Hello!
I was just wondering what kinds of increases in fuel economy people here have seen from switching over to higher compression pistons. I've been pretty curious about this for awhile, but I couldn't find any specific numbers online. If you could, list how high you raised the ratio to and how much better the car did per gallon of fuel (ballpark). If a few people could give me some numbers that would be awesome.

Thanks,
- Ian

 

An increased compression ratio will improve power output throughout the powerband, broaden the powerband, and improve fuel economy. There is not number set in stone since it depends on many variables. The combustion chamber and piston design have a lot to do with it, and so does the tune. Octane rating, spark plug selection, etc. also apply. The gain in fuel economy is also not set in stone.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ddd4114 &raquo;</TD></TR><TR><TD CLASS="quote">An increased compression ratio will improve power output throughout the powerband, broaden the powerband, and improve fuel economy. There is not number set in stone since it depends on many variables. The combustion chamber and piston design have a lot to do with it, and so does the tune. Octane rating, spark plug selection, etc. also apply. The gain in fuel economy is also not set in stone.</TD></TR></TABLE>

true. i ran zc pistons in my y8 had it tuned and got an avg of 31-34 mpg. which it didnt move up too much from 29-32 mpg previously...

depends how the tuning goes as well along with how conservative the timing is.

sometimes gotta be careful running high compression. if the tune isnt right and its quite high compression, that motor will take a dump on you. very small margin of error on high compression setups.

if you plan on doing it, i would suggest getting a na after market cam as well, reason being it bleeds of more compression than the stock cam can do due to duration. this will also help save your motor, such as the rings,ring lands and head gasket.

 

simple, higher compression motor will need less throttle for any given load than the lower compression one