turbo trim??????

[drifting_changed_mylife]

i know i know imma noob :doh: , but when they say turbo trim size what the hell do they mean??? some kid wants to sell me a turbo and he's saying its a 60 trim... what is that and how to i check if hes not bullshitting me????

[Def]

It's a formula that takes into account the ratio of the minor and major diameters of the wheel. I think it's

trim = minor dia^2/major dia^2 * 100

[drifting_changed_mylife]

i dont get it..............

[xsparc]

well thats close

trim = ((exducer dia ^2) / (inducer dia ^2)) * 100

http://www.turboford.net/spreadsheets/spreadsheets/trim.xls

trim just shows the size difference between the inducer blades and exducer blades.

just knowing the trim really tells you nothing about the turbo. you need the whole number and AR ratio.

[Def]

A bigger trim means it can flow more air given the same size major diameter since the "choke point" is the minor diameter of a wheel(compressor or turbine). That's really what it means when generally comparing turbos/wheels.

[shmiddy]

i think hes asking how to check a turbo for its trim

[xsparc]

well to be sure you have to take the housing off and measure it, but alot of times it stamped on the housing

[Def]

I've never seen the trim stamped on a housing of a genuine Garrett/Holset/KKK turbo. The Chinese stuff sometimes has the trim on there, but who knows if the wheels actually measure out correctly.


As far as how you'd tell - how else would you tell? You measure the minor and major diameter(i.e. the small and big diameters) of a wheel - plug into the above formula and you've got your wheel trim.

[golfer17]

trim only lets you know the differences in similar sized turbos. also, usually, when i hear someone refer to their turbo only by trim size, it is usually a garrett t3/t4.

go here for more info
http://www.turbobygarrett.com/turbobygarrett/tech_center/tech_center.html