so I decided to do a bit of reaserch since there isnt much good reaserch out there.

ok lets get to talking about A/R

WTF is A/R exactly how many people really know ? im not sure. i kind knew that A/R reffered directly to housing size but didnt understand its exact relationship to anything else.

Ok if you familar with tire sizing the a/r is actuall Aspect ratio.

yeah its that simple.

A/R is the Aspect ratio of the wheel.

So how does this affect your turbo decisions ?

well. for instance in the turbine side of things there are stage 1,3,5 turbine wheels ( from garret) so that means that there a nine possiable combinations of t3 turbine setups

a stage 1 a/r .48 is ------- tiny. a stage 3 .48 is a might bit bigger a stage 3 .48 is bigger yet

So if you wanted to compare outflow vs outflow a stage 2 .48 is almost the same as a stage 1 .63. but the .63 stage 1 will have a slithgly higher spool up time. but they will both flow the same or fairly close to the same amount of overall exhuast

it goes on so on and so forth with other turbine housing wheels combos ( im only talking about t3 trims but this is universally applicable to other turbos)

however the same holds true for compressors

IE a 42 trim with a 40 mm inducer vs a .42 with a 45mm inducer are completely diferent units.

the 45mm inducer ( the aspect ratio is derived from this ) will flow more total air then the 40mm. even though the housings share the same a/r the wheels will dictate the size of the housing. even with the same A/R

So when selecting your next turbo make sure to ask all the right questions

Ill see what i can do to come up with a guide to turbine side's etc.

Sean out.

 

Good info. Nice work. Something like this should be added to the FAQ.
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wow seam just when I think ive figured it out... damn youre good

 

Nice writeup Sean. Straight forward and in laymens terms...

 

Yeah man Nice writeup....Now I know what to choose

 

Well if anybody wants to get in on this id like to make Garret turbo spit up the info on the hot sides of there turbos.

 

Ok I had 2 turbos
#1 SVO .60/.63
#2 volvo .42/.48 both were T3 garretts

The turbine housings ( .48/and .63 ) were totally swapable with out changing anything, just take one off and put the other one on.

My question lies at the compressor side. Lets say I wanna use a 50-trim wheel in my SVO turbo that comes with a 60-trim. Can I just get a 50-trim .60A/R compressor wheel and slap it in the SVO turbo, get it balenced and I'm good to go ?

OR do I have to match the compressor wheel with the compressor housing. Like a 50-trim has a "50-trim .60A/R compressor housing" and the 60-trim has a " 60-trim .60A/R compressor housing" and they both are different and can't be interchanged like the turbine side.

BTW I'm pretty sure both the volvo and SVO have stage1 turbine wheels.

 

IMO the housing has nothing to do with the wheel. IE there could be a .42 a/r housing on a 60 trim or a 50 trim wheel. the housing would of course if designed for each wheel be different in terms of overall size. A/R has to do with wheel size. Not anything else. The wheel determines flow and the A/R determines peak effiecncy etc etc etc. they are related but not in the snese your trying to make them related.

 

nice write up, sean.

The turbo I want for my d16 is a 60 trim 48ar tubine and 60ar compressor.

What do these numbers mean? and do you think this too big of a turbo for a mild 8 psi application?

 

A/R =
The "A" is the AREA or size of the opening at the end of the turbine housing where the exhaust gasses exit into the turbine blades.
The "R" is the RADIUS of the turbine housing measured by the distance from the center of the turbine shaft at a given position on the turbine housing.