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Lithium last won the day on February 20 2018

Lithium had the most liked content!

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About Lithium

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    Rank: RB30E

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    Wellington, NZ

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    2007 Mazdaspeed Axela
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    Mr Lith

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  1. Those turbos look smaller than EFR7670 as well, probably 6758s or 7163s in that frame - definitely not 1600hp worthy haha. Guess they figured they can use the bigger Precision turbos and use other tech to try and spool them faster was a nicer setup than making less power with naturally more responsive turbos. Simplicity is not the theme of this car haha
  2. Lol! That would be pretty grand, and to be fair - they are using pretty advanced lag reduction techniques so they can probably run a relatively potato turbo and it shouldn't be too much of an issue. Pretty funny seeing the now old/iconic Precision "bullet" antisurge ports on something this fancy.
  3. Absolutely, I realise the variables... though haven't had the data to play with to say much about how all that will be but just some thoughts I'm curious about or which come to mind * MAP/TIP - You sound to be targetted 3500mbar MAP, and the pressure at the turbine outlet will be down as much as the pressure at the compressor inlet... give or take (not sure how restrictive the feed to your compressor is). Are you finding at altitude that TIP is going significantly past where it would be at sea level? * Makes sense that you will need to bypass less exhaust gas to support a higher pressure ratio * Turbine overspeed - I think you already alluded to this in a previous post I didn't get to before you added more... so you are pushing THAT hard already that you don't have much wriggle room. Are you basically "off the map" already? * Comp map - I'm guessing this ties with the above comment, as otherwise the EFR9180 looks (to a point) to actually hold better efficiency at higher flow rates than it does at lower ones. Assuming the pressure ratio needs to be 10% higher to contend with the lower compressor inlet pressure the EFR9180 seems to be in the region of 2% more efficient for flow rates >74lb/min at >3000mbar It's a shame that the likes of Precision and Xona Rotor don't publish compressor maps, anecdotally they are VERY friendly to high pressure ratios Probably going a bit off topic for this thread, but pretty cool!
  4. Oh my god, I'd heard about this thread and for some reason decided to have a look. Kudos to the people who have tried to help, @Slap... I say this not to be a hater, but to try and help you. You really have so many of the fundamentals quite quite wrong, please slow down and listen, think and research a bit more - you are sprinting with scissors through a minefield blindfolded and it's scary to watch.
  5. Are you talking specifically your case of 1000m above sea level? That is around a 10% difference in inlet pressure, so maybe .4 higher PR for the same absolute manifold pressure? Realistically that is not a huuuuge amount different... a safely matched turbo I'd hope would absorb a lot of that change, overly simplified but on an EFR9180 compressor map the efficiency is pretty good between 3.5:1 and 3.9:1... almost favourable to the higher PR. The guys who are running their turbos on "kill" will suffer though. The topic of setting up and tuning for varying altitudes is one which off the internet and over bourbons or laptops has definitely been one I've enjoyed and head scratched on a lot, turbo matching isn't necessarily even the least of the issues. Thermal management (lower air density = less efficient heat transfer from things you are relying on to cool stuff), and on the other side of the coin - less air density also means less drag, or less power needed to cut though the same volume of air which is more of a thing when you have a lot of speed and/or aero involved. I feel like this all fits into typical turbo/setup matching strategy, work out what you need from it and make sure it will be able to supply what you need in the situation it will operate in. Do you think you will be going off the map at 1000m above sea level? Or have you already run into issues with this?
  6. Lithium

    FMMMLLLL, it's hard enough trying to keep things under control in there
  7. Lithium

