GTSBoy

I'm pretty sure that HK would only have the same blend all year 'round, but whatever.

Just put a Haltech in it. Be aware that there is little extra speed available, so almost any money spent on NA "tuning" is wasted. Far better to spend on brakes, suspension, etc. Be also aware that the auto will die behind a turbo, so a manual swap is not a bad idea. Be aware that parts for these tasks are becoming very difficult to find.

Yes, it is entirely possible to twincharge a Skyline. It is not....without problems though. There was a guy did it to an SOHC RB30 (and I think maybe it became or already was a 25/30) in a VL Commode. It was a monster. The idea is that you can run both compressors at relatively low pressure ratios, yet still end up with a quite large total pressure ratio because they multiply, not add, boost levels. So, if the blower is spun to give a 1.4:1 PR (ie, it would make ~40 kPa of boost on its own) and the turbo is set up to give a 1.4:1 PR also, then you don't get 40+40 = 80 kPa of boost, you get 1.4*1.4, which is pretty close to 100 kPa of boost. It's free real estate! This only gets better as the PRs increase. If both are set up to yield about 1.7 PR, which is only about 70 kPa or 10ish psi of boost each, you actually end up with about 1.9 bar of boost! So, inevitably it was a bit of a monster. The blower is set up as the 2nd compressor, closest to the motor, because it is a positive displacement unit, so to get the benefit of putting it in series with another compressor, it has to go second. If you put it first, it has to be bigger, because it will be breathing air at atmospheric pressure. The turbo's compressor ends up needing to be a lot larger than you'd expect, and optimised to be efficient at large mass flows and low PRs. The turbo's exhaust side needs to be quite relaxed, because it's not trying to provide the power to produce all the boost, and it has to handle ALL the exhaust flow. I think you need a much bigger wastegate than you might expect. Certainly bigger than for an engine just making the same power level turbo only. The blower effectively multiplies the base engine size. So if you put a 1.7 PR blower on a 2.5L Skyline, it's like turboing a 4.2L engine. Easy to make massive power. Plus, because the engine is blown, the blower makes boost before the turbo can even think about making boost, so it's like having that 4.2L engine all the way from idle. Fattens the torque delivery up massively. But, there are downsides. The first is trying to work out how to size the turbo according to the above. The second is that you pretty much have to give up on aircon. There's not enough space to mount everything you need. You might be able to go elec power steering pump, hidden away somewhere. but it would still be a struggle to get both the AC and the blower on the same side of the engine. Then, you have to ponder whether you want to truly intercool the thing. Ideally you would put a cooler between the turbo and the blower, so as to drop the heat out of it and gain even more benefit from the blower's positive displacement nature. But that would really need to be a water to air core, because you're never going to find enough room to run 2 sets of boost pipes out to air to air cores in the front of the car. But you still need to aftercool after the blower, because both these compressors will add a lot of heat, and you wil have the same temperature (more or less) as if you produced all that boost with a single stage, and no one in their right mind would try to run a petrol engine on high boost without a cooler (unless not using petrol, which we shall ignore for the moment). I'm of the opinnion that 2x water to air cores in the bay and 2x HXs out the front is probably the only sensible way to avoid wasting a lot of room trying to fit in long runs of boost pipe. But the struggle to locate everything in the limited space available would still be a pretty bad optimisation problem. If it was an OEM, they'd throw 20 engineers at it for a year and let them test out 30 ideas before deciding on the best layout. And they'd have the freedom to develop bespoke castings and the like, for manifolds, housings, connecting pipes to/from compressors and cores. A single person in a garage can either have one shot at it and live with the result, or spend 5 years trying to get it right.

There's a whole subforum right here. 3rd sticky down.

I'd be surprised if it's a problem. A highflow cat doesn't present a massive restriction. You'd have to be tuned on the ragged edge for there to be any likelihood of something going wrong.

Definitely needs ceramic coat and fresh wax every week. And cats. Running with no cats is a (unt act.

2630s work perfectly well. There is something to be said for just using the 30 head, as it saves all the pain of the conversion, still makes tons of power, still sounds cool, etc etc. 2630 will obviously make more power again, but the differences are not stupidly big. It really depends on whether you're racing for sheep stations or not. If it's dead serious, then it's a 26 head. If it's just for fun, it could go either way. But the 26 head and the effort to get it set up, etc etc, is part of the fun.

No no. The Audi boost controller was made from a Norgren (or equivalent) 1/4" pneumatics pressure regulator, a similar (looking) relief valve (to create the "gated" function to keep the boost off the actuator until wanted) and a check valve plumbed in parallel with those two, to relieve the boost back out of the wastegate line after the boost event was over. It was the inclusion of that check valve, used sort of "backwards" as a relief valve, that was the stroke of genius that made the rest of it work nice. The only reason I stoped using it was because it was like any other manual/pneumatic boost controller - it's settings changed from season to season. The Profec is much more consistent winter to summer.

