How much timing can a 5.3 gen 3 p01 00 silverado handle

[mikefain215]

Just started playing with high and low octane tables this week i started lessons with the tuning school about a month ago. Anyways i have a 00 silverado 5.3l P01 gen 3. Motor has 3,000 miles. Truck ran real sluggish before. I tuned the VE tables and MAF, then started turning my WOT timing up, im at 26 degrees rn and truck feels way better then ever. My question is can i go any higher, running on 87 octane. I have 0 knock at WOT. Also if im adjusting my timing do i need to re adjust my VE tables and MAF to help with my LTFT? One more question is ther any need to adjust my timing on idle and part throttle, if so do i only select the cells in shows in the book? Truck is all stock at the moment just trying to unlock some power for now. Thanks for any help and advice.

[Fast4.7]

Just started playing with high and low octane tables this week i started lessons with the tuning school about a month ago. Anyways i have a 00 silverado 5.3l P01 gen 3. Motor has 3,000 miles. Truck ran real sluggish before. I tuned the VE tables and MAF, then started turning my WOT timing up, im at 26 degrees rn and truck feels way better then ever. My question is can i go any higher, running on 87 octane. I have 0 knock at WOT. Also if im adjusting my timing do i need to re adjust my VE tables and MAF to help with my LTFT? One more question is ther any need to adjust my timing on idle and part throttle, if so do i only select the cells in shows in the book? Truck is all stock at the moment just trying to unlock some power for now. Thanks for any help and advice.

It might take up to 28-29*, that being said leave it at 26, work on the timing curve a bit and the fueling. The engine may like a bit more timing in the low-midrange. Hard to say for sure without looking at the timing curve. You need to datalog to see what removing or adding timing in places does. Generally speaking at part throttle, you want to run a steady speed on flat road and find out what timing value results in the lowest TPS and MAP/MAF readings. You should dial in the VE table with the MAF disabled to bring the fuel trims between 0 and -5%. If it is currently adding 8-10% which is common on E10 fuel, need to adjust the stoich value from 14.7 to 14.1. That will help bring the fueling back into the desired range for the real ethanol free gasoline the truck was calibrated for when it was built.

[mikefain215]

Screenshot (3).png Screenshot (2).png

Is this what your needing to see?

I did dial in the VE with MAF disable, got fuel trims good, Then I tuned the MAF. Then i started adjusting my timing up 2 degrees at a time from 20 degrees and up. Truck def runs better then before i just wanna make sure im doin everything correct or what i need to do to do better.

[kingtal0n]

Optimal Timing depends on cylinder fill and temperature and fuel quality and combustion efficiency and other details
Power comes from the airflow mass rate not maximum timing
Max timing delivers max stress and max engine damage potential


I experimented with 87 and 93 octane on an LM7 with 200,000 miles
I found that after 3300rpm with nearly 100% cylinder fill optimal timing is about 20 to 22* btdc on 93 and 87, it didn't matter which fuel on paper result

By optimal I mean the minimum timing that can produce within 4 to 7% peak torque on a dynojet , this is best daily driving timing leave some on the table for future problems like hot fuel, high iat, extra load, heavy vehicle, numerically lower gear ratio, etc...

Here is my curve successful for 87 octane fuel
2000rpm 16.4
2400rpm 17.6
2800rpm 18.2
3200rpm 19.5
3600rpm 21.2
4000rpm 21.5
4400rpm 21.6 280lbf-ft torque peak start, peak cylinder fill
4800rpm 21.4 280lbf-ft torque peak end
5200rpm 21.0
5600rpm 22.0 275rwhp peak
6000rpm 23.0
6500rpm

Bottom blue curve is 87 octane fuel on the tired ass LM7 using a couple psi of boost pressure to make up for the age and obstruction of the turbocharger to get back the 100% cylinder fill , relatively speaking and IMHO of course

[mikefain215]

Screenshot 2023-11-17 145453.png

Im still learning how to make the right adjustments. Ive work on cars my whole life i just got into tuning and i understand alot more then i thought i would. i just wanna make sure im headed in the right direction or pointers along the way thanks in advanced

[kingtal0n]

End of the day ecu only does 3 things for wot tuning: fuel, timing, and when to spray fuel.

