Stock timing question

[Turbo6Smackdown]

I looked all over and couldn't find it but was was stock SPARK timing for our 87's? Not stock TIMING COVERS. What did our cars come with from the factory in 1/2 and 3/4? I always thought it was 19/17. Is that right? That was WOT though, right? Then what was it for half throttle bursts?
Does the 2/3 timing variance have to be 2 degrees? What's the idea behind that? I realize you gotta pull it a little as engine speed increases, but are there any advantages to say three degree variances for example?

I heard that even the stock chip was a little aggressive on the timing. What do you guys say?

 

[bison]

The stock timing table was posted in another thread somewhere. It depends on the load. It was considerably more than 17 degrees in 3rd. The stock chip only had 14-15psi boost and had timing to reflect the boost. You are wrong about pulling timing as engine speed increases also. You actually add timing then. The stock chip was a force to be reckoned with. Low 12 sec potential and some high 11's just by switching to the old Bosch blue 36lb pintle injectors, crushing fp regulator, open exhaust, adjustable actuator, 112 octane and tires. Many on the stock fuel pump even.


BPE2013@hotmail.com

 

[mikestertwo]

The stock BBKJ chip had pretty aggressive timing for todays gasoline. At full load the timing was 22 degrees. Back in the day I went 11.98@112 on a stock chip with 36lb blue top injectors at 21lbs boost with race gas.

 

[Turbo6Smackdown]

The stock timing table was posted in another thread somewhere. It depends on the load. It was considerably more than 17 degrees in 3rd. The stock chip only had 14-15psi boost and had timing to reflect the boost. You are wrong about pulling timing as engine speed increases also. You actually add timing then. The stock chip was a force to be reckoned with. Low 12 sec potential and some high 11's just by switching to the old Bosch blue 36lb pintle injectors, crushing fp regulator, open exhaust, adjustable actuator, 112 octane and tires. Many on the stock fuel pump even.

So what was it full load at 1/2 and 3/4? Anyone? And by pulling, I meant making the spark event happen earlier in the cycle. I was thinking too fast. And does anyone know what it was 1/2 and 3/4 with only half load for example? I ask because I want to know what to set my timing at when I have just normal 93 octane in it when I don't have alky and just want to cruise. And maybe pass someone without blowing up the engine.


BPE2013@hotmail.com

 

[mikestertwo]

At full load (256) no matter what gear the trans was in the timing was 22* barring any timing change due to knock retard or temperature compensation. The stock chip backed off the boost in higher gears. It had a boost scalar of 75% in 3rd gear and 50% boost scalar in 4th. At mid load, say 128, the timing was anywhere from 23* to 34* depending on rpm.

 

[Turbo6Smackdown]

So when I was told the factory timing is 19/17, when was this timing happening? And when my chip says 23/21, when is that? What load range? What rpm or boost range?

 

[bison]

So when I was told the factory timing is 19/17, when was this timing happening? And when my chip says 23/21, when is that? What load range? What rpm or boost range?

You would need to ask the chip burner. Also none of that matters unless you know your base timing is accurate.


BPE2013@hotmail.com

 

[34blazer]

 

[Turbo6Smackdown]

I see. Are there any standards in advertised timing in chips? Meaning would a chip burner tell me his timing at a different load and rpm position than say the stocker? For ex, would a 17/19 chip from TT have the same timing as a 17/19 chip from Bob Baily? And when I change timing on my TT chip in 1/2 and 3/4, is that wot full load I'm assuming?

I'm trying to do 2 things: 1. learn about how this all works and 2. trying to figure out where I should put my timing on my chips for when I have standard issue 93 octane in the car if I don't have access to xylene or meth at the time. I know that I should just drive it and not floor it but sometimes you may have to pass someone and I don't want to blow the engine up by doing that. My boost is all the way down at 17 psi so that won't go any lower. I have a TA61 turbo & gn1 SLIC. My TT chip came with 23/21 on the chip and I put the parameters of tables 3 and 4 at 118 each, which is like running 17/19 now. Is that good enough because I heard that even the stock chips timing was a bit aggressive but their gas was a lot better too. Should I be below stock timing with today's gasoline?

 

[bison]

You would have to tell them what you wanted. If it's possible it can be done. They probably aren't going to have time to do a comparison unless you paid them to do a spreadsheet? Yes WOT and that's not actual timing. The base timing determines the total timing . There's a sticky about checking base timing .


BPE2013@hotmail.com

 

[ijames]

If you look at the main spark table at the rightmost column, load "256", that is the column the engine will be in once the boost is over a couple of psi (that varies a smidge with turbo, etc, but compared to full boost it doesn't matter, you will always be in column 256 once the boost is up ). If you look at the bottom right of that column you see that once the rpm is over 3200 the timing is always 22.15 degrees. Doesn't have to be, but that's the tune GM developed. That's what we mean when we say the stock chip has 22 degrees of timing at wot. The stock chip does not vary the timing based on the gear, it pulled boost back a little in 3rd and a little more in 4th as others have said. Because lots of people don't use the wastegate solenoid but run "tuner style" with no solenoid or have external wastegates and boost controllers independent of the ecm, chipmakers came up with a way to vary the timing based on gear to squeeze out some more hp in 1 and 2 where the load is lower and thus the detonation limit is a little higher. They usually run one advance in 1st and 2nd, and then pull a couple of degrees for 3rd and 4th - that's what a 21/19 chip usually is. It has 21 degrees of advance in 1 and 2 and 19 degrees of advance in 3 and 4. That little "WOT advance" table is basically not relevant, because if you notice it is only for wot below 2000 rpm at low to medium loads. Based on the turbo and converter most engines don't even pass through that region. So that's the simple version of how the main table works. If you want to actually tune by making chip changes you first need to verify the base timing, as Bison noted, and then you need to understand the handful of other places and tables in the chip where the timing is trimmed, to make sure your changes get you what you actually want. If you need more detail, I think Eric has some articles by Dennis Leek on his website (www.turbotweak.com), and you can do searches and read back postings in the ecm forum, and of course there are the spreadsheets and other files at www.gnttype.org in the tech region, and ... ... ... .

 

[Turbo6Smackdown]

I see. Thank you for that info.