Karlos G

iTrader: (4)

Does any know how much more the head will flow with the slightly larger valves? I'm interested in actual figures rather than 'my car went well quick with my stage 3 head' lol

According to the PumaRace Engines website it's hardly worth the change and 45mm is really the way to go.

http://www.pumaracing.co.uk/CVH.htm

"The CVH responds very well to big inlet valves. I have my own valves made and offer 43.5mm and 45mm inlets in addition to the standard 42mm heads. Other so called "big valves" available are only 42.6 or 43mm and hardly worth fitting which is why I designed my own"

haz87

You can only do the 45mm's on the "best" cast heads tho can't you. Think they're the ones with the webbing in a certain place. I know C&B had a pic of one (more than likely his own cylinder head)

Rick

you need the cross hatch head for the 45's. They are huge huge valves, and need changing regualry so u don't drop a head and ruin your engine. Mine were ceramic coated but still ended up dropping one eventually.

Karlos G

iTrader: (4)

ok thats interesting!

But still is there much to be gained form going to 43mm over 42mm?

B16CVH

Not really, the fact that the air is forced through anyway by the turbo. In my experiance of modifying turbo heads, you are better opening up the valve seats to just into the seal area and porting slightly.