Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

Moe, I'm way out of the game, but I have a couple questions for you. Are you turbo or supercharged? What did you do when the MAF reading max'd out (~500 gm/sec?)? On mine, the MAF reading would flat-line well before peak power.

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

At the time I was supercharged, now Turbo, I basically maxed out the multiplication factor in the MAF tables and controlled the rest in the Power Enrichment scale. Also another trick is to manipulate the IFR and control your off boost fueling by the MAF, Like I stated, this worked, my fueling was on target on and off boost and I still got in the upper 20's MPG on the highway. But some people were saying the controlling the fuel in the PE mode was the wrong way to do it. I ran like this for about 8 years. If I still had old graphs I would post them so you could see where the A/F was just like an NA motor but to my commanded A/F. Tip in was great, no Problems...I will be tuning my Turbo setup soon and I will get back with you and post what I did, But I know with the Turbo setup, it will be a little more tricky to setup due to the boost producing load vs the load producing the boost...

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

Exactly. The factory settings are to allow PE in at 30-66% throttle. The funny thing about a turbo is that you can be at full throttle but only be making 40% of your max power (before spool-up). You can also be at 50% throttle but make 90% of your power.

I ran MAF and handled Power Enrichment just like you when I was running 15 psi from a T-trim. It worked pretty well and got me into the mid 10's at over 130 mph. When I switched to turbo, I had bogging problems off the line, because PE would kick in before the turbo spooled up. It would go pig rich and fall on its face. I got some decent times in colder weather like that, though. Perhaps I could've spent some more time playing with it and got it better, but I finally just switched to 2-bar SD since that's how my PWC was from the factory at the time.

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

You are correct, I was at the infant stages of tuning on the turbo just to get it ready for the LTx shootout so I had only a few dyno pulls, Mine too had a bad bog off the line but I was also launching at idle due to the entire motor, drive train set up was brand new with O miles. Here is where getting into the MAF tables can help. You will have to data log your Hz of the maf vs the KPA and start adjusting, In some instances the PE mode might help to but like you said the % of throttle vs the Power differs, I'll let you know what worked best for my setup when Im done...

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

Moe, can you post a copy of your 2 bar maf tune.

Also, what are you using for data logging? I am using the history table feature in TunerPro RT.

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

When I get my final tune in, hopefully in a few weeks, I will post it. I am using Datamaster for logging...

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

What a long lived post/thread :)
I've downloaded dookies file (Dan_156) and made the changes for my smaller displacement (355) and my larger injectors (95 * 35% = 33.3# in the Injector constant.
I kept my timing from my old tune for the time being but used all of Dookies fueling cells.
I bought a new GM 2 bar sensor and will install it all over the weekend and test fire her up. Thanks for all the hard work and input guys!
Dave

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

I never made it to the shoot out so I am now concentrating on all the other items that needed to be fixed, going to get some custome 1 3/4 headders maded up so I can change the dang plugs, Then I will dial in the meth kit and get her tuned, I will send you and mike my files if you like and then you can see what I have done, also as mike was stating about the %TPS vs full power ect, What I also found was being in the deep negative in the PE where your KPA is in the off idle parameters.

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

Thanks man!

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

Because my Tunerpro software doesn't show the baro reset parm, can I assume that Dookies latest downloadable file already 'has' the baro reset value set?
Thanks,

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

Well the sensor didn't arrive on Friday but was here on Saturday at 11am. Wish I'd had more time to play with it but...

1. Installed 2 bar sensor
2. Loaded Dookies .bin with my cubes, 95# injectors factored to 33%
3. Test fired her.
4. Would start immediately but died within 2 seconds
5. Tried again while trying to capture sensor info via Datamaster and my wideband
6. Moved the injector constant from 31# to 40, started it up, same start/stall behavior.
7. Moved the IC (injector constant) to 50, same start stall but I noticed that the pulse widths were minimal.
8. Switched the IC to 40, copied my original MAF tunes lower range VE into Dookies tune and she fired up and idled, though a bit rich.
9. Changed the IC to 42 refired her up, better WB readings at 13 to 14.
10. Took her for a test drive and as long as I stayed in the 800 to 2,000 RPM range it was okay. Once I ventured into the upper VE ranges which I hadn't modified, it would go instantly lean and sputter/try to die.
11. Had to stop there and take the wife to get her new car :(

I'm pumped! Even at this small RPM range, the throttle response seemed better. Looking forward to next weekend(I work out of town Mon - Thur) so I can get her more refined. (And possibly install my new PT76 GTS turbo too!)

