Cascade Crew

blue89 · Posted: Thu Jun 07, 2007 9:37 am Post subject: Tuning Spark Advance

Does anyone have a TPI 5.7 that they have tuned? I have a question, why is there a dip in the spark map at 3200-3600RPM? Its visible in the AUJP.bin file.

Once spark advance is done, how do you add more fuel? I can't seem to find the table.

Dewey316 · Posted: Thu Jun 07, 2007 9:47 am Post subject:

Can you post a picture of it? You also need to check the spark adders, it could be adding spark from something else in there.

Both paul and myself have had the best luck tuning, when we got rid of all the secondary spark tables, and tuned with the main spark table and made it a nice smooth table. ramped spark up to about 32*-34* at 2500 rpm, then just held that advace from there on.

--John

blue89 · Posted: Thu Jun 07, 2007 9:59 am Post subject:

This is a stock SA.

This is the one Mike modified for me.

Both have the little dip.

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

Looks like a thermal image of a volcano ready to erupt.

Dewey316 · Posted: Thu Jun 07, 2007 10:55 am Post subject:

Right, but you need to look at your spark adders, it may be that your final timing advance does not have that dip.

FYI, here is how mine is, nice and smooth. But, I got rid of all the adders so the car is running only on this spark table. IMHO it makes it much easier to tune when you zero out all the secondary spark tables, and just tune with the on table. The only other thing that can modify spark on my setup, is hiway-mode.

blue89 · Posted: Thu Jun 07, 2007 11:08 am Post subject:

The only tables that I see are

Spark advance closed throttle vs rpm
Spark advance main
Spark advance main extended
Spark advance startup vs temp
Spark advance temp correction vs load vs temp
Spark latency correction

What other things add spark advance? Are you and I running the same bin?

Dewey316 · Posted: Thu Jun 07, 2007 11:13 am Post subject:

We are running diffrent bins, but GM's code does a lot of the same stuff. You would want to look at the extended table, and temp correction vs load to see if any of them have a RPM refrence. If none of them have an RPM refrence then you just have a dip in the main spark table, I would smooth it out and get rid of the dip. But, when you are dealing with GM code, you want to double check and make sure that you don't actualy have more timing in there coming from something else.

blue89 · Posted: Thu Jun 07, 2007 11:32 am Post subject:

I don't see any. The other spark modifiers are idle and enrich. Good thing I looked, Enrich Power Spark Advance vs RPM adds up to 8* at 4800+. Other than that it doesn't modify vs load. Should be good to just modify the Spark Main table.

What bin/engine are you running in yours?

Dewey316 · Posted: Thu Jun 07, 2007 11:35 am Post subject:

I'm still TBI, so I am running the 8746 computer.

blue89 · Posted: Thu Jun 07, 2007 11:41 am Post subject:

Cool. Nothing wrong with TBI. I personally like the TBI for their manifold design.

So what part controls AFR? Looks like Enrich does a lot, and Highway Mode AFR is easy. Seems like there should be a Pulse Width Vs MAP vs RPM table. That could also be handled in the Enrich tables.

Dewey316 · Posted: Thu Jun 07, 2007 11:52 am Post subject:

You should have a Main and Secondary VE table. You will also have a whole selection of diffrent adder tables, for PE enrich, temp enrich, etc.

--John

blue89 · Posted: Thu Jun 07, 2007 12:05 pm Post subject:

Found them.

Is that how its done? I take the Wideband o2 readings and add as much spark advance and VE as possible without pinging or running too rich? Then you blend in the idle to the WOT curves? Sounds simple when you say it.

Dewey316 · Posted: Thu Jun 07, 2007 12:08 pm Post subject:

when you are in closed loop (non WOT), you use the BLM's and figure the percantage change for the VE table based on the BLM readings. For WOT you use your wideband readings.

The goal is not the most spark advance, the goal is the most power. Chances are that is in the 30*-36* advance range, but really the only way to tell is dyno time.

scott in wa. · Posted: Thu Jun 07, 2007 12:15 pm Post subject: ya

Oh Man I just went through this with you guys....

I was a pain.

blue89 · Posted: Thu Jun 07, 2007 12:17 pm Post subject:

I have to have a real-time scanner to get the BLM's though don't I? I do not have the ALDL cable and the last time I tried to connect one it didn't work. I blame all problems on my shoddy adapter harness.... Is that the only way to do it? Is it possible watch the o2 sensor and make adjustments VE to keep the engine slightly lean (except for WOT)?

Dewey316 · Posted: Thu Jun 07, 2007 12:18 pm Post subject:

No, you weren't a pain. We all went through the learning curve on this, (and we keep learning, its a process). That is why the board is here, so everyone can learn. And we don't yell at you and tell you to search. Laughing

Dewey316 · Posted: Thu Jun 07, 2007 12:21 pm Post subject:

You will need an ALDL cable, the o2 sensor swings back and forth on either side of stoich, it isn't a steady voltage. Just build a working aldl cable, I think paul can post up the scematics for the one he builds, its really a good setup. Once you have that, you should be able to use TunerPro to log it.

Mangus....Do you have auto correction based on BLM data built into tunerpro?

--John

scott in wa. · Posted: Thu Jun 07, 2007 12:24 pm Post subject: ya

Well TGO does LOL....they yell a lot!!!!

As far as real time readings you are using tunerpro R/T correct.

You do need that cable to do that.
If you are using it you may want to e-mail Craig Moates, he is a great guy and always gets back to you.

there may be another way but the cable is the way to go.

scott

Twilightoptics · Posted: Thu Jun 07, 2007 1:08 pm Post subject:

That's alot of reading. I'll read it later.

But the big spark dip in the main table is probably to make up for the Power Enrichment spark table.

blue89 · Posted: Thu Jun 07, 2007 2:24 pm Post subject:

I missed the post by Scott. Seems like I'm where scott used to be...

http://cascadecrew.org/phpBB2/viewtopic.php?t=3002&highlight=tune

Do you have a bin I can snag from you Scott? I'll have to tweak it a little to make it work. This is all for my V6 car Very Happy

It would be good to compare the spark advance and VE tables. My six is cammed with the biggest non-roller cam I could find. 108 separation with 206 duration on 0.430" lift.