Turbo LQ4 startup tune

[Sharkbaithuhaha]

Howdy y'all, im getting ready to fire up my turbo lq4 4l80 truck for the first time. It had the same cam but 1 7/8 long tube headers before (i could tell they killed some torque down low)
Mods-
Elgin 1839p
stock 317 head with valvesprings
t4 log manifold with stock driver side manifold
vsracing billet next gen 7875 turbo
bosch 210 injectors
twin walbro 450 on 10psi hobbs switch (still need to install but thats the last thing)
will be on e85 and coming from pump 93
efi source 3 bar map

i took the tune i had when it was N/A and i multiplied some transitionary rpm/load areas by about 20% and added at least 50% to the sections i extrapolated that would be in full boost. All i did to my spark tables was put in a soft limiter at 4400 as the timing was already fairly conservative but it ran good. I already added injector data from injector dynamics for id2000s and converted the tune to 3 bar map. Im mostly hoping some more experienced individuals could say whether or not im on the right track or if there are any gaping holes in this tune.
sd6 3 bar map bosch 210 soft limiter 4400.hpt

[5FDP]

The VE table is way too fat, it doesn't exactly work like you are thinking. Adding 20 or 50% to the table doesn't work like that when you have increased the injector size by 10 times the stock value. Put the stock VE back in for 15-100kpa and slope the rest up. The last row of 305kpa will still be a low value like maybe a little over 100 and it's likely that you'll still be rich on a stock VE while you dial it in.

You have way too much injector for this too, it may be a struggle to get fueling completely under control at low rpm/pulse width on a stock computer. I'd honestly get injectors like half that size or so.


I don't understand what you mean by soft limiter, don't see the need to do any of that. You can't run that negative timing in boost either, that won't be good. You timing needs to level off after 1.00 cylinder airmass. If you want to stay safe just put in 12 degrees of timing in that whole area and leave the rest how it was before.

[Sharkbaithuhaha]

How does this ve table look, a little more reasonable? the fact that fueling is going down as boost is theoretically going up worries me. it has an 8 pound spring in it but well see how it responds. should i have it carry the fueling curve higher/longer? could you give me an example of tapering off the timing as cylinder air mass goes over 1.0? thank you for the response, i appreciate the pointers.
sd6 3 bar map bosch 210 take 2 ve.hpt

[Sharkbaithuhaha]

Oh and i forgot, i had read about a decent amount of people having good luck getting these to idle even on pumpgas 5.3s with a turbo so i figured id give them a shot. if i have some trouble getting it to run right ill trade somebody down the road, but for right now i chose what was reasonably priced, sized and not hard to get. i needed to get my truck back running so i can do some maintenance on the daily.

[5FDP]

It's likely that your timing curve and VE tables will look like these. Not exactly but similar. The values in the VE don't need to be very high to provide it with the correct amount of fuel.

You are setting the commanded AFR in the PE and the BE which you'll need to finish settings up. Then with a wideband you'll be logging the wideband error against the commanded AFR/Lambda do make things match. You have very large injector that can spray a ton of fuel, it takes a lot less to make them spray more.

[The Black Sheep]

I made quite a few changes to your tune to get you in the right direction. Under Airflow > Dynamic > High RPM Disable was set to 4000 RPM. Raised that to the max value so the MAP will always be used for fuel calculations. Also smoothed out your timing table and set it to 10? at WOT. Set PE AFR to 12.0:1. I remade the entire VE table just to get it smoother. You should absolutely have to make changes to it if you use it, but hopefully the smoother transitions will make it easier to dial in your AFRs.

Hope this helps, but of course use it with caution if you should choose to.

[Sharkbaithuhaha]

After seeing yalls VE tables i think i understand my mistake. is the volumetric efficiency calculations taking boost and injector into the equation? meaning that the ecu doesnt need to compensate for extra fueling in the sense of bigger numbers because it KNOWS what X efficient displacement at Y boost comes to in terms of fueling?

[The Black Sheep]

VE is how efficient the cylinder can breathe air at any given map value. With your injector data and a well tuned VE, the ecu knows how much fuel to spray at any given map value. In your VE, every value after 105 kpa is positive manifold pressure, or boost. 100-105 Kpa is generally atmospheric pressure at sea level, so 200 Kpa for example would be around 14 psi of boost in the manifold so the ecu does see the positive pressure and knows how to control it, that?s why you don?t need to have a value of 150% in these areas for the ecu to know what fuel to spray. As 5FDP also shows, the VE will more likely be around 100-120% depending on the setup.