Single Turbo Rb26 Guys: What Turbine A/r Do You Run?

[002-M-P]

I posted this on another forum to, but you guys generally know more, just not as many rb26 people it seems....anyway. Pretty simple thread, just curious as to what single turbo you run, is it ball bearing or journal bearing, and what A/R do you use on the turbine side...also is it split flange or not. Then if you wouldn't mind commenting on spool and how the car pulls to redline.

I know my TO4R on my stock ported rx7 had a .84 A/R and it spooled decently quick, but it def died out about 7300rpm and I rev'd to 8100rpm, I would hate for that to happen again on my RB, but also don't want to wait forever for boost to hit.

[R31Nismoid]

Depends what sort of power/aims/use of the car to be honest

[002-M-P]

Depends what sort of power/aims/use of the car to be honest

I guess I may have worded that weird...I'm just more intested in what people are actually running, not really looking for recommendations for me.

[R31Nismoid]

http://www.skylinesaustralia.com/forums/in...showtopic=93880

well that has all the results...

[002-M-P]

http://www.skylinesaustralia.com/forums/in...showtopic=93880

well that has all the results...

I realize this too (looked through that thread a bunch of times), but to be in there you need dyno results, which everyone might not have. Anyone elses experiences are always helpful too.

[002-M-P]

bump...

[Adriano]

GT35R, .63 ex housing, stock rb26 550cc inj PFC d-jetro 16 psi. 309rwkw. Hakes max power at 7500-8000, comes on as early as i would expect a 700hp turbo to be able to, starts pulling about 3600.

HKS T45s .90 T04 ex housing, stock rb26, 550cc inj, remap. laggy as hell, got car with 1 smashed piston, was supposed to make 380rwkw at 20psi, made 260rwkw at 14psi(with 5 pistons), so 380 isnt out of the relms of possibility.

[discopotato03]

I think I can see what your getting at but possibly you could have asked about single turbos for RB26/results/turbine housing A/R .

That last one (turbine housing A/R) is going to depend on turbine and compressor size and availability . Its as simple as that . Often you'll find that three sizes are available (ie .6x .8xx 1.xx) and if you had no information to work off the mid sized one is the logical starting point . That way you get a result and know which way to go if the first try didn't get you what you wanted .

There is a tendancy for people to look at maximums with turbos and while a turbo may be capable of high specific output it doesn't necessarily mean an engine can run it to its limit . A huge turbo with a small A/R turbine housing is wasted because even if you could spin the thing fast enough to make the compressor work the small turbine housing won't pass the exhaust gas required to make the ENGINE work properly .

Balls vs bushes . Its hard to make a direct comparison these days because manufacturers like Garrett use different (read more modern) turbines and compressors in ball bearing turbos that bush type . It stands to reason that they wouldn't sink development dollars into a turbo with an expensive ball bearing centre section and use dinosaur wheels . Many of their bush bearing turbos like TO4S's and T04R's use old world designed turbines like the P trim TO4 which work ok but not what you'd call brilliant , its because they are based on 1970's technology and thats not yesterday . TO4Z's are an example of dinosaur turbine with modern bearing system and a well matched compressor , in HKS form the housings were designed to get the best from the wheels they use .

Bush bearing GT40's are more modern designs and sort of cover the TO4S/TO4R/TA45 range of older turbos . To look at a GT4088R ball bearing turbo next to one of the larger GT40 bush bearing turbos the differences are not always obvious and they can at times use the same style of housings . The ball bearing one is usually designed around higher temp spec turbines and housings and trim better suits petrol engines higher EGT's . The bush bearing type is usually intended to suit diesel engine characteristics like less expensive materials (lower EGT's) and different exhaust flow vs power characteristics . In the case of the GT4088R the turbine trim is good for its frame size and it uses the later 7/14 blade compressor design in 52 trim and has impressive comp map . The larger GT40 bush bearing turbos use a larger trim turbine and A/R turbine housing to suit some OEM diesel app . Volume sales to diesel engine manufacturers dictate the market here .

Bottom line you get what you pay for so sometimes old wheels in good housings with a good bearing system are plenty good enough .

Cheers A .

[DVS JEZ]

rb26 forged internals, PFC, 800ccsard,bosch 044pump, garrett T04Z .7 front 1.0 rear housing, full boost by 4-4500, doesnt diue off boost at all, holds past 8500rpm.

excellent turbo

[Faid]

Forged engine, HKS T04Z turbo 0.81 AR, PFC twin Z32 AFM, hits full boost by 4600 and puls all the way to 10k. No problems with this config what so ever. rinnung the engine nearly daily driven on 22 psi of boost. no complaints so far

[T04GTR]

hhhhhch. 10k

230k old 26. ebay manifold garrett t04z .84 rear split.

loaded gear. fullboost by 4k

1st 2nd 3rd full bost by 5k 4600 4300 respectivly.

nice turbo. abit laggy but when it hits it hits hard