Lithium

Haha. I wouldn't say I am either but I've definitely been around it plenty. I'm guessing you know the dial in is basically to make a handicap to level the playing field between racers. The car with the slower dial in goes first and in theory if they run their dial in time and the faster car also does then they cross the finish time if they also have exactly the same reaction time - if you go faster than the dial in them you lose, but if you are too slow there's a good chance the other person will get to the finish line first. I'm normally supporting other cars but they were all pretty dialled and were egging me on to race as well, here's one of the cars I tune (Starlet) which ran within like 1 hundredth of its dial in through the competition: https://www.youtube.com/watch?v=inEBu-d9Gn4&t=69s

Traction wasn't bad, l couldn't give it everything off the line but was able to go WOT about half a second after rolling - good for NZ drag strips. Like one run I did a 1.96 60ft and pretty sure I was on for a 12.4 but lifted early as I was on a 12.5 dial in, and still won haha

Took the dirty BMW to an actual drag meet so I could do a legit full pass on a sticky enough track and had a quiet goal to try and beat my PB in the old R33 GTS25t The time to beat: R33 on stock RB25, Internal gate GT3076R on stock manifold tuned to about 17psi on BP98 and running on drag tyres: F20 M135i with intake, dump pipe and MHD OTS Stage 1 tune on street tyres - didn't even drop the tyre pressure: Kinda similar, and kinda way different

A lot of what you said there are fair observations and part of why I made that list, to make some of these things (like no advantage between the GSeries and GSeries II at PR2.4 in a lot of cases) however I'm not fully convinced by other comments. One thing to bare in mind is that compressor flow maps are talking about MASS flow, in terms of the compressor side you shouldn't end up running more or less airflow vs another compressor map for the same advertised flow if all external environmental conditions are equivalent if the compressor efficiency is lower as that advertised mass flow takes that into consideration. Once the intercooler becomes involved the in-plenum air temperature shouldn't be that different, either... the main thing that is likely to affect the end power is the final exhaust manifold pressure - which *WILL* go up when you run out of compressor efficiency when you run off the map earlier on the original G-Series versus G-Series II as you need to keep the gate shut to achieve similar airflow. Also, how do you figure response based off surge line? I've seen people claim that as an absolute fact before but am pretty sure I've seen compressors with worse surge lines actually "stand up" faster (and ironically be more likely to surge), I'm not super convinced - it's really a thing we won't easily be able to determine until people start using them. There are some things on the maps that actually make me wonder if there is a chance that they may respond no worse... if not BETTER?! which brings me to your next point... Why G2 have lower max rpm? Really good question and I've been wondering about this too. The maximum speed *AND* the compressor maps both look like what I'd normally expect if Garrett had extended the exducers out, but they claim the same inducer and exducer size for the whole range. If you compare the speed lines between any G and G2 version the G2 speed lines support higher flow for the same compressor speed, kinda giving a pretty clear "better at pumping more air for the same speed" impression. Presumably the exducer includes any extended tip design instead of just the backplate, but nonetheless I'd love to see good pics/measurements of the G2 compressors as everything kinda points to something different about the exducer - specifically that it must be further out from the centerline, which means a lower rpm for the same max tip speed and often also results in higher pressure ratio efficiency, narrower maps, and often actually can result in better spool vs a smaller exducer for the same inducer size... no doubt partly due to the above phenomenon of needing less turbine speed to achieve the same airflow when using a smaller trim. Not sure if this is just camera angle or what, but this kinda looks interesting on the G35 990 compressor tips: Very interested to see what happens when people start testing these, and if we start getting more details about what's different.

No worries. They have a section on their website with some RR options listed, no doubt you can find out more by EMailing as well tho Reverse Rotation Motorsport Turbochargers – Xona Rotor

Updated with the latest <68mm Xona Rotor turbos. The two XRA options are on paper some of the compressor performance I've seen

I've edited the original post to include include Turbosmart turbos - the first list is "entry level", or up to 68mm. The second is "for those who like to party" and starts at 62mm.

