454 TBI Spark Advance Table

[seads505]

The engine: 7.4L TBI out of a 1992 Suburban

I've been searching the internet for some time trying to find the factory spark advance table for this engine. Specifically, I would like to see actual timing BTDC based on Ign Load % (MAP) vs RPM. Is this information that you tuners can easily extract from the bins? Maybe its in a different format than MAP v RPM?

Did these advance curves differ between different years of the TBI 454 and if so, was there a "better" one in terms of power and/or fuel economy? I'd be interested in looking at the different variations, if there were any and I welcome your thoughts and opinions on which you prefer or your experience with them.

I appreciate your input and hope I've come to the right place for this info...feel free to re-direct me if I should be looking elsewhere or if this has already been covered.

[Fast355]

The engine: 7.4L TBI out of a 1992 Suburban

I've been searching the internet for some time trying to find the factory spark advance table for this engine. Specifically, I would like to see actual timing BTDC based on Ign Load % (MAP) vs RPM. Is this information that you tuners can easily extract from the bins? Maybe its in a different format than MAP v RPM?

Did these advance curves differ between different years of the TBI 454 and if so, was there a "better" one in terms of power and/or fuel economy? I'd be interested in looking at the different variations, if there were any and I welcome your thoughts and opinions on which you prefer or your experience with them.

I appreciate your input and hope I've come to the right place for this info...feel free to re-direct me if I should be looking elsewhere or if this has already been covered.

The 454 SS trucks had a spark map designed for performance, but it was a light, regular cab truck with 4.10 gears. Using the spark map in a heavier truck, with taller gears can cause knock.

[EagleMark]

You can download TunerPro or TunerPro RT so you can use it for data as well. Then open .bins and look/compare for yourself too!

[seads505]

You can download TunerPro or TunerPro RT so you can use it for data as well. Then open .bins and look/compare for yourself too!

Found 7060 bin/xdf info here: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?317-16147060-PCM-Information-85

[1BadAction]

The stock spark map from a 454ss works just fine in a Suburban as long as you change the spark adders to match. If you load it down with 10000lbs of shit and pull up grades you might need to run mid grade gas, though.

[kevinvinv]

Hey BadAction, do you have a spark map or a bin from a 454ss?? I havent been able to find the BCC for these trucks just yet....

[1BadAction]

Hey BadAction, do you have a spark map or a bin from a 454ss?? I havent been able to find the BCC for these trucks just yet....

Everything you need from a 1991...

[kevinvinv]

Thanks man!! That is sweet!

Question for a 454 guy... what Idle speed do you run your rig at? Mine is like 1000 RPM+ ... I tried to lower it a bit but things got a little wonky... never had a 454 before... is the idle RPM in general a little high?

[1BadAction]

BBCs tend to idle a bit higher than SBCs, 750 RPM when it's up to temp is stock for the burb, and that works good with the mild cam. 850rpm or higher and it's stalled up against the converter pretty hard.

The stock 454ss idle is 100rpm lower (650rpm). Same engine and transmission. Probably just GMs way of giving it a bit of thump. lol.

[kevinvinv]

Hmmm... mine doesnt idle well when I try to get down to 700 rpm or so... when I thump the throttle (in park)... it revs up and then dips so low it nearly stall's... I'll have to work on it... massive trans problems now though... so it looks like that will have to take a back seat :(