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joshuaho96

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joshuaho96 last won the day on December 18 2019

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  1. https://www.shell.com/business-customers/aviation/aeroshell/knowledge-centre/technical-talk/techart-18-30071600.html Gasoline went unleaded in the 70s, no reason to look back. Arizona E85 may be inconsistent but it's nothing a flex fuel sensor can't deal with. Ethanol blends vary between E30 and E85 at the pump depending upon season as ethanol doesn't want to start in the cold and evaporative emissions are harder to control. Leaded gas is nasty stuff. Lead is a potent neurotoxin and when you burn leaded gas it's being spewed into the air in a form that is easy for the body to intake. There is a lot of research out there that strongly correlated a crime spike in the 1970s and 80s to leaded gasoline. General aviation is the only major consumer of leaded gasoline at this point and it's only because the engines they run were originally certified on leaded gasoline and the aviation industry is extremely conservative. They still use magnetos and carbs. An RB26 is designed to run unleaded fuel and not designed for leaded fuel at all. So why bother with the thing that's more expensive than ethanol mixed with mogas when lead poisoning is a real risk and lead could damage the engine in unexpected ways?
  2. I wouldn't run 100LL on any reasonably modern car engine. Even if you decat the O2 sensors will foul, the lead oxides will foul up and corrode exhaust valves and spark plugs. Just way too much effort for an especially toxic blend of gas when E85 is cheap and is comparable. Water/meth is complicated but if you're willing to spend a lot of time and effort on making it work then it's great too.
  3. 91 AKI Canadian is equivalent to 95 RON. 93 AKI is equivalent to 98 RON as you have suspected. I believe that 91 octane in Arizona, California, and Nevada is so exceptionally bad that many tuners have special maps to dial back the timing if you plan on using gas in those states.
  4. Water meth injection is no joke to implement. If you’re serious about I would either try to figure out how to source the Bosch system or Aquamist. Port injection should be used if you want to spray a lot as the OEM plenum and runners are not designed to ensure equal distribution of liquids for each cylinder. The post IC spray flow has to be pretty low to make sure it vaporizes before it hits the plenum. In small amounts it’s probably fine because it’ll go towards cylinder 6 but too much and the AFRs will be uneven. Also make sure to get a tank that is properly baffled with a flow sensor of some kind to verify delivery. I would also integrate control into the ECU.
  5. The easy way would be to link a kit for a low mount single that is bolt-on and keeps all the things I’m asking for. I’m not exactly chasing after performance here either. The M4 has dead steering, sounds pretty terrible, and is kind of a pain to see out the front due to the tall hood from the charge cooler and pedestrian safety regulations. I also want the driving dynamics of ATTESA-ETS. It is extremely competent technically though. Yeah I'm a big dumb American. I don't know enough about this stuff to attempt to make a single turbo conversion from scratch. I think the BMW S55 engine does have more advanced control systems but at the end of the day it's a parallel twin turbo setup like the RB26. They have neat tricks to play like fully electronic wastegates and soon 48V mild hybrid but the core architectural trade-off between a bigger single and small twins is still there. I suspect it's really a packaging, thermal management, and emissions problem for BMW but that's just me armchair engineering.
  6. I'm aware it's been done for a while now, just not in the form I'm looking for. Not interested in high mount, low mount manifolds are few and far between and generally not recommended, I would really want a cast manifold for longevity reasons, bolt-on kit with heat shields, piping, etc all ready to go with a proper airbox/paper filter/snorkel for cold air intake. I don't think I've seen a single single turbo conversion that actually looks like what I'm interested in. Also, the HKS GT3-SS really helps with low-end spool and mid-range for a mostly stock car, based on the dyno curves I've seen. The cost benefit analysis doesn't necessarily make sense per se but frankly if I were buying based on performance per dollar I would get a Corvette.
  7. The headache is in validating that the thing will fit correctly, won't crack/corrode, that the oil lines and water lines for the turbo are properly routed and won't fail 50-60k miles down the road, that the intake is properly designed to not suck rain into the engine, properly mounted, has appropriate flow characteristics without weird resonances, can fit a MAF without a bunch of signal noise if ITBs are retained, and all the unknown unknowns that come with trying to make significant changes to the intake and exhaust of a turbo car without the experience or knowledge of what works and what doesn't. I just don't see a convincing case for spending a lot of money on a single turbo conversion when the power goals are conservative and the primary interest is in a reliable street car. The goal is to drive the thing, not to keep it in the garage as a permanent project.
