joshuaho96

10:1 or 11:1 is normal for GDI-T. With PFI-T you can probably only run 6-7 psi boost when not running E85 with that kind of CR. Most people want to make more power on E85, not less. So you see relatively low CRs. Personally one of the bigger pet peeves I have is how rich these RBs run, either on pump gas or E85. Hopefully someone comes out with a proper water injection kit for these cars at some point.

If you're running E85/race gas full time you can bump CR up, but if you're running pump gas only 9:1 CR is pretty much as high as it gets. If you want to run 10-11:1 CR on pump gas you need direct injection. You would have to dramatically drop boost if you used a flex fuel setup when using pump gas, with PFI engines 10-11:1 CR is pretty common for 98 PULP.

Why use more fuel pump than the turbo could ever possibly use?

For a practical car it's indisputable, a newer car is better. Modern engines are better in so many different ways you could write a textbook on the subject. Same goes for safety, that floppy chassis is going to end poorly when everyone drives crossovers these days. Maybe Aus/NZ emissions are harder to meet than US standards but modern gasoline engines don't have a lot of trouble meeting emissions, it's only the EU where you have power-robbing GPFs. You can free up some power by running a high flow cat in the downpipe of most turbo engines but that's about it, the rest of the exhaust is basically sized for full flow with minimal restriction. Tire technology has advanced so far since the 90s that an F40 is slower from 0-100 km/h on 90s tires than a modern Mustang GT. Modern transmissions are so much better and more reliable generally as well, just keep up the fluid changes. With that said there are definitely issues with modern cars, some of which stem from higher safety standards. Others stem from just stupid design choices. The new Audi RS6 Avant now only comes with a choice of 21 or 22 inch wheels. The 21 inch wheels get 35 profile tires. The 22 inch wheels are 30 profile. These kinds of trends are horrendous for ride comfort and pothole resistance but somehow it keeps going on anyways. Infotainment does age like milk but frankly with Carplay/Android Auto you just plug in your phone and ignore all of those issues. The fake engine noises can usually be coded out but yes, it is obnoxious.

For anyone curious, I ended up going GT3-SS because the turbine a/r is 0.54 which is closer to the OEM turbine a/r of 0.49, multiple tuners that have tuned both GT3-SS and GT-SS in the US have mentioned that the GT3-SS trades power for low/mid torque compared to the GT-SS with a 0.64 turbine a/r. The goal has always been street-oriented so fingers crossed I don't regret paying way too much for a Civic Si turbo with an HKS stamp on it. I'll try and update with dyno results once I get it in.

I don't know the exact details of your GTS25t, for some reason though in the 1993-1996 GTS25t it shows the power steering solenoid at the rack as a single part: https://nissan.epc-data.com/skyline/ecr33/3898-rb25det/trans/492/49361/ On the BCNR33 it's a separate part from the housing that you can remove that is somehow triple the price because GTR tax: https://nissan.epc-data.com/skyline/bcnr33/3935-rb26dett/trans/492/49810/

https://www.gtrusablog.com/2017/05/nissan-skyline-power-steering-system.html Might be power steering solenoid? Also check your HICAS control unit capacitors. I would probably start with the HICAS unit, then check the solenoid. Capacitors in a car this old are almost certainly dying.

The best security system is a locked garage. Add bollards if you're extra worried. Alarms are a huge waste of time and really only good for giving you hearing loss when it goes off for no reason but not much else. Transponder immobilizers might discourage casual theft/hotwiring but certainly nobody determined. GPS trackers, maybe with a tilt sensor/geofencing might help you locate your car if someone tries to tow it away and you're extremely quick to react.