Yeah I did, was a good one Also pretty sure Xona do mirror options

90lb/min @ 20psi is wonderful, not so much of a problem with the G35-1050's compressor efficiency (aside from how bad they roll back at higher pressure ratios). The issue is more to do with the turbine's flow, which is why I'm not sold on going an even higher flowing compressor with the same turbine. I'd say go back over Motive DVD's testing of the G35 1050 and Hawkins's comments regarding exhaust back pressure issues with it, I'd need to go back but I have in my head he went to the biggest hotside and ended up sacrificing a lot of spool (so it ended up behaving like a bigger turbo) and still had EMAP issues. I've heard various other experiences along the lines of that. At this stage at least I rate all I've seen about Xonas (for transparency I've not used one directly, but I have spoke plenty with people who have) to have low exhaust restriction for the response they offer for any given setup - basically they allow the engine to breathe, which is good for the engine and makes making power a lot easier. You arguably don't have to even push quite the same amount of airflow through an engine to make the same power if you don't have the bum plugged up with exhaust gas struggling to escape the engine due to an underflowing turbine. In terms of reliability, to be fair I've had great luck with Garrett turbos as well - my GT3076R lasted forever, then I sold it and the next owner had no issues, then that car got sold and it was still going strong last I ever heard about it. The trick is with the old GT-series turbos the compressors etc were no way near as efficient as what we have these days, it was almost hard to push them into severe overspeed situations without having a boost leak or something - and that is what often starts the failure situation. In terms of your G35 I'm pretty sure you're running yours within sensible limits, something people with Xonas and Precision turbos aren't often so inclined to do. The "compressor maps" are "Joe blogs ran 45psi through his 6466 so I can do the same" and built their setup to send it to the moon. I've seen EMAP and compressor speed data where people have actually set that stuff up on Precisions and Xonas which have been run hard and the comp speed numbers are very very exciting at times - like I've seen 76mm Precisions run at rpm that you ideally shouldn't run a G35 1050 lol. I know people who have run G-series Garretts hard and hard a failure, then replaced them with Pulsar turbos as a cheap "get it going" stop gap with the intent of doing a proper upgrade when THAT fails... and are still running the same thing. Like anything, ymmv and it's not always to do with the quality or trustworthiness of said product. I've been provided with a bunch of compressor maps for Turbosmart turbos and will update my list based off that, they could prove to interesting reading and an interesting alternative as well.

You'll find this link is probably more useful Performance Turbochargers - Garrett - G GT GTX GTW Series Turbo TBG G35 1150 map may not even get added to my list depending on how it looks, the G35 1050 already is a mixed bag for making the numbers you would expect from the compressor map due to mismatch - I don't know how another 10lb/min of compressor flow is going to make that any better. I've left out others for similar reasons as it's already getting quite big. In terms of Precision, provide me with legit compressor maps for them and I'll do my thing I'll add some more of the newer Xona Rotor options are they're pretty boss, I'd take a 68mm Xona over a G35 "1150" any day of the week - or Precision for that matter.

BTW, the reason I came in here to "update" this list was that the Garrett G Series II range have been released and I've updated the list with their flow details if you're curious to check how they fit with previous Garretts and other brands The G-Series II G35 990 looks like a banger...

Hi all, I thought I'd put one of these references in here before but it seems I haven't - not sure how many people are actually using this place still but I feel like there are guys lurking about who might find this reference useful or interesting. A lot of the time people don't catch key details or even fully understand how compressor maps work - or don't even look at them and just go from heresay about deciding how different turbos may compare, but I've been putting together this table over the years as a quick reference to get a gauge of how certain compressors compare to cut down the time that can be wasted looking around aimlessly. * This relates purely to compressor flow, so won't necessarily reflect the outright capabilities of these turbos as the power potential also comes down to the turbine side. If you understand this, you should be able to use this 😃 * The inducer and exducer size listed are the mm of just the compressor wheel * The values under the "psi" headings are "lb/min airflow" and reflect the maximum airflow that compressor supports before it's efficiency dips under 65%, or it reaches it's maximum speed - whichever comes first. Any questions, or requests for other turbos which the compressor map is available for then let me know 🙂

Nice, is there a post with the new 4" dyno curve?

