1998 Vortec Timing Table (Black Box Computer) Open / Closed Throttle ONLY!

[dave w]

I've copied / pasted a 1998 Vortec Timing Table from EFI Live into a Microsoft Excel spreadsheet. I've adapted the (Black Box Computer) factory Vortec timing tables for other GM ECM's / PCM's for a SBC TBI engine that has been updated to Vortec heads. I've only posted the FACTORY BLACK BOX COMPUTER TIMING TABLES for Open Throttle and Closed Throttle. In Total, The Factory Black Box Computer has 21 Timing Tables and Spark Parameters!!!!!!!!!!!!!

dave w

[pmkls1]

Awesome !!! I've been wanting to see these tables for a long time now ! I'm curious about a couple values that you would have to be able to see some of the other parameters the PCM/VCM uses to calculate the "total" or "actual" timing. I would like to see what the typical timing value is at idle and what the total timing advance looks like at WOT throughout the RPM range. The way that I have the timing parameters set in my 7427 PCM is that there is no advance added while in PE. So, when looking at the open throttle timing table, the values in the 85-100kpa range reflect the total timing. Overall, the timing tables that I am using currently are surprisingly similar to these tables. Thanks for putting these up for people to see. I know that at least for me, the most difficult aspect of tuning after swapping in the vortec was the timing tables. Vortec heads are so sensitive to timing curves and are a bit different than traditional cast iron heads so they can be a challenge.

[dave w]

Awesome !!! I've been wanting to see these tables for a long time now ! I'm curious about a couple values that you would have to be able to see some of the other parameters the PCM/VCM uses to calculate the "total" or "actual" timing. I would like to see what the typical timing value is at idle and what the total timing advance looks like at WOT throughout the RPM range. The way that I have the timing parameters set in my 7427 PCM is that there is no advance added while in PE. So, when looking at the open throttle timing table, the values in the 85-100kpa range reflect the total timing. Overall, the timing tables that I am using currently are surprisingly similar to these tables. Thanks for putting these up for people to see. I know that at least for me, the most difficult aspect of tuning after swapping in the vortec was the timing tables. Vortec heads are so sensitive to timing curves and are a bit different than traditional cast iron heads so they can be a challenge.

The free version of EFI Live can be downloaded here:
http://www.efilive.com/index.php?opt...=48&Itemid=124

The .tun (aka .bin) files (also free) can be downloaded here:
http://www.tunefiledepot.com/index.p...Type=P&Stock=Y

dave w

[1project2many]

Awesome !!! I've been wanting to see these tables for a long time now !

Hmmm....
http://www.gearhead-efi.com/Fuel-Inj...tart#post10257

[pmkls1]

Hmmm....
http://www.gearhead-efi.com/Fuel-Inj...tart#post10257

After I made that post I thought that I may have already seen them, but I couldn't remember where. I will be the first to admit that my memory isn't what it used to be. I remember now that I gave up on those tables in that post because it was hard to read them and that's probably why I eventually forgot about them.

Thanks for the links Dave, I'll definitely take a look at that stuff.

[1project2many]

A-ha. No problem. You've had a lot of other stuff going on by the sounds of things.

FYI in a case where the info's hard to view I'm more than willing to send it offlist or in a different format.

[PJG1173]

I did the same thing several months ago. I didn't see that many spark tables, but who knows I looked at several .tun files and they all seemed different. I found that these tables ended up being very conservative for use in both my vortec headed motors and I ended up adding up to 12* in some areas. IDK might be from having aftermarket cam and port work. some of them had an optimal spark table which looked very aggressive though.

[dave w]

I did the same thing several months ago. I didn't see that many spark tables, but who knows I looked at several .tun files and they all seemed different. I found that these tables ended up being very conservative for use in both my vortec headed motors and I ended up adding up to 12* in some areas. IDK might be from having aftermarket cam and port work. some of them had an optimal spark table which looked very aggressive though.

I might have been more accurate if I had posted, a total of 21 spark parameters including spark tables. I think the spark table has to be tailored to the camshaft profile.

dave w

[pmkls1]

A-ha. No problem. You've had a lot of other stuff going on by the sounds of things.

FYI in a case where the info's hard to view I'm more than willing to send it offlist or in a different format.

