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

[jks67ss396]

guys

im about to start on my 408 ls twin turbo build. i need to know what to buy...

I had a FAST b2b system on my BBC, and liked those VE and spark tables. easy to use.

So for this twin turbo build (2 bar to start), do i just modify the tune on my ecm (03 Sierra lq4 ecm going into a 67 Camaro) or do i need one of these custom OS's? how much do those cost?

will i use the MAF on the turbo setup? or straight speed density? id like to get nice mpgs when off boost. its a 5 speed car.

I need to buy from someone who can help with the tuning..especially turbos. ill have a lot of questions at first. im in the LA area, so it would be nice to buy from/know someone here that can help if needed.

its just the one car. so i dont need to tune anything else. what do i buy and do i have the capability to log data and then make changes?

thanks guys
jeff

[joecar]

Hi Jeff welcome to the forum

If the PCM is from a 2003 Sierra LQ4 then you can use either of these:
- FlashScan V1 (cheaper, LEDs only, BBL only, analog wideband).
- FlashScan V2 (LCD and LEDs, BBL and BBF, serial comms wideband, SD card slot for logging/flashing).

V1 will work, you will need your laptop in vehicle to read/flash the PCM; able to do BBL (black box logging (i.e. no need for laptop in vehicle)).

V2 allows BBF (black box flashing (i.e. no need for laptop in vehicle)) and BBL [i.e. no need for latop on logging trips].

V2 also has serial comms AFR support for the most popular widebands (the AFR/Lambda is read directly from the wideband using RS-232 serial comms protocol, avoiding analog voltage/ground offsets).

Of course, both V1 and V2 allow passthru reading and flashing (i.e. with laptop in vehicle).

I'm not sure about 2003 COS (custom OS), but it seems that 03190003 would work on the 2003 LS1/LQ4 style PCM (I'll ask tech support).

COS's are free (no cash required, no PCM/VIN license required), there is a tutorial for installing the COS (see attached).

[joecar]

It looks like COS 04073003 might also work.

[jks67ss396]

so with these COS's, do i use the MAF or just speed density?

Can i map timing and AFR?

where are you in So Cal? Who do you use to tune?

thanks!

[ScarabEpic22]

The COSs let you run up to 3Bar of boost in SD, you will probably max your MAF out quickly with a 408 TT.

You'll need a wideband of course to get your fueling in check, yes you can log spark timing and see knock, map fueling to see what your A/F is. Also, you should perform an AutoVE and get your VE table dialed in properly N/A then move onto boost fueling and timing.

[jks67ss396]

Ive got dual widebands... so does EFI do autocorrection based on what the wideband O2 says?? can i command an AFR based on rpm and map?? my old classic FAST efi setup had an AFR table....

Is AutoVE included with the V1 and V2? or is that extra or more $$

who should i buy this setup from? Id like to have a good guy available to help with this FI tune.

thanks

[joecar]

Taz has a good point on electronic vs cable throttle... you might need a 2002 LS1 PCM, part # 0411.

This PCM has COS3/02020003 (boost) and COS5/02020005 (boost, nitrous, throttle position VE) available.

[Taz]

Minor point … wanted to confirm you are aware all 2003 and newer LS1-B truck tunes are DBW (Drive by Wire) only. If you want to use a DBC (Drive by Cable) setup, you have two choices - use a 2002 LS1-B PCM and truck tune, or access a 2003 Express / Savana tune that used DBC (some were DBW).

All 2002 512Kb LS1-B PCMs supported DBC and DBW tunes. Not all 2003 and newer 1Mb LS1-B PCMs will support DBC tunes.


Regards,
Taz

[jks67ss396]

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

thanks

[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...?