slickfx3

I never got proficient with tuning, but the car drives well, I switched to an 700r4 automatic and the gas mileage when to crap,

I was messing with the timing to remove the bucking for my stick, hence the graph was all over the place, I mean I butchered it, but it ran without pinging and well enough for the stick.

NOW, I just slapped in a supposedly stock Corvette spark table and the car hauls ........!!!!!!!

a little pinging above4400 rpm, I am going to pull some out, it this an art or science?

my engine is highly modified, with afr 195 heads, 230/ 236 cam 383, 10.7 super ram

can I get away with just leaving this spark table in it an call it a day?

going back to the title,

is spark just spark? and if it aint pinging and runs better than ever before, do I stop looking for MORE?

My GAS mileage jumped from 9 MPG to around 14 immediately, how is this????

comment would be great and thanks!!!

Orr89RocZ

iTrader: (20)

Possibly with some minor mods where it pings, but timing is also dependant on air fuel ratio.

Timing can alter the mixture that comes out of the cylinder which the o2 sensor will see. Based on that the car can be making unnecessary fuel changes which can cause lean spots/rich spots and cause the hesitation/bucking you may be feeling. Changing the timing can sometimes mask a bad fuel curve and make the car seem like its running ok.

Based on this I would look at your air fuel ratios while cruising and driving around, if you have a wideband. If you dont i'd look into getting one to verify.

YOu can tune BLM's/INT's to 128 as close as you can, but to do this its best to keep timing table a set table and play with air fuel first before you change timing.

I would adjust the timing table first only in some of the idle and WOT spots to get the timing you think it should have. Like for your setup and a decent sized cam, idle cells may like 25-30 deg timing. WOT with eliminator AFR's usually likes 32-34 deg because they are pretty efficient. Set those values then take it for a drive and tune air fuel ratios or your BLM's as necessary. That comes from MAF tables and few other little things.

From there you can fine tune part throttle timing advance. Advance it in some spots and see how the motor reacts. Watch air fuel, watch blms and watch knock sensor. Adjust it until the motor seems happy and feels smooth.

Being that you say vette table, it maybe the ARAP bin which has aggressive timing, much too aggressive for a good set of AFR heads. Being so efficient they can use much less timing. Where the timing table shows values over 40, bump them down to like 36 and work from there. My 383 seemed to like 35-36 at most cruise cells. Thats a decent starting point.

slickfx3

thanks for the step by step, will give it a try, the car is running decent now...

looks like the arap bin, is there a better table I could start with?

when you say drop the over 40 to 36, then there is going to be alot of 36's

I drop the LV8 112 and higher 4400 rpm and higher to 95% of what they were; drove it and the pinging stoped, at idle the car want to go forward, bucking a little, I will try to pull some at the 800 and 1000 rpm row.

the advance on this table goes to 47 in some places yet there is no pinging,( that I can heard) have not datalogged to confirm, would I be leaving horsepower on the table if I drop it all to 36?

Orr89RocZ

iTrader: (20)

Just a suggestion. Not necessarily a step by step but I've always just adjusted the spark tables to what I believe they should be based on experience and from other known combos and worked it from there, but only after I did fueling to get it running ok. Its a balancing act...timing and fuel.

slickfx3

well to me it a sort of a step by step,
start fuel
then go to spark

this helps my thinking, thanks....

anything else I should look at to tweak?

Orr89RocZ

iTrader: (20)

Datalog to verify its not pulling anymore timing. Sometimes it will knock before you can ever hear it so may need to back off timing abit more. It may want a few degrees less than 40. The places that its really 45-48 deg, you want to back down to 40 and then datalog with knock sensor hooked up to make sure it likes it. If its pulling timing and your air fuel can be verified as satisfactory, then it will need less timing. You wont be leaving hp on the table by going down alittle in the cruise areas. Make sure its not too lean with too much timing. Add fuel to richen up the lean spots and then check the timing. Sometimes abit too lean will knock/ping but the timing can be ok if only it was abit richer mixture.
Also check to see if PE mode is adding spark. There is a table for PE mode spark advance. Set those to zero and work from the main table. Its easier that way.

How much timing do you have at idle? That cam may want a good bit more than stock.