To be fair passengers who aren't silly and have been in proper fast cars have often been pretty impressed once you hit 4th gear

Outstanding!

The S2 R33 and R34 both run a nylon composite compressor on a ceramic turbine. R34 has a larger a/r turbine housing

Good luck!

Whoa, that's a name I've not see for a long time! Sorry to hear about the engine / turbo damage. Fwiw with any engine problems it often really a case of just seeing what happens when it's apart, ymmv - I wouldn't rule out the possibility that the damage isn't even from the turbo failure, or possibly from a combination. The airflow between cylinders isn't dead even, injectors can go off over time as well, with the turbos overboosting if you didn't have upgraded fuel system there could have possibly been a bit of leaning out - stock triggering is often a bit unreliable by this age too. Basically its an old engine and a few things could have been going on, and you won't know how much work is needed until the engine is apart.

I feel like this is due an update

This is a story of my life things, I learned eventually (thanks to someone calling me out) that my enthusiasm for discussing and sharing ideas that it came across as arrogance and I'm like... WTF?! One thing I'm pretty sure I justifiably pride myself on is knowing that everyone will have things they can teach you, and you're always going to find out that something you think you know turns out wrong - you just don't know what it is until you get there. Just the bursting enthusiasm that comes with ADHD when you hit something that gives you dopamine dumps can come across like you think everyone else is wrong or don't matter. But yeah, I'm a software engineer by trade and also do tuning in weekends and 100% have long had a reputation for quickly making connections when resolving problems or forming solutions that I've sometimes had to take people form a long walk from start to end to explain how I ended up where I did when it's seemed "too simple" when I've stated my initial case, and had the "WTF" type reaction when they've realised how much was actually considered haha. My reward is that I get all the curly problems thrown at me.

Cheers, and cheers for sharing so much of the build and also sharing the glimpse of what turns out to bring a lot of us poor decision makers together haha. I do recommend learning more about how to manage it, if not considering getting a formal diagnosis. The discussion with the psychiatrist I got my diagnosis through was quite eye opening, things I'd not even considered to be ADHD related and hadn't mentioned were things she asked about out of the blue and were common themes with people with my flavour of ADHD. It's not a label for people who are hyperactive and ill-attentive, there's more to it than that and some of it can be much more challenging or damaging - though there are of course two sides to the thing, and a lot of the stuff we have to go through and work on to live with it make us effectively "better" at other things as well. Aside from the fact that there is some argument I could have a bit of ASD seasoning in there (came up during the diagnosis, and neurodiverse things seem to not stay as a cookie cut) I suspect you need to learn more about ADHD if you are puzzled about how hyperfocus could possibly apply. I *do* personally use "superpower" with quotes deliberately, but it's 100% an ADHD thing due to the exact reason that lack of focus is also an ADHD thing... Loosely speaking the inattentive side of ADHD isn't the inability to focus, it's the inability to control where the focus goes. Not being able to sleep because brain is more interested in thinking about a stupid thing I said to a girl I liked 30 years ago, not being able to focus on work because my brain is more keen on putting together the torque management strategy we're going to try out with a drag car next weekend, not being able to focus on a conversation with someone I WANT to listen to and respect because there is a flickering light in my peripheral vision. If I could just stop work and build the torque management setup right there and then I'd not hear anything else until it was done.

I've been quietly following this thread for ages, but this one got me. Since my ADHD diagnosis (and associated learnings and prescription) I'm way less inclined to wade into forum yarns when there are better things to do with my time, as half the time I'd end up in some kind of forum debate even if that wasn't my intention. I've not lost the ADHD "superpowers", just am a lot better at directing my hyperfocus into slightly more constructive things, but haven't stopped quietly lurking in here in my spare time.

