Lithium

Sorry, I didn't mean getting into the full on tuning of it all - more the fact that because of the fact you have pressure waves bouncing around etc there is could be more likelyhood of contamination between the two sides than he was speculating. I wouldn't make a certain call on it, just stating that its one aspect to possibly consider... the fact that twin scroll makes a substantial difference over single scroll suggest that the science is certainly more than just a bunch of pipes pointing exhaust flow generally in the direction of a turbine wheel.

Because you said this much and obviously like to think about the whys of the different ways of doing things... don't forget that the gases at this point in the system are not as simple as a fluid flow. There are high pressure pulses and there are gaps between them, hell the reason people call race manifolds extractors is a reflection of the fact you are effectively playing with acoustic tuning. I assume you have heard of the use of balance pipes on V8 exhaust systems...

So which turbo / turbine housing combo did you go?

I honestly haven't seen enough first hand to be able to say for sure that there is a big difference. All the "big results" you see are twin wg, and its the way I'd go just because I like knowing its going to work - however one of my mates who swapped to twin scroll (from .95a/r single to 1a/r twin on a T04Z on a 300ZX) just changed the collector to suit the twin scroll, everything else including single wastegate remained. He made 300 or so rpm spool, more peak power, and HUGE midrange torque gains so it can't be too bad.

Be assured I will hunt this thread down when there is something to be reported

Very cool, I had always had the impression the Precision turbos were a bit laggier than the Garrett equivalents but its starting to sound like thats not the case. Particularly forward to seeing results from the 5557 on the RB25! Shame we aren't seeing BB results but look forward to seeing your impending posts. I am STILL on the edge of my seat waiting for a mates RB25 running a ball bearing PT6765 to be fired up and tuned, its all pretty near ready to go but he's lost momentum. That is a fairly serious build, everything should be there to make the most of the turbo so will be interesting to see when it is all go. My car is nearing 200,000km on an unopened RB25 which has been making >270wkw for nearing 100,000 of those kms - I have to assume something is going to start complaining sooner or later so whether I like it or not I have to consider myself at a cross roads with my car's development. Seeing as I have to think about what next, the latest Precision, ForcedPerformance and Borg Warner (EFR) turbo results are all particularly interesting.

I've seen higher from 56Trims Nytsky on here did 363wkw on a Mainline dyno: http://www.skylinesaustralia.com/forums/Rb...e85&st=540# and obviously on Dynojets and Dynapacks people have made substantially higher again but its not apples and apples. I know the billet Precision turbos do real good power, seen some amazing things from people running the 62mm and 67mm ones particularly. What I would like to see though is if they can do as good on pump fuel, EVERY impressive result I've heard of from them are on E85 etc.

Just looked at Powertunes site, saw they use a DD... crikey. That suggests its a crapload.... very impressive result then. Thought it was a dynapack

350wkw on stock manifolds, stock RB25DET, 52trim GT3037/GT3076R with .68a/r turbine housing - I could be wrong but you use a Dynapack as well?? If so, add some kw... not to mention potential gains from using better manifolds etc.

52trim is 55, 71R is 53

Its a GT3076R size - and making GT3076R power

Will be very interesting to see how it goes then

Whats the rest of the setup the 5557/RB25 is going to be using? Manifolding wise etc? Completely unopened engine eh?

Maybe some of the Borg Warner EFR turbos might end up being interesting prospects, I believe the smallest of the range are going to be GT2860R equivalents. The PT5557 would be hellishly laggy in twin form, they are well above -10 flow wise. I personally don't think there is any worthwhile gap between the -5 and -10s, they aren't THAT different in flow that Garrett have options for in between. Maybe Greddy T518Zs... I wonder if Forced Performance can do a version of their 68HTA which would bolt onto a GTR. That'd be pretty serious....

Hi man, do you have a dyno plot you can share? I actually tuned a mates GTSt (Looney_head off SDU) last weekend which is running a VG30 turbo and I was quite interested to see how that'd go, partly thinking about your results. We ended up with about 201rwkw on MacLennan's dyno from a 149kw starting point so yeah, quite different results. Have you looked into sorting out the cam timing?

Agreed on the first half, but everyone I know who has changed to twin scroll with the same (sometimes another "same" CHRA but with different housings, sometimes the exact same turbo but with the turbine housing swapped) CHRA and manifold modifications to suit have improved spool by a few hundred rpm, increased midrange torque by HEAPS and ended up with similar peak power.

Not sure why they would, they have medium singles which would outperform many of the existing bolt on twin setups out there and for a large part the Americans aren't as tied up with the messy low mount twin turbo way of doing things the lower Hemisphere seems to be. I'd just bin the twins and go a high mount PT6262/GT3582HTA or bigger

Twin and single scroll a/rs aren't comparable. .82 is a happy medium for open housing on a but I would personally not go anything other twin scroll 1.06 for that power level.

What housing and power do you currently have?? I haven't seen the combo on an RB25 myself but from what I have seen on other cars I'd go with a 1.06a/r T4 Twin scroll housing... I am guessing you have a .82a/r hot side from that spool level, so maybe shift that to around 3800-4200rpm range for a twin scroll setup with generally more torque as it builds boost and more midrange at full boost. Just a semi-educated guess...

Without any alcohol? Actually one of the dudes over here made just over 600whp on his RB30DET with a GT3582R on BP98

Nice solid result - I've never doubted the possibility of 200kw by 4000rpm.... I'd be able to do it fine with my GT30R but I'm personally not keen enough to push the boost through a stock motor needed to make 200wkw by 4000rpm (would be around 20psi or so), but its a nice power delivery. Seems to come on a bit faster than the other ones you've posted - should drive well. Be interesting to know what was changed!

Borg Warner S300SX 91/79?

You have a GTS4, eh? Who tuned it, I am guessing Aaron? Has he ever tuned an R32 GTS4 before? One of my mates had similar issues trying to get power out of his GTS4 years ago on a steel wheeled VG30 turbo, he tried running more boost than you are (peaking at like 19psi) and all sorts and never went north of 190kw. Even in RWD mode the ATTESA setup seems to drain the poor wee RB20

I'm personally much more curious about the HTA turbos, though the PT ones are pretty neat - a little more $ and you can get real fancy like a GT3794HTA... omnomnom.

Damn you kids and your E85