car running lean?
Thread Starter
On The Tree
Joined: Apr 2002
Posts: 184
Likes: 0
From: Knoxville TN
car running lean? ok bear with me on this, i am still new at the lean/rich stuff. running lean is to much air and not enough fuel? and just the opposite for rich? correct? ok so when these other people are doing some mods to thier cars and causing them to run lean what exactly are they doing? and what other mods will cause you to run lean?
sorry about rambling but i am still confused
d <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
sorry about rambling but i am still confused
d <img border="0" title="" alt="[Confused]" src="images/icons/confused.gif" />
Re: car running lean? Here are a few Mod's that can lean an LS1, sometimes with a very nice power gain.
Hand ported MAF housing. The air metering is no longer accuarte due to the porting and more air goes by than is measured. This causes the car to lean out, sometimes more than is desired so the car pings or gets KR.
HPP3 or other aftermarket programmer will usually lean the car out some.
Aftermarket MAF - usually they are calibrated to lean the car out a little or bump the timing up or both to get the power gain. SLP, Granitelli, Pace all offer MAF's and use some combo of this approach.
MAFT - can be used to lean or richen the car up. Atap or a few dyno runs with an O2 are needed to get this right.
LS1 Edit - can be used to lean or richen the car as desired. Much more flexible than a MAFT or HPP3.
Headers can cause a car to richen up, because the O2's are usually moved and see a slightly diffrent exhaust mix. Usually for best results tuning using a Atap to monitor will get best results.
Bigger fuel injectors than stock will richen a car up.
There are others things but these are few basic's to keep in mind. Mod's like Frenco's, Baker Hose, Ported TB's etc occur after the MAF and do not affect the A/F unless their is a leak or vaccum leak. Most bolt on cars make their best power in the 12.9 to 13.1 A/F range usually.
At the dyno my car showed an A/F of 13.0 on the wide band, which the dyno operator said was pretty ideal and not lean it out with the MAFT, because under load on the street, in the summer the car would tend to lean out a little more and it might ping.
Hand ported MAF housing. The air metering is no longer accuarte due to the porting and more air goes by than is measured. This causes the car to lean out, sometimes more than is desired so the car pings or gets KR.
HPP3 or other aftermarket programmer will usually lean the car out some.
Aftermarket MAF - usually they are calibrated to lean the car out a little or bump the timing up or both to get the power gain. SLP, Granitelli, Pace all offer MAF's and use some combo of this approach.
MAFT - can be used to lean or richen the car up. Atap or a few dyno runs with an O2 are needed to get this right.
LS1 Edit - can be used to lean or richen the car as desired. Much more flexible than a MAFT or HPP3.
Headers can cause a car to richen up, because the O2's are usually moved and see a slightly diffrent exhaust mix. Usually for best results tuning using a Atap to monitor will get best results.
Bigger fuel injectors than stock will richen a car up.
There are others things but these are few basic's to keep in mind. Mod's like Frenco's, Baker Hose, Ported TB's etc occur after the MAF and do not affect the A/F unless their is a leak or vaccum leak. Most bolt on cars make their best power in the 12.9 to 13.1 A/F range usually.
At the dyno my car showed an A/F of 13.0 on the wide band, which the dyno operator said was pretty ideal and not lean it out with the MAFT, because under load on the street, in the summer the car would tend to lean out a little more and it might ping.
Thread Starter
On The Tree
Joined: Apr 2002
Posts: 184
Likes: 0
From: Knoxville TN
Re: car running lean? 99 BlackBird T/A
thanks for the response and it will give me something to think about, but you said that sometimes making the car more lean will increase horsepower, i thought that a car that was lean would be bad(sorry still learning all of the tearms and what they mean)
thanks
d
thanks for the response and it will give me something to think about, but you said that sometimes making the car more lean will increase horsepower, i thought that a car that was lean would be bad(sorry still learning all of the tearms and what they mean)
thanks
d