I'm definitely going to try and get all the supporting mods in to make sure the engine can perform well. I was thinking of getting the HKS GTIII-SS because of this chart: I don't mind that at the end of the chart the GTIII-SS isn't much to write home about, what interests me is the pretty ridiculous amount of torque it puts out by 3300 RPM. But maybe this is just what happens when you're loading up the engine on the dyno from like 1500 RPM? But even -9s from the same tuner with VCAM Step 2 doesn't make ~213 whp by 3300 RPM, and it appears to also start from 1500 RPM: Kansai Service put out a little blurb from their testing of the HKS GTIII-SS, personally I don't know how much stock I put into it but it suggests a decent mid-range bump, just not as good as what UP Garage is seeing: But the GTIII-SS is a journal-bearing turbo and more than a few people have mentioned that it's not as responsive because of it. So not sure what to do here.

Here I believe it mostly relates to the belief that Skylines are often used in street racing. These days the people who can afford to run a Skyline GT-R are not going to be racing them on the streets.

Maybe that's the answer in the end, feels like it at least. Probably not wise, the other minor detail I didn't mention is that if you get pulled over by a cop that wants to give you a hard time you get sent back to the smog referee. Then it's a scramble to put everything back to what looks like stock.

Laws aside, plenty of people running straight pipes, full decat, the works. So I’m not too worried about a bolt-on turbo getting noticed in an emissions check. So should I do -7s? -9s? Is there some mythical BNR34 turbo that isn’t ceramic turbine?

Engine is 100% stock, just noticing some oil on the compressor outlets so given the mileage of the car it's probably a good idea to replace the turbos. Depends on your risk tolerance I suppose. Once the car is registered your average smog shop doesn't really know what they're looking at, just have to pass a 2500 rpm tail sniffer test.

You would have to get engineering certification for the kit, which basically requires you to do a test of the emissions of the car stock on the FTP-75 (ADR 27 cycle with an extra warm start repeat after a 600 second cooldown), US06, and SC03 drive cycles using 11.5 AUD/L certification fuel. This is easily like 4000-5000 USD. Then you have to modify the car with the specific part/kit you want to certify. You are not permitted to do things like use end user programmable ECUs, usually this means you're limited to the factory ECU. For R33 GT-Rs this is a huge headache because you can't easily remap the ECU, I don't even think you can buy new Hitachi H8/534s anymore. You must follow all of the relevant emissions regulations around PCV, evap control, and retain full functionality of the onboard diagnostics system from the original ECU. Once you've modified the car you then repeat the same emissions tests that were requested by the California Air Resources Board engineers and send that data to them. You also need to send detailed engineering drawings, specs, etc to them so they can understand exactly how the part is made and how it differs from the OEM part. You're only allowed a small deviation from stock emissions, basically to account for measurement error. In this case it would be the car post-emissions compliance for import. The cost of this is insane, it only makes sense if you can amortize over a bunch of different vehicles. You're probably easily looking at 10k USD per "item" if everything goes mostly right, there's no single vehicle certification process. In theory whatever the car has on it when it passes the original import emissions compliance testing/modification is "certified", but a condition of initial registration is another emissions inspection after you receive emissions compliance. You can't just take it to any emissions tester, it's a state "smog referee" that will look at the car and expect it to basically be stock. So if you roll up with a single turbo swap it doesn't matter if you've passed the nightmare FTP-75 test + evap test, they'll fail you and send you away when they see that the intake isn't stock and lacks a CARB EO number. Personally I care about improving fuel efficiency and emissions where practical but I'm not rich enough to put down 10k just to prove that R35 injectors are in fact better atomizing than the OEM 440cc injectors. Or that a bolt-on turbo won't have any impact on emissions if constrained to the same mass flow rates as the OEM turbo on the OEM tune. Or that hot film MAFs are in fact better than the OEM hot wire MAFs. Or that a simple change to the twin turbo piping has no impact on emissions. The list honestly goes on and on. But the onus is on you to prove it through the same tests that the OEMs have to do to certify entire engine/transmission pairings.