A couple of months of gentle driving will be fine. There is a risk that you will kill it. A heavy workout will probably kill 3rd gear. Continued use will wreck the input shaft bearing.

That's because R34 RB25DET is a pull clutch gearbox. I have that clutch, behind 25Neo, in front of R33 gearbox. I have brand new R34 turbo gearbox, in a box (cardboard) in the shed right now, and it will be getting used with the same engine and clutch, because I also have, in a much smaller box next to it, the front plate to convert the new box to push clutch.

Yeah, no matter what bad things people can say about Julian from Autospeed, he at least was capable of thinking and his inclusion of a check/relief valve in the plumbing for the Audi boost controller, that I made a copy of and used for years**, completely eradicated that problem. **It's still lying on my workbench where I put it about, um, 18 years ago and have never found a home for it!

That's essentially the clutch that I have behind my Neo. Big box of course, but it won't matter that you have a small box, as you won't have it for too long.

Yeah, but knowledge of one wire's insulation worn through to short on earth implies the possibility of other wires doing the same. I had my power steering die, because the wire that runs to the solenoid valve on the rack runs in the same loom as the power wire for the O2 sensor. And when the O2 sensor/wire did something stupid and burnt part of that loom to death, the only indication was the shit(ter) fuel economy and the heavy steering. It took deep excavation of the looms in the bay to find the problem. Not wear through in that case, but similar shit.

I don't think he's got it on a gauge and on the ECU. I think he's got it on the gauge and on the HPTuners DAq thingo. Remember, we're talking about oil temp here, not something that the ECU is actually interested in for its own sake.

A GT-V would be a fine daily. Not fast, and no point in trying to make one fast. Well, that used to be true, but perhaps if the only nice R34 you can find is an NA, then the "sell it and buy a turbo instead" advice we used to give becomes out of date.

HAL 9000 The Butlerian Jihad Mother & Ash Skynet The Matrix Ex Machina And now..... The AIs are taking our tyres.

That's true for things that are treating the input as a "temperature" input, ie that are interested in measuring the resistance of the sensor. But in the case of Greg's MPVI3, he's just measuring a voltage. Voltages are measured with a high impedance input, so no significant current flows, so they have almost no effect on the circuit being measured. It is exactly the same as probing the sensor's terminal with a multimeter set to DC volts.

AIs new frontier is as "personal shopper" for people too lazy to do their own research. You should try to get one of these AIs to purchase some of these "Pirellys". Would seem like an Inception moment.

That would be the better outcome. The one where the car is burning to the ground while also being broken down in the dark of a wet rainy night is also possible.

Yeah, it's f**ked up. The boss of the trucking co might be in a world of hurt saying "it's all our fault" and that their insurance company will cover everyone's damages. I think his insurance co might object to him accepting liability out in the open like that, and things might start to suck for him from some point in the next day or 2.

Welcome. We're all grumpy old men (and a few grumpy old women) who are slowly coming to hate these cars. Any of the newer owners who have joined in the last few years are rapidly catching up with us as they realise they have bought a basket case and that parts are getting difficult to find. Just be realistic about your goals. You'll need a fat stack of cash to buy an R34 GTR, and you'd be far better off using that to buy absolutely anything else (ie, shares, a house, scratchy tickets) unless that fat stack of cash is only ~10% of the actual fat stack of cash that you have. You'll never want to drive an R34 GTR on the street if you have fear of it getting destroyed. That's more or less true of the 33s and 32s also. Most of the RWD cars have been drifted backwards into power poles. No-one knows what they are worth these days because they are not changing hands. My car has notionally been down to <$10k value at some point and was probably sellable for $40-$50k in the height of COVID stupidity, but I have no idea what it's really worth now. It's irreplaceable anyway, because... where would I find one to replace it? Being realistic means either paying a lot of cash for a really really clean example that you will only drive on sunny Sundays, or buying one to daily that you will not want to be really really clean, for the same fears of destruction that applies to the GTR. I daily mine and some people think I'm crazy. But....to me it's just a car that I bought last century with the express purpose of driving it as my daily. The silliness that has happened since doesn't affect my original purpose. I have well and truly amortised the initial purchase cost and most (probably all) of the subsequent modification costs. But I don't think I could go out and buy one now to daily.

I'm thinking that this is such a small part of the problem that you could easily forego the vac pump and just achieve 90% of what you need, which is keeping the gate open when off boost. It's not as if there are not already techniques to keep a gate fully closed under boost. After all, you have boost. Just use a wastegate actuator that will allow you to apply the boost on the appropriate side, just like every external gate out there.

I said "Matlab clone". I could throw one onto one of my linux VMs. Probably only take 10 or 20 hours to sort out the dependencies, relearn how to use it, etc etc.

If you ask just me you'll get 3 different answers.

Do not ever trust ChatGPT with anything math related. They can't do math. They have no idea what it is. With enough data we can fit a decent equation in Excel, or if the available fits in Excel aren't good enough, a Matlab clone.