I definitely have had a lot going on since I installed the engine. And as far as you sending info goes, I appreciate that and will keep it in mind for future reference. I didn't ask at the time because I didn't want to feel like I was begging someone to do all of the work for me. I wanted to be able to figure out things for myself, but I was having a hard time getting the ecm to do what I wanted. Ultimately, I had way too many issues to resolve before I could tune properly.

I did the same thing several months ago. I didn't see that many spark tables, but who knows I looked at several .tun files and they all seemed different. I found that these tables ended up being very conservative for use in both my vortec headed motors and I ended up adding up to 12* in some areas. IDK might be from having aftermarket cam and port work. some of them had an optimal spark table which looked very aggressive though.

Even a stock Vortec can handle a little more aggressive timing curve. I am running more total timing at WOT in my car without any issues, but the rest of the table is pretty similar. Once you open up the ports a little and throw in a more aggressive cam, you will more than likely end up with a much more aggressive table. It is my experience that Vortec heads like more aggressive timing in low-to-mid range loads, but will only want 32-34 degrees of max advance under heavy loads. I think that this is where people get confused when trying to tune the ignition curve on Vortec headed applications. Of course, you also have to consider that, while it is good to be able to observe what the factory ignition curve looks like, there is always room for improvement as the engineers usually stay a little conservative for numerous reasons.

[PJG1173]

Even a stock Vortec can handle a little more aggressive timing curve. I am running more total timing at WOT in my car without any issues, but the rest of the table is pretty similar. Once you open up the ports a little and throw in a more aggressive cam, you will more than likely end up with a much more aggressive table. It is my experience that Vortec heads like more aggressive timing in low-to-mid range loads, but will only want 32-34 degrees of max advance under heavy loads. I think that this is where people get confused when trying to tune the ignition curve on Vortec headed applications. Of course, you also have to consider that, while it is good to be able to observe what the factory ignition curve looks like, there is always room for improvement as the engineers usually stay a little conservative for numerous reasons.

I have experienced similar results with mine too. it likes alot of timing low but I'm only able to get 26* WOT without knock. I'm assuming this is because of the long duration of my cam. just goes back to every motor is different.

[1project2many]

it likes alot of timing low but I'm only able to get 26* WOT without knock. I'm assuming this is because of the long duration of my cam. just goes back to every motor is different.

Good heads with a fast burn chamber and tight quench will require less timing. People seem to think more is better when it comes to advance but the goal is to make the most power with the least amount of spark advance. When you start spark advance before TDC some of the energy from combustion is wasted as increasing pressure tries to prevent the piston from achieving TDC.

I'm still waiting for the day when in cylinder pressure sensors are part of the hotrodder's tuning arsenal.

[PJG1173]

Good heads with a fast burn chamber and tight quench will require less timing. People seem to think more is better when it comes to advance but the goal is to make the most power with the least amount of spark advance. When you start spark advance before TDC some of the energy from combustion is wasted as increasing pressure tries to prevent the piston from achieving TDC.

I'm still waiting for the day when in cylinder pressure sensors are part of the hotrodder's tuning arsenal.

All things being the same except the cam i run 33* on my other motor with about 10* less duration. I think the bigger duration cam gets more cylinder filling raising the dcr, and coupled with a tight quench and fast burn chambers is what
is reducing the need for timing.

[EagleMark]

I'm still waiting for the day when in cylinder pressure sensors are part of the hotrodder's tuning arsenal.

I priced them, it's not going to happen. Unless we all chip (Ha!) in to share one. One spark plug with sensor was in the $800 range.

[1project2many]

priced them, it's not going to happen.

The WBO2 was $2500 when I first started this game and now it's around 1/10th that price. GM uses active coil current and voltage detection to determine TDC on Ecotec engines and produce a cam sync pulse. And ion spark detecion circuitry can be adapted to measure cylinder pressure as well. We just need to get together and adapt or redesign some OEM circuitry.

[PJG1173]

The WBO2 was $2500 when I first started this game and now it's around 1/10th that price. GM uses active coil current and voltage detection to determine TDC on Ecotec engines and produce a cam sync pulse. And ion spark detecion circuitry can be adapted to measure cylinder pressure as well. We just need to get together and adapt or redesign some OEM circuitry.

Eh, sounds good. When yall figure it out write good instructions so us small brained people can figure it out.