Compression Ratio and Turbo's

[greg_D]

A quick semi-tech question for all you mechanics out there to answer for me on a dull monday morning.

"Could someone explain why the compression ratio has to be different in a turbo engine as opposed to N/A, why do you not just differ the boost to take into account the difference in compression."

ps. my understanding of the compression ratio is the amount that the fuel:air mixture is compressed immediately prior to ingition.

These sort of threads are where i learn all of my boring motoring knowledge, so don't let me down lads

Greg

[greg_D]

I am doubtlessly massively oversimplifying this, but my thinking goes thus:

If it takes a N/A engine x-psi to start detonating (and x is an absolute due to engine design) then surely altering the CR and bolting a turbo on is a big no no, because with the boost that the turbo produces is surely going to be x+++ hence the power gains to be had by turboing an engine.

am i making myself clear? it makes sense in my head!!!

i know that i am missing something, but what??? please tell me because it is doing my head in

Greg