7.4 timing curves

[300stw]

wondering what kind of timing curves a stock ecm has vs tuned ecm

i have a black bear tune, watching a scan tool while driving i show 32 degrees at idle and at 2600 rpm cruing down hwy i see 28

old school tuning on an hei with vaccum advance on a 454 i usually have 16 initial 36 by 2500, and a vaccum advance to get around 50 for mileage ect,,,
below is a couple charts i seen posted on a chevelle forum a guy is running, i tow 6000lbs regularly, looking for some power and mileage, even with the black bear tune i havent seen any results i can speak of, lower fuel mileage than the stock tune is for sure though, solid 3 mpg i have lost,
done all thge things to a fresh motor tune up parts ect, new blue knight injectors from 5.0 with fuel pressure regulator, cat back dual ekhaust 2ea 3in pipes and mufflers,

looking for advice, i have been intouch with christian on here about a 0411 swap and tuning

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[Elroy]

i have the new injectors and BB tune too, bb tune helped w shifting but the biggest difference i think i did was new magnaflow cats and downpipes in addition to the exh.,,, a manifold back system, , maybe mine were collapsing internally, but that helped alot, if you still have the old original cats you may want to think about that

 

[Elroy]

and im getting close to 14 mpg unloaded on the highway

 

[ZRoe]

What are you using to scan the timing? I've heard that the black box on these Vortec motors doesn't display the same timing via a cheap OBD2 vs a proper mechanics scan tool. This is why it is hard to fix a cam-crank misalignment fault without going to TDC or getting a proper scan tool.

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[300stw]

i have a 100.00 harbor freight tool ive been using

 

[300stw]

is there an app to use from a phone, or which scan tool should i buy

 

[Elroy]

my HF scanner doesnt even want to connect to the computer in my 96

 

[Supercharged111]

Mine brings in the timing a lot sooner than stock. I do have a problem where it refuses to advance past 32.5 which surely costs me mpg and throttle response. WOT timing is 26 or 28.

 

[L31MaxExpress]

Mine brings in the timing a lot sooner than stock. I do have a problem where it refuses to advance past 32.5 which surely costs me mpg and throttle response. WOT timing is 26 or 28.

Look at your maximum timing advance value. I had one refuse to advance past 35° on a small block 350 Vortec with the black box. Ended up moving the value for max up to 50 from 40 and bam 40. The maximum limit value was 10 offset for some reason. If your CMR is set at 0 you are limited to 42 maximum by physical limitation of the distributor. Anything beyond that will cause misfiring.

 

[Supercharged111]

Noted, will definitely give that a shot. Waiting for clean roads to release the dually from the hangar at the moment. I hadn't thought of the max timing being off, but it could be due to some stuff left unlocked by the tuners.