe and spin just outside of break-in mileage or drop valves or some other catastrophe -> cycle repeats. I usually only find out about this because I'm perpetually helping random friends with diagnosing car troubles, Skyline or otherwise. The single turbo stuff if I'm honest is mostly secondary, it just doesn't seem to achieve the numbers in the ~2000-3000 rpm region that I would expect given the results I've seen here or in Motive's videos. I don't really know what we're missing here in the US to be causing this. Lots of people like to emphasize the necessity of finishing the project first and foremost, but I'm not made of money and I can't afford to be trashing a 15k+ USD engine build with any regularity. Or spending my relatively limited garage time these days unable to triangulate problems because too much was changed all at once. Also, even if it isn't a catastrophic failure I would consider spending the cost of single turbo conversion with nothing to show for it to be pretty bad.

Among other things yes. Making sure to either use an oil pressure regulator or the right restrictor size for your oil pump/range of oil viscosities you intend to run, making sure you plumb the lines correctly, turbo should be placed such that it siphons properly even when the water pump isn't turning so you don't boil coolant in the turbo after shutdown, oil return should be low resistance and also preferably picking the one that is most likely to return to the pickup as opposed to some other irrelevant part of the pan. It's far from impossible to figure this out but I have seen people really, really struggle and if that's the case it's easier to just take the path of least resistance. To me, bolt-on twin turbos are a fixed cost whereas single turbo is almost unbounded.

Turbos don't require pulling the motor apart so that's "easier". I would recommend the Nismo R3 turbos instead if you want to do stock twin turbo. It doesn't make as much power as the 2530s but it's only like ~50 whp off the mark and should have better response (ball bearing CHRA, slightly smaller turbo). A local that went with a Garrett G30 and 6boost manifold recently nearly burned his car to the ground after the hood insulator started melting and and burning so if you go single turbo I recommend doing a lot of research and validation work to make sure you don't do the same.

That's what the people want, unfortunately. We can argue about whether this is cultural or marketing but in the US people like big SUVs because they want the capability all in one vehicle.

There's absolutely no way the turbine is nylon when EGTs peak somewhere in the region of 800-900C. The compressor can be nylon.

I mean yes, if you're starting from scratch on an unknown engine yes you don't need to be doing all kinds of math in the background but if you're doing relatively minor changes like AFM + injectors + boost up with some aftermarket turbos it takes quite a bit of math if you want to do something like maintain OEM fuel + timing tables but compressed and then a bit more load scale up top. I think I've spent too much time working on big engineering nightmares though so I'm a big fan of trying to constrain the scope of whatever work I'm doing as much as possible and trying to get it right before moving on. For example, a local owner just did the usual E85 + single turbo conversion to his R32 GTR and nearly burned his car to the ground doing some spirited driving up the local mountains. Turbine is unshielded and too close to the hood insulation. It's tough to balance "just get the project done" and "seemingly small details can cause massive setbacks I'm not willing to deal with".

Nistune needs something like an entire excel spreadsheet in which you build an abstraction layer that converts everything from real units you can actually measure into all of the various tables. The number of unexpected dependencies hiding in how the Nissan ECUs do math is a pretty impressive optimization trick for 8-bit MCUs but good god is it awful to actually work with in practice.

Kind of surprising, with cars this old I've seen a lot of them suffer from high idle due to internal vacuum leak. Fuel trims look fine but the cold start valve just wore out from all the heat cycles and won't close up all the way. Rather notorious issue in some models of the Toyota 4Runner:

IACV has an air bleed plug in this part of the engine manual. I'm guessing if it isn't bled it will cause weird idle behavior as the cold start valve won't get hot enough to close properly at the usual rate.

If you fully flushed and filled it's probably good for 5 years. I would not push it any further than that. Generally speaking coolant is more by time than by mileage. Rust wants to happen whether you're driving it 50,000 km or 80,000 km.

Modern transmissions like the 8HP lock up as low as ~12 km/h. And they will stay locked even with full throttle in gear. Far, far cry from the days of 3/4/5 speed automatics when they only locked up on overdrive gears and even then only if you didn't put too much torque through it. Manual transmissions are pointless unless you personally enjoy shifting gears.

Now that you mention it I can see those too. More subtle. The lighting and low resolution makes it hard to assess super well what's going on but what is visible is bad enough to pull the motor.

To me that looks like a rust ring in the bore. An engine that has sat for too long in humid conditions without fogging oil in the bores?

