maro z28

What's the difference (physically and functionally) of ball bearing turbos vs. journal bearing turbos? They are seperated on forcedinduction.com's online catalog and want to know which kind to get for a 1995 TA.

Also, will T6 turbine flanges fit on LT1s using Garrett or Precision turbos?

Alan Namsa

A journal bearing turbocharger uses similar bearing technology as does your crankshaft. The connecting rod or main journal is encased in a bearing with an oil film barrier. The rotating assembly of a turbocharger has a main shaft which is encompassed by bearing surfaces and an oil film barrier.

A ball bearing turbocharger uses a ball-bearing assembly with two races, *****, and a cage. The outer-race contacts the center-housing while the inner race contacts the rotating shaft. Precision ***** are retained by a cage between each race of the ball-bearing assembly itself. Oil is fed to lubricate both the race and the ***** inside.

Ball bearing turbochargers will have less friction and thus spool quicker. They can withstand oil starvation (lack of flow or extreme temperature) situations much longer than a journal bearing turbocharger. These features are nice additions, but journal bearings still work.

A T6 housing can be made to fit, but elephants also fit in aircraft—you will need to get creative.

DirtyDaveW

As far as knowing which turbo to get for your car, the best advice any rational, knowledgeable person can offer is to tell you to contact a well known, respected and proven turbo supplier. I used Forcedinductions for my recommendation but there seem to be many "good" guys/sponsors here. Just poll the forced induction list for their experiences. I will vote for FI just because I had good feedback, response and delivery of my T76 and Wastegate. Call the company you find to have the most positive feedback. Tell them your engine combo, transmission, make/model of car, weight of car, differential of gears, intended use (street only, strip only, combination of the two in ratio), Horse power goals, cam specs, head flow,...everything. Too much information is fine. The more info they have the better they can zero in on the Turbo size, A/R, etc. Sure, some DIY can adapt any turbo on the planet to make more HP/TQ than a stock car but the proper turbo has to have the best compromise for you to get the maximum enjoyment out of a very labor intensive and custom setup.

As far as the ball bearing vs non-ball bearing, someone had a short video online that portrayed the difference like that <Dirtydavew snaps fingers loudly>. It shows a guy grabbing a hand held non-ball bearing Turbos spindle and spinning it once with his thumb and forefinger. The turbo spins for about 4 to 5 seconds, then stops. He then picks up a ball bearing turbo and spins it in a similar fashion. It just spins and spins and spins, barely decelerating, near frictionless in comparison to the non-ball bearing.

Alan Namsa

That is a horrible misrepresentation of the two technologies because a journal bearing assembly is designed to operate with a replenishing oil barrier between both surfaces. Yes, there is a difference between the two technologies, the ball-bearing will create less friction, but it is not as extreme as that example portrays.