Engine is out for a chassis refresh, I've been going in circles for the better part of a year now trying to figure out what turbos to select. Power goals are basically nothing to write home about, probably ~280-300 kW to the wheels on an honest australian dyno, wouldn't be surprised to get 280 kW on California 91 AKI (~95-96 RON AUS) but a good amount more if I go E85. To make emissions testing simpler it has to be a bolt-on twin turbo setup, doing anything else is going to be problematic. Most important to me is response at 3000-3500 RPM and the shape of the power curve, I don't want the turbo to choke the engine at 6000 RPM with 2000 RPM left to go or a turbo that takes until 4000 RPM to really get into the torque. In practice from what I've seen the R34 GT-R stock turbos are as responsive as it gets for stock mount twins, but I'm pretty sure those are ceramic turbines that can't take much more than 1 bar of boost or any mistreatment. I'm planning on running VCAM to try and compensate for the loss of the ceramic turbine. Should I get -7s? -9s? HKS' GTIII-SS turbos? Hypergear T25 high flow with BB CHRA? I've seen evidence that the GTIII-SS is really, really good for mid-range torque with VCAM but it still feels like a gamble, Garage Yoshida seems to suggest that it still feels lazy compared to -7s due to the bush bearing. -9s are supposedly just a little less responsive than -7s but with more favorable efficiency for high boost. GTIII-SS is supposed to be more response than -9s in the low/mid range, but boost tails off at high RPM from the small turbine so it can't sustain much more than 1.2 bar or so. The hope is with enough work the engine will feel more like a more modern engine in power delivery with VCAM and the right turbo choice instead of a more distinctly early 90s turbo power delivery.

Have you seen prices on 993 Turbos? The 996 Turbo is effectively the same car but with water cooled heads and various other improvements. Many pieces are literally stamped 964 or 993 to indicate when they were first used.

I can't speak to legal issues but 255 is the right width for a 9.5" wide wheel. The R33 GTRs shipped with 245 width tires on a 9 inch wide rim. You can safely run either 255 or 265. If they don't know something as basic as that I wouldn't want them to be anywhere near a set of work wheels.

It's definitely an option, Brave Auto and Pacific Coast are supposedly good brokers. You do an inspection before bidding, then bid. If you get the car, do another full PPI after buying it. If it's good ship it out, otherwise put it back up for auction and hope for the best. Not for the faint of heart though, you need to put up like 4-5M yen at a moment's notice. I bought a car sight unseen with a friend paid to PPI it and I still was extremely jittery about it.

You mean those 480p photos taken from 20+ feet away with zero underbody shots? Many of those have severe issues, you can't just go by the auction report and expect to get something in decent shape. I would not expect to pay less than 50k AUD.

Set your rev limit to 5000 RPM and a hard fuel cut at 22 psi, find a way to get max pressure on the wastegate spring to keep it closed. If response is any better then you might need to dial in the boost control. Also I hope your wastegate spring is strong, like at least 12-15 psi. Otherwise I think the problem is just your turbo is mismatched to the engine.

If your goal is reliability and low running costs then it's definitely the Evo. The GTR tax is real, even more so than an Evo. Also the GTR is substantially more complicated which leads to unreliability when combined with poor maintenance/general neglect. I will say if running costs are a big concern don't try and go for a lot of power on either of these cars, that's a recipe for a lot of headaches. Modding a car is a lot of thinking, research, and testing. If you're not interested in that I would pass.

Only you can decide which is "better". What do you want and why?

Evos are already 40k+ AUD in the US: https://bringatrailer.com/mitsubishi/lancer-evolution/

That's pretty surprising, I would figure that the RB26 would at least do better iso-power due to the extra displacement. Curious to see what data you have there.

I think claiming the RB26 is some lag monster compared to a 4G63 is probably overstating things a little bit. I buy that argument with the 4B11T which is a much more modern engine design. Compression ratio on a 4G63, even in the Evo 9, is barely better than what the RB26 shipped with. Run a touch thinner head gasket on the RB26 and you're already at 8.7:1. The biggest advantage is that Mitsubishi shipped intake side VVT, Nissan didn't bother to ship it on the RB26. Speaking of VVT, anyone know if PRP is actually going to make a double VCAM setup? I'm guessing it's going to take a substantial amount of work for benefits that most people don't really understand. That would make for a substantially more responsive RB though.