Turbo Tech. questions

[Mpatient]

This was originally posted in another forum by 1civic

"Wheel "trim" refers to the squared ratio of the smaller diameter divided by the larger diameter times 100. Generally, the larger the trim number the more flow the wheel has.

For compressor wheels , larger trim tends to mean slightly lower efficiency.

For "families" of turbine wheels (those with the same inducer diameter), larger trim usually means better flow with less backpressure but longer spool time.

A/R is a ratio of the exhaust discharge area vs the distance from the center of turbine wheel to the center of the cross sectional area. Smaller A/R housing has faster spool up. Bigger A/R housing has less back pressure, more flow for the top end.

.........Does This Help you at all......"



Now when referring to the smaller and larger diameters, what is being referred to the turbine diameter from inside to outside or what? and how does this effect apply towards increasing horse power? I know the more flow the more air to combust but still need more info I guess.

I'm truelly not trying to sound like an idiot I just don't have alot of experience with how turbos actually make power, and I'm planning on building my H22A and I truelly want to know what is going to be the most effecient way to meet my power requirements and what is just giong to be a waste of money.

[1civic]

The A/R in a relationship that is obtained when dividing the interior area of the turbine where the inner walls are found, through the turbine housing radio from the center to the tongue....

A/R values are expressed as .35, .47, .68, .84, 1.00, 1.15, etc.

A small A/R indicates a small interior volume in the small turbine and a large A/R indicates a greater volume.

At a minimum A/R the motor's response is produced at small revolutions per minute but at high revolutions we will not achieve an adequate caudal. We should always find a compromise between achieving the lowest response possible and have enough caudal at high revolutions.....

[1civic]

Each turbine wheel y compressor wheel model generally have the same turbine diameter (highest diameter), but different steps (lowest diameter). Each type of step (trim), has different blowing characteristics.



TRIM values are expressed as 45, 50, 55, etc... and can only go from 0 to 100. A value of 100 means Dp = Dg
A large TRIM indicates a large turbine diameter.
A TRIM of 55, gives 10% more caudal than a TRIM of 50.
TRIM is used in the same way for turbine wheels as for compressor wheels.
TRIM is calculated through the following formula.

TRIM = ( Dp / Dg )² x 100
Si Dg = 50 mm y Dp = 35 mm
TRIM = ( 35/50 )² x 100 = 49

[1civic]

I know this is hard to understand and I hope I was of some help to you...Best of luck on your build... ...Later..

[Mpatient]

Great info. It will actaully help me greatly considering it gives me the basic dynamics of how turbos work and how hybrid turbos can be more beneficial. I definately appreciate it.