Newbie... what to get. twin turbo ls build.

[jks67ss396]

can i still get good mpg with SD?? (off boost of course)

thanks

[Taz]

If you have a 2003 LQ4 truck (Sierra / Silverado) tune it is DBW only. The PCM you have MAY support a DBC tune - from an Express / Savana.

Post the service number (Serv #) and hardware number (HDW #) affixed to your PCM and I’ll check compatibility.


Regards,
Taz

[jks67ss396]

got all that stuff at the machine shop getting the block cleaned up.. if i am stuck with dbw, can efilive adjust the "sensitivity" of the throttle signal? i dont want delays....

[Taz]

No sure what you mean by “adjusting the sensitivity” of the ETC (Electronic Throttle Control). DBW and DBC work equally well - comes down to the physical setup you want / have in place.

In a boosted application DBC is easier to tune - as you don’t have to worry about ETC “limp mode” being triggered by excessive / unexpected air flow.


Regards,
Taz

[jks67ss396]

well, maybe its just my experience, but in the dbw cars ive driven, seems like if i punch it, the computer slows the acceleration and "slowly" opens the throttle. Can i tune that out?

what is excessive airflow that would trigger limp mode? vac leak or something?

[Taz]

It may be helpful to invest some time reading the threads in the "Forced Induction" portion of this Forum - as well as the user manuals for both the Tune Tool and Scan Tool. You could then make an informed decision as to whether you want to undertake tuning the vehicle yourself - given your comment about not wanting any delays. Tuning it yourself is rewarding, and can be cost effective if you are cautious, but it will take time.


Regards,
Taz

Edit: the perceived throttle delay you described in some DBW vehicles could be the traction control system - which is also tuneable.

[jks67ss396]

ha! by delays i meant the "momentary" delay felt by dbw throttles that i seem to experience. im coming from a metal throttle rod and then cable on my 67 camaro, so im used to punching it and going sideways... not this "computer controlled acceleration (delay)" that ive felt with some new dbw cars...

i tuned my SD 540 BBC using the Classic FAST efi system and liked that a lot... i definitely want to tune this new setup myself. i will poke around the other forums though

what i would like to know is who in So Cal do i buy this from that knows turbo tunes? just in case i have questions...

thanks!!!

[jks67ss396]

traction control is a good thing. but sometimes i just want to light them up

[joecar]

...

what is excessive airflow that would trigger limp mode? vac leak or something?

With DBW differences in various airflow/throttle sanity check tables may trigger reduced power mode... DBW tuning requires special attention to these other tables.

As Taz said, your PCM's service/hardware numbers will determine if your PCM can run a cable throttle OS (from a Savana/Express file).

[joecar]

can i still get good mpg with SD?? (off boost of course)

thanks

In SD if you correctly tune the VE table(s) using a wideband then MPG will not suffer... in OLSD you have the opportunity to set cruising AFR's leaner, giving you improved MPG.

Some points:
- many people have observed the same HP/TQ between running with SD or MAF.
- some people have observed the smaller diameter MAF's may impose a small airflow restriction (due to the airfoil).
- some of the earlier [LS1 ] PCM's limit the MAF airflow values to 512 g/s.
- if using MAF, you will still need VE corrected (since PCM falls to VE during transients throttle).
- running in SD is a failover/error mode, it alters the operation of some other things like adaptive spark/knock (unless you run a COS) and transmission operation.

Which transmission will you run...?