Stock ECU has compensation, you won't damage the engine. Personally I recommend getting an acceptable catalytic converter, it doesn't need to be OEM and super expensive but a cheap universal one to keep it from being super obnoxious to be around. Decatted cars smell pretty awful.

It is correct: https://www.amayama.com/en/genuine-catalogs/epc/nissan-japan/skyline/er34/6617-rb25det/engine/220 Looks like you can get one for 50 USD each from the UAE which is a pretty good price IMO.

Ah yeah I forget we aren't talking about an RB.

Pretty sure the factory assembly doesn't have any gasket at all, just RTV.

There aren't boost creep issues, it's not engineered around the restriction of the cats but if you haven't tuned the engine a full decat + exhaust can flow enough air to run off the end of the OEM load scales and you will get a pretty substantial reduction in ignition timing as a result. I recommend using DFCO, avoiding ignition cut limiters, and avoiding popcorn tunes along with running a cat unless you enjoy a perpetually soot-covered and potentially burnt bumper.

It really helps that light duty vehicles have absolutely appalling average efficiency due to poor average load. Like 25% average brake thermal efficiency when peak is somewhere around 38% these days. So even a 60% BTE stationary natural gas plant + transmission and charging losses still doing much better with an EV than conventional ICE. And that's before we get into renewables or "low carbon nonrenewable" nuclear which makes it a no-brainer, basically. In commercial aircraft or heavy duty diesel pulling some ridiculous amount of weight across a continent the numbers are much more difficult to make work. I honestly think in 5-10 years we will still be seeing something like the Achates opposed piston diesels in most semi trucks running on a blend of renewable/biodiesel. Applications where the energy density of diesel is just too critical to compromise. CARB is running trials of those engines right now to evaluate in real world drayage ops, probably because they're noticing that the numbers just don't work for electrification unless our plan is to make glorified electric trains with high voltage wires running along every major highway and only a token amount of battery to make it 30 miles or something like that after detaching. Transport emissions is not insignificant especially in the US, but yes there's a lot of industrial processes that also need to be decarbonized. I agree the scale of the problem is pretty insane but EDF managed to generate ~360 TWh from their nuclear reactors last year and this is with decades of underinvestment after the initial big push in the 70s and 80s. I don't think the frame of reference should be solar-limited. France is not exactly a big country either. Maybe it doesn't work everywhere, but it doesn't have to either. We just can't live off of fracking forever and expect things to be ok.

Somehow Vertimass/Oak Ridge National Labs has figured out a catalyst that can convert ethanol into C9-C10 hydrocarbons in basically a single step without ending up with a bunch of ethylene or similar waste products: https://patents.google.com/patent/WO2023224867A1/en I still don't think anything like this will keep us from needing to transition to EVs regardless along with all kinds of other electrification, but things like this will go a long way towards alleviating the problem of how to electrify things like planes. Renewable diesel is seemingly an easier problem as well, Chevron is already running refineries for the stuff and the primary feedstock is tallow and other waste fats from agriculture.

What about renewable diesel and/or gasoline? I see some projects spinning up like de-oxygenating ethanol to make drop-in compatible bio-gasoline especially in CA. I still think the future is EVs and we should've all gone full throttle on nuclear power after the 1973 oil crisis like France. Despite 15 years of work in CA to reduce the CO2 intensity of generation with renewables our electric grid is still far worse than even "low carbon" nuclear power. ICE is pretty cool when you aren't depending on the stupid thing to be practical and reliable and cheap as possible to get you to work every day. It's kind of like mechanical watches or vacuum tube amps.

Reminds me I really need to install that HKS oil cooler I bought years ago.

I just did an oil change on my daily which used oil that is probably 2-3 years old. Normally I try to follow exact viscosities, but my LS400 is fairly tolerant. Dumped something like half a quart of 0W30 Mobil1 ESP X2 in there, followed by 2 quarts Pennzoil 5W30, followed by ~1.2 quarts of liquimoly 5W30 LL04 spec oil. Then the rest was QS euro 5W40 which is actually so thin it's basically a 30 weight oil. All this is to say it doesn't matter that much. We aren't talking about brake fluid. For an RB I would recommend a high ZDDP oil because it doesn't use rollers in the interface between the cam and valve, but a 5W30 or 5W40 is fine to use for street use. The 10W60 guidance really only applies if you're getting it hot and pushing the engine hard.

Yep, looks like some random aftermarket bit that is likely generic as well. Personally I just log everything to a google doc.