Garrett wrote:I made some test today on a 2003 Cavalier with Cobalt SC and 2.5 Cobalt Map sensor
There is big resolution problems since 20 is 50Kpa, and 30 kpa is 75 kpa (10 psi)
it give us only 2 columns to tune the timing for the entire mapping fromd -20hg/in to 10 psi...
someone has a solution?
I think to use the 2 bar map sensor, and give a bit more resolution
There are some resolution issues, but it's not exactly how you mentioned. The 50 and 75 kpa you mentioned are absolute, not relative, pressures. What that means is you're starting at complete vac, not barometric pressure. 0 kpa on the table is complete vac, ~100 or so depending on where you live is 0 of boost and 0 of vac.
John02 wrote:Garrett wrote:I made some test today on a 2003 Cavalier with Cobalt SC and 2.5 Cobalt Map sensor
There is big resolution problems since 20 is 50Kpa, and 30 kpa is 75 kpa (10 psi)
it give us only 2 columns to tune the timing for the entire mapping fromd -20hg/in to 10 psi...
someone has a solution?
I think to use the 2 bar map sensor, and give a bit more resolution
There are some resolution issues, but it's not exactly how you mentioned. The 50 and 75 kpa you mentioned are absolute, not relative, pressures. What that means is you're starting at complete vac, not barometric pressure. 0 kpa on the table is complete vac, ~100 or so depending on where you live is 0 of boost and 0 of vac.
ok... but when I use the 1 bar, on the intake manifold the pressure goes up to 75 kpa....
when use the 2.5 fake, and the tMAP(2.5 MAP from SS SC) it goes up to 30 kpa
nice write up helped me out so much but i still get so confused that i would prolly never buy hptuners unless i could get someone else to tune for me lol
Garrett wrote:John02 wrote:Garrett wrote:I made some test today on a 2003 Cavalier with Cobalt SC and 2.5 Cobalt Map sensor
There is big resolution problems since 20 is 50Kpa, and 30 kpa is 75 kpa (10 psi)
it give us only 2 columns to tune the timing for the entire mapping fromd -20hg/in to 10 psi...
someone has a solution?
I think to use the 2 bar map sensor, and give a bit more resolution
There are some resolution issues, but it's not exactly how you mentioned. The 50 and 75 kpa you mentioned are absolute, not relative, pressures. What that means is you're starting at complete vac, not barometric pressure. 0 kpa on the table is complete vac, ~100 or so depending on where you live is 0 of boost and 0 of vac.
ok... but when I use the 1 bar, on the intake manifold the pressure goes up to 75 kpa....
when use the 2.5 fake, and the tMAP(2.5 MAP from SS SC) it goes up to 30 kpa
You're talking about under idle correct? If so, then that's normal. Under boost, with the 2.5 bar sensor, depending on how much you're pushing it might go up to about 70-80 kpa
no, In the scan it goes up to 30 kpa when full boost (10 psi) on the gage
and I don't understand why
Garrett wrote:no, In the scan it goes up to 30 kpa when full boost (10 psi) on the gage
and I don't understand why
Something must not be set up right then. I'm not sure what off hand, but I'd double check how you set up the gauge in HP Tuners.
fine , what could I show you to help me?
I still had the same problem
not ready the booost...
I have HPT and the eco SC kit and we were able to load this the other day. It started and idled fine. That's all we tried, but I was very happy to have this thread help me out, thanks to John02.
_______________________
Project L61 - Slowly but Surely
16.2@82.54 Auto w/ Intake and Exhaust
14.9@89.79 w/ a Blower
listening in.
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
So could I still use the -IPW Multiplier vs. VAC table to increase fuel in boost even though I am using a 1 bar?
I was thinking about changing only the values in the 5 and 0 only to get what I will need. What do you all think?
Darryn
2004 Cavalier coupe, 5 speed, White
GO
Hahn Stage 2, Eagle rods, Wiseco 8.9, SS Valves, Dual valve springs, valve job, Ti seats and retainers
spec stage 3, Fidanza 7.5lb flywheel, Short Shifter
Slotted and dimpled rotors, EBC green stuff
SHOW
VIS EVO CF hood, KOBE KAM 5 17", Nexxen N3000, Ebay Black tails and filler, 5% tint
Gold line springs, Tokiko D-spec struts
ELECTRONICS
Kenwood in-dash DVD and Navigation, single Kicker CompVR
http://www.cardomain.com/ride/2974835
thats what i did at first but for some reasons i had probs. I want a 2 bar so that i can give gas to the exjact psi but after reading all these stickies on how to do it i need something more simplified. im not tuning smart.
