Front pipe

[victorb]

Hi guys, I recently installed the greddy sp elite. Now, I am planning to change the front pipe, the invidia resonated cat less or the Megan cat less

Car mods: Perrin drop in and greddy sp elite axleback.

I've been reading two threads (fa20's post zn86's post). Currently confused if I still do it as it will make the a/f richer thus decrease in HP.
I don't plan to have it tuned.

Your Inputs will be appreciated

[WatchmaN]

In the same line of thought, does anybody know which pipe makes the most hp?

[SubaSteve]

Worries about performance but doesn't want a tune.

[mad_sb]

Originally Posted by victorb

Hi guys, I recently installed the greddy sp elite. Now, I am planning to change the front pipe, the invidia resonated cat less or the Megan cat less

Car mods: Perrin drop in and greddy sp elite axleback.

I've been reading two threads (fa20's post zn86's post). Currently confused if I still do it as it will make the a/f richer thus decrease in HP.
I don't plan to have it tuned.

Your Inputs will be appreciated

You can always start by checking where your ARF's are now... the ecu reports wide range sensor data via OBDII. Also check your long and short term fuel trims. And honestly, this is a good idea anyway. You can us torque a supported Bluetooth obdii adapter if you don't already have something to log with.

Then add the pipe and check again... if it is appreciably richer then you can choose an intake that is known the lean out the afr some.

If your trying to choose parts that gain performance without requiring a tune your gonna have to do some serious mixing and matching to get the balance.

[victorb]

Thank you for your responses. I will be checking my a/f ratio within the week. If I am pretty lean now, I will be getting the front pipe. Also, does anyone know the exact +/- values of thee stock trims, af ratios?

Thanks!

[mad_sb]

trims are going to vary.. there are 3 or 4 ranges for long term trims (idle, low medium, and high load) long term trims need to be figured into the afr readings. you will see 14.7 in closed loop, open loop will vary but ideally you want to see between 13 and 12.5 under open loop.

Mine seemed to run a bit lean from the factory... It stacked up long term trims between +5% and +10% and ran 13.2 open loop thorugh the midrange tapering to 12.1 and richer by 6500.

[victorb]

Originally Posted by mad_sb

trims are going to vary.. there are 3 or 4 ranges for long term trims (idle, low medium, and high load) long term trims need to be figured into the afr readings. you will see 14.7 in closed loop, open loop will vary but ideally you want to see between 13 and 12.5 under open loop.

Mine seemed to run a bit lean from the factory... It stacked up long term trims between +5% and +10% and ran 13.2 open loop thorugh the midrange tapering to 12.1 and richer by 6500.

Appreciate the information you gave. really nice of you guys. I will be downloading the torque software, I have an elm obd2 connector. I hope it works. =)