QTR FMS

hi,

just wondering how would you map your timing table on the street or before dyno,

from which rpm would you target 24 or 28 from 3000rpm and above or maybe lower like 2000rpm and how much timing would you run for low rpm and this is my main question as we cant use timing for below 1500rpm or even 2000rpm how much do you guys run below 2000rpm

the way i think about it is
from 0-1000 5 degree
interpolate in between
1600rpm 16 degree
1800rpm 18degree
2000 rpm 20 degree
interpolate in between
from 2800or3000 24 or 28

and for cruising are do you feel the engine like 10 degree or 15 degree more on lower load, like if the wot is 24 would the cruise be 39 as in 15 degree more, or how would you build your map i have seen a tuner only target 31 and the car had awful fuel economy

i know every engine is different but it seems that the ls in general are very similar in timing map if not optimized properly as most tuner choose one number like 28 from any rpm at wot leave it flat as long as there is no detonation and near mbt

fst100

iTrader: (5)

a lot of factors but ideally its best to use a wideband when doing the tuning. make plenty of logs to scan the timing, fueling, and AFR and adjust each time. to me they all go hand in hand. for idle and cruising, I typically go a bit leaner than 14.7 and closer to like 15.0-15.7. timing and fueling is adjusted. WOT is a bit different as other factors come into play such as detonation, different (richer) AFR and timing that's ideal and having a dyno greatly helps on whether timing is maxed/tapered off at a specific RPM range.

ChopperDoc

The is no cookie cutter for this, but a good start is the stock table, and go from there. If you are street tuning timing, there are a few ways to measure gains through increased timing. You can use a race logger, and two known points in rural Mexico, or go to the track and go for trap speed, not ET. In both cases focus on consistent starts with no wheel spin. Add timing until you see no further improvements, and in most cases, go back to the value where you last saw a gain. Only bump up 2 degrees at a time, no more.

If you have messed with compression, as in decked your heads, stroked the engine, or you're running a cam, then you will definitely have to visit your timing table, but most likely to DECREASE timing in many areas. More compression = less timing. For instance, my 427 stroker doesn't make gains on anything beyond 24* on WOT, however in the midrange I am near 30*. The general shape of the table will see the most timing through the mid ranges, then fall off and plateau above 4k rpm typically. There should be a "ridgeline" right through the low to mid range, with two plateaus on either side under it. Idle is whatever the engine likes at idle, and isn't that important so long as you can get the idle RPM down to a reasonable level in the 600-800 range.

Big cams also hate lots of timing in the low end, like 2k - 3.5k, and it often will cause surging and bucking. Pulling timing will correct this.

Detonation isn't something that will immediately destroy your engine, so long as the fueling is on the safe side. Make sure you're running on the rich end of the spectrum to avoid the engine ending threat of a pre-ignition. That's why it's generally safe to start with a stock table, add 15 to 20% fuel across the entire VE table, and work your way up slowly, as in don't just go WOT on the first few drives. If you see detonation (KR), stop, correct it, then carry on. If you don't have any, it's not something you want to go looking for either, especially at WOT.

ChopperDoc

Also, acceleration rate can help determine gains made from timing. This will log MPH increase per second. so if you go from say 12 to 14, you've made gains. This will highly depend on consistency, but is another option for street tuning spark. Here's how to set it up if you haven't already:

Under "user maths" pick an open slot and do this:

1. Select "new variable" and then either the generic MPH PID or your specific vehicle one.
2. Under the "Edit PID", select "Average" and under "period" write in -1000 (it will only let you type -100, but you can add another "0" after you have it on the formula area.
3. Add a " - " symbol
4. Repeat step 1 to add in second reference frame (same MPH PID again)
5. Select "Average" for second PID and under "period" write in 1000
6. Use 3 decimal places
7. Select MPH as units.
8. Name it something awesome like "Scare factor" or something.

If you use MPH under Generic Sensors, then it should look something like this:

([50020.114.avg(-1000)]) - ([50020.114.avg(1000)])

Note: 50020.114 = Generic MPH PID on mine, individual results may vary.

Another Note: for all PID's and units make sure you are using MPH. The PID's will normally populate with m/s which is meters/second. Should be good to go after that.

Now you can log this and put it on a graph to monitor gains and so forth. Also helps determine drivability.

QTR FMS

thanks this is really useful

QTR FMS

i understand what you guys said but most people dont really try to find mbt timing as hptuner is reflash ecu and no one will bother finding mbt for every cell unless you are using rtt im asking what is your rule of thumb when you make a base tune before *testing* if you want to add or remove timing, now i understand that i can target flat timing but can i target 24 degree from 2000rpm to rev limiter or would you use a curve from maybe 20degree increasing 1 degree every cell

on a stock tune let say it target -18 degree under 800 rpm and -10 under 1200rpm, with a tune like this one im not gonna bother adding two degree at a time im asking what is the starting point can i target 5 degree or maybe 10 degree from 800rpm wot

let leave the afr out of the equation as i dont believe it will effect mbt but it would effect detonation and detonation is something i would look for after getting on the street not when building base map

thanks

ChopperDoc

Okay, so I wish I could just tell you some values to put on your table, but really, the stock table is where most start this. Also, spark is the LAST thing you mess with. You want to get the fueling right first, MAF and VE. I don't know where you are with the process, but most of us start with VE, then move on to MAF, then spark. I won't insult your intelligence on this, but I know very little about your setup, parts, compression, cam and so forth.

