joshuaho96

https://www.gtr.co.uk/threads/attesa-accumulator-nitrogen-canister-change.572973/#post-5815458

VCAM step 1?

If you don't already have a factory double DIN you need a kit to relocate the HVAC unit: https://www.suncoastparts.com/product/9X6DDIN.html My experience is that the 996 is not exactly a quiet cabin, I would not mess with the speakers at all, don't be the guy that drills random holes in the chassis, there's a guide out there for how to retain all of the speakers here: https://rennlist.com/forums/996-turbo-forum/1157084-double-din-stereo-install-retaining-bose-and-most-interface-long.html

I'm not suggesting it, it could cause issues with compressor surge because the BOV doesn't see vacuum when the throttle snaps shut, and I don't know what differential pressure is required to cause the BOV to open up significantly. Personally I would just run wastegate pressure if "boost" is a big deal. A low compression N/A engine is nasty to drive.

The BOV needs a pressure/vac source post-TB so it doesn’t crack open under boost but does open when the turbo is in boost but the intake runners are in vacuum. If you disconnect the vacuum line for the BOV and cap the fitting on the intake it creates a substantial boost leak. Whether it’s enough to avoid leaking boost at all is hard to say.

I would love to buy the MHI turbo that it's based on and not pay a thousand dollars for an HKS logo, unfortunately nobody is really interested in figuring those pesky details out. Doesn't seem like anyone is really interested in small power builds these days.

My goal was to find the smallest aftermarket bolt-on twin turbo. The HKS GT3-SS is the smallest turbo out there, to the extent that it cannot sustain much more than ~1.35 bar at high RPM due to the small turbine, which basically means that it was competing with -7s and -9s. From what I've seen it is roughly competitive with -7s in terms of peak power, but is capable of delivering a lot more power down in the 4000 RPM range. -9s can deliver more peak power, but the narrower compressor map seems to affect how well they respond down low. The GT3-SS is also a pretty new turbo, came out ~4 years ago, I don't put a lot of stock into their marketing literature but they basically admit in it that they've just borrowed a turbo from a more recent engine and modified it to suit the RB26.

Decats cause tremendous amounts of carcinogenic and lung irritating gases to be constantly coming out of your exhaust, everyone in traffic will hate you, as will your neighbors. You will smell of exhaust well after you stop driving and get out of the car. Leave well enough alone.

I have to go stealth so we’ll see what the HKS GT3-SS “modern” turbos do. It’ll be the only modified part on the car.

I would be inclined to give a real answer but there's no point in answering when it's clear it's just in search of affirmation. OP probably bought an auto Skyline and is now experiencing buyer's remorse.

Not a great comparison point because it's VCAM step 2 vs step 1 but they did have an EFR7163 VCAM step 1 comparison: "The Black run is a Step 2 V-Cam with a GTX 35/82The Blue run is a Step 1 V-Cam with a EFR 7163The Orange run is NON V-Cam with our DR500s These runs were all done in 4wd with 92 octane in similar weather conditions. I tried to grab an average run from each turbo setup as not be to be misleading." Also seems like people like the G25-660 for big power which is surprising to me:

Pretty sure it’s an actual GTX3582. Dyno is a Mustang 4 wheel dyno as far as I can tell so it’s not laughably high reading. Spectrum Motorsports sells both single and twin turbo kits.

I've been wondering how they've been doing it too, they tend to get results that others don't.

It’s different turbos, supposedly same engine spec within reason. Both running VCAM Step 2 with an HKS 272 exhaust cam.

Curious to know what others think of this data point, this is supposed to be a more modern twin turbo setup for the RB26 vs a GTX3582: "More info Twins vs Single. 4WD mustang dyno, 92 octane, similar weather condtions, Step 2 V-Cam, 272 exhaust cam on both, both running metal cats.Blue run are the DR500 twinsOrange run is GTX 35/82 Again this is just more info for everyone. Each of you will have your own opinions on what setup is better. Its coming to my attention that when we post up data, that we have collected, and speak highly of our results its because we are in love with what we do! Its unfortunate that it has come across as being competetive and that is not our intent. The information is there for you to use, only if it applies to what you want to accomplish with your GTR. And yes we have watched the Motive video." Link: Looks like the turbos are made by Spectrum Motorsports in 42R configuration: https://www.spectrummotorsportssolutions.com/products/r32-r33-r34-rb26-smr600

Higher numeric final drive (shorter gears) would affect the RPM you spool by because the engine will reach higher RPMs sooner. But if you were to do a time to torque/boost measurement you would find it to be faster because the engine is getting up to an RPM where it can spool the turbo sooner. You can play games with dyno load to do this, it's effectively brake boosting.

