Ported MAF ends and LTrims?
Ported MAF ends and LTrims? I put a set of ported MAF ends on my car a few days ago to try to lean it out some. Before the car was running .925-.945 O2's, LTrims 4%-6%, 0 KR, and 25 max timing. After 150 miles or so I autotapped it again and got the following #, .885-.915 O2's, LTrims 8%-10%, 0 KR, and 27 max timing. I'm very pleased with the O2's and 0 KR along with an extra 2 degrees of timing, but the LTrims are getting too lean. I was lean before at 4-6% and now it is pretty bad. What ill effects will running this lean have on the car until I get a MAFT? Outside temps were in the 90's and car pulled very strong. Thanks in advance!
TECH Apprentice
Joined: Nov 2001
Posts: 392
Likes: 0
From: Williamsburg, VA
Re: Ported MAF ends and LTrims? I don't see where you have a problem with the ported MAF ends. You aren't running lean, just showing less of a load to the PCM, so you get a bit more timing. A/F ratio is unaffected at non-WOT. Looks like WOT O2's are in the zone. Get on a dyno with wideband to verify WOT A/F to be certain.
TECH Senior Member
Joined: Nov 2001
Posts: 7,036
Likes: 1
From: Lake Zurich, IL
Re: Ported MAF ends and LTrims? I tried ported maf ends on my car yesterday...
Took my GMAF ends, and put them on the stock MAF .... On the way home last night I was atapping and my LTRIMS were maxed out and I was getting up to 6 degrees of KR at part throttle....
I'm back to stofck MAF now (spraying nitrous and heard that the GMAF (non nitrous tuned) would lean the car out too much)
Took my GMAF ends, and put them on the stock MAF .... On the way home last night I was atapping and my LTRIMS were maxed out and I was getting up to 6 degrees of KR at part throttle....
I'm back to stofck MAF now (spraying nitrous and heard that the GMAF (non nitrous tuned) would lean the car out too much)
Re: Ported MAF ends and LTrims? I've read in several places that you want to get your LTrims as close to 0 as possible. I running 10% lean and was wondering if it matters as long as I'm getting no KR. I have a deal pending for a MAFT just in case the car needs some tweaking. Thanks for the input guys and keep it coming.
