joshuaho96

There is no replacement for actually driving it yourself and feeling how the shift feels in your hands. I can make a gearbox on its last legs seem fine by shifting gently and double clutching. Shift just a little faster and it'll grind. Usually in a private party transaction the easiest way to do it is at a bank yes. They bring car + anything else. Verify that they didn't forget anything that was part of the deal. Walk into the bank, do a bank transfer using a cashier's check or similar. Do the paperwork on the sale, make sure to not screw it up on either side as many of these documents are void from any strikethroughs. I'm in the US though so I can't speak to the specifics in your region.

I do have legal/emissions compliance to keep in mind unfortunately. But even if there were no such concerns the things I want out of a single turbo RB26 doesn't really exist as far as I know. Short runners, low-mount, proper heat shielding instead of just having an exhaust manifold + turbo inches away from heat-sensitive components, real thought given to minimizing the changes to things other than the turbo + manifold + intake piping, and twin scroll. Basically look at a BMW B58 or N55, that's the goal in my head. I know that's a really tall order but this is a street car, not a track build. Someone I know has gone through stock turbos -> HKS GT-SS -> GTX3576R gen 2 and he absolutely loses power at the critical ~3000-4000 RPM area where I spend a lot of time at on the street contrary to what Motive found.

Genuinely confused here, I've never seen a dyno result where -9s/GT-SS didn't give up a pretty substantial amount of response relative to stock turbos. I figured staring at turbine maps that you want to size it to the actual amount of exhaust CFM you expect or else either you have really awful response or the turbo becomes entirely backpressure limited. Everything I can find suggests that for the same exact turbine wheel, adjusting the turbine a/r moves the choke point up and down. The turbo definitely chokes somewhere around 18-21 psi up top from what I've seen but for my purposes that's actually ok. Funny enough looking at the BMW S55 the turbos they use stock are comparatively tiny. 51mm compressor exducer, 43mm turbine inducer:

Isn't the trim for the GTIII-SS listed somewhere? The tag for it says 5652 55T 01786 on mine. I'm guessing the 55T is for the compressor. I don't understand, I thought when you make a smaller turbo for smaller power output everything gets smaller. 0.64 a/r on a -9 but 0.83 or 1.01 a/r on a single turbo is not unusual. Stock is 0.48 turbine a/r so it's pretty much right between stock and an N1 or GT-SS. I was never really interested in it for "billet", I just want a tiny turbo to make very pedestrian levels of power. Pretty much stock, just without the ceramic turbine wheel. Each turbo only has 1.3L of displacement to work with after all. I think more than anything my concern is I make an irreversible change to the car that really affects reliability or driveability. It would've been nice to have the same turbo but ball bearings instead of journal bearings but I'm willing to bet that a larger ball bearing turbo is ultimately going to have more lag than a smaller journal bearing turbo. Even if there's more drag from the bearings, the issue is more the inertia of the turbine/compressor wheels. I don't know if I'd ever recommend a bolt-on turbo for the kind of power that the GT-RS turbos are targeted at.

Is the GTIII-SS actually mismatched between compressor and turbine? I've never been able to find any information on it. Only thing I know is the exhaust housing a/r is 0.54.

As a general rule you do not mix gaskets and RTV. That is a recipe for disaster.

In the US V35s and V36s are mostly disappearing because they've been crashed and modified to death like any other cheap RWD car. Such is life.

Pretty much yes. I'm attracted to poor life decisions which is how I ended up with a GTR after all.

The FA has a ton of technologies in it that make it halfway acceptable for fuel economy compared to the positively stone-age EJ. GDI allows for scavenging without a bunch of fuel missing the combustion chamber and going straight out the exhaust. Cooled EGR allows for a lot more knock margin than the engine would have otherwise. TGV allows for good fuel mixing even at low RPM with GDI. There's also part load Atkinson cycle operation.

Stock block or stock bottom-end? I can believe stock block. The question is also how long you can make that power for. Subaru has killed 100% stock STIs under warranty by shipping poor tunes.

The F82 M4 is technically extremely competent. It's also kind of emotionally dead and somehow sounds absolutely horrible with the stock exhaust. To me that car exemplifies the fact that we don't drive spec sheets, there are a ton of little details that affect the experience.

With an EJ25? The limit for ringlands I thought was due to combustion chamber pressures. While any one knock event can instantly kill the pistons at 250 kW to the wheels or so my understanding was even normal combustion could still damage the piston ringlands. Then from there the next thing to break would be conrods.