Doesn't this imply that you would want less CR anyways? I can't imagine running rich all the time is healthy for an engine.

Yeah, probably going to just disconnect the FPCM and use the PWM controller then.

Doesn't that imply that you would have to run rich for too much of the load/RPM map? Modern gasoline is up to 14:1 CR for NA, or even as high as 16:1 for the Skyactiv-X, as high as 12:1 for turbo. I can't think of why emissions would factor into it. NOx obviously goes up with high CR, but 10:1 PFI-T is nowhere near what diesels have done for a long time now.

That is a properly buff pump but probably too much fuel pump for something making 300 kw. Something like the Fuelab 48402 seems to be what I'm looking for, around 10A draw and capable of 300 lph at 70 psi outlet pressure to be able to turn up the FPR to 3.5 bar differential pressure. I might run some experiments to see if the OEM FPCU/FPCM has the right resistances to be able to actually function as the pump speed controller, have to see what the impedances look like. Probably have to just accept that it's a horrendous idea though and just use a standalone ECU to run the PWM controller. Anyways, I don't doubt that high CRs improve driveability, I'm just skeptical that you can run high CR with low duration cams and no tricks like advanced VVT/cooled EGR/E85. I'm sure that Mitsubishi and Nissan would've raised the static CR on the 4B11T and VR38DETT to 10:1 if they could've done so while meeting power targets on pump gas. The VR30DDTT has a 10.3 CR but uses GDI and dual VVT to get there.

I like to spend my hours reading about interesting things, not necessarily productive though. Feels like this has been the answer a number of times I've looked into this. I'm probably going down that road in the end, just want to figure out a good 340 lph brushless in-tank pump solution.

I'm actually just hoping to be able to get an RB to be more modern, running something like high 13 AFR deep into boost and revs instead of 11.5 and maybe push back the knock limit enough to get power equivalent to 98-100 RON fuel with 95 RON. RBs also seem to be thermally challenged so water injection might help in that regard as well if it ever makes it to a track. But if the trade-off is I never actually get to drive the car or I have to pull the engine because water contaminated the oil and trashed the engine it isn't really worth it.

I dunno, random PhDs? Working fine is a relative statement. Even in the M4 GTS there are some reliability issues. If the design goal is OEM reliability and refinement I don't think the aftermarket systems are there. Even the OEM systems may be a bit touch and go. A fuel system just works for the better part of 200k miles or 15 years. A water injection system should be similarly expected to work just fine with just added distilled water for 200k miles or 15 years. The military is ok with 50 hours of maintenance for every 25 hours of flight or a total engine rebuild after 5 minutes of WEP, modern performance cars are basically expected to survive on not much more than fluid and brake changes for 15 years.

I'm not as sure, pretty much every tuner I talk to is not a fan of WMI due to reliability issues, every paper I read mentions water contamination of the oil and cylinder wall scuffing. WMI is really interesting to me as a concept but feels like the details aren't quite there yet. Not worth wrecking an engine over it.

Not a fan of any of the easily available water injection systems. If you're going to do it, you should do it right. PWMing the motor to get the desired flow rate is really, really slow and imprecise. Aquamist is the only company doing a "fast acting valve" so you can control the injector more precisely but the flow isn't to individual injectors, it's to all cylinders all at once. I've seen a lot of literature about injecting water during the low lift phase of the intake cams leading to crankcase water contamination and scuffing of the cylinder bores so it seems unwise to have such poor control over when you're injecting water. Bosch's water injection system is one injector per two cylinders, so it's semi-sequential which is probably ok, but I'm unwilling to spend 2000 USD per injector to find out. The only other option is Nostrum Energy, and they don't actually have a real product to buy, just the director of R&D's testbed R35. We'll see if they manage to ship something as promised.