timing question

[4.8t]

ok with the maf disabled and in 1 bar sd at wot the truck runs in the high octane table but with the maf enabled it runs in the low octane table but there is no knock retard. and at idle my timing jumps up and down really fast is this normal? how do i get the truck to run in the high octane spark table at wot with the maf connected?

[WS6FirebirdTA00]

thats odd that shouldnt happen, how do u know what table you are in? idle timing will jump around a lot depending how well the idle is tuning and what your over and underspeed adjustments are

[4.8t]

well at wot one table is at 28 and the other at 30 at the high end and at 4000 to 5200 one is at 26 and the other at 28 and on the data log i'm getting 26 at 4000 up to 5200rpm then i'm getting 28* the rest of the way up until shift.

[Russ K]

Are you saying that your os is upgraded the the 1 bar sd enhanced? If so that is for mafless tuning only.

Russ Kemp

[WS6FirebirdTA00]

post a log and the tune

[4.8t]

it was set up that way then i put it back to maf tunning. i did this by loading a old tune before sd and i did the write entire feature. just like when going to 1bar sd. here is the log and the tune file.

[Russ K]

Try this one. I copied my stock 2001 ZO6 idle over & under speed spark tables, set your LTFT map boundaries for your cam since your idle map is 59-60 kpa.
I set the pe delay rpm to 0. You had pe delay untill 3000 rpm. Why are you commanding 12.18 afr? I would use 1.13 (13.0) afr. Are you tuning with the maf on? Your ve table is quite rough. 30* - 31* of timing is excessive unless your afr is too rich.
Could you post your stock file?

Russ Kemp

[4.8t]

so why do we set the ltft map boundaries to idle map? the pe delay was set to what i found in a write up because i have a 3000 stall tc the write up said put it at you stall speed. i'm comanding that because other wise it was too lean and ran like but i put it up there and it ran better and less knock. i've been messing with this thing alot latley and last week it was at the point were a stock yukon was keeping up with me even though i thought it was good it wasn't now it is pulling alot stronger no knock. i set up the ve then i turned the maf back on. as far the ve goes i did what all the write ups said to do this cam is really weird and i think that is what alot of it comes from. maybe this is why lingenfelter doesn't make it any more lol. good cam good power just hard to tune. i haven't even hit 30* of timming yet on a wot run everytime i've added timming i can feel the power but i can't get it to hit 30 i think because i add to the low table as well as the high table is the only reason i get more timing on any run.

here is a stockish tune but not bone stock i can't use much stock stuff because i have a dif motor,cam, and tc. lol

[Russ K]

Your low map LTFT boundary needs to be higher than your idle in gear map. Since your map with your cam has raised the map to 59-60 kpa, the stock high range map has to cover both the low & mid range map fuel trim cells. You lost the use of your low & mid range map trim cells. My car idles at 48 kpa with a 234/228 cam. Any chance your timing gears are out of line?
Are you using a wideband O2? If your maf table is not scaled to match your airflow, than that might be affecting your timing tables. When you disable the maf the low octane spark table is used. If you unplug the maf, you loose the IAT sensor.

Scan your commanded afr with the pe delay set to 0, then 3000 rpm, then you will see why you what it at 0 rpm.

Russ Kemp

[4.8t]

timing gears were dot to dot crank dot on top cam dot on bottom striaght across from each other. my friend had this cam and wound up advancing it 4* and it ran a whole lot better. i just figured he needed that because of it being in a 5.3 not a 5.7 but maybe this cam is just better at 4* advance. no wide band just going by ogs at the track. and when i was doing the ve table i has the maf pluged in just disabled.

[4.8t]

ok i loaded your tune. didn't get to do a wot run for the timing thing but i do know that it wouldn't idle for crap looks like i need to keep the cray up and down timing thing going on lol. with your over under table it wouldn't have enough timing to catch itself up when i let off the throttle suddenly or when trying to park and the truck would lung forward and pause and lung forward again. but my ltft weren't too bad as they set in. i'll have to do some more logging later. i couldn't do a wot run because it was raining and i have no traction in rain.

[Russ K]

Lingenfelter GT1-1 camshaft will produce excellent power and still have a streetable idle in six speed manual transmission equipped vehicles. Not recommended for automatic transmissions.

Suggested in 350-427 CID applications

Camshaft specifications: 229/242 duration @ .050 .631/.631 with 1.7 ratio rocker arms 114.0 CL. This camshaft will require dual valve spring kit 26921-KIT. Camshafts ground by Competition Cams for Lingenfelter.

Is this your camshaft? I can't find your cam specs on this site.

Russ Kemp

[4.8t]

nope its the old gt1 not gt 1-1 go to ls1tech and do a search for gt1 or gt-1 cam and you should find some stuff on there i did but didn't really find any one that used it. i did find one where lengifelter was talking about the cam and they said they stoped it because they didn't like the way it idled.

[4.8t]

http://www.ls1tech.com/forums/showthread.php?t=58