can ball bearing turbos be hi flowed?

[BomberMan]

hi all, excuse my ignorance, but does semi ball bearing mean roller bearing? and did the australian delivered s15 200sx's come with roller bearing or ball bearing turbos? i am assuming that the adm s14 and s15 came with roller bearing turbos as they both produce the same output (147kw) shitloads less than the jdm s15 which i am sure they had a ball bearing turbo. why is it that there is such a huge difference in power between the japanese and australian models? also could someone tell me if ball bearing turbos can be hi flowed, as i have been told that ball bearing turbos cannot be rebuilt. thanks for your help ppl!

[Forg]

The power difference is purely in the ECU tuning; the turbos may be different, I don't know about that, but the Oz vs JDM spec 200SX power difference is purely about tune. They claim it's due to fuel; whereas I think it's halfway between the JDM power being a little bit exaggerated, and possibly pollution/cost issues for Nissan Australia (note how they're ditching the 200SX in Japan due to new pollution laws ... I may be jumping to the wrong conclusion, but then I enjoy doing that :)).

As far as roller-bearing, ball-bearing & sleeve-bearing is concerned; it's about lag. If your housings & wheels are the same, the maximum power is the same regardless of the bearing used (OK, something always changes, but the difference would be miniscule). Ball-bearing turbos just tend to have better response; as well as allowing a bit less accuracy in sizing with aftermarket installations (ie. because they spool up more easily, you can screw up your sizing & the car still drives nicely).

Sejanus has said that he's done a before & after comparo on a 180SX where the original non-ball-bearing turbo has been replaced with a ball-bearing one, and he reckoned there was bugger-all difference. Hopefully he'll elaborate; I may be misremembering what he said (maybe he meant that there was just as much lag but more power because the replacement turbo was a larger one) ... but he seemed to be of the opinion that there wasn't a gain from the extra money spent for the ball-bearing centre.

As far as high-flowing is concerned; probably, dunno why not. Don't think they touch the cartridge in the centre when they do that; if they replace the wheels then I think you're looking at pretty big dollars to doa BB turbo though (I've been told by a few places that BB turbos don't come in mix-'n'-match wheels yet, although I'm pretty sure there's a place in Queensland that does it for a fairly hefty price).

[GTSBoy]

It is easy enough to highflow many BB turbos. The RB20 one is an obvious candidate. They put a bigger comp housing and wheel on and replace the exhaust side with 13B turbine housing and steel wheel. Leaves the BB centre alone and fixes up all the problems with the factory one.

Ball bearing and roller bearing mean the same thing. Balls are just a particular type of roller (actaully the correct term for a ball bearing is a spherical element roller bearing) and AFAIK they only use ball type roller bearings in turbos.

cheers

[BomberMan]

what would it cost and who could do it in brisbane? also, does anyone know where the cheapest places to buy tyres in brisbane is? im after 18s

[GTSBoy]

Hmmm....dunno about Brissy, but Ray Hall is in Cairns and GCG are in Sydney...both have good reps.

Cost depends on what you want done (ie some exhaust or comp housings that you might choose cost more than others and teh amount of machine work needed will vary also) but you could expect to pay between $750 and $1500, with $1000-$1200 covering the normal range of mods.

cheers

[JiMiH]

Originally posted by GTSBoy
It is easy enough to highflow many BB turbos. The RB20 one is an obvious candidate. They put a bigger comp housing and wheel on and replace the exhaust side with 13B turbine housing and steel wheel. Leaves the BB centre alone and fixes up all the problems with the factory one.
cheers

What kind of improvement can you expect from the turbo if you get this done?

What power figure will the high flowed turbo be capable of?

[GTSBoy]

Normal RB20 turbo maxxes out at about 160-170 rwkW. With a T4 front and a big rear end on them they should be able to do 250rwKW easy. It is just a question of how long the centre of the turbo will hold up under load imposed by a big wheel at either end. But theoretically it could be as much power as you can get out of the best trim T4 wheel that will fit in the compressor housing.

cheers

[JiMiH]

so is it a viable option to hi-flow the rb20 turbo?

or would it be a better idea to get a new turbo?

the vg30 turbo seems to be a popular option but i'm not sure exactly how good one of these would be. i always get the impression that it's only a mild improvement over the stock turbo?

[GTSBoy]

The VG turbo is still limited to 14psi but will make about 190-200rwkW if properly set up. Many RB20s will need more fuel by the time you get to this point.

But the VG's are starting to get old so they might be a simple upgrade but may not be a long lived one....but then again you might get lucky.

An RB20 turbo should be about $1000 to get done up to your spec (which is basically just walking in with a good one in hand and saying I want XXX horsepower please).

I have been thinking about my turbo options for when I get around to it...and I suspect that picking up a secondhand GT2540 or similar might be the better plan.

cheers

[JiMiH]

Will the GT2540 give a lot of lag?

I'm thinking that I will want to upgrade the turbo but not sure what to yet. I want something that's streetable ie with not much lag, but I still wanna make some good horsepower.

[GTSBoy]

JiMiH,

You will have to put up with whatever amount of lag comes with the turf. Using a BB turbo like a GT series will make sure that you get the best spool up possible for your compressor/turbine combination.....but your choice of that combination is your choice. The GT2540 or a similar size..(maybe slightly smaller) is probably where the best compromise between big HP and lag is to be found.

cheers