Big Changes--Need tuning advice

[coachcrow56]

Guys--getting ready to install Gen 3 Stage 2 Intercooler, 3.0 pulley, Northstar Throttle Body 77mm, Lucas 42.5 injectors, TAC Adapter. This car is my daily driver---so I really don't need any big issues after the install. What tuning suggestions do you guys have for the MAF and AE to get a good start on my tune?

[JerryH]

When doing as many and as major changes as you are at once, there is no one answer. Dialing it in is not a simple 1 tune affair and you will likely need to do some basic changes, get it running and do some serious tuning and dialing in.

For basics, you are going to need an LQ4 MAF or if your car can idle/start, it will need several MAF tunes before it runs right.

You obviously will need to change the IFR to reflect the changes in larger injectors.

The more effective S/C with smaller pulley... I would definately think it wise to slap a larger pulley on it and dial down the general things, then change pulleys and see if your car can handle it... its not a must, but it *does* add a greater margin of safety.

As far as tuning suggestions go... VE tune, MAF tune and dial in your O2s (or wideband numbers)... you know... just the basics. Don't do any WOT runs until the base is nailed down!

Once that is done, some adjustments to things like torque management and timing tuning are in your future.

Basically my friend, you have a lot of work cut out for you. I hope you weren't thinking that after doing ALL those mods, all you had to do was press the secret "perfect race tune" button and think it was good... lol !!

[coachcrow56]

I know that I have a lot of work to do, and NO WAY will I go WOT until I feel comfortable with a base line tune. I was just hoping someone would give me an idea as to how much I should scale down the MAF (percentage wise) and the Injectors.

[JerryH]

MAF... your scans will tell you what to do. Do a VE tune before you do a MAF tune.

Injectors? What year/make car are you using? If its a 97-03 GTP multiply your IFR by 0.874. This will lower the numbers in there to a good base numbers to start from.

Stock GTP injectors are 36#. 36 divided by 42.5 = 0.84705(etc...) hence 84.7% of original numbers.

[Russ K]

Jerry,

You would multiply the IFR table by 1.18. Making the IFR table lower will richen the AFR. And I always leave the VE table stock, just tune the Maf with the Maf AFR % Error histogram. The VE table is only used if the Maf fails and during throttle transients.

Russ Kemp

[ct06gto]

Jerry, you still stuck on the pt ways.
42.5/36= 1.1806

So the whole table needs to be multiplied by 1.1806

[damojo2003]

LOL...Jerry will not be the only one. Remember that you will be flowing more air and the adjustments in the max positive airflow in the MAF will need to be increased. The AE, I would start by increasing 10% and see how she feels. You might need a bit more to offset the additional airflow

[JerryH]

LOL... yeah, some changes of thought are overdue coming... thanks for putting up with my PT-based obtuseness.

"The VE table is only used if the Maf fails and during throttle transients"

That is where I will agree... and disagree. The VE table is used a lot more than most suspect, and indeed at least on my car, it makes a great deal of difference at various levels. The engine runs smoother, MPG increases, trims lock in easier (and of course the car doesn't ru like crap if the MAF fails).

This is not something I say lightly after doing one or two chages, but over the course of 3 years I must have done at least 60-70 VE "tunes" starting out from 100% stock and well modified bins, and not only of 1999 based bins... but also bins coming from 98 and 00 to 02 on my car. I've done VE tunes on at least 20 other cars and all show similar results.

Even the 97's benefit. Foghorn's car was noticeably smoother and stronger... to the point it even sounded different. Don't believe me? Ask him, he was driving the car as we were doing it.

Many others also noticed strong benefits. The further that you take away a car from stock, the greater the benefits of modifying the VE become.

I've proven many times that one of the main reasons I get *consistant* 39 MPG on my GTP is a well massaged VE table. Returning the VE to stock and massaging the MAF lightly back results in a 4MPG drop on my car... and thats not 4 MPG on the DIC... but distances measured on my GPS and fuel amounts as measured from my gas receipts.

I encourage anyone who has never played with their VE tables... give it a try. This process has become a tried and proven part of a complete methodology to tuning our cars for best effect.

[Russ K]

Jerry,

If the tune is in closed loop, the AFR will be ~14.7 no matter if the LTFT's are 20% positive or negative. Of course you would want to get the LTFT's close to 0, but changing the VE when the Maf is being used makes no diff in the closed loop AFR.

On the LSx cars & V6 trucks, you can lower the O2 switch point MV to lean the closed loop AFR.

Russ Kemp

[JerryH]

That is what many say, but Russ... all my tests and hundreds of PT users and other tuners in the 3800 community all cannot be claiming results falsley. If you have never tried it... please do. You will be pleasantly surprised.

[Bandit gs]

Which AE table are you guys changing? Nobody ever seems to have the answer, always hear add to the AE table, there are tons of AE tables.

[damojo2003]

Good point Bandit

I change the AE Enrichment table. Now if HPT has more than PT in this case, then I don't know which one to change

[ct06gto]

Which AE table are you guys changing? Nobody ever seems to have the answer, always hear add to the AE table, there are tons of AE tables.

acceleration enrichment vs tps maximum delta is the table in hpt that pt users know as ae enrichment.

In hpt i multiplied this table by 1.12 on my impala ss.

[damojo2003]

acceleration enrichment vs tps maximum delta is the table in hpt that pt users know as ae enrichment.

In hpt i multiplied this table by 1.12 on my impala ss.

That be the one

[Bandit gs]

acceleration enrichment vs tps maximum delta is the table in hpt that pt users know as ae enrichment.

In hpt i multiplied this table by 1.12 on my impala ss.

Thanks, i'll give that shot, finally an answer.

[85DropTopTA]

That is what many say, but Russ... all my tests and hundreds of PT users and other tuners in the 3800 community all cannot be claiming results falsley. If you have never tried it... please do. You will be pleasantly surprised.

could this definition of the VE table also apply to the V6 cars
http://www.hptuners.com/forum/showthread.php?t=687

It goes along with the working theory we had before.

[louvered97gtp]

Jerry,

You would multiply the IFR table by 1.18. Making the IFR table lower will richen the AFR. And I always leave the VE table stock, just tune the Maf with the Maf AFR % Error histogram. The VE table is only used if the Maf fails and during throttle transients.

Russ Kemp

Sorry guys, i'm really trying to follow along and learn but it's all moving faster than i can keep up with so far. Where is this MAF histogram? i've only seen this on the editor, not the tuner. Does it need to be created? Couldn't find info on accesing or creating this in help files.
Thanks

[Russ K]

You can use my V6-FWD-WB config file. Just insert your brand of wideband in the table display. The Maf histograms are all set up.

Russ Kemp

[louvered97gtp]

You can use my V6-FWD-WB config file. Just insert your brand of wideband in the table display. The Maf histograms are all set up.

Russ Kemp

Thank you so very much. Appreciate the nudge.