topend noise

[hotrodbanshee]

I rebuilt my topend and bored it .020 over and put in weisco pro lite pistons in. I have a 185 psi compression in each cylinder and I have my timing advanced 4 degrees. I am running 93 octane with octane booster added to my gas. I am noticing a crackling noise in the topend when I am accerlating really hard. Is my motor detonating? Should I be running race fuel? If so, what octane level should I be running and what brand? Can it be mixed whith pump gas?

[rideblue_05]

That may be detonation. From what other ppl have told me anything over 160 or 170 compression u need race gas. I may be wrong but this is just what I have been told.

[bkabina]

I rebuilt my topend and bored it .020 over and put in weisco pro lite pistons in. I have a 185 psi compression in each cylinder and I have my timing advanced 4 degrees. I am running 93 octane with octane booster added to my gas. I am noticing a crackling noise in the topend when I am accerlating really hard. Is my motor detonating?  Should I be running race fuel? If so, what octane level should I be running and what brand? Can it be mixed whith pump gas?

311033[/snapback]

 

With 185# compression you could get away with a mix of race fuel and gas.What do you mean by crackling noise?What was the ring gap and piston cylinder clearance when you put it together?It could be piston slap.Or maybe you have spark jumping from the plug cap or crack plug.I don't know I never came across a crakling noise.

[joshv5.0]

sounds like detonation

[hotrodbanshee]

Ring gap and piston clearance were set to specs.I am going to try and get some race fuel this week. They don't sell it where I live so I have to travel 60 miles to get it.

With 185# compression you could get away with a mix of race fuel and gas.What do you mean by crackling noise?What was the ring gap and piston cylinder clearance when you put it together?It could be piston slap.Or maybe you have spark jumping from the plug cap or crack plug.I don't know I never came across a crakling noise.

311098[/snapback]

[hotrodbanshee]

If I mix 1/2&1/2 the vp c12 108 octane with 93 octane that would give me 100.5 octane. Would that be enough octane for 180-190psi compression?

[dlnoss]

With that compression and the timing advanced +4, that mix would be minumum IMO.

[brock_fuzzy_69]

to me its worth it to jsut run straight race gas

 

the race gas is 4.25 a gal and pump premium is like 2.00

 

so a mix will cost you 3.15 a gal or so

 

but by the time you buy premix to go in that a 5 gal can will cost you

about 15.75 + 3.50 for premix=19.25

and 5 gal of straight race gas is 21.25+3.50=24.75

 

worth the extra 5 bucks a can to run it straight

just for added assurance

and race gas will almost never leave varnish in the bowls of the carb evan if its sitting around for awhile