TELL ME why an 18G is "junk"

[terminaltsi]

from what i read and hear, 18G's are not worth anything. any real reasons why? i don't want opinions, i want reasons.compared to a 16g or 20g....

 

[KeltonDSMer]

The 18g is actually really efficient; more so than any of the 16g turbos. The big 16g is the most inefficient compressor that mitsu produces, (71% peak). This is not good for applications on the stock IC, for my personal experience shows that it is hard to controll knock with a big 16g on the stock SMIC anywhere past 15psi on pump gas; where as I have seen the more eficient small 16Gs and 18Gs run at 20+psi with the stock IC.

This doesn't matter as much with a FMIC, but efficiency is huge as far as limitations go with the stock ICs and pump gas. This is why people are having such great luck with the 50Trim turbos on pump gas because they are really efficient and don't heat up the intake charge very much.