Does timing advance really help?

[wes350x]

Have a cr ignition not advanced, just ondering would it even be worth the trouble of advancing it? What do you guys think? Id like to hear pros and cons.

[deathman53]

c-leigh stated in another site that the esr adapter plate is far advanced from the stock trx250r. If anything he has instructions on how to retard it as much as it will allow.

[destey]

I believe all the ignitions are advanced before TDC, if i'm not mistaken. I think what you're getting at is you believe your ignition would benefit from an ealier spark. I'm not knowledgeable enough to answer that.

At any particular load and RPM, there's a timing advance that produces the most torque. Any more advance and you start to knock. This point is called MBT, or spark advance for maximum torque.

Higher loads create more cylinder pressure. Squeezing in more air into the combustion chamber yields more molecules in the same space, which means closer molecules. The closer the molecules, the faster the flame front is, and the less time is needed for combustion to happen. Therefore less spark advance is needed at more load.

In the other direction, less load = more needed spark advance. The molecules are further apart and it takes longer for combustion to happen. If you didn't start the flame early, the flame would happen too late and the flame would be chasing the piston as it raced down the cylinder (and causing little pressure for crankshaft torque).

I think I have all this correct, if not critique away ;)

anyone know how the CR ignition decides timing advance? Is it just a mapping of RPM x spark?

[Buttermilk]

Here's a dyno run (my own) showing the effects of the CR ignition advanced as far as it will go on the ESR adaptor plate.

Run 041 is advanced, while run 030 is in the stock location. These runs were on the same motor, same day, same dyno, on my 250R.

Rog

[wes350x]

That dyno is interesting. Does it make your engine run hotter?

[Buttermilk]

I did not notice an increase in operating temp.

[wes350x]

Buttermilk I found one of your old post, I think Im gonna try and advance it. Once I remove the little plate behind the bottom screw (I think) then I rotate the stator counter clockwise, Am I right?


Quote:

Something you can do with the CR ignition is advance it, if you haven't already (there's about 5 degrees or so that you can play with...you'll have to remove a small plate on the stator mount or remove it... I slotted mine...)

Advancing the timing will give you better throttle response, improve your bottom end and mid range acceleration, plus increase your top peak hp (but will also **** the curve to the left....).

Bump up your compression some too will help with bottom to mid power, but at some point you would need to run higher octane fuel.