Thanos

Can't really find a solid answer on here so far.

If I installed the ARH long tube's with cats and y pipe, is there still a need for a new tune? I figure with a catless setup there would be more reason for a tune. Might be a simple question but I want to make sure before I waste money on a system with cats.


thanks

B52bombardier1

I changed NOTHING in my tune as it relates to the use of long tube (in my El Camino) or short tube headers in my Catalina convertible. Nothing got changed for upping injector fueling or changing airflow. I did notice that the PCM is able to cope with the headers by adding some fuel as seen at the Long and Short Term Fuel Trims in the OBD2 parameter streaming data. Maybe three percent extra fuel added by the PCM, not much - it could have gone up as much as twenty five percent in this operating system at max coping ability in the PCM.

Sure, you could tinker with fueling if you wanted to get everything back to a zero LTFT and STFT but I saw no reason to do that. If it ain't broke, don't fix it.

Rick

Thanos

Ok cool, this a 98 T/A, would you recommend catless then if the O2 can just keep it happy enough?

B52bombardier1

Catless? Yes but . . . . but . . . . ONLY if you live in a state that does not require catalytic converters for emissions control. My engines perform well without cats and the exhaust has no "eyes burning" obnoxious smell at all. Some people do complain of that in their vehicles.

Rick

Thanos

ive never had any issues with aftermarket catless setups here in Indiana.

Nathan C

Keep in mind not having catalytic converters will throw an SES light. Tuning should eliminate the light.

Thanos

so the ARH kit with cats would keep the ses light away? Lots to digest!

B52bombardier1

The O2 sensors after the catalytic converters, their operation and their response to the operating system must be turned off in the operating system tune to not throw an OBD2 trouble code.

Rick

RPM WS6

iTrader: (3)

WOT fueling will suffer from elevated fuel trims. It just makes sense to clean up the tune for headers if you care about getting maximum benefit from the modification and especially if you already have tuning capabilities. It would make zero sense to leave this power on the table if you already have a tuning suite, there is no downside to "fixing" it.

Not necessarily. Many folks will still get an SES light with aftermarket cats, so you might have to tune out the light even if you go with the catted Y. Personally, I would not put cats on anything unless it was subject to a visual and/or sniff inspection.