1. What are trims basicaly. The engle of the blades or the length, etc.



2. What are the different trims and what is the difference between them, ups and downs vs eachother.



3. Does the compressor turbine has a trim also or is it just the exaust turbine.





thanks guys

Try the pinned turbo terminology link in this forum. It'll explain a lot.

read it and it bearly talked about trims. From what I get a "trim" is the trim of the compressor turbine wheel.



now I still dont get how can a huge turbo spool up at 2k with an O trim I think (not sure, jspacer7 mentioned it somewhere). So if triming alows for better controll at high rpms them how can this be? This trim puts MORE metal on instead of taking it off?



also quoating that thread:



"Clipping the turbo reduces this restriction and allows more air to flow past the turbo wheel at high RPMs, thereby improving airflow through the engine and increasing top-end response."



by that he means, lets take this as an example:



turbo X spools fully at 5000rpms, now with a trim once you hit 4000rpms it will go to 5000rpms faster then if it was not trimmed?

((minor dia.)^2/(major dia.)^2) x 100= trim

I see.... but that still doesnt answr my question. What is the benifit of trimming the blades? Someone said better responce at high rpms, and that means what? faster spool going from high rpm to higher?

Are you refering to "clipping"? This is something that is done to the exhaust wheel to increase high rpm flow without affecting spool up to bad. There is no such thing as "trimming", but there are "trims" and it refers to size and shape of the wheel.

I see. Then I have another guestion. I cant remember in which thread but jspecracer7 has mentioned that with ?-trim a turbo which would normaly spool at 5k will spool at 2k. Now why doesnt everyone has the exaust wheel of that trim is it makes the turbo spool so fast. Infact why to other trims exist if they take longer to spool. I understand there is a backdraw to this, what is it?

I found the post, here:

That was an example to prove a point. The problem with the small housing and wheel is that you cannot make power and the motor will fall on its face early, which is not good on a motor that likes revs. There is a balance between spool up and power and the only way to have/improve both is to lighten components or use a bearing system with less friction.

Here's some info that I have been posting on Honda sites for years.



Compressor A/R is determined by dividing the radius of the compressor housing by the smallest diameter of the compressor outlet . Exhaust housing A/R is determined by dividing the radius of the exhaust by the smallest diameter of the exhaust inlet . As the A/R numerically increases so does the housings ability to induce/exduce a specific volume of air. Lag and effective power range will also be affected by A/R changes. Look at the attached A/R pic.





formula for determining trim

[(minor wheel diameter)x(minor wheel diameter) / (major wheel diameter)x (major wheel diameter) ] x 100= trim





T04E 60

[(2.290)(2.290)/(2.950)(2.950)] x 100= trim

(5.2441/8.7025) x 100= trim

.6026 x 100 = trim

60= trim