Again to all you contributors here, a generous THANKS!

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

Got back late yesterday and got to do some testing/tuning today.
I copied in my old tunes VE setttings(which, I discovered are stock). I set the IC(Injector Constant) to 44 and started her. Good high 13.x to low 14.x idle WB readings but flapping the throttle got instant lean stumbling. Fark.. So went down to 42 again on the IC. Same stumbling. Set the IC to 40, got some stumble, but slighty better. Took the IC down to 38. No stumbling but rich now. Dropped every VE in -2 increments and tested each time. It got better with each drop though still slightly rich. I decided to take her for a test drive. VERY crisp responsiveness! And... I got into a fair amount of boost. The WB showed 11.x all through it and it pulled hard! Had to quit for the day (date night) but I'll try again tomorrow(Saturday). Loved the DFCO setting too. Complete lean, lol... Thanks for everything Dookie and EngineerMike.

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

Because this thread is referenced so often when folks have 2 Bar SD questions, I'd like to keep it 'fresh'. I've seen elsewhere where people have made blanket statements regarding the 2 bar SD tune to "Just divide all your MAP based tables/Scalars by 2 and that's a good baseline".

The results look unusable to me.

Stock AFR...
http://www.taekwondoplus.org/z28/Turbo/Stock_AFR.JPG

Halved AFR...
http://www.taekwondoplus.org/z28/Tur...AFR_halved.JPG

Stock High range spark...
http://www.taekwondoplus.org/z28/Tur...high_spark.JPG

Stock High range spark halved...
http://www.taekwondoplus.org/z28/Tur...ark_halved.JPG

Stock Low VE range...
http://www.taekwondoplus.org/z28/Turbo/stock_low_VE.JPG

Stock Low VE range halved...
http://www.taekwondoplus.org/z28/Tur..._VE_halved.JPG


I halved my injector constant from 95# to 38# then tried halving the VE's. It would start but not run. I put the stock VE back in and it would stay running.
I had to do some trimming but the typical deviance from stock VE in the 400 rpm to 2,000 rpm is -1.95 to -3.91(in other words, my VE is less that stock VE by those values)

My wide band says it is still a tad rich so I'm continuing to test/tune. Performancewise, in boost, it seems stronger than ever. Especially in the lower boost levels where, with the SD tune, I can keep my timing agressive. I've tailored the spark to where all but one spot of RPM is free of knock retard.

When my tune is finished, I'll put it on here as a basis for others with a similar setup.
In the meantime, as I make progress, I'll post it here with my triumphs and setbacks so folks can see what was done and the effect of it.
Thanks,
Dave

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

My latest effort (2 bar SD number 29, whew..) is great! I've been to 16psi with it, trimming out any knock retard as I encountered it. Trimming fuel via the VE Tables and it's damn near perfect. I cut and pasted the Spark Advance, MAP and RPM from my 1 bar MAF tune to a spreadsheet, highlighted it with Yellow, then cut n pasted my 2 bar SD tunes Spark Advance, MAP and RPM to the same columns, leaving them uncolored/highlighted. I then sorted the 3 columns by RPM, then MAP, and finally Advance. I had excluded the rows for 0%TPS and zero MPH. In every situation, I had a LOT more spark advance throughout the RPM range till Max Boost. The result is a smooth acceleration in traffic, crisp acceleration when getting aggressive and huge grin production when flooring it. I have to drive 250 miles each way in my travel to/from my job site. I drove it tonight on the freeways with the cruise control set on at 75mph. The Wide band typically shows 14.2 right now. Gas mileage seems to be better too.

The only thing this is still 'off' is the DFCO settings when in cruise control and I start going down a decline. It bucks very noticably till it figures out it's decelerating. Now, with foot pressure (non-cruise control) it's fine.

Re: 2 Bar Stock PCM Speed Density Tune for >6psi (Forced Induction)
 

In researching DFCO settings, I found a forum where the recommendation was to zero out the DFCO Enable vs TPS Threshold vs RPM. I did that this morning and the car is MUCH improved getting in and out of the throttle at low speeds. It was bucking quite a bit but now I have only a hint of that under certain conditions.