help with tuning a built car...
05-04-2009, 11:19 PM
#1
help with tuning a built car... Here are my mods:
ms4
prc 2.5 5.3's milled .030
with stock mls gaskets
42lbs delphi injectors
fast 90/90
underdrive pulley
electric water pump
harland sharp rockers
85mm lid
forged bottom end with -4cc valve reliefs
Pretty much everything you can buy for an ls1.
I've taken the efi university 101 class, and have a good basic understanding on how tuning works. I want to tune the car in sd mode and make as much power as possible. My friend has a mustang dyno and has tuned ls1s before. He tuned another one of my friends cars that I built with a forged bottom end and a 232/234 cam that made 397 on the same mustang dyno. This time I'm going to be helping him tune the car since its mine. I was wondering if you guys have any pointers such as:
How much timing
What afr should be ran with that kind of compression
Little things to watch out for.
Any help people could throw in will help and will be greatly appreciated.
Sorry for the long post...
ms4
prc 2.5 5.3's milled .030
with stock mls gaskets
42lbs delphi injectors
fast 90/90
underdrive pulley
electric water pump
harland sharp rockers
85mm lid
forged bottom end with -4cc valve reliefs
Pretty much everything you can buy for an ls1.
I've taken the efi university 101 class, and have a good basic understanding on how tuning works. I want to tune the car in sd mode and make as much power as possible. My friend has a mustang dyno and has tuned ls1s before. He tuned another one of my friends cars that I built with a forged bottom end and a 232/234 cam that made 397 on the same mustang dyno. This time I'm going to be helping him tune the car since its mine. I was wondering if you guys have any pointers such as:
How much timing
What afr should be ran with that kind of compression
Little things to watch out for.
Any help people could throw in will help and will be greatly appreciated.
Sorry for the long post...
05-05-2009, 12:03 AM
#2
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Join Date: Aug 2006
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Timing: I'd say start around 23-24 max and see how much power it makes, then move up from there in 1 degree increments until you don't see anymore power then stop, of course monitoring KR and what not.
AFR: I'd shoot richer than ideal simply because you want a safety zone until you get your VE right on the money. I'd set your EQ table to 1.0 across the board, and set your PE to command something like 12.5:1. Once you have your VE closer, move more toward 13:1 and see if you make more power there.
Other tips: Pay attention to your TB when tuning, those 90's can be finiky (moving blade at with idle surging, etc).
Also, I can give you advice on your injectors. Scale your IFR accordingly, and then you will probably want to use the Injector Offset values out of a 05 Silverado 6.0L. They came stock with disc type injectors, so you will be closer using that table over your stock LS1 table. If you still have idle issues (rich idle, even when you drop VE) try dropping the min injector pulse width to around 1ms.
I'm sure there is more stuff, but these are just some things off the top of my head.
AFR: I'd shoot richer than ideal simply because you want a safety zone until you get your VE right on the money. I'd set your EQ table to 1.0 across the board, and set your PE to command something like 12.5:1. Once you have your VE closer, move more toward 13:1 and see if you make more power there.
Other tips: Pay attention to your TB when tuning, those 90's can be finiky (moving blade at with idle surging, etc).
Also, I can give you advice on your injectors. Scale your IFR accordingly, and then you will probably want to use the Injector Offset values out of a 05 Silverado 6.0L. They came stock with disc type injectors, so you will be closer using that table over your stock LS1 table. If you still have idle issues (rich idle, even when you drop VE) try dropping the min injector pulse width to around 1ms.
I'm sure there is more stuff, but these are just some things off the top of my head.
05-05-2009, 12:22 AM
#3
ok thanks.. sounds like a bunch of good info... Right now its set at 22 degrees and has a base tune from a shop that recently closed that i was going to have do my final speed density tune. it doesn't have the injectors in yet but it stumbles all over itself at 1500 rpms, if you are shifting that low the car will stumble then jump out.
05-05-2009, 02:37 PM
#5
your question is very vague; it's kind of like "how do you tune?" To some extent, things like spark and fuel will be determined by what the car likes rather than a value that we post here, though Rodan's response is definitely relevant.
You will get more responses asking about specific issues that you are having that can be addressed such as: At 35MPH in 4th I get surge at light/no throttle 1500RPMs, or I get a hang or dip on decel, or my car is very rich at decel... etc.
Best of luck.
You will get more responses asking about specific issues that you are having that can be addressed such as: At 35MPH in 4th I get surge at light/no throttle 1500RPMs, or I get a hang or dip on decel, or my car is very rich at decel... etc.
Best of luck.