Use wideband sensor to dial in wot fuel, dynojet to find ideal enrichment if needed
Use dynojet to dial in timing or experience and common sense

General rules minimized in natural aspiration are
1. Use the minimum timing possible to acquire reasonable EGT and torque curve
2. Add enrichment and adjust end of injection spray for bonus HP
3. Never depend on knock sensors as wide open throttle tuning tools


Power comes from the potential of a air mass throughput, not timing. Timing is like the fuse for an explosion, not the source of the power behind one. Adding timing is not the right way to search for power. It can give some temporary dyno or situational bonus when timing is on the fringe of detonation or severe cylinder pressure but that bonus will evaporate with the headgasket or piston ring-lands when the conditions change later like more load or higher IAT. Modern LS style engines are robust and able to tolerate alot of abuse so it may not happen suddenly leading you to believe everything is fine for a long time.

I recommend peak torque timing values in the 20-22* btdc range for 100KPA regions of 90-100% cylinder fill VE.
You can ramp in up to 24* after peak torque and even 25* is fine if the torque is falling off rapidly due to a stock camshaft. 26 is pushing luck unless the engine is very anemic and has trouble breathing.
Stock camshaft makes a powerful cylinder fill at low rpm and quickly anemic as rpm climbs which is why the increased timing may feel like it is helping, it may just that. But when things heat up or load changes due to gear it may become problematic to have so much timing.

[horsepowerguru427]

Screenshot (3).png Screenshot (2).png

Is this what your needing to see?

I did dial in the VE with MAF disable, got fuel trims good, Then I tuned the MAF. Then i started adjusting my timing up 2 degrees at a time from 20 degrees and up. Truck def runs better then before i just wanna make sure im doin everything correct or what i need to do to do better.

Theres some big jump from column to column in some areas. Id smooth it out some just so its not such big leaps. Timing curves should be as smooth as possible. I cant say ive gotten quite that high on WOT timing (26*) for a stock engine but i think kingtalon covered that pretty well. Id agree with him on lowering it to around 24* (ish)

[Fast4.7]

End of the day ecu only does 3 things for wot tuning: fuel, timing, and when to spray fuel.

Use wideband sensor to dial in wot fuel, dynojet to find ideal enrichment if needed
Use dynojet to dial in timing or experience and common sense

General rules minimized in natural aspiration are
1. Use the minimum timing possible to acquire reasonable EGT and torque curve
2. Add enrichment and adjust end of injection spray for bonus HP
3. Never depend on knock sensors as wide open throttle tuning tools


Power comes from the potential of a air mass throughput, not timing. Timing is like the fuse for an explosion, not the source of the power behind one. Adding timing is not the right way to search for power. It can give some temporary dyno or situational bonus when timing is on the fringe of detonation or severe cylinder pressure but that bonus will evaporate with the headgasket or piston ring-lands when the conditions change later like more load or higher IAT. Modern LS style engines are robust and able to tolerate alot of abuse so it may not happen suddenly leading you to believe everything is fine for a long time.

I recommend peak torque timing values in the 20-22* btdc range for 100KPA regions of 90-100% cylinder fill VE.
You can ramp in up to 24* after peak torque and even 25* is fine if the torque is falling off rapidly due to a stock camshaft. 26 is pushing luck unless the engine is very anemic and has trouble breathing.
Stock camshaft makes a powerful cylinder fill at low rpm and quickly anemic as rpm climbs which is why the increased timing may feel like it is helping, it may just that. But when things heat up or load changes due to gear it may become problematic to have so much timing.

The 4.8L and 5.3Ls I have tuned with 706/862 heads and stock cams hit MBT around 26*. 24* will not sacrifice much output. I also only run 26* at 5,200+ RPM. I have tuned multiple examples on the dyno and backed up the tuning on the street using a Draggy and timed datalogs.