BOOSTED BABY wrote:thats what i did at first but for some reasons i had probs. I want a 2 bar so that i can give gas to the exjact psi but after reading all these stickies on how to do it i need something more simplified. im not tuning smart.
Thats not exatly how it works, The way john describes this is SO much easier than anything you will find, he tells you everything to do, step by step, WITH PICTURES
if you cant get this to work than you should probably send your car to a dynotuning shop.
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nice write up, definitely sticky this thing. this will come in handy this summer when ill get HPT and start wanting to tune the SC
12.33 @ 111.67 mph [Oct 2009]
Dyno'd on 08/02/09 - Mustang Dyno:
327.6 WHP 333.6 WTQ [10.1 AFR]
I dig the research put into this but I'm not convinced that the lost resolution isnt a problem
I still feel that a standalone is a much better solution for those that want to make changes with ecos on boost or at the very least a low ratio FMU to compensate for the top end fuel needed for those that keep the stock pcm
1989 Turbo Trans Am #82, 2007 Cobalt SS G85
Bringing this back up.
So who's had luck with the 2.5 bar tune.
I tried it, but I couldn't get the car to run well at all. Granted, I had never touched a car's tune before in my life. lol
Admiral Jedi wrote:I tried it, but I couldn't get the car to run well at all. Granted, I had never touched a car's tune before in my life. lol
Didn't you have problems with your MAP sensor or something? With that not working right it will throw off some of the tuning. I'm not sure who all has tried this, but it's worked for me. If you want to try it and have any questions I can try to answer them.
I successfully was able to create and run a 2-bar tune on my LD9.
It's actually a skidge harder than this how-to lets on, there are a few odd nuances to figure out.
But it can work.
-Chris-
-Sweetness-
-Turbocharged-
Slowly but surely may some day win this race...
John02 wrote:Admiral Jedi wrote:I tried it, but I couldn't get the car to run well at all. Granted, I had never touched a car's tune before in my life. lol
Didn't you have problems with your MAP sensor or something? With that not working right it will throw off some of the tuning. I'm not sure who all has tried this, but it's worked for me. If you want to try it and have any questions I can try to answer them.
I had that problem after I tried using the TMAP. Unrelated issue.
So after doing a ton of research, all this scaling the map readings just allows you to change timing when in boost. The negative side is you loose timing resolution in the lower pressure (vacuum).
(Tom) S/C Fire wrote:So after doing a ton of research, all this scaling the map readings just allows you to change timing when in boost. The negative side is you loose timing resolution in the lower pressure (vacuum).
The issue is if you're using a computer that's not been reflashed (so that it's expecting a 1 bar map sensor) and if you use a 2.5 bar sensor then all the timing values are going to be off because the computer will read it wrong. This "faking the 2.5 bar" not only allows you to fix that problem but also to adjust timing in boost. I believe there are some other areas besides timing that the map is used as well. I don't remember the exact table names off the top of my head, but they should be in the first post of this thread (the original faq post).
The first reason that made me do this though is that I wanted to be able to use HPT to tune my car, and I couldn't with the reflash, so this was the solution. This includes everything, not just timing.
So far I've been able to run the car with hptuners, it runs really rich at idle. I've used the injector constant you've provided and it runs fairly rich. (I even tried what the constant is suppose to be with hptuners formula) Did you tune the idle ve? Also what is everyones ve offset? I have mine at 135 and it seems to be maxed out.
Thanks for you help I already found this post extreamly helpful.
Update: (this is all on the stock 3.34 inch pulley)
So i spent a couple hours today trying to tune my car. I got the high rpm ve's dialed in. Right at 135% (35 is my offset so that is the max). Now the biggest problem now is the car idles at 10-1 afr. realllllly rich, Now being tired of it being so rich at idle, I changed most of the idle ve to 35 which is the minimum ve possible, it still idles at 10-1. what am I doing wrong, John do you have this same problem?
I also worried that I won't be able to tune it for the 42lb injectors I have and the 3.0 pulley. How would I change my injector constant?
Can I use the injector pulse width multiplier vs. vacuum to lower the afr at 20-30 kpa?