How far are you from stock?
What is your goal with a base map of your timing table?
Are you adjusting the High Octane/low Octane tables or are you messing with the MBT table? <<<< NEVER mess with the MBT table.

I understand your concerns and I think I know what you are asking, but really, stock table is going to be a decent start. Even if it knocks, it's not a big deal so long as you're not going WOT right off the bat. Knock under WOT and knock while cruising or decel are two very different things. Depending on your compression and parts, 24* is a safe place to set your WOT timing in most cases, then push a degree or two monitoring gains as explained above. A dyno is honestly the best way, but if you just want to get it decent and close, then the methods above work too.

Also, -18 or -10, if you're talking about retarding the timing from zero or from 24, which I'm failing to understand, are not numbers you set that way. You set idle timing based on cam size, and what the engine likes. There are whole write-ups on idle tuning, and how to set this up. 18* might work for some, 14* for others, and 22* for others. Depends on setup and cam, and how low you want your idle to be. Mine idles at 800, stock is around 600. I cannot get it lower without many issues due to the cam size... 244/252 .634/.634 114+3 LSA < and I'm running 16* at idle. I'm also at 12:1, with a 427 stroked LS3, with all the goodies on top. My setup isn't terribly far off from the stock timing table really, shape wise.

I will try and post a pic later on what it should generally look like.

But basically, there is no clear standard on how to just set timing across the board. Like I said, no cookie cutters, and what works for one may not work for another because it is such a complicated subject.

ChopperDoc

So I was a little high recalling from memory on what I am currently set at. Pulled the tables, got some snips for reference. One is a stock LS1 table (minus idle area) that worked on my LS3 swap for years, but wasn't ever dyno tuned. You can see the general shape that both tables follow.

ChopperDoc

Alright... So I took the table and marked it up a little to explain the "general" areas on the table, and why it's shaped the way it is. Above 6800 RPM as you see on mine is a backup "rev limiter" so in case fuel cutoff is delayed I won't end up popping the motor. Not truly necessary but also not going to hurt anything.

*Disclaimer* These depictions are GENERAL in nature, so please don't try and sharpshoot it, unless you have something to add that's constructive. I didn't go into a log and plot this stuff so I realize that it may be very inaccurate cell to cell. However, it gives the general idea and shape of the table and should help some folks understand it a little better. This is set up for a 427 Stroker with 12:1 SCR, 8.2:1 DCR. This is after many successful runs/miles (thousands) without issue, and not fully optimized. Sure I might be able to squeeze a pony or two out of a few spots, but not worth it IMO.





In all honesty, my bottom row is actually the WOT area after about 3200 RPM, due to injector size, airflow and all that stuff. If I wanted to actually use the rest of the area, I could scale the tune down and do it that way. Also not worth the extra effort IMO.

Hope this helps. Also adding a few decimal points allows for a nice smooth table, as you see.

truckdoug

iTrader: (25)

did you make that diagram? thats awesome. I will say it's worth the effort to extrapolate the cells you really cant hit (unless you're on a loaded dyno) since the computer will use them as reference checks if the cell you're in comes near them.

and yeah we're pretty much working with the bottom two rows for timing once the computer recognizes the engine is at max g/cyl

ChopperDoc

Yeah I thought it would be helpful to try an explain the shape of timing and how it generally goes. I have seen cars with laggy cams hit the bottom left corner, just recently in fact from a log someone posted on here. I still map them as you see on my table above, but was just conveying that typically not something you'll see the engine hit often. My engine spools way too fast to even come close to that corner, and winds down fast too. Just wanted to make something new guys could use to visualize the curve and the track the engine makes through the table, generally.

I appreciate the compliment. Thanks. Feel free to borrow it, that's why it's here.

Jim Blackwood

Older thread but still much help for setting up a new spark table. So I have a question or three. First and most importantly, is it possible to go into the XDF Info/Rows and add more rows at the bottom to accommodate more boost? Can the controller ('411) handle that? (I mean, 29 seems like such an odd number after all)
If not, does bumping up the numbers on the last couple of rows work? I mean like going to rows 128 and 129 and increasing them from 1.16 and 1.20 to something like 1.3 and 1.5? I'm running no more than 7psi at the very most so it seems 1.5 should be more than enough.

Thanks for the advice!

Jim

ChopperDoc

As far as I know you cannot edit the values on the 0411. I just tried lol. Can't do it. However, you can in fact gain more depth on the table by scaling it. If you scale it down by chopping ALL the airflow tables down, including injector flow rate and so forth, you can gain more depth on the spark tables. Due to my injectors, my camaro already maxes out halfway through the RPM band. That's about the only way I know of to do it.

Jim Blackwood

Thanks.
Using TunerPro. I changed the values of the last two cells (grams/cyl) and it seems to work.

Jim