2014 Silverado 5.3L w/Vortech + SD (reduced ignition timing issue)

[r2r]

Hey guys. Hope someone can spot the issue.Sitting on the dyno for day #2 and still haven't resolved the reduced ignition timing. The few runs that it put down the requested timing (or at least close) it made decent power. It's got 60% ethanol in it currently but 91 oct behaved the same. Knock hasn't been an issue and the max/peak torque table doesn't affect the issue. Within the VTT editor I've gone from 1.2-1.5% across the entire top rows (800 airmass and 100 map) and still the same result.

Can you spot the issue? Really need a second set of eyes on this as I know you guys on the Gen 5 sub have probably done a lot more of this than me. Also, running SD as whoever put this together cut corners and the MAF signal is unusable. It runs very stable on SD with an upgraded MAP sensor. Thanks for taking a look and any help you can offer!

[SultanHassanMasTuning]

why are you opting to tune SD when boost will not vary?

also your out of injector

you cant run ethanol with those tiny injectors and low fuel pressure

[r2r]

Hey thx for the response. I don't agree about the fuel injectors being out of flow. They're sitting less than 8ms at 5k RPM in the log, which is about 35% IDC. Normally DI can run up to 50% as long as you have fuel pressure behind them (generally speaking). It's running SD because the MAF airflow was turbalent at low demand/high vacuum and couldn't be tuned out. But anyway, do you have an idea as to what is causing the reduced timing?

[SultanHassanMasTuning]

your torque model will need to be changed

MAP and MAP E85

[cadillactech]

Hey thx for the response. I don't agree about the fuel injectors being out of flow. They're sitting less than 8ms at 5k RPM in the log, which is about 35% IDC. Normally DI can run up to 50% as long as you have fuel pressure behind them (generally speaking). It's running SD because the MAF airflow was turbalent at low demand/high vacuum and couldn't be tuned out. But anyway, do you have an idea as to what is causing the reduced timing?

How many milliseconds does the intake stroke take to complete at 5000 RPMs?

[r2r]

How many milliseconds does the intake stroke take to complete at 5000 RPMs?

This isn't a trivial question. There's not an issue 'before 5k'. The ignition timing is reduced by the begginning of the pull/run way before that.

[SultanHassanMasTuning]

the scanner is reporting/calculating based on port injections math

i think that you will be somewhat ok on that boost with close to zero ethanol

your timing drop is based on two issues

your IATs are shooting to the moon
second your torque model needs to be adjusted

[r2r]

I've been stressing over the IATs from the beginning. Originally spoke to the owner and said the 'hot air' intake wasn't going to work well, espcially without and IC. The boost is low but still, the IATs are high. He asked that I get it done and then bring it back for fab work later. Just trying to work with what's been presented to me. I did talk him into doing NGK one step colde plugs gapped down a bit and 10mm plug wires but he wasn't ready to do the rest.

Still working on the VTTs. Had a brain fart on the table offsets. Only modified the 0* offsets the first time around lol.

What do you mean "port injection math"? IPW doesn't change based on PI vs DI.

[cadillactech]

I've been stressing over the IATs from the beginning. Originally spoke to the owner and said the 'hot air' intake wasn't going to work well, espcially without and IC. The boost is low but still, the IATs are high. He asked that I get it done and then bring it back for fab work later. Just trying to work with what's been presented to me. I did talk him into doing NGK one step colde plugs gapped down a bit and 10mm plug wires but he wasn't ready to do the rest.

Still working on the VTTs. Had a brain fart on the table offsets. Only modified the 0* offsets the first time around lol.

What do you mean "port injection math"? IPW doesn't change based on PI vs DI.

IAT is pulling at least 2 degree of timing based on your IAT spark tables, I would log all timing parameters as you may have other sources taking timing away. Obviously fix the source of the hot inlet air as well.

You can only inject fuel once the exhaust valve is pretty much closed(or you waste it) and anything past BDC of the intake stroke is not going to mix well in the chamber as the piston is rising. So at higher RPMs you only have 4-6ms of time to inject(depending on valve events) fuel. 8MS, you probably are spraying into the combustion stroke but you have no log of SOI or EOI.

If you spray into spark, the ECM can pull timing as well. I would log SOI and EOI data so you can see where your fuel is going.