If everyone only knew the pain in the assery this is to create a tune for.....
and a couple giggles.
Edited 1 time(s). Last edited Wednesday, June 25, 2008 1:03 PM
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
^^^^
shut up you, we still got something else you need to work on
Wrench Monkey wrote:
If everyone only knew the pain in the assery this is to create a tune for.....
been there and done that..
P&P Tuning
420.5whp / 359.8wtq
Ryan... I know you do a ton of tunes! Have you faked a 2 bar on a 2.2? That would be a good setup too....
Have you ever tried it on a 2.4? If so I'd love to see what you did to see if I'm on the right track.... you're the experienced tuner, I'm just trying to cobble together something that works... lol
Btw you gonna be at the bash again this year?
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
LAFNGAS wrote:^^^^
shut up you, we still got something else you need to work on
Im using Chris as a test bed for a fake 2 bar to help create a fake 3 bar for the GMSC
SweetnessGT wrote:Ryan... I know you do a ton of tunes! Have you faked a 2 bar on a 2.2? That would be a good setup too....
Have you ever tried it on a 2.4? If so I'd love to see what you did to see if I'm on the right track.... you're the experienced tuner, I'm just trying to cobble together something that works... lol
Btw you gonna be at the bash again this year?
-Chris-
I started doing a fake 2bar on a 97(speed density LN2) , but the guy decided to sell the vehicle... On mine and my wife's car, I flashed the LD9 SC reflash and rescaled everything.. Mine was perfect, although I will be redoing it all when the new engine is built. (finally popped #3 ringland).. My wife's is an auto and her car has been more tempermental. Her tune tune is perfect at cruising/boost and spray, but finicky when starting and at cold idle. I am still in process of fine tuning it. The hardest part is trying to get the injector constant close do to the 2 different displacents and stock constants. I would love to know GM's exact formula for how they came up with the SC reflash....
I will be at the Bash again this year, but without the car... Not enough time to get new engine built and broke in... We will be bringing Wife's new rear mount setup
P&P Tuning
420.5whp / 359.8wtq
Chris and i may have figured out why the constant is high on the GMSC
Wrench Monkey wrote:Chris and i may have figured out why the constant is high on the GMSC
I always thought it was high to keep the VE off set low.
FU Tuning
I think its a combo of a couple of different things.
Like John said the VE offset may have to be higher with a lower inj constant. Which we all know bringing up the VE offset creates idle tuning problems.
Another thing is GM probably didnt want to have to completely redo the computer software so they stretched out the tables a bit kind of like doing a fake 2 bar. Just like doing a fake 2 bar you need to bring your inj constant UP (higher numbers).
Damn.... i lost my train of thought... ill post back some more when i think of it.
I thought the IPW vs VAC table was missing on the pre2k ld9's?
Wrench Monkey wrote: Damn.... i lost my train of thought... ill post back some more when i think of it.
Please do Tom. I know Todd even said it was kinda funky... (possible estimated VE from the SC).. I just would like to know more in depth so I can better it on the LN2...
P&P Tuning
420.5whp / 359.8wtq
2 bar faking isn't as hard as it seems, you just need to tune in your values correct.
I borrowed this from one of Slowolej's posts from the LT3 discussion board. This is probably the key you will need to translate into your tables to get proper values.
While the below was posted for the 2.0 TBI OHV motor, it is relavant to our motors as well.
Depending on what software you are using to tune your tables, it is possible. My latest version of the $36 in tunerpro should be able to tune all existing map based tables.
I don't have a dyno, and my boost setup on the car yet, or i'd probably upload a base 2bar and 3bar tune for everyone.
I recently had a daughter, so my boost project is on hold until i have some more spare cash.
"Here's why the conversion isn't simple. There's only 5V to represent the MAP signal. A 1 BAR MAP uses that 5V to represent a range from 20" of vacuum to 0 psi boost. a 2 BAR sensor uses the 5V range to indicate readings from 20" vacuum to 14.7 psi boost. For each sensor, a change of 1 volt indicates a different change in pressure. If the 1 BAR sensor supplies 3 V at 5" vacuum, for example, and you replace it with a sensor which produces 3V at 10 psi boost, the poor ecm will "think" the engine is at 5" vacuum. Because both fuel and spark values are highly dependent on MAP readings, the ecm would deliver less fuel than needed while supplying more spark advance than needed.
