Spark timing

Blue)(Fusion · #1 09-12-2009, 02:38 PM

I am interested in advancing my spark timing for best performance and economy. I have the computer tuner to do it, but don't want to break things. Is it okay to advance it by 1 degree at a time until I hear ping?

Also, I was curious if there's any way (besides strapped to a dyno) if I can estimate how much power is extracted from each degree of timing.

By the way, I'm tuning it for 93 octane.

way2old · #2 09-12-2009, 05:06 PM

A dyno is the best bet. That way you can find exactly where you want it tuned. Post pictures of the ride. Kinda interested in it since I have read a lot about it.

Blue)(Fusion · #3 09-12-2009, 05:17 PM

It's nothing worth looking at, really. It's got a few good scrapes in the paint on the rear bumper and driver side rear door (the week after I had it replaced with a brand new door and paint job after someone hit it) since my dad got too close with a snow blower...Oh well. But I'll go snap some pictures now anyway.

I'm still just trying to learn as I go along but wouldn't I want as much timing advance as I can get without it knocking? Or at a certain point would the advance start to lead to a decrease in performance/efficiency?

way2old · #4 09-12-2009, 10:26 PM

Really the only way advancing or retarding the timing will give you much long time result is if you go the camshaft upgrade. You need the additional lift and duration to compensate for the timing adjustment. You will also need to program the fuel to go along with any adjustments. I guess you could adjust and then drive to see if there is much improvement. Good luck.

Blue)(Fusion · #5 09-12-2009, 10:43 PM

While I do want to get PI cams installed in the future when I have the time, money, and someone nearby with some know-how to supervise, it likely won't happen this year.

But thanks for the info. I decided to leave it as it was initially. Yesterday I added two degrees of timing advance to see how it worked out and it was the first time I've ever heard engine knock before. So I took the two additional degrees out to prevent that again. There was definitely no seat-of-the-pants difference anyway so I felt it was not worth it.

But I didget those pictures. Take a look here for pictures:
http://richgannon.info/gallery/thumbnails.php?album=14

And here for some video:
http://www.youtube.com/user/BlueFusion1087

All were taken today at your request, too!

way2old · #6 09-13-2009, 06:28 PM

Not too bad looking for an Ohio car. If you can find a totalled Lincoln and get all the wiring, computer and engine, you can get about 300 hp.

Blue)(Fusion · #7 09-14-2009, 01:01 AM

Thanks. I'm happy with the power I'm getting now. I like this engine modding thing too on account of it's a great way for me to learn about the engine and how to do certain stuff and get a few extra ponies out of it.

My only other future mods are 3.27 rear end gears with Trac-Loc and the PI cams. After that, I'll drive it until she dies which may be a while. Although it's deep in the snow belt, the only rust on the car is surface rust on the underside components. Hope to make it another 100,000 before I have to give it up.

The Silver Goat · #8 12-02-2009, 05:42 PM

I'm not sure how your software works, but you can advance the timing and increase the fuel or pulse cycle on the injector to increase the flow of fuel to the point where you begin to hear ping under acceleration. In looking at the tables your software provides it appears you can do thin in degree's.

I've been using a handheld (Diablo) on my GTO modifying the performance setting to increase the power. I also had to monitor the rear o2 sensors to amke sure she wasn't leaning out. I have to go negative on the fuel adjustment because the program is set up for is set up for larger injectors. I dinked with this for a while and as told ToOld stated above - I took it and had her dyno tuned to optimize current mods. My next mod will be a cam, new springs, lifters and push rods. Cuurently at 332 hp at ther ear wheels with 246 #'s of torque. With the right cam I should get to 375 or a litte better. I'm a high end guy - anything over 5,500 rpm is waste.

Blue)(Fusion · #9 12-03-2009, 12:04 AM

I'm looking at getting new cams in the future. Possibly new ported heads, too (see my thread regarding a leaky head gasket). But that's a ways away as I have a few other things to get done before then (school being one of them

).

And the software pictured sadly only does data logging. I also use a handheld tuner (SCT X3 with a custom Blue Oval Chips tune) to play with a few of the options. I believe I'm running rich, too, but until I get new O2 sensors, I'm not going to be changing that.

Also, from what I've read, you don't want to use the factory O2s to play with the air/fuel. I had heard it's not safe to do without a wideband O2 sensor.

The Silver Goat · #10 12-03-2009, 04:51 AM

It's not safe if you do not think they (O2 sensors) are accurate. My hand held can't log data so I had the wife reading the O2 sensors as I ran the goat through the gear box and set it up to be a touch rich for what LS1 motors like for optimum performance which is 12.5-6 to 1. On my hand held every 5% = 1 degree of timing.

I went from 28 mpg on the highway to 30 mpg running along in 6th gear @ 75 - 80 mph. But I don't use cruise control and feather the gas pedal running along the eway.

You have to remember the pcm is always trying to get to 14.7 to 1 and within a short timeframe you'll get a lean or rich code if the STFT's can't make the LTFT's average within the parameters of the PCM.

Blue)(Fusion · #11 12-03-2009, 10:35 AM

Well the upstream O2 sensors and the PCM determine the fuel trims in closed loop mode, anyway, do they not? Like you said, over time the LTFT and STFT will trim to be as near stoichiometric as possible. Only air/fuel mix I can set on the handheld is WOT open loop mixture and I dare not play with that without a wideband O2.

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