Ignition Retard

[talon_boy69]

ok, I've heard thath for high boost or nitous applications you need something to retard the ignition.At how many psi I would need this??? And can I use an MSD Ignition w boost retard like the MSD 6 BTM or I need an Apex or something like that??? I have a 1g.

[galantvr41062]

the reason you would retard the timing is ither to assist high compression engines to start and to help prevent detonation, to flame fronts start and colide in the middle and vibrate the side walls and act as a blow tourch to your piston and you get a hole and a ping (flame fronts coliding). so to prevent this the computer retards the ignition (sparks later down the power stroke), this intern decreases HP because there is less time for the fuel to burn, the engine stops igniting fuel only 27deg after TDC power stroke, and starts a few deg befor TDC so the later you ignite the fuel the less power you get but this reduces detonation. remedys are less boost/Nos or More Fuel. Thats how I think it works any other thoughts corrections are welcome.

~John

[dsm4eva]

Acually the flame fronts start from the center out (well almost the center), not outside in. Also, the wavefronts are moving at supersonic speeds which cause a jackhammer effect on the parts.

You already have the timing and knock undercontrol if you are running a factory turbocharged DSM. If you are not... well, I would look into the J&S Safeguard. It does everything you need to make sure you are not turning your engine into a piece of modern art.

[galantvr41062]

o ya the 2 flame fronts were on the side spark plug engines, I was not sure if it was the same for our engines I guess not thanks for the correction.

~John

[dyezak]

Also one thing to remember...flamefronts travel differently with piston/combustion chamber design. A cloverleaf combustionchamber is the most efficiant, and also the best at dealing with detonation. Since we have a semi-cloverleaf combustion chamber you're good there. Also a flamefront travels better in a dished than a domed piston, especially on a centerfire combustion chamber. Since you have a dished piston and a centerfire combustion chamber you're golden there too. Really these little 4cyl engines (most DOHC low compression engines) can take a LOT of ignition and a LOT of boost/NOS because of a supurb combustion chamber design. Almost the same design of the old HEMI engines, that's what made them so powerful.