slickfx3

47.11 47.11 47.11 45.00 40.08 36.91 36.21 33.40 28.48 28.48 28.48 28.48
47.11 47.11 47.11 45.00 40.08 36.91 36.21 31.29 27.42 27.42 27.42 27.42
47.11 47.11 47.11 45.00 40.08 39.02 37.97 30.94 27.07 27.07 27.07 27.07
47.11 47.11 47.11 45.00 40.08 39.02 37.97 30.94 26.02 23.91 23.91 23.91
47.11 47.11 47.11 46.06 41.84 41.13 37.97 30.94 26.02 22.85 22.85 22.85
48.16 48.16 48.16 47.11 47.11 43.95 43.95 34.10 29.88 26.02 22.85 20.04
48.16 48.16 48.16 47.11 47.11 46.06 43.95 41.13 31.99 28.13 23.91 22.15
48.16 48.16 48.16 47.11 47.11 46.06 43.95 39.02 33.05 27.07 23.91 22.15
48.16 48.16 48.16 47.11 46.06 45.00 43.95 36.91 34.10 27.07 23.91 22.15
46.06 46.06 46.06 46.06 46.06 43.95 37.97 35.86 34.10 27.07 22.85 20.04
43.95 43.95 43.95 43.95 41.84 37.97 35.86 31.99 28.83 27.07 22.15 17.93
41.13 41.13 41.13 41.13 40.08 36.91 34.10 30.94 29.88 23.91 20.04 17.93
29.88 34.81 40.08 40.08 40.08 35.86 33.05 28.13 26.02 22.15 17.93 17.93
20.04 29.88 40.08 37.97 35.86 34.10 29.88 26.02 22.15 20.04 17.93 17.93
20.04 20.04 29.88 29.88 29.88 27.07 22.85 20.04 17.93 17.93 17.93 17.93
20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04
20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04 20.04

I am at stock idle for the bin it was at 8 advance so I can take off on the stick in bumper to bumper traffic here in LA, that nonsence when away with this table.

there's PE vs rpm

PE vs temp

PE mode SA


it's kind of superfluous is it not, cause the main table will adjust according to load ( Power requests from the throttle) and PE is a fancy term for maximum load correct?

Orr89RocZ

iTrader: (20)

Yeah depending on rpm and LV8 (load) it will pick one value from the table.

However PE mode can be setup to engage in a variety of conditions. usually there is a minimum load, temperature, tps setting or voltage, etc that will determine if PE is enabled or not.

I would make PE mode SA all 0 in that table and just use the main table. However you will want to correct the main table to include the extra advance that PE mode used to give. This is better to do because its more precise timing curve than just global PE mode adders based on RPM ranges.

See at max throttle and load, you have 28 deg. PE mode normally would add I think 8 deg for a non vette L98 bin. So 28 + 8 is 36 which is a common WOT figure for timing. ARAP adds 1 deg over 4800 so your timing is only 29 which is abit low. BUT it adds 9 deg between 3200-4800 rpm so your timing is about 34-36 thru the mid torque band which is good but then drops off at higher rpms, probably costing you power.

You want to ramp in your WOT timing to include the proper advance. So i'd make that top value like 34-36 and taper down alittle from there. Make PE mode SA all 0. Understand what I am suggesting?

I ran my 383 for the longest time with PE mode SA but eventually switched over to make it all main table. Just a preference that I found easier to work with.

Another trick for idle is to make all cells around the idle rpm/LV8 the same value and definately increase it over stock. Stock is like 20, i'd run abit more timing. More seems to stabilize idle so try moving it to 26 and up. If the car wants to idle at 900 rpm and LV8 of 64 then make all cells around 800 to 1000 rpm and LV8's from 48-80 all the same value. Helped on my big cammed 383 as well as my mild 401 turbo motor with large injectors.

slickfx3

idle done , as you can see above table the idleSA in that area had some 40's and 39's etc,it pulled the car forward, I have not burned this change yet, but the stalling the car experiences now I hope will stop.( was not the case with the SA was at 8 for the stick shift)

so to keep it simple can I plug in a generic series of PE entries, I notice differing values for differing bins giving me the impression there is wiggle room, albeit the ones that came with the bin originally I can use, but see no rhyme or reason for the escalations in SA, and would I limit it to LV8 208? I have not taken notice as to what LV8 is to WOT on my car

are they approximately the same with all cars at WOT "full load?

can you scoot a table over I can copy and paste to try try and compare?

Orr89RocZ

iTrader: (20)

Over 208 is generally considered WOT. Timing table only goes to 208 so thats it for timing control.

PE mode SA matches the bin main table for specific bins. Dont mix and match. If you want to keep generic values in the PE mode SA table, go ahead, just do the math to see what final timing would be when in PE mode which is generally fairly heavy throttle but not just WOT. Depends on your settings when PE activates.

I attached my 383 timing table that worked pretty good for me. Fairly conservative in the midrange stuff but idle and WOT was tuned for best results. May want to play with most of the midrange LV8 timing for cruise stuff to see if more is better on your setup. I never messed with it much.

My turbo motor doesnt seem to like more than 34-35 deg at most cruise cells as well and I'm using same heads. They were used on both motors so timing is similar so far even tho its a totally different cam/cubes/induction setup.


High idle timing raises desired idle rpm. That will definately put load on the converter and want to creep forward and if fuel delivery is abit off, it will surge abit.
Try running car at idle then unplug the EST wire and watch timing drop to just base timing. Rpm should drop as well. Just the way it works. More timing can be more stabile but keeps the rpm up abit higher. My car liked 900-1000 rpm idle. 28 deg seemed to work good for me.

slickfx3

Thanks,

I suppose cruise state can tolerate a greater range to be optimal, I suppose the demands to perform is limited to a static load and vehicular speed..I see limited reason to adjust cruise spark advance, I would have no barometer to determine optimization, other than to dial in wideband at those cells, or perhaps to optimize throttle response in transitioning from cruise to cruise missile.

