explain please

[swagner]

SORRY FOUND THIS THREAD. IF SOMEONE COULD EXPLAIN THE FUEL TRIM % I WOULD REALLY APPRECIATE IT. NOT SURE IF I SHOULD BE COPYING THIS BUT I DID SORRY.

A couple things to note here before I post the results.

Thanks to all the Vendors that Supplied kits for testing
Cold Air Inductions
K&N
Airaid
Injen

Thanks Nick P. and Nick D. for helping me make this happen.

The V6 Has a totally different computer system than the V8 so I spent a full day Data logging and Dynoing around 25 dyno pulls with the car stock to get familiar with how the car responds to different test procedures and temps and so forth, this way I would know what to expect when doing the actual testing.

This car V6 AUTOMATIC CAR is Very consistent at 250 RWHP and 226 RWTQ, It repeats time and time again, I was happy to see this in the prelims.

All Testing was done on 1 tank of 87 Octane fuel.

Clearing of the fuel trims was performed before every Air Intake testing, this included the Stock Air Box.

A long Drive Cycle was done with varying loads and speeds until fuel trims settled in.

5-6 Runs were made with each system,

In the Sheet you will see AVG HP and AVG TQ, this is a measurement ch from 2500 RPM to 7000 in 50 RPM increments added together and divided by 90 test points, giving you AVG HP and AVG TQ over the whole dyno pull

In the sheet you will see Peak HP and Peak TQ, this is a measurement of the highest HP and highest TQ measured during the dyno pull.

In keeping with ACCURACY, I took the Highest and the Lowest Peak numbers (for example runs 1 & 4) added the Peak numbers together and divided by 2 for the Peak Number Gains.

I also included A/F information by request.

http://spreadsheets.google.com/ccc?k...udUNoYmc&hl=en

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Jannetty Racing Ent


SORRY FOUND THIS THREAD. IF SOMEONE COULD EXPLAIN THE FUEL TRIM % I WOULD REALLY APPRECIATE IT. NOT SURE IF I SHOULD BE COPYING THIS BUT I DID SORRY.

[swagner]

This is a copied thread. My question is at the bottom

[swagner]

Umm the link won't work on my copy for some reason. Nm I was just wondering about the fuel trim%. Stock is at -3% and the CAI intake is at +14%. I looked up fuel trim % and it says if its a positive number its a bad thing. Possibly leak or something. Just confused me.

[stock block]

the +14% fuel trim means that the car is running lean [not enough fuel to keep the motor from burning it self up]. when you add a cold air intake you change the way the air hits the mass air flow sensor. that change can cause the fuel trims to go out of wack [from -3% to 14%] in this case.

what you can do to try and prevent this is buy a intake that has been tested to keep the fuel trims at a safe -3% , or get a dyno tune right after the install of the new intake to correct the fuel trims that may be out of wack

[stock block]

a leak could cause a bad fuel trim too ,but in the case of being after new cold air intake it would be a safe bet that the sensor is getting out of its range and the ECU needs to be tuned.

[swagner]

Okay. I appreciate the explanation

[christianchevell]

It takes time for the ECU to relearn the AFR mixture and adjust the car to run richer for one and it is constantly monitoring the richness through the 02 sensors as it is. If you have a fuel trim gauge you may want to ignore it for a while until the computer of a car learns and adjusts for one, and pulling timing is what a car would do to adjust also to avoid knock with its knock retard if the car is not "happy" with the new intake for one.
And running 87 octane sucks but hey its cheap gas, not something I could use. But hey this is all without even seeing what ever this table represented as a dyno comparison.....