MrNuke

I am curious.
I've been messing with the timing tables on my '85 vette since I starte dburnign chips for it, and made some good improvements by changing the stock minimal timing table.

I checked out some friends' custom chips and I've noticed they always leave the timing table totally stock. How come? There is quite a difference I have tested between stock timing table and modified timing maps.

silver84

Nuke, please post, before and after tables.
And your comments about what changed.

MrNuke

That's just one table I'm using as an example. I have seen many bins that use the stock GM timing table. I am just wondering, why people don't seem to dwelve into it?

The table I am using is noticeably better in the mid and upper when I compared 2 chips using only the two tables in the car.

J Z06

I wonder if Mr. ski_dwn_it will chime in here.

He seems to be "MR CHIP"

How'd things make out today Gabe? Sorry for the rush. We we're swamped after I dropped you off.

lead foot 85 vet

I hate those graphs....can't read them.......do you have it in table form?

MrNuke

I'm not tryig to get into specifics, just wondering why it seems that the spark table is overlooked when making custom chips..

lead foot 85 vet

Thats a good question ....I made a post about a month ago asking if any one knew where the full timing should come in under differrant conitions and such and didn't get a single reply........I've asked around here locally and got nothing........nobody knows a thing about changing the timing map..........the drag race boys bring in full advance at what ever there stall speed is ............the tunning book I have says bring it in until it knocks, but I can't hear my engine and I'm not sure my knock senser is working because I never see any counts.........I wanted to see yours just to compare.

MrNuke

Ohh .. gotcha..

Well my compression is only around 10:1, slightly under even, and with this chip, if it is above 80F it pings, at 60-70F car goes liek a raped ape.

Here is my table. Don't forget, it has to be cool out, my initial timing is set at 4Degrees, and make sure you haev good gas. I even add a can of Outlaw O2 booster to my 1/4 tank before racing.

:

20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0
20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0
20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0 20.0
28.1 28.1 28.1 28.1 28.1 25.7 23.9 23.9 23.9 23.9 23.9 23.9
29.9 29.9 29.9 29.9 29.9 27.4 26.4 26.0 26.0 26.0 26.0 26.0
35.9 35.9 35.9 35.9 35.2 33.8 32.0 28.1 28.1 28.1 28.1 28.1
39.4 39.4 39.4 39.4 39.4 33.8 32.0 29.9 29.9 29.9 29.9 29.9
43.2 43.2 43.2 43.2 43.2 43.2 40.4 35.9 32.0 32.0 32.0 32.0
43.9 43.9 43.9 43.9 43.9 43.9 41.1 39.0 35.9 34.1 34.1 34.1
45.0 45.0 45.0 45.0 44.6 44.3 42.2 40.1 38.3 35.9 35.9 35.9
46.1 46.1 46.1 46.1 45.4 45.0 43.9 42.9 41.8 40.4 39.0 38.3
47.8 47.8 47.8 47.8 46.1 45.4 44.3 43.2 41.8 40.8 40.4 39.7
47.8 47.8 47.8 47.8 46.4 45.4 44.6 42.9 41.5 41.5 41.1 40.8
47.8 47.8 47.8 48.2 46.1 45.4 44.3 42.2 41.1 41.1 41.1 41.1
47.8 47.8 47.8 48.2 46.1 44.6 43.6 42.2 41.1 41.1 41.1 41.1
47.8 47.8 47.8 47.8 46.1 43.6 42.2 41.5 41.1 41.1 41.1 41.1
47.5 47.5 47.5 47.1 46.1 42.5 41.1 41.1 41.1 41.1 41.1 41.1

lead foot 85 vet

Thanks Gabe............no way in hell I can go that far advanced, but interesting that you can.

MrNuke

The reason I can is that I lowered the initial timing form 8degrees to 4, so in essence I am hitting 37.x degrees max at higher rpms, which in cold and dry weather works great with the 94-95 octance I run, otherwise when it's hot out I have to run another chip with less timing.. But this one makes a noticable difference on t
eh butt-o-meter,

gbody5

Help me understand. Did you mechanically set your base timing to 4 degrees or just change that in the chip, or both? If only in the chip, then wouldn't the ECM just add more timing across the board to get at your values set in the timing table?

MrNuke

I just made the mechanical timing to 4degrees.

The chip still thinks it is at 6 degrees, so in addition it is pullign 2 extra degrees out of the total from there.
(More liek if my initial would be at 2degrees, not 4)

The reason I've done this was that during tuning the car and testign new chips and changes, I found this mapping to work best all-around, and wanted to keep it, but as I am changing A/F mixtures and new mods, I can just lower the timing with one stroke, instead of lowering the whole table..

scorp508

To clear this up, look at his timing table and -2 from the whole thing for total timing numbers.

Ramanstud

or Nuke could just keep the stock mechanical 6 degrees advanced, and change the ECM setting of initial advance to... 8 degrees, etc etc to trick the computer. Whatever works, so long as the total advance is where you want it to be.

MrNuke

Actually that would defeat the whole purpose of making easy changes. If i did it that way I'd still have to burn a new chip every change I make. Might aswell adjust the whole timing table then..

Nah I chose to do it this way, so i can increase or reduce my overall timing but not have to burn a chip every time, and keep the well-working table runnign in the car. Once everythign is final I can burn a chip with an adjusted spark table that I can set at the normal 6degree mechanical advance.

scorp508

Hmmmm... I can flash a new chip faster than manually readjusting my timing. In fact the last time out that is exactly what I did. I kept changing the base timing in the chip between runs.

MrNuke

Unfortunately on an '85 it doesn't work that fast..

Maybe once my ecm burns out I may switch to a '165 ecm, but meanwhile I am stuck using the 2732 eproms and UV eraser and
willem burner to do my chips..

scorp508

Damn, I feel your pain. Make the switch!!

MrNuke

Hehhe. Right after I get my 11, I will start on a few smaller projects..