While it's possible to get into the spark and fuel tables and recalibrate them, it's extremely time consuming. What's worse is that the sensor signals aren't linear. You'd need to use the pressure to voltage relationships of the two sensors to decide how to rescale any MAP related tables. Not impossible, but more work. And to top it off, I don't know of anyone who has the tuning software available for the TBI 4 cyl ecms.
You might look at Mega-squirt or the 1227749 turbo Sunbird ecm as suitable replacements. It's also possible that you could adapt an ecm which uses a MAF sensor to run your TBI system. None of these answers are plug and play, although you might find the Mega-squirt to be the least intimidating."
SweetnessGT wrote:BP wrote:I thought the IPW vs VAC table was missing on the pre2k ld9's?
Nope... pre 98 LD9's.
I have a 97 auto, 98 manual, 98 auto, 99 auto, 99 manual, and a few 2002 supercharged LD9 pcm's..... and the only one missing the IPW vs VAC table is the 1997 manual Speed Density pcm.
-Chris-
I have also a 97 (non SD) and it does not have it. Every other J file 98+ I have seen has it.
FU Tuning
I was right....
The gmsc flash and n/a flash have the same size tables all they did was change the values between the two....
They basically did a "fake" 2 bar but had the ability to change the values in the table where as we have to calculate the values. WOW gm really did a hack job with this tune.
John Higgins wrote:SweetnessGT wrote:BP wrote:I thought the IPW vs VAC table was missing on the pre2k ld9's?
Nope... pre 98 LD9's.
I have a 97 auto, 98 manual, 98 auto, 99 auto, 99 manual, and a few 2002 supercharged LD9 pcm's..... and the only one missing the IPW vs VAC table is the 1997 manual Speed Density pcm.
-Chris-
I have also a 97 (non SD) and it does not have it. Every other J file 98+ I have seen has it.
97's are the only ones I have seen that have "one" o2 sensor also. Does the Sd and Alpha-n only have one o2?
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
I think david is happy with his 00 GM tune.
PRND321 Till I DIE
Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
M45 + LD9 + 4T40-E, GO GO GO
I know he's happy with the functionality of it but msising gauges... all the lights lit up...
It's not for me I guess. I couldn't live with that. I have an airbag light on that pisses me off. lol
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
so your not even using a sd tune at all, ur using alpha-n but taking advantage of the ipw multiplier?
now i know nothing about writing code or programming, but these pcms are the same. if we wanted we could flash a 98 or 99 calibration onto a 97 comp. either way you could start out with no ipw table, flash a diff calibration and now have it. what im trying to get it is, is there anyway to manipulate the code, or add the code of the ipw table to say the 97 sd tune? its not the pcms incapability to have the ipw table on the sd one, its just the code for it isnt there. so i ask can it be added without doing a write entire, or what im really saying is can it be added without using hpt but say someone go in and program it in?
Yes I'm staying Alpha N and exploiting the Injector PulseWidth table since its map based.
No way to add the table to the SD tune... GM didn't put it in there so... it's not there. Sadly it makes the 1997 SD tune mostly useless from what I can see, unless there is something I'm missing.
As for somebody programming it - I have no idea. I'm not as deep into tuning as say Todd or Slowolj or Ron....
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
I've got a 98 z24 auto and it has no IPW vs VAC table... from the other vcm files i've looked at (with HPT) the IPW vs VAC tables are right under the injector constant, right?? Does this mean trying to fake a 2-bar is useless when I turbo since I can't change the fueling in boost since my car is alpha-n? I'm just upgrading to 440cc injectors and was planning on using HPT to do all the tuning (and yes I have a wideband).
Jeremy
Well thats not the first I've heard of that. Send the VCM out to HPT and tell them the table is missing it should be there. It was missing from 2 tunes last year for me for LD9's and I sent an email over with the VCM and they found out it wasn't showing up and added it.
Also, if worst comes to worst... pay 2 credits to license a 98 VCM with the table, and fake the 2 bar if you want.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