    No, it cannot. From your posts it comes across like you have a LOT to learn, I'll try and give a bit of a concise enough ramble which if I get where you are at right and you are willing to take something on board it may help you think about things a bit differently and maybe learn something. So, think of knock sensors not as something measuring knock... but measuring the vibrations being transferred through whatever it is attached to. The sensor is effectively communicating the movement of those vibrations to the best of it's ability, it isn't giving a voltage representing the rate of the movements (aka frequency), but the strength and direction of those movements. If you had a sensor which was outputting a 1KHz square wave signal with a 1volt amplitude, and another sensor which was outputting a 1KHz square wave signal with a 2volt amplitude and tried to analyse that signal with a voltmeter you would not read the same voltage from those two sensors which are signalling the exact same frequency. Bearing that in mind, this pretty much explains why there is no set voltage where you are experiencing "knock". There are a few things which can influence what the signal from a knock sensor looks like - for starters: * Is it a resonant (more sensitive to a given frequency range) or a flat response sensor? * Where is the sensor located? * What is the resonant frequency of the engine being used? * What rpm is the engine operating at? * How noisy is the engine itself? You need signal processing of some sort if you hope to intelligently identify knock. You can probably do it with analog components but given the level of naivety you are indicating I could be forgiven for assuming you aren't going to be building custom circuits with effective utilisation of band pass filters etc to suit your given setup. There is a lot more data that comes from a knock sensor than just a threshold voltage which means knock, which means you really have to work to make reliable sense of it if you want automated detection of "stuff"- but you also can use them for a lot more too. This may give a bit of an indication of the kind of thing you can expect to see from a knock sensor, and what you can use the data for. In this case I was trying to identify the cause of a misfire on an car which pulling the plugs on to check was a non-trivial job, so I used windowing (split the signal from the knock sensor based off which cylinder was in it's combustion cycle so I align the noise with the busiest cylinder) and some signal filtering to even out the noise versus engine speed. Using that it became pretty clear which cylinder stopped firing when the car hit full boost.... check out the red line in the top graph. That's basically using less noise than "normal" to identify the lack of combustion, as opposed to using excessive noise to identify uncontrolled combustion. Analog tuning, what? PS, all of this is just trying to teach something with no rational thought process to react to a specific bunch of parameters you have set. It can't be guaranteed to always detect knock, and it can't be guaranteed that when it reacts that it is really knocking. It's just responding in prescribed way to a signal which meets some rules you've provided.
  8. Sorry, I should have clarified what I meant there - I agree (and it should be obvious) that the stresses will be higher on the 80mm, the thing I was talking about being nonsense is the higher rpm limit that is bandied around referring to the compressor speed limits. There is no published max turbine speed limit from Borg Warner that I've seen anywhere, just an indication for compressor speed limit. Somehow people have got the idea that you can use the 83/84mm max compressor speed indicator for the 91/92mm compressors which IS nonsense. The compressor won't suddenly be more capable with a smaller turbine, you're just going to be pushing further off the map and putting things under more strain. Sure, the smaller turbine will be more tolerant but at the end of the day when you're starting to do that kind of thing you're starting to have to admit the turbo is not the right match for the setup. As @RICE RACING has said, he and other people I know have gone a bit past the max compressor rpm for the 9180 and not had failures... albeit closely monitoring shaft rpm to make sure it hasn't gone wildly out of hand. Anecdotally it seems that you increase the odds of failure (funnily enough), however the turbine failure speed is typically higher than the compressor failure speed and the cases people have had failures there is likely to be more sinister things at play than slightly exceeding Borg Warner's "uredC".
  9. If you are referring to the question above asking about stock, I think they were talking about the black series EFRs - not the original series like Kudos are advertising
  10. Get among it
  11. Turns out they mentioned in a short snippet in a video that they touched 1000whp on a US dyno with the EFR9274, then dropped it back slightly. And yeah, I've mentioned before I know folks who have pushed 9180s off the map and are still running them fine without failure - that max rpm thing is nothing to do with "max turbine speed", it's actually a number that they came up with for determining max compressor wheel speed. The EFR9174 vs EFR9180 "higher max rpm thing" is nonsense. From Borg Warner's own analysis of expected life time of an aluminium compressor while adhering to different maximum tip speeds: As we've agreed before, essentially with racing etc "power is nothing without control" leaks through to parts picking, ECU and calibration of the whole lot. Using data and managing the variables you should be able to work out a balance between pushing hard enough to justify the parts and not so hard you don't get an acceptable amount of use. Pretty much what Borg Warner were doing when they decided on their own limits they suggested for the max tip speeds.
  12. I kinda wish I made more measurements when I had one of the ATP ones in my hands, they're pretty unusual to come by these days.
  13. Ahh yeah, that's one of those big cases where "a/r" is a bit of a flawed measurement as you kinda need the "area" value as well to get a real gauge of the scale being dealt with. A 1.06a/r T4 twin scroll housing from ATP was pretty equivalent in effective size/flow to the .82a/r T3 Garrett open housing, but more efficient due to being a divided housing so despite being a bigger number - it wasn't much "bigger" in effect, if at all... but more efficient being divided so still flowed a bit more but also at no real cost to response. Arguably better transient response, a mate did the same conversion (.82 T3 open GT35R to a 1.06 T4 divided one) and the thing felt much better on the road. Garrett's T3 divided housings actually are much more "equivalent" to the open housings, so if you want the divided equivalent of a .82a/r T3 open housing then you get a .83a/r T3 divided housing - as opposed to going up an a/r like you would with some options. Basically the .83a/r Garrett T3 twin scroll housing is much more comparable to the ATP 1.06a/r T4 housings used in those comparisons than the 1.01 is - though realistically its a bit hard to compare. One thing is for sure, you're not likely to choke your compressor Anyway, I've been looking forward to seeing a GTX3576R on an RB25 and know you'll have done it well so very much look forward to seeing how it goes, kudos for trying some cool shit out Hopefully the result ends up driving the way you want it to anyway, and it's worth knowing that if on the off chance the spool isn't as good as you were hoping - you can try going down a size in exhaust housing and are unlikely to lose too much up high.
  14. Oh wow, I've missed that one - been following 240Z's experiments which have been pretty cool but I've not seen him try the .83. In his testing the 1.01 GTX3576R was real laggy from memory, he went to a GTX3582R with the ATP T4 1.06 housing (which actually have a much smaller cross section than the Garrett T3 divided housings, so actually downsized despite the a/r) and picked up spool. Who did the .83 to 1.01 comparison?
  15. Keen to hear how you find it. I'd have gone with the .83 as well, but it will be a very interesting setup to see how works as it's going to be something a bit different