  8. I'm aware that it's a DI motor with VVT + VVL and a number of other changes. My point is that even now when BMW has the option to ship a single turbo for an I6 in their 500 hp+ models they elect to continue with twin mono-scroll turbos instead. Clearly it's not as cut and dry as is being claimed by Andrew Hawkins et al. The RB26 turbo shuffle is a problem but isn't intractable, it seems like much of the problem is related to the twin turbo pipe and the near 90 degree merge. I don't think that alone really justifies the expense and headache of figuring out how to retrofit a single turbo to a motor that never shipped in that configuration.
  9. It matters in the sense that it's easy to hide bolt-on twins when they're crammed under a bunch of heat shields and piping, unless you've really attracted some serious attention for whatever reason nobody is going to be trying to carefully read off what the turbo says to identify it as stock or not. Similarly, no one is going to be opening up an ECU or removing the kick panel to verify that you are actually running the stock ECU. As long as the exhaust gas sniffer says you passed and nothing is clearly wrong it's not hard to pass. Rolling up with a high mount single is going to be a very different story. It's also weird to me that you would make this comparison between being born deformed and the twin vs single turbo choice. Clearly there is still value to twin mono-scroll turbos as seen in the BMW S55 and S58 I6TT engines and they manage a far wider powerband than anything an RB30 is capable of with better BSFC everywhere, higher knock threshold everywhere, significantly lighter weight, and overall much better refinement. Clearly there's something there that is not as simple as single turbo good twin turbo bad. I'm not advocating for cargo cult engineering here but I'd like to know why BMW engineers would elect to go with twin turbos on the S55/58 and single turbo on the N55/B58 when they have the resources to spec a larger single on the higher spec models.
  10. I'm not speaking about what will and won't pass the local emissions laws. As far as most places are concerned the instant you modify anything between the air filter and the last catalytic converter you've failed emissions. But looking at the header design it seems pretty clear to me that the exhaust manifold on a high mount single RB26 is going to have a longer path from exhaust valve to a catalytic converter. Cold start emissions is a big problem with these engines and I'm pretty confident that will make the problem worse. To me that is a problem but YMMV. A low mount manifold could in theory do better but everything out there doesn't look like a good fit for the use case I'm thinking of. Everything else is true if you're talking about a clean sheet design. Single turbos are easier to package, less headaches regarding how to merge the two turbos. Modern engines use twin scroll single instead of bothering with this twin turbo nonsense. But this isn't a clean sheet design, the two paths are bolt-on twins vs a single turbo conversion. The bolt-on turbos are a known quantity and the OEM engineers have already gone through the effort of making sure it meets their internal metrics for quality. A single turbo conversion is just not going to measure up to that if the goal is to play it safe and try and keep it as reliable as OEM, if not more so.
  11. But why bother for such conservative power goals? The HKS GT3-SS turbos are pretty good at modernizing the mid-range of the RB26, the rest is just the limitations of fixed valve timing and low compression ratio that comes with an engine designed in the 80s. I'm not arguing against the logic that a larger single turbo is more efficient and you can run a more modern single turbo to get better response. But I think top mount single raises questions in my mind regarding emissions compliance, long run durability, thermal management, and proper intake design. I think the answer isn't as clearcut as that Motive video makes it out to be. If the only metric of value is how much power the engine can produce across the RPM range then the answer is simple but there are more variables to consider.
  12. Twin turbos make sense if your power goals are something like 300 kw.
  13. Why would OP mention a resistor box then? Sounds like something is interesting there.
  14. Depends on the resistance of the injectors. If they're near stock like 2-3 ohms then you need them. If they're 12 ohm injectors you have to bypass the resistor box.
  15. I was under the impression that the cam signal is not particularly difficult to parse and could be left alone, it was really just the crank signal that was particularly problematic. Has anyone tried running the OEM cam signal + aftermarket crank trigger?
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