Right. I'll try my best at a concise "bring you up to speed" on stuff that may be missing here - obviously open to questions or further input from others as relevant. Here's a datalog from a responsive turbo setup with electronic boost control being used a bit, to keep it simple I've marked 3 points of interest. All of these charts are on the same time scale on the X-axis, so you can reference what engine rpm is doing in the top graph, boost and EMAP (exhaust backpressure) in the second graph, and turbo rpm in the bottom graph. A) The turbo gets it's power from exhaust gas, and pumping air takes work. As a result you can't just spin a turbo with a fixed amount of exhaust energy and expect it to keep spooling - the bigger the turbo (ie, the more air it can push) the more exhaust energy you need to drive it. The most obvious ways of getting more exhaust energy are by adding displacement, adding boost, or adding rpm - but as you add any of these the turbo also needs to do a bit more work so there is a big balance of these things needed to even get to your target boost and sometimes that's not even possible. What you can see in step "A" is that there isn't enough engine rpm or boost to reach the level we want, so this is where "lag" is. The dyno run continues and rpm increases, which gives enough energy to increase boost, which helps spool the turbine speed up even more - so you can see that the rate that the boost (and turbo speed) are starting to ramp up faster than the engine rpm is, so turbo is really starting to wake up as the graph gets closer to point B.... B) At this point we've been able to reach the boost that is actually desired at this point. To stop the boost from going further than this the wastegate will open and bypass gas past the turbine, meaning it doesn't continue accelerating at the point it was before but instead carry on at a more progressive rate which matches what the engine needs. The wastegate will have a spring in it which is rated to a specific pressure where it will start bypassing, but electronic boost control (managed by the ECU) can adjust how much pressure the spring sees in order to allow some tunability on how much boost the wastegate actually sees, and therefore how much exhaust it bypasses. The tune in this case stops boost from ramping up HARD at around 21-22psi just before 4000rpm, then as the rpm continue it allows boost to continue up to around 25psi higher in the rpm. You can see the turbo speed fairly steadily increases through the rpm to ensure it's keeping up with the increasing airflow demand due to the engine speed being higher and boost being pretty steady. If the boost dropped off after a point then you may see the turbo speed level off or even drop. C) You can see that despite the boost pressure staying pretty flat here, the exhaust pressure is steadily increasing and at this stage has overtaken boost pressure. This isn't unusual, and is largely as a result of the increasing energy needed by the turbo to pump more and more air to suit the needs of the engine as it revs out further. There are a bunch of variables in regards to how much back pressure there will be on a given turbo etc, but its one of the factors we manage when sizing and tuning a turbo setup. When exhaust back pressure starts exceeding boost pressure you will eventually start seeing signs that the turbo is running out, the engine gets less keen to make more power and it gets harder to raise boost further. In this case it's a fairly acceptable compromise for the power level (around 630kw on a 3litre engine with full boost by 4000rpm), but you'd not want to push it a lot harder than this. The maximum speed rated for the compressor wheel on this setup is around 125,000rpm so you can see its starting to get close on that side as well - I feel like this kind of illustrates some of the turbo related things we both decide on how far to push, and are also limited to how far we can push depending on the parts combination. Hope this helps more than it confuses things

I was actually going to try and dig out a datalog with turbine speed and EMAP haha

As someone who has been playing with turbo things for some time now, be prepared for this to not be the first time feeling this way I'm busy as atm, but if no one else covers the things I'm realising are worth mentioning to you then I will when I have a chance as it seems like I overestimated your knowledge on how turbos and wastegates work. Otherwise I recommend having a look around how wastegates and boost control work, really anything on understanding the general mechanism of boost control as it will help you find the answers to the questions you're looking for. Your initial question jumps some fundamentals.