should your compression go up

[peterlocal22]

whats up guys

had a quick question,

as you advance your timing should your compression go up as well?

 

thanks

[2001Stroker]

It'll change with port timing, and cam timing on a 4-stroke. 93.72% sure that spark timing won't change it.

[travis6767]

theres no reason that spark timing would increase compression,

[peterlocal22]

theres no reason that spark timing would increase compression,

 

thanks

[FireHead]

It'll change with port timing, and cam timing on a 4-stroke. 93.72% sure that spark timing won't change it.

I am 100% sure that advancing ignition timing will not raise your static compression. :geek:

[blaster2006]

I am 100% sure that advancing ignition timing will not raise your static compression. :geek:

 

a question, which im sorry to change the subject on your thread, but i know when you advance timing, it makes the spark plug spark earlier, which sends the piston back down earlier than normallly.

 

why does everyone do this and how does that make your performance better?

[firebanshee]

a question, which im sorry to change the subject on your thread, but i know when you advance timing, it makes the spark plug spark earlier, which sends the piston back down earlier than normallly.

 

why does everyone do this and how does that make your performance better?

 

Advancing your ignition timing starts the burn earlier in your cylinder it doesn't make the piston go down any sooner. If you advance your timing too much the piston will have to fight to get up to the top of it's stroke causing it to ping and a loss of power.

When you advance your timing and have it set properly for the kind of fuel you are running it burns the fuel more efficiently and gets the most energy out of it. A higher quality fuel takes longer to burn but it is a more controlled burn, so you can get away with advancing your timing more with a higher quality fuel and bump your compression more. If you advance your timing to far with a low quality fuel it will finish it's burn before the piston gets to the top of the stroke.

[BigRed350x]

I am 100% sure that advancing ignition timing will not raise your static compression. :geek:

 

What about dynamic compression? Don't make me bust out my engineering physics books.

[FireHead]

What about dynamic compression? Don't make me bust out my engineering physics books.

Dynamic compression is a much more complicated deal since cylinder pressure is directly related to it, as is temp., altitude, fuel, porting. etc.

 

Ignition timing can effect dynamic compression, but it would only be noticeable in the ends of the timing range (BTDC / ATDC).

[killshee]

so will a +4 be good on high grade pump gas? or no?

[RollinRhino]

Yes, it will.

[AKheathen]

Dynamic compression is a much more complicated deal since cylinder pressure is directly related to it, as is temp., altitude, fuel, porting. etc.

 

Ignition timing can effect dynamic compression, but it would only be noticeable in the ends of the timing range (BTDC / ATDC).

x2 on that, timing will absolutely effect dynamic compression because the fuel is expanding sooner before it finishes compressing mechanically, but static compression will not change at all. purely mechanical influence. that's my 2 cents