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joshuaho96

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joshuaho96 last won the day on January 30

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  1. 250k is conservative. 8% of the country getting infected is super, super unlikely considering how lax the measures were. Florida didn't shut down the beaches and the net effect is that they helped seed the disease across the entire country:
  2. Motul 8100 should be good. If you're going full race the 300V stuff is supposedly better but the change interval is something like 2000 miles.
  3. Foaming in gasoline engines occurs when you do something like hard cornering and oil sloshes up the sides of the crankcase and gets whipped up by the crankshaft. Or the piston squirters in the OEM and Tomei RB26 pistons that cause oil to fall onto the crank that gets whipped up. Do this at 8000+ RPM and you will create some foam. Or overfill and the crank will start whipping up oil as soon as you turn the starter. I'm always super, super skeptical of oil discussions because it's pretty much cargo cult stuff or straight up pyramid schemes in the case of Amsoil. But there is this post: Whether there's any truth to this post is hard to say, but the source is here: Personally nothing I run is ever going to need more than whatever full synthetic is 5 USD/quart online or at a local store. I would probably be just fine with Rotella T6. But I would be very cautious of making that recommendation to all people for all things.
  4. Foaming is created in dynamic conditions, you usually need high RPM to cause it. Low RPM conditions it shouldn't happen. Unless you have a viewing port in the crankcase you wouldn't know. Personally I'm not a tribologist and I don't feel like gambling an engine on oil selection. There is a Rotella T6 that is dual rated. But I don't think it's wise to run an engine oil that is not rated for gasoline engines or only has bare minimum certs. Especially when you can find a lot of different oils that meet whatever spec you're looking for for any given engine. Maybe a dedicated diesel engine oil works great for you but it seems unwise to recommend that in general.
  5. Rotella T6 is not recommended for high RPM engines due to the lack of anti-foaming additives. It works great on low RPM engines like diesels and low RPM gas engines like LS engines but the RBs rev high and tend to create a lot of oily air.
  6. That is true, 90 kph is generally going to yield better mpg than 120 even if the BSFC is worse. But most highways in my area will have everyone doing 100+ kph, late at night 130 kph is not unusual. May as well go a little faster and not risk getting rear-ended. Only on certain arterial roads is it possible to safely do 75-90 kph in my area.
  7. If fuel efficiency is immaterial then there's no reason to have any shifting algorithm at all. It literally doesn't matter as long as you don't stall the car or lug it to death. Or you could just stay in the lowest gear possible at all time which I suppose is an algorithm, just a terrible one that I've never seen anyone do. Anything other than those two choices implies that fuel efficiency matters at least a little bit, if only because running an engine at WOT all the time will kill it sooner than later. You can data log pretty much every automatic transmission within the last 10-20 years and see that it's going to try very, very hard to put you right at the max efficiency point for any possible power request give or take some hysteresis and other second order considerations. My original recommendation is to emulate that behavior, with the added benefit that you can be more intelligent and predictive than a TCU that will never be able to know whether you want to maintain momentum when coasting and select the highest possible gear without stalling to reduce engine braking or if a long red light is ahead and to downshift aggressively to maximize engine braking. There is nothing in that guidance that says you shouldn't rev the car past 3500 RPM under any circumstances. It depends on the power you're requesting from the engine. If you want to extract maximum power then you have to go WOT and keep RPMs as close to the peak power RPM as possible on average. If you want something in between max power and max efficiency then it's further down the RPM range. If anything if you think carefully about what I'm saying there is a minimum amount of power you should be using from the engine because below that point you're going to be running it inefficiently. If you're going to accelerate you should accelerate enough to apply a good amount of load on the engine. Gasoline engines are also terrible at doing something like cruising at 30 kph unless you're driving a kei car so driving below the speed limit for the sake of "fuel efficiency" is stupid. If you can do 120 kph it makes sense to do 120 kph because it's likely that your mpg will be constant, unless you're limited by gearing and lack a ratio tall enough to keep RPMs low enough.
  8. Excellent, why does it matter in the context of answering OP's question? How badly other people screw up their cars with bad engineering and tuning is really not something I'm concerned with, it's not like I'm the one that has to live with the thing. It just seems ridiculous to answer a question about shift points with non-answers and gatekeeping.
