87GNTurbo6

First.... I have an '87 Buick GN that I want to do a conversion to a 6.0L truck engine.... possibly ECU..... with the truck manifoolds turned upside down and modified and run two smallish turbos...

What are you guys tuning a boosted LQ4/LQ9 truck with? Software? Tuner? What is the most economical way to tune one yourself? drawbacks?

Is anybody running "closed loop" at WOT and tuning with a wideband....??

I would assume the 5.3L and 4.8L trucks share similar electronics.... so they might be the same as well....

AgFormula02

iTrader: (9)

HP Tuners, stock pcm. You can upgrade to a 2 or 3 bar speed density. I do not believe it supports closed loop at wot.

87GNTurbo6

thanks for the quick response...


Are any of you guys running alky injection to get away with more boost on pump gas? I am running one on my car.... (at the time it was completely stock internally.... just bolt-ons) The Alky allowed me to go from 14 psi boost..... to 23 psi......on a near stock setup.....still running on pump gas.... just wondering if any of you guys were using alky.... and how that affects tuning the ECU....??

Phantom

iTrader: (16)

seems like most everyone with boost runs meth/alky injection around here.

hp tuners or efi live for your tuning needs (great support for both around here)

yes a 4.8/5.3 wiring harness will work for you

87GNTurbo6

After reading alot today..... I'm overloaded with new info..... admittedly that is still processing......

I read about EFI LIVE COS5 ....... seems like some posts "say" that is the way to go..... I assume the "COS" means Custom Operating System.... and the 5 is the 5th generation... or iteration of this.... What does this do for me? Is it possible to stay MAF......and not go to speed density.... yet get 3 bar functionality and tables.....?

I'm not sure if MAF is or isn't better. I have messed with my car....('87 Grand National) which is MAF..... stock ECU with a custom chip that accepts a wideband input..... and I can set AFR targets for WOT that it will tune itself to (closed loop).......using the wideband data..........and I have also tuned another turbo V6 with a FAST XFI running speed density. I am familiar with their software.... and don't think EFI Live will be a huge learning curve should I choose to go that route....

I would be a little concerned w/o closed loop WOT tuning capabilities..... that with a speed density system..... you tweak all those maps when it is 60 degrees outside..... and things are going to be "off" some at WOT when the temps get cold... like 35 deg or something.... I would think MAF systems might tolerate the temp changes better since they actually measure the mass of air in lieu of calculating what it "thinks" for the air entering the engine at any given RPM....

How does Autotune for EFI Live fit in to all this.....??

Isn't it fun when a newbie comes in and starts firing questions?

1989k1500

iTrader: (23)

Your still going to have an inlet air temp sensor, just not in the MAF. If you go speed density that is.

There was a thread about this just a few days ago.
https://www.performancetrucks.net/fo...d.php?t=453311

TurboBerserker

iTrader: (1)

How much boost do you plan on running? Most of us throw the maf on the bench because we are maxing it low in the rpm curve (and are then tuning blind).

87GNTurbo6

I dunno on the boost.... shooting from the hip.......I would say I wanted a LQ4 based stock longblock.....not even a piston change...... to go to say..... 14-18 psi... on pump gas.... and alky......on maybe a single 76 turbo.... or a couple 62mm billet wheel turbos....

I might be a little ambitious....

I really don't know "what" to expect for HP for the boost..... as I have been focused on 231 cu in for so long with real crappy heads....I shoot for 25 psi on pump gas and alky.... which nets around 500-550 RWHP with a combo like I have....130 mph trap speed

I didn't think about the maxing the MAF meter... we have (turbo Buick guys) a workaround.... called an extender chip (and extender extreme) .... and a translator.... where we can read up to 768 gm/sec airflow capabilities....and use that for fueling changes. At this point... I don't have a clue what the stock PCM see's before you "maxed" it out. FWIW... the stock turbo 6 MAf meter and programming maxed out at 255 gm/sec .... and it wasn't until a guy named Bob Bailey cut some chips and developed a "translator" for using the larger LS mass air meters on our cars.... that gave us the capabilities to go "up-to" 768 gm/sec.

Anyway.... good point on maxing out the MAF....

zippy

If you plan to make any kind of big power with it you'll just want to go to SD 2 bar. You can do a closed loop system which will compensate some anyway for changes since LTFT's will still be active during power enrichement. No changes can be made to the LTFT's during power enrichement, but they will work. With the factory pcm if you get the injector info set correctly in the pcm and still use the IAT the pcm has calculations in it to adjust with the barometer changes. In general once you put in the correct info and then get the v.e. table correct you'll be fine and within a few % of the desired afr at all times.

87GNTurbo6

Thanks for the info..... but I have a couple questions:

1.) Why SD 2 bar? I would think the 2 bar is only good for 14.7 psi boost no? The 3 bar would be good for nearly 30 psi boost. (My initial boost target is 14-18 psi)

2.) What are LTFT's? edit: After a search... Long Term Fuel Trim? - we had BLM's (Block Learn Multiplier's) in the turbo Buick stuff....

That is cool the IAT sensor will give you the flexability..... will the PCM still make any changes at WOT (open loop) based on different IAT readings?

Also.... all the reading I did suggested EFI Live is the way to go.... Is this your conclusion as well? Flashscan V2 with COS5 on a 411 PCM?