LS1 running lean after supercharger install, help!
10-02-2005, 10:16 AM
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LS1 running lean after supercharger install, help! 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 50-52#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 run, they are negative for the most part.
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 50-52#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 run, they are negative for the most part.
Here's my dyno chart. We stopped at about 3.5K due to the AF not coming down.
10-02-2005, 12:43 PM
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You definitely need to richen it up substantially.
11.5: 1 is a safe AFR for the street.
Edit: BTW was this at speed dreams?
11.5: 1 is a safe AFR for the street.
Edit: BTW was this at speed dreams?
Last edited by sscam68; 10-02-2005 at 01:19 PM.
10-02-2005, 01:21 PM
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Thanks for the input. I was thinking the same (need to richen up) but wanted second opinions. This particular pull was from Dyno Edge, but the one from Speed Dreams (did it about 3 weeks ago) looked basically the same. Now to figure out what needs to be done.....fix mechanical issue or address via tune??
10-02-2005, 02:17 PM
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Do you have a boost referenced fuel pressure regulator?
If not you are going to need to adjust your fuel curve to compensate for the positive pressure inside your manifold.
The rest is a matter of adjusting your VE and PE tables. I assume you have some sort of a fuel pressure gauge? Are you maxing out the MAF?
Chris doesn't do any GM stuff, only fords.
If not you are going to need to adjust your fuel curve to compensate for the positive pressure inside your manifold.
The rest is a matter of adjusting your VE and PE tables. I assume you have some sort of a fuel pressure gauge? Are you maxing out the MAF?
Chris doesn't do any GM stuff, only fords.
Last edited by sscam68; 10-02-2005 at 02:39 PM.
10-02-2005, 02:43 PM
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Originally Posted by sscam68
Chris doesn't do any GM stuff, only fords.
Looks like I'm going to have to get HPT and do this myself 
10-02-2005, 02:57 PM
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Originally Posted by muncie21
Yea he mentioned that. Too bad as it seems like he had a basic understanding of modern EFI principles... Looks like I'm going to have to get HPT and do this myself
Looks like I'm going to have to get HPT and do this myself I've got a twin turbo kit that is going on my car pretty soon but there are a few odds and ends that I need to do before I install it. I've got a pretty good idea of what I need to do, it's just a matter of doing it. Previos job didn't give me the time, working for a new company now and have 2hrs more a day. Trying to figure out what to do with all the extra time
. I'm a mechanical engineer by education, design engineer by trade.I'm also writting algorithms to handle a lot of the work for me, on top of what HPT already offers.
Edit: do you have any of the above mentioned hardware?
10-02-2005, 02:58 PM
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Hmmm...wonder if your fuel pump is getting enough voltage or if it's strong enough to keep up with the new setup. I thought we were supposed to run at 58psi?
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10-02-2005, 03:24 PM
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Originally Posted by SSpdDmon
Hmmm...wonder if your fuel pump is getting enough voltage or if it's strong enough to keep up with the new setup. I thought we were supposed to run at 58psi?
