Ignition timing

[Seandonato73]

Ok so most other country's use a different method of checking octane(like previously stated) if athena is saying 96 octane it's more like 91 here in the states. Hence the toss another shim in it. Wouldnt make a big power difference and then you know you should be in the safe for high test zone. Just a suggestion if it's a pain to get race gas.

 

[Z.hb71]

Ok so most other country's use a different method of checking octane(like previously stated) if athena is saying 96 octane it's more like 91 here in the states. Hence the toss another shim in it. Wouldnt make a big power difference and then you know you should be in the safe for high test zone. Just a suggestion if it's a pain to get race gas.

Race gas is 6 miles away ?

 

[Seandonato73]

There ya go ?

 

[cbaker65]

Ok so most other country's use a different method of checking octane(like previously stated) if athena is saying 96 octane it's more like 91 here in the states. Hence the toss another shim in it. Wouldnt make a big power difference and then you know you should be in the safe for high test zone. Just a suggestion if it's a pain to get race gas.

All I ever see is 91 ,I think if there was 96 ,every freakin hot rod person would be lined up!...

 

[Seandonato73]

Theres a gas station down the road from me that has 97 at the pump ?

 

[Z.hb71]

Theres a gas station down the road from me that has 97 at the pump ?

Nice!!!

 

[Polar_Bus]

Want all the compression even if it means running octane booster or getting this more expensive Sunoco fuel

Be carefull about what you wish for..... High compression and asking on the internet "what timing should I run" can bite you in the azz big time. To much advance and / or compression will absolutely fester the "silent killer" detonation. You can blast a hole in the piston very quickly from too much advance. I STRONGLY suggest keep a watchfull eye on the sparkplug and the top of the piston for blasted particles. This is the tell tale sign of detonation, as is the imfamous "crackle". Lastly for the Big Bore guy who is always crying poverty, race fuel is going to run you about $10 / gallon if you're lucky enough to find it local to you.

 

[Z.hb71]

Be carefull about what you wish for..... High compression and asking on the internet "what timing should I run" can bite you in the azz big time. To much advance and / or compression will absolutely fester the "silent killer" detonation. You can blast a hole in the piston very quickly from too much advance. I STRONGLY suggest keep a watchfull eye on the sparkplug and the top of the piston for blasted particles. This is the tell tale sign of detonation, as is the imfamous "crackle". Lastly for the Big Bore guy who is always crying poverty, race fuel is going to run you about $10 / gallon if you're lucky enough to find it local to you.

I have it local. And $10 isn't that bad considering premium 92 is always $4. And I definitely will keep an eye on it! I will try running 20 btdc with 104 octane, I think it "should" be okay, but if not I'll go for 24btdc and go from there. Also I'm running the coldest plug I have, would this help with detonation?

 

[Seandonato73]

You would retard the timing not advance it if it pings. @Polar_Bus I suggest 20* as it's a safe place to start, and where I start on all my high compression 2 stroke builds. Seems to work for me.

 

[Z.hb71]

You would retard the timing not advance it if it pings. @Polar_Bus I suggest 20* as it's a safe place to start, and where I start on all my high compression 2 stroke builds. Seems to work for me.

So go 17° btdc? Cuz I thought going 24 would be retarding

 

[Seandonato73]

Advancing timing is before tdc. So at 20* advanced it will spark 20* before the piston reaches tdc. If its retarded it sparks after tdc. So regarding timing is less until you hit tdc. Then you have 0 timing the positive timing ( or retarded) after tdc. So if you start at 20* before tdc. To retard the timing a bit you would want the plug to fire closer to tdc so 17* or 10* before tdc would be retarded compared to 20* before tdc.
Clear as mud?

 

[Z.hb71]

Advancing timing is before tdc. So at 20* advanced it will spark 20* before the piston reaches tdc. If its retarded it sparks after tdc. So regarding timing is less until you hit tdc. Then you have 0 timing the positive timing ( or retarded) after tdc. So if you start at 20* before tdc. To retard the timing a bit you would want the plug to fire closer to tdc so 17* or 10* before tdc would be retarded compared to 20* before tdc.
Clear as mud?

Well I've been wrong this whole time ?‍?‍ thanks