xsspeed

Also rotarily ignorant and I was gunna ask same thing, is that a factory 20b thing? (im sure ive seen other 3+ rotors with slimmer/same sized plates but no idea if those are factory plates or specifically built)

welcome aboard/giz p10

Trying to bend my head around what's happening to the gas, is it that with lower duration cams you're getting fast squirts of gas and that has more momentum than longer lower velocity durations

Thanks guys even from this am feeling heaps more informed and it's given me a few more rabbit holes to go down

Cheers, had been meaning to look at holset so thanks for link rookiedave Are you saying that cos of kind of knowing the turbo geometry needed something consistent will more or less perform same way Can you explain this like I'm 5? Lol. This 'putting the components together harmoniously' type advice is good oil

That one is a "RB24" (redtop rb20 with rb26 crank and 80mm pistons, actual capacity 2.22l) and on e85

doing the equivalent compressor map markup:

Perhaps it was the neo I was thinking of for head cc cheers fletch

Yeah I've thought the same re improving with vtcs, I presume it will be achievable but I have a major skill shortage relative to @kpr I need to work out the static CR from scratch given the hks pistons are intended for rb26 but will be paired with a 25 head which will have different combustion chamber volume

Sorry I thought it was in other projects

Thanks guys @shrike I'm still putting together parts from the nissan bin and and need to decide where im going with things I could just do a r32 20det As an option I have a couple of rb20 neos I could swap the vct head onto a det bottom end but this is a lot of work I could stroke and bore one of the 20s to rb22 They way I'm leaning which is all just for fun not for logic (and have most of the core bits for) is to destroke a rb25, with rb20 crank, use hks rb28 low height pistons and buy some long rods (hence maxpeedingrods thread) which gives a 2.4 with 69.7mm stroke and rod ratio of 1.8. This is just a s1 head atm so not neo and I think it's just on/off vct (I thought the neo vct is just on/off anyway?) Cams I don't have in hand yet but would be buying regardless, I haven't looked too hard at the options, many seem to run tomei or kelford cams seeing there's lots of support there

Starting a thread on turbo selections 2025 edition mostly to see if there's anything new in terms of thinking, products etc as most info on here and elsewhere online (at least for RBs) seems to be 10-20years old, which may be fine but no harm in asking I will start by admitting I havent played with forced induction like at all besides owning/driving some stock ones so I am trying to close a bit of a knowledge gap at the same time I have been doing a bit of digging into proven formulas for rb20/25det engines (which like i say seems to be 10+ years old as far as threads on forums go, and have run through a bit of the material on garrett website (this doc was pretty useful in understanding how compressor maps relate to engine capacity/rpm/power 'target' https://www.garrettmotion.com/wp-content/uploads/2019/10/GAM_Turbo-Tech-103_Expert-1.pdf) Now I'm only looking for something mild power wise by todays standards, for purposes of round numbers I've called that 400whp (460bhp) and lets say thats at 9000rpm (maybe this is a bit high but I am hoping to have high revving thanks to small stroke but also acceptable response/lag, suspect these are competing priorities with more low rpm response probably becoming a restriction at such high rpm. Ive plotted the left mark based on the link above, with a guesstimate of i think its was peak torque at either 6000or 6500rpm - now i dont fully follow this but supposedly this line crudely represents how the turbo will perform from peak torque to peak power, so for both these compressor maps the line is through some of the most efficient parts of the curve, so, good so far? Any expert thoughts on have I done it right/completely missing the point? (should say gtx3070r on right) Where I don't get where to go now is how does one judge what lower RPM response is going to be like, or is that where it just becomes experience based? So more to come, fire away any insights/learnings Im trying to be a sponge atm Also any thoughts on turbos for 2l - 2.5l IL6 looking for that sort of power level or even a touch less? These are just two seemingly compatible garretts based on ready to hand info, but theyre also a few grand new, so open to ideas of older/cheaper turbos to take a look at even if they need rebuilding. Anything to look out for on turbine A/R (perhaps this is the lag vs higher rpm judgement), Flanges (lots of RB seems T3 based), internal/external wastegate? (I'm only starting to scratch on some of these) Will no doubt be asking some system design/arrangement questions in due course too

Fwiw imo just get the tuning in then worry about fine tuning the sound, I'd be pretty confident that you'll find a combo that works in time /I heard there's a guy you can hire

Sounds like rb20 /thread

and maxpeeding rb25det by comparison from a joker on SAU