joshuaho96

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

You can try shoving a borescope down there to see what's up.

I could see someone trying this to save money on oil changes.

65601-05U00 is the hood latch. 62550-08U31 is the support that holds it to the radiator core support. They are all super discontinued so I don't really have any great leads on how to source this stuff.

AA000 is for R34 GTT. 11140-05002 is not a part number that exists in Nissan's parts catalog. R33 GTST is 11140-21U00. 11140-05U02 is for the RB26.

Bumping this thread yet again, has anyone ever tried putting yet another vacuum regulating valve on the hose that goes between the turbo inlet? Something local owners have mentioned is the Radium breather pipes de-restrict the valve cover but it actually produces an undesirable outcome in practice, way too much air is sucked out of the crankcase and a ton of oil comes with it as well. As far as I can tell the PCV diaphragm in these modern euro wet sump performance engines is active during boost as well, there's just a check valve to block boost from entering the valve cover and crankcase as there's no inherent check valve function in these diaphragm-type valves. Hopefully I'll be able to try some of this out soon. The Volvo XC90 4.4 V8 has a nice external version of these things.

AFAIK does the base map for Haltech even have the 4D compensation enabled? It's been a while but when I looked at it I remember it was actually using pure TPS as one load signal and MAP for another. Seemed workable but not ideal by any stretch. A lot of people have "make the event-itis" which leads to stuff like this happening.

It's weird to me that you say this because I'm pretty sure locals with relatively standard standalone tunes (boost/barometric compensated alpha-N) still have driveability issues when they pop intercooler hoses. Maybe with enough data I can just train some kind of model that spits out an expected grams/cyl given every sensor input except MAF like what FCA did with their Pentastar 3.6 ECU logic. Basically stock everything. The main motivation honestly is to have a sensor that can be a decent baseline source of truth. In scenarios you're describing obviously it won't work every time but it seems to me the number of corner cases that exist in MAF load is maybe not as severe and difficult to manage vs ITB alpha-N with some MAP/barometric compensation.

Is MAF load really that bad? I'm not trying to do big power, my only real desire is VCAM and flex fuel support so I'm not terrified of blowing my engine apart from CA's appalling 95 RON "premium" fuel. Stuff like playing with closed loop boost control and really dialing in my transient fueling and ignition are frankly just to prove to myself I remembered something from uni.

Right, but I thought the problem has been for a while now that even if you know manifold pressure + throttle position you still have non-linearity and aliasing issues vs actual engine load? One way I can see things simplifying is going DBW, then all air going into the engine is represented by the throttle position. As opposed to a random bimetallic strip vaguely linked to engine temperature opening and closing a shutter or some random power steering air valve suddenly allowing a bunch of bypass air. But the same throttle position/RPM at ~atmospheric MAP in different gears is not guaranteed to be same engine load? Honestly, ITBs are of such dubious value IMO. I don't know why these things are hyped up so much. The main benefit as far as I can tell is you reduce the likelihood of cross-cylinder EGR scavenging with significant cam overlap at idle. I would absolutely run speed density and be done with it if not for this fairly esoteric control problem.

You're not wrong, but this is one of those things I need to learn the hard way. I really, really dislike alpha-N for ignition or fuel load and I don't feel like pulling apart the manifold again for single throttle body conversion any time soon. I might be tempted to buy an Emtron for the throttle mass flow setup though, that might work well enough to get me off of this whole factory MAF setup idea but the way I see it the end result is still going to be scaling the load axes in cylinder airmass regardless.

The general simplicity of the generic conditions/triggers in Haltech kind of drive me nuts. For mysterious reasons I felt like trying to replicate OEM catalyst light-off ignition timing but there's no reasonable way of doing any kind of math like finding the delta between IAT and CLT at engine start to set a flag that indicates cold start. Stuff like that is easy with Link. On the other hand, Link straight up doesn't support dual MAF load on the RB26 so...

-9s are discontinued supposedly. But you can still get Nismo R3 turbos which are something like a -7 but subtly different? -7s are also available. HKS GTIII-SS and GTIII-2530 are also available but they're journal bearing MHI turbos.

Rather it's the OEM thing these days. I don't think I see single turbo monoscroll on any I6. Obviously back then twin scroll turbos weren't readily available so I saw a lot of "twin entry" designs which had a divider on the manifold but nothing on the turbo.

Yeah, but twin scroll is the OEM thing and I love pain.

Wasn't there some discussion of how the Hypergear high flow actually has different dimensions so it's not a true bolt-on replacement? Honestly if that's the case I would consider just going true twin scroll and go down a massive rabbit hole of getting all that to package as close to stock as possible.

FWIW a lot of the local owners that do a big build tend to have cars that are perpetually broken.

I have an Elite 2500, honestly most of this has been a lot of smaller tasks chasing little details and a whole lot of life getting in the way of bigger projects. I don't mind too much looking at a spectrograph vs having audio knock ears.

1. Factory knock sensors for now, honestly the RB26 OEM knock sensors seem ok as they're flat response instead of resonant type but they appear to be internally grounded to the block. If I do replace the sensor it would just be to get ones that are not internally grounded so a differential input can be used to reject common mode noise. Definitely plan on fixing this as a part of the tuning process. 2. Never deliberately induced knock, though I guess I could try that experiment if I really wanted to. 3. All of this is basically on a stock engine + ECU, only modification is HKS GTIII-SS turbos and a Nismo plenum. Currently I run it with the wastegate solenoid unplugged so it won't try to raise boost past wastegate pressure.

Are the factory timing tables actually that far off the mark? Even on CA ~95 RON I don't hear any gravel in a can. I do get some vibration around 1200 rpm just off idle and a light grumbling noise, but even when I've filled up with 106 RON fuel at 4.24 AUD/L none of that goes away. ECU also has never showed signs of switching over to knock maps. My plan was stick to factory timing up until it's at the last load column and ask for a trusted RB tuner to handle the rest. Probably not exceeding 1 bar on 95 RON, but we get E85 here so flex fuel should make it safe enough to run basically MBT timing considering I have no plans to bump the compression ratio over stock.

I know it'll run, but from what I've seen the Haltech base map is actually quite a bit more conservative than the OEM stock map.

You're not wrong, but more than a few times I've heard of people running into issues where their injector characterization isn't quite right and that approach works for that specific configuration but once they switch over to a new set they discover a whole bunch of stuff wasn't set up correctly. It's slightly more annoying to reverse engineer the OEM MAF transfer function but you already have the sensor wired up to the factory harness so keeping it around for a few weeks more while you figure out the tune is easy enough. I've seen GM also use a combination of both MAF + MAP in their ECUs before, MAF is for steady state and a calculation of the cylinder VE to correct the base VE table, then in transients it uses that calculated VE + raw MAP to determine cylinder filling somehow.

The second part yes, the first part about easy VE calculation is something I've seen a few people talk about online.

Honda's hybrid system can be easily scaled up to PHEVs. Series hybrid at low speeds, at higher speeds the engine directly drives the wheels but there can still be some power bled off to charge the battery + the electric motor can still provide parallel assistance too. It's really only a question of will at that point. Toyota's PHEVs are selling incredibly well at the moment because of the flexibility. You can run on EV mode when it makes sense, but if you're planning on doing a long highway drive you can still fire up the gas engine and not have to worry about dealing with the rather miserable state of public charging infrastructure.

Only reason to keep a MAF on your RB25 is to be able to easily calculate true VE if you know what the factory voltage curve represents in grams per second of flow. Also allows you to do things like pull the original OEM ignition + AFR target tables and use those as a starting point for your base map. Once you're well and truly done tuning though there's no need to retain the MAF.