C/R vs Boost......
Turbo Mini Forums

Does anyone know of a table or reference that gives a rough idea
of what compresion ratio is suitable for X amount of boost pressure...?

Its not as simple as that...

It varies massivly depending on your combusiton chamber design.

Alex

AlexF

Can appreciate that.. just wondered if there was a rough rule of thumb or not

go for 7-8:1

You have two choices with enignes:

low CR and high boost crams in LOADS of fuel/air and makes good power

high CR and low boost will produce less BUT if you up the RPM you make good power

The high CR route is favoured these days as its much better off boost (not to mention fuel econo, emissions). You also have very good control with modern efi.

In short, we don't have control so we end up medium CR and medium boost!

Alex

AlexF

Ok thanks for the advice Alex