Twin Scroll Journal Bearing Turbo? KA-T ideas

[No Rotr]

Can I just use a divided exhaust housing on a twin scroll manifold and have the same effect as running a GT series twin scroll manifold? I would like to use Full Race's manifold for the KA, but I'm not a fan of non rebuildable ball bearing turbos. So would something like this work with FR's twin scroll manifold?

http://www.atpturbo.com/mm5/merchant.mvc?Screen=PROD&Store_Code=tp&Product_Code=GRT-TBO-060&Category_Code=TBO

Can I go this route, (full race twin scroll manifold and divide housing journal bearing turbo) or am I just would I just be better off to get something like a PFabrications tubular manifold and a regular old turbo. I only want 325-350 whp on pump gas, but want the best response per dollar(so gt-series ball bearing turbos are out).

[e1_griego]

Holset? Those are twin scroll, right?

And cheap!

[Def]

A Single scroll BB turbo will have better transient response than a twin scroll journal bearing jobber.

Smaller turbo manifold volume also makes for better response, as well as smaller charge piping volume.

IMO, BB turbos rock. The extra cost over a journal bearing turbo is easily the best bang for the buck in a turbo build as long as you value response.

Honestly, a GT2871R in the stock SR location sounds like a winner for a KA concerned about response. Plus you've got tons of off the shelf parts availability.

[WorkInProgressK]

BB rocks. Even if you manage to surge them, they won't fail because of trust load, well not as quickly as none BB turbo's.

Also they use almost half the amout of oil. That way you can have more oil for the rest of the engine. Also, cold starts are almost inexistant because of low friction of BB.

[jspaeth]

BB rocks. Even if you manage to surge them, they won't fail because of trust load, well not as quickly as none BB turbo's.

Also they use almost half the amout of oil. That way you can have more oil for the rest of the engine. Also, cold starts are almost inexistant because of low friction of BB.

Not disputing what you wrote, but I would be curious to know just how much oil the turbo actually uses relative to the whole engine.

[tonto]

if u want cheap and disposable get a chinese 2871

er, maybe get the 2-pack

[Def]

if u want cheap and disposable get a chinese 2871

er, maybe get the 2-pack

Even the ones that work seem to spool slowly and not make as much power as the "real thing." Most likely due to crappy bearings and bad wheel to the housing clearance.

[tonto]

i was wondering about the wheels themselves too. jet engine cfd modeling is no joke, so i would assume similar deal here. but i guess the chinese have the advantage of copying the garrett wheel.

what i still haven't figured out yet is why all of the 1980's designed wheels are still popular. weren't they made before the computer cfd models and therefore are kind of crap?

[Def]

i was wondering about the wheels themselves too. jet engine cfd modeling is no joke, so i would assume similar deal here. but i guess the chinese have the advantage of copying the garrett wheel.

what i still haven't figured out yet is why all of the 1980's designed wheels are still popular. weren't they made before the computer cfd models and therefore are kind of crap?

They were tested a lot. And CFD isn't *that* accurate today. It gives a good idea of different directions to go, but in the end, the design must be fine tuned via flow testing.

But you're right, the newer wheels are better than the older wheels. Usually flowing near as much while being much smaller and quicker to spool, not to mention the better BB CHRAs.

[No Rotr]

Anyone have any thoughts or experience on using a Borg Warner S2B instead of a GT3071R? Comparing compressor maps between the two they are very similar.

http://www.pure-tuning.com/catalog/product_info.php?products_id=1928&osCsid=b2ca51fad0f24178100bfa0cf47a0edb

[Def]

No direct experience, and BW is really stepping up their game in the "mid-field" turbo sizes. I just wish they brought out some T2 flanged stuff to compete with Garrett in that arena. More competition is only going to bring us better turbo choices in the long run.