What Cylinder Mead cc's ????

[DarrylA]

Hi guys

Can anyone tell me what cc's I need in my cylinder head chamber to achieve a compression ratio of 10.5-1, and 11-1.

Head is a BP4W.

Many thanks

[Magpie]

http://www.csgnetwork.com/compcalc.html

However you can adjust the head gasket thickness instead, depending on what you have already done to your engine.

[manga_blue]

OEM head gaskets are around 40 thou. Victor Reinz gaskets from mx5parts.co.uk are the cheapest high quality thin gaskets at 30 thou. You can take 60 thou off the head. You can swap to NB8B pistons for an extra 0.5 in CR. etc etc. Try googling chamber volume or piston crown volume on miata.net. Plenty of ideas there.

[project.r.racing]

you wont find those compression ratios by machining the head. you can get about 0.2 extra compression. buy pistons instead.