  9. I have no idea who started this thread, it's bizarre that you would suggest this is some conspiracy to troll people. OP asked a question, I gave the actual answer to the question. Do you guys just sit around ridiculing everyone that has a potentially dumb question like that's a productive use of time? You must be a very cool person to spend your life like that.
  10. So clearly then fuel consumption does matter? Or it doesn't? I'm unclear here. Just because a high performance vehicle has a high energy per mile requirement doesn't mean that it's pointless to try and optimize the efficiency with which fuel is converted to KE.
  11. I too disable DFCO and run a lambda 0.7 target globally for all my tunes because fuel consumption doesn't matter.
  12. If you want the answer to the question of when to change gear the map helps though.
  13. Your 14.7 AFR gas target is stoichiometric. That's pretty normal and where the TWC operates best. You can run leaner like 16 or 17:1 AFR gas for cruise but as a general rule the efficiency benefit is not going to magically turn a throttled PFI gas engine into a diesel engine in that regard. I don't know RBs well enough to say whether they can efficiently cruise lean, some engines really need to stay near stoichiometric, some particularly bad engines like the L26 4.9L actually had to run rich to avoid stalling and did an "interesting" trick where it would operate at stoich and run like complete crap until you turned on the AC or heater at which point it would enrich the mixture. Even a turbo RB26 can wait until ~3-5 psi to start enrichening, it's a 8.5:1 CR naturally aspirated engine until the turbos really wake up and the ITBs really screw with intake runner pressures so it's really easy to hit 0 psi. Helps a bit with the spool as well to keep EGTs as high as you dare. I don't blame you for staying conservative beyond that though, RBs are ridiculously expensive to build and kind of fragile. Generally speaking the problem with staying at too low an RPM is that the engine is just not tuned to breathe well at those RPMs, either because of valve timing or intake runner tuning or exhaust runner tuning or some other fluid dynamics problem I don't understand. If injection timing is not adjusted to avoid the low lift portion of the intake cam opening you can also experience higher covariance of IMEP from stuff like pre-ignition. So the best strategy is to increase the RPM to the sweet spot, whatever it is, and stay right around 100 kPa MAP to maximize efficiency. NA engines tend to have less dynamic range and you tend to want to be closer to ~70-80 kPa MAP instead. It's not a perfect comparison but we can compare the 2.0L Skyactiv-G to the 2.5L Skyactiv turbo engine: If you squint and compare between these two engine maps actually at 180 Nm of torque at 2500 RPM the Skyactiv turbo engine is more efficient, not less. If you drop down to 140 Nm of torque the 2L NA has a ~4% advantage in BSFC. As you go down you can tell the turbo engine is less efficient due to the extra displacement, but that just means you need to apply some more load, either in the form of accelerating harder, gearing, or increased speed. Or your car is just too light. So as a general rule I think if you drive a turbo engine correctly and use the lower compression ratio to run right around atmospheric while accelerating and keep the load high the efficiency hit is not terrible, and when you compare to a bigger displacement NA engine the efficiency will be better at low loads, but if you have a lot of boost enrichment like these early turbo engines then pretty much any kind of scenario where the turbo engine has to run boost + boost enrichment and the NA engine can stay out of high load enrichment is an easy win for the NA engine. If you toss tricks like E85 or water injection in though you could keep the same amount of torque and reduce enrichment for better efficiency. Same goes for GDI which allows for quite lean AFRs even at WOT.
  14. Depending on the engine the map might look different but you can see that full throttle 1500 RPM to have the same power as you would at 2500 RPM you need to basically be right around full load. Your BSFC is going to be in the high 280 g/kWh range if you keep the engine at 1500 RPM. If you instead let the car sit at the 2500 RPM or whatever RPM it wants to really be at you can instead be in the 240 g/kWh sweet spot for thermal efficiency. So the conclusion for turbo engines like this one is basically try and stay right at the edge of boost if you're accelerating. If you're cruising you want to maximize load by using your gearing, but you don't want to overdo it either. The US EPA has a lot of very nice public data on some engines where they took the time to run through the dyno with a fuel flow meter to derive BSFC and thermal efficiency: https://www.epa.gov/vehicle-and-fuel-emissions-testing/combining-data-complete-engine-alpha-maps Maybe you guys have less traffic but around here you're almost entirely limited by traffic and lights unless you get out of the city and into the back roads. Trying to drive efficiently helps to make things a little less boring.
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