Do you remember the orgin of your SA table, which bin did it come from? the PE mode SA is factored into your table, I presume from our discussion... and If I were brave I can give this table some run time and datalogging....
running the Comp Cam 280 xfi with 1.6 RR's just to be specific

Thanks again I check out your car 9 second machine, crazy stuff cool man....

Orr89RocZ

iTrader: (20)

That table was originally a modded version of the AUJL bin from 89 TPI 350 camaro. PE mode table is zero'd out, and all that spark is added into my table, so there is just the main table to work from.

For cruise stuff, you can try running the car and advancing the timing until the knock sensor is not happy and starts to pull some timing. Then back off timing 2-3 deg and call it a day.

Another 350 HSR car with 280xfi cam is using a table thats very similar to ARAP bin. It runs 41.8 deg timing in all load cells for cruise/part throttle, and tapers off to 36 deg at WOT. It has 30 deg timing at idle cells and ramps in very quickly to 41 part throttle. I consider it very aggressive but its working on that setup.

dan0617

The timing table you posted above is very similar to mine over to the far right. I do have alot less timing in the light and moderate load than you, and I idle around 25 to 26 degrees timing, at around 800 to 850 rpms.

My setup is almost the same as yours, I'm running quite a bit higher compression (12.2) and a HSR intake tho. 28 degrees of timing at WOT is the most I can run, at 30 I start getting detonation. I 0'd out all the PE SA and such. I think my high compression and the AFR combustion chamber efficiency is why I can only run 28 degrees timing, and still have great performance. As a side note, when I put the heads on for the first time, I was at like 11.8 CR and I was running 32 degrees timing. I had to pull the heads and fix a burnt valve (went lean on the spray), and decided to shave the heads while they were off. Although it runs great at the 12.2 CR, I now have to run 93 octane and keep the idle on the lean side, otherwise it will "diesel back" or "run on" when I shut it off on a hot day when heatsoaked. In other words, be happy with your choice of compression, you have flexibility in tuning and fuel choices that I no longer have.

Around the area that you are idling, make sure your timing doesn't ramp up or down too quickly. If it does, and the idle surges just a bit for any reason, it will pick up the additional timing and surge up even more.

If you can't get rid of the idle surge with timing, try looking at the IAC motor steps at idle, by datalogging. Try to get it down in the 20's to 30's, that worked best for me. Some say to get it to near 0 steps at idle but that wasn't what worked out for me. If I am idling at 60 or so steps, I get an idle surge.

You mentioned "bucking and surging" with the stick. I still have a very light touch of "bucking and surging" (very very light now) if I lock my torque converter below 48 mph in 3rd gear. It's much better now that I have 3.45 gears than when I had 3.07 gears, but it's still there just a touch. I blame the 110 lsa cam, if I ever get that deep into the engine again I'm going to stay with the 230/236 durations but go to a 113 lsa cam.

slickfx3

the such part I don't get....which such should I zero?

Orr89RocZ

iTrader: (20)

In the tables section, there is PE mode spark advance (SA) (Power enrichment mode spark advance)

There should be a small 2 column table with RPM's in the left side, degrees on the right. Make all the degree values 0. That will prevent any additional spark to be added to the main table.
See picture:

slickfx3

oh yeah I got that, when he said "and such" I thought there were more table other than this one to "zero"

just to prevent starting another thread, I am going to break down and and buy a wide band, i go to my friends shop and we hook up the wide band but lately he's been too busy, so....


the bung is already in place, what brand should I look into, and what is the minimum investment I should make, I see the range from 50 bucks to 350 bucks but never noted what spending the "extra" would provide.

should I go with a tradition gauge, or digital for an easy read on the fly? or both? suggestions?

my friend mentioned a fuel pressure gauge, is this necessary? trying to keep the clutter down in the car or is there another gauge that is MORE important than the wideband for what I what to accomplish?

dan0617

I have an underhood cheapie fuel pressure gauge, just to look at while idling in the driveway or whatever to see that the fuel pressure is in check. A fuel pressure gauge in the cockpit is nice, but not necessary. You can always borrow one to hook up and tape to the windshield to check things while driving if you have issues in the future.

I run an Innovate LC-1 wideband. I like it. It has a feed for a wideband gauge, and also a feed for a narrowband, which you use to feed your computer. This way you can get rid of the stock 02 sensor and use the one that comes with the LC-1 for both the wideband gauge and the computer feed. Was nice for me at first but I now run full open loop so I don't need my computer to see an 02 sensor anymore. The LC-1 can also datalog but I haven't needed to do that. Install was very easy. I use a digital gauge, and in the LC-1 programming you can change the gauge feed rate, so that it isn't changing numbers 10 times a second. About 2-3 times a second is right for me. That's about all my brain can process in a second anyway.

slickfx3

http://prosportgauges.com/45mm-gauges.aspx

look what I found these guys are cool....