MikeJ-2009

I've finally decided to try to figure out what the ---- is actually going on. When someone says 15 degrees, 12 degrees, ect. Where exactly is this in relation to the crank pulley?
From what I know, the stock timing fires before TDC because it takes time for the flame to get going, and by the time it does, the rod has swung over to the right point for the booya.
So the red mark is where you put the stock timing, and the mark to the clockwise is the TDC mark. When someone retards their timing (in my thoughts) would be moving the timing beam to the right, closer to the TDC mark. The TDC mark would be 0 degrees? And how could someone be at 12 degrees? Is it like a +/- degrees before and after the TDC mark, or am I on the wrong track. Where is the beam when someone says 12, 15, ect. degrees? I'm lost.
Here's some PS action:

FooK

The TDC Mark that sits alone is zero degrees TDC.

on a d16z6 pulley, the red mark is stock timing aka 16* BTDC

on a d16y crank pulley, the red mark is stock timing aka 12* BTDC

less timing = closer to TDC, more timing = farther from TDC

MikeJ-2009

Ok, well I see people posting that at 13psi thier timing is at 16 degrees. Wouldn't that not make any sense?

If someone is taking out .5 degrees per pound and running 13psi, than that would equal 6.5 degrees retard, so they should be at 10 degrees or there about? I think I've even heard of people boosting with 18 degrees timing That would mean that they are actually advanced. Or wait, is the red mark just the idle mark, but naturally the timing advances with rpm (stock) and they are retarding, therefore retarding timing and landing at 16??

Minor Threat

Stealth,

Things start making a lot more sense when you look at the timing maps in Crome/Uber/Turboedit/Whatever.

Idle timing is 16 degrees, but timing varies throughout the map. Most people talking about running xx timing and xx psi are talking about the timing they're running when their engine is it full boost/close to redline.

MikeJ-2009

I realize they are talking about the timing at full boost, that's why 16 degrees doesn't make any sense if the idle is 16 degrees. Unless the timing increases with the rpm, which I guess is the reason why I'm not getting it.

So if someone says "At 13psi I'm running 16 degrees", how is that informative if the reader doesn't know what the redline stock timing is? It wouldn't really tell you how much retard they are running unless you just knew.

Minor Threat

Here is a stock NA GSR map, for example.


Take a look at the lower right area, where the engine is at high RPM, right before the timing says -6, it's around 28 degrees BTDC.

Now when we intro boost, you know you need to retard timing which means you want the ignition mixture igniting further after TDC.

So check out this map, same GSR map, only I've set the timing retard to 1 deg per psi of boost.



Timing at 10 psi is 18 degrees in total, or approx. a 10 degree retard.

Minor Threat

If you know that a stock map is set to about 28 degrees of timing at redline, then you can figure out how much retard they're running in boost. In your example, a little under 1 degree of retard for every psi. 28-16/13=0.9

MikeJ-2009

Ok, I think I'm a little bit smarter now. Damn those degrees people. Just say you're running X degrees retard per pound.


haha. Thanks. Woo hooo, I'm smart.

Minor Threat

I think I deserve an oil kit for this post.

MikeJ-2009

I'll send you an e-oil line kit. :P