has anyone had experience with a cossie yb with a compression as low as 6.7.1? im just a little unsure on how it will drive and how laggy it will be. cheers.

 

anyone?

 

Don't know why you'd need to run a c/r that low.......ceretainly not goin to be a nice snappy engine

 

yes, lower actually...

people who say its more laggier and not as responsive clearly and simply dont know what they're on about...

you'd never be able to tell the difference between a 6.? and a 7.?? engine

Run as high a comp you can get away with

 

So a 9:1 engine won't be any more responsive than a 6:1 engine when both are mapped to their optimum on the same components/turbo?

You then go on to say run as high a c/r as you can get away with, which seems to totally contradict your first point?

 

you can tell mate i could feel the difference from 8 to 7.5 in off boost response.

 

i run a comp of 7.2 and that runs fine ticks over and drives nice but thats on a 2.9 t/t

 

I realy didnt notice any difference when i went from 7.2 to sub 7 , but there were other changes to the spec at the same time.

 

ive had a 7, 7.5 and 8 and they all ran perfect its just the off boost area will have less response.

 

6.7 cr will feel crap of boost simple!!!why make your engine less responsive when you dont have to???depending on spec iv always found engines around std cr feels very good..

cheers danny

 

There is absolutely no need to run that low a compression unless you are using 87 ron fuel and over 50 psi

Anything below 7.8 is just plain crazy !!!!!

Besides the poor off boost power response you will have terrible emissions !

A 600bhp YB road engine I know of, has a CR of 8.0:1 and runs SUL pump fuel.

Its all about the total engine set up and reducing CR to overcome other issues is bad tuning IMO