harness and pcm question, swapping in an lq4 in place of my ls1

[ryans1000]

I'm going to sell my ls1 and swap in a forged 2004 lq4 truck motor for my turbo setup. Still keep my t56. Will my ls1 pcm and harness work???? Or will it be easier to use the lq4 computer and/or harness

lq4 is drive by wire but I'm thinking of using my cable driven ls1 throttle body

I'm going to use
lq4 motor and stock 317 heads
ls1 oil pan
ls6 intake manifold
ls1 cable driven throttle body
ls1 pcm
ls1 harness
ls1 water pump
ls1 accessories (alternator, tensioner, water pump and crank pulley)

[Taz]

As long as you use the LS6 intake assembly (manifold, injectors, fuel rail, TB), which necessitates using the LS6 accessory drive - it should be a straight "plug & play" conversion using your existing wiring harness.

Obviously, the PCM will need to be retuned for the new engine.


Regards,
Taz

[ryans1000]

I'm about ready to drop in my forged 6.0 lq4 in place of my stock 5.7 ls1. I'm using the same computer and old tune as a base. need advice on any possible changes to the tune. I'm guessing about 6% more fuel roughly to cover the 6% increase in displacement. leave timing maps the same? any other tables that need altered?

here is the details on the setup/motor swap
-same open loop, speed density tune, using the 3 bar OS
-moving to a 2.5 bar map sensor vs the old 2 bar
-moving to ported 317 heads vs the stock 341 ls1 heads
-same ls6 intake manifold and cable driven throttle body as the old setup
-same ls1 pcm and harness
-same fuel system
-all sensors and accessories
-same turbo

[ScarabEpic22]

Start with changing the displacement to match the new engine and maybe add 5-6% to the VE table for the initial startup. You will have to redo your VE and Boost VE tables, displacement, heads, and cam all determine them and putting a new engine means you need to redo them. Same with the spark table(s). Make sure you use the new values for the 2.5 Bar MAP in the tune as well.

[joecar]

I'm about ready to drop in my forged 6.0 lq4 in place of my stock 5.7 ls1. I'm using the same computer and old tune as a base. need advice on any possible changes to the tune. I'm guessing about 6% more fuel roughly to cover the 6% increase in displacement. leave timing maps the same? any other tables that need altered?

here is the details on the setup/motor swap
-same open loop, speed density tune, using the 3 bar OS
-moving to a 2.5 bar map sensor vs the old 2 bar
-moving to ported 317 heads vs the stock 341 ls1 heads
-same ls6 intake manifold and cable driven throttle body as the old setup
-same ls1 pcm and harness
-same fuel system
-all sensors and accessories
-same turboNot 6% in fueling, but 6% in cylinder airmass (VE), and fueling will follow the airmass... this would be your tuning starting point.

note:
- VE in % units: displacement affects displayed VE table, after increasing displacement you have to make a minor change to the VE table and/or close/reopen the tunetool.
- VE in g*K/kPa units: VE table directly shows normalized cylinder airmass, increase VE by 6% (regardless of displacement).

See what Erik said above.

Idle air tables may need editing.

OR... can't you simply copy the various tables from the LQ4 tune file...?


edit: correction (I had accidentally omitted one key word).

[ryans1000]

thanks guys. joecar, that is useful info about the ve table. my ve table is in percentage, i changed b0104 cylinder volume table and noticed the ve table change after i reopened the program.

now for timing. i can pretty much aim for any desired wot timing, I never get any knock because i have e85 and meth injection together. are you guys talking about adjusting the wot timing or idle/cruise timing? I was guessing the idle/cruise timing would be about the same.

i'd like to peek at a stock lq4 tune, is there a central location/database for stock tunes somewhere?

[joecar]

If you run E85, you can set B3601 to the stoich AFR for E85 (9.7)... you may still need to make PE a little richer if it is not already.

I'm not sure, I think low load timing can be as is, but E85 allows you to run more WOT timing.


www.tunefiledepot.com (http://www.tunefiledepot.com) look for LQ4 and LQ9 under Stock->Chevrolet->Petrol/Gas.

[ryans1000]

thanks scarab and joe, the new 6.0 fired right up . my tweaked tune from the 5.7 put my afr's real close to what they needed to be. was able to get driving right away and started the motor break in/ring seating

[joecar]

Cool :cheers: let us know how you go.