Any ideas why I'm running lean?
Any ideas why I'm running lean? Prior to the install of my Magnuson supercharger my AF ratio came down to around 12.4 or so after 2K RPMs and stayed there. After installing my supercharger and downloading the provided tune I'm seeing high to mid 13's all the way up to 3K RPMs.
New 42# injectors were installed with the supercharger
Fuel pressure at the manifold is about 52-55#s
I've been all over the motor with starting fluid looking for a vacuum leak..didn't find anything.
Had someone with a scanner log my LTFTs during a street run, they are negative for the most part.
Called Magnuson, they say that they've been sending out the same tune for years. Supposedly no way I could have gotten a bad one.
Here's my dyno chart. We stopped at about 3.5K due to the AF not coming down.
New 42# injectors were installed with the supercharger
Fuel pressure at the manifold is about 52-55#s
I've been all over the motor with starting fluid looking for a vacuum leak..didn't find anything.
Had someone with a scanner log my LTFTs during a street run, they are negative for the most part.
Called Magnuson, they say that they've been sending out the same tune for years. Supposedly no way I could have gotten a bad one.
Here's my dyno chart. We stopped at about 3.5K due to the AF not coming down.
99 C5
Originally Posted by MECHAM
#1 - tune
#2 - what vehicle is this on? LS1 base fuel psi is 58-60...
#3 - add a rising 1:1 regulator
#2 - what vehicle is this on? LS1 base fuel psi is 58-60...
#3 - add a rising 1:1 regulator
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Just a thought, but could your calibration on the wide band be off. Looks like the entire AFR band is a little lean. Like if it were rescaled it would be right on. It is reading over 15 afr at around 2,250 rpm. At that ratio it should almost be bogging. Have you checked or verified this with another wide band?
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Originally Posted by nitrorocket
Just a thought, but could your calibration on the wide band be off. Looks like the entire AFR band is a little lean. Like if it were rescaled it would be right on. It is reading over 15 afr at around 2,250 rpm. At that ratio it should almost be bogging. Have you checked or verified this with another wide band?
and correct it if there's any issues. Gotta luv that kind of support. Unfortunately, I'll be without my car for about a week while this takes place. 
TECH Apprentice
Joined: Jul 2005
Posts: 354
Likes: 0
From: Wilton Ca. (Sacramento)
Originally Posted by Jaegermeister2k
Ok. Just read you stopped the run. I don't see why. I've seen cars do a full dyno run with worse A/F. My a/f is awefull untill i hit around 4k. But i'm N/A. Get her tuned.
You don't make a full pull on a blown motor when it's that lean or you may be picking up parts after the run. They were smart to stop until they figured out what's going on. My first thought is that the tune may be made for a boost referenced regulator and this one isn't.
Jody
TECH Apprentice
Joined: Jul 2005
Posts: 354
Likes: 0
From: Wilton Ca. (Sacramento)
Originally Posted by Jaegermeister2k
Is 13.5 that bad on a blown motor at 5 psi?
Jody
Originally Posted by camcojb
I think eventually it'd wound it, but maybe not in one pull, especially on a dyno that doesn't load as hard as on the road/track. But it is lean. Some guys will go mid to upper 12's on A/F, but on the higher power stuff it's usually high 11's to low 12's.
Jody
Jody
