Octane needed for 13.5 to 1

[kingofvenus]

81.5 mm 13.5 with dot head combo. How much Octane will i need?  

[Gixer1460]

Depending on cam timing, at least Super Unleaded maybe race gas 105/106 RON, maybe more.

[dupersunc]

40 minutes ago, kingofvenus said:

81.5 mm 13.5 with dot head combo. How much Octane will i need?  

Have you measured your compression ratio?  Or areyoujust quoting part specs?

[kingofvenus]

Just going by specs, motor is not assembled yet. Was going to use .30 copper base and layered steel head gaskets. Lightly used pistons and cylinder block purchased off of that site...  

[colinworth79]

I used my bandit with 13 to 1 compression JE pistons for a few years with no problems . 82mm bore ( 1246 )  Yoshimura stage 1 cams and stock ignition timing  . Always run on shell optimax . As stated above ignition and cam timing play an important role .  

You will need to build the motor and meassure everything and work out the compression ratio . I would also be concerned with piston to valve clearance using the dot head .

[dupersunc]

13.5 pistons and dot head are  bad Idea.  You'll  have a sky high CR, and no valve to piston clearance as the dot valves are longer and sit closer to the deck.  Base gaskets and head gasket might make thing work, but you'll bugger up you squish height. This is bad.  the dot cams are worth using if you are starting with a Bandit lump.

[Kamikaze]

What Duncan said.....