I checked online and Garrett seems to suggest that at warm idle minimum oil pressure at the inlet needs to be at least 15 psi and at redline no more than 45 psi. Can you really separate oil pressure and flow rate in these systems? I assume that when the spec says a certain oil pressure it implies a certain resulting pressure drop across the CHRA and a resulting flow rate.

The STI in particular still had an EJ engine in it. It pretty much never had the ability to take big power. The entire block flexes easily and is not conducive to a long and healthy life with big power. The factory top-mount intercooler heat soaks very easily. The factory cast pistons put the compression ring very high up making it very vulnerable to knock in order to reduce crevice volume for emissions. Considering how weak the block is the 2.5L EJ257 used in the US is basically not designed to ever be stroked as the rod ratio is already on the low side. Normally not a problem, plenty of Honda engines run pretty extreme rod ratios but an EJ block is a delicate thing. The S209 in the US made 340 hp using an HKS GTIII-RS turbo and that is probably the absolute limit of what Subaru/STI powertrain engineers were comfortable with warrantying.

¯\_(ツ)_/¯ The Kinugawa bolt-on turbos for RB26 are far larger than the -7s, it also lacks the HKS logo for extra JDM tyte points for cars and coffee. The goal isn't really to go for big power. The GTIII-SS obviously is down on response from bearing drag but it's a smaller turbo than the GT-SS. It's pretty much the smallest turbo readily available for the RB26 other than the factory ceramics. It's not going to impress anyone with numbers but if that was the goal I'd buy a Lucid Air.

There's a lot of drama that led up to that. Tomei USA started using different sources for camshafts and other parts and sometimes it wasn't equivalent in quality to the Tomei JP brand version. Supposedly they stopped paying the JP branch as well. You can look up Real Speed Engineering to see Tomei USA parts being sold in Japan. Personally I stay away not because of this business drama in the background but because multiple people have posted issues like the Tomei USA cams physically not fitting in the head and head gaskets failing on the very first engine start. Maybe one is a fluke but multiple people going to different machine shops and generally pretty knowledgeable about the requirements around surface finish/flatness/etc for MLS all having issues is too much for me to even bother risking it.

Doesn't the turbo call for a specific oil pressure at the feed? So in theory at least a super high pressure oil pump will need more restriction and a low pressure oil pump would need less restriction. How much that actually matters in the context of real parts I don't know.

I still debate what to do there honestly, the original turbos were covered in either a ton of blowby from the decades or seeping a little from the seals and I couldn't ship them with the car anyways. As far as I can tell nobody really rebuilds turbos with the factory ceramic turbine either. I'm also not sure that anyone cares about having the factory ceramic turbos, even for weird obsessives like me. Then again you have the Contempo Concepts of the world trying to source series 1 R32 steering wheels because the later revisions have slightly wider spokes which is unacceptable to them. I'm pretty sure you're right but it's kind of interesting to see the kinds of results that this tuner got with the magical beans. They also report differences between the HKS 2530 turbos and the Garrett -5s which is interesting: How real any of this is an open question but they sure sold me on the HKS magic bean journal bearing nuggets. Well, that and a lot of staring at Kansai Service/Midori Seibi dyno charts to get a sense for how they compared to the other relatively low power bolt-on turbos.

I like my gloves, but I'm a desk jockey that gets sore all over after rotating my tires and bleeding brakes.

A lot of workshops I talk to don't even do intake plenum/collector with the engine in the car.

Removing or installing the twin turbo setup with the engine in the car is a pretty miserable experience. I have no idea why anyone would bother with that.

Nismo R3 turbos for the Nismo logo in the compressor housing. It adds 50 horsepower at least.

I wouldn't allow the engine to turn until you've verified that you haven't gotten a bunch of ceramic bits from the turbine going backwards from exhaust gas reversion. Letting off at high rpm you can see the manifold pressure reach high levels of vacuum.

I haven't really heard of these venturis being replaced very often in most R33s. For a 450 lph pump it may be necessary but with the 276 lph drop-in pumps it's probably not. From what I see online people don't report issues like this on the R33: https://www.skylineowners.com/threads/help-identifying-this-part.317169/

The design seen in the OEM part would definitely not pop off even under boost. Pretty substantial lip with a hose clamp to apply pressure to keep it from moving. The trouble is finding an aftermarket pipe that would replicate that design feature.