Not sure what you mean by the stock cam offering excellent cylinder fill at lower rpm. It is short duration but wide LSA and late IVC, which makes the stock cam pretty lame on the low-end. Just about any aftermarket cam will increase the cylinder fill at low rpm and offer more dynamic compression.

[kingtal0n]

The 4.8L and 5.3Ls I have tuned with 706/862 heads and stock cams hit MBT around 26*. 24* will not sacrifice much output. I also only run 26* at 5,200+ RPM. I have tuned multiple examples on the dyno and backed up the tuning on the street using a Draggy and timed datalogs.

Issues with communication in the context of timing
1. MBT is given per cylinder density, fuel/air temperature, rate of change of engine rpm (load and gear), and also cylinder density for static camshaft engines changes dynamically throughout the rpm range.
e.g. MBT for 3000rpm is different timing and density than MBT for 3500rpm if torque changed, and even if torque is the same if the fuel and air is warmer now it also changed

This is the nature of chemical reaction and extraction of energy using a piston which relies on heat input and output to drive pressure over area relationship, i.e. higher temperature or pressure = faster rate of combustion.


2. When we discuss timing numbers and MBT the relationship is to octane, vehicle weight, gearing, etc... because of these examples
A. decrease octane = decrease timing sometimes, but not always
B. increase vehicle weight = decrease timing sometimes, but not always
C. use overdrive gears = decrease timing sometimes, but not always

What determines whether it is sometimes but not always?
:Significant changes with respect to combustion chamber technological year range e.g. 92-02 Nissan/Toyota and 02-08 Chevrolet are practically identical and far from SBC style chambers
-Sustained output considerations e.g. X-mile and boat sustained applications where MBT shifts during the subsequent heating of combustion chamber and EGT/piston/etc
-Rate of change of piston/lever with respect to expanding gas and fluid behavior e.g. rodxstroke ratio, rate of change of acceleration of the engine, fluid momentum
-Environmental changes different from dynometer



IMO a typical street driven performance engine should not be anywhere near MBT except perhaps on the dynometer once for a graph. It is no longer a stock engine when we start to make changes and those rules and safety nets no longer apply.

It is one thing to find ideal timing on the dyno and replicate a similitude for a race or street runs, and a completely different thing to drive the vehicle set fringe of MBT every single day where it will encounter hundreds of variations in operating conditions which push and pull the quandary of MBT and gradually abuse the engine's bearings and rings. Factory engines may get away with closely MBT because of the relatively anemic performance aspect, particular knock tuning and timing threshold safety nets which we may not replicate, and flushed out drivetrain configuration (load rate, piston rate, gear ratios, fuel temperature, injection window, cooling aspects, etc...).

Not sure what you mean by the stock cam offering excellent cylinder fill at lower rpm. It is short duration but wide LSA and late IVC, which makes the stock cam pretty lame on the low-end. Just about any aftermarket cam will increase the cylinder fill at low rpm and offer more dynamic compression.

Typical OEM camshaft for any engine from any manufacturer will develop a higher cylinder pressure at low RPM than any aftermarket camshaft with longer duration. This is the nature of an OEM camshaft for any engine, generally. I find the max cylinder pressure is decreased with aftermarket long duration camshafts in any engine with static camshaft timing. It is the harsh early peak of factory camshaft profile which can place tremendous stress on rod bearings at low RPM with high timing values. We identify peak torque wherever it is and then envision the cylinder fill as a component of the combination as a whole- 80%, 90%, 100%, 105%, whatever. Notice that timing values drop out as power increases, not the other way around, look at my dynojet results, the highest power has the least timing advance, this is the safety and procedure of tuning far away from MBT. If we analyze a single curve and raise it using timing alone then we are doing it wrong, the percentage of difference can easily show us benign engine stress increases for minimum timing results with massive power increases while destructive abusive timing increases results with the minimum power increase.

[SiriusC1024]

I mean do your knock sensors even work? That's a lot of timing for 87. The engine is stock. Shouldn't be doing what you're doing.