Exhaust diameter?

[Mkid]

Yeah, I'd imagine as long as you have a working cat... HFC or not... it shouldn't be an issue. Now, if you were running a test pipe, then yes, you'd have CEL all day.

[Rralliart09]

Since your running stage 2 on your AP let me ask you something. On the Cobb site for the Evo to run stage 2 you have to remove a boost pill. Is that the same for our cars?

[Jackal]

Originally Posted by Mkid

I have a UR HFC and a Cobb AP and have never had a check engine light due to the O2 sensor...

FYI: I have the UR complete Turbo back exhaust and I have a test engine light on probably 5 out of 7 days of the week. I have gotten extensions and have taken it to dealership and checked code. P something or other. Description was Cat operating below minimum efficiency threshold.

Here is the funny thing about a 1/4 of the time when I fill up the car with gas it goes away then comes back when I get down below 1/2 a tank. Other times when I go out a play in sport mode and really heat up the exhaust it goes away only to come back on hours later if I drive it cold.

I believe it to be the 2nd O2 sensor the one further back and I think it is because it may have gotten damaged during one of my Rally Cross off road driving events. I got a quote from the dealer ship at over $600 for the sensor so I never did get it replaced.

[Mkid]

Possibly. I also live in florida so the environment is completely different. Maybe mine burns it all off easier due to the heat.

[Rralliart09]

Quick update. The car is in the shop with a broken leg right now and should be getting her back on the 9th. Back ordered lower control arm. But I did end up ordering the Tactrix cable and boost pill. Unfortunately I crashed her before I got to install either the pill or flash.

As for the exhaust I'm pretty sure I'm going to go with the 3" mainly because I'm pretty seriously considering a Radlite turbo in the future now. At that point I'd swap the DP as well.

Anyone here gone with a 3" exhaust and wished they hadn't?

[deprydation]

Originally Posted by Rralliart09

Quick update. The car is in the shop with a broken leg right now and should be getting her back on the 9th. Back ordered lower control arm. But I did end up ordering the Tactrix cable and boost pill. Unfortunately I crashed her before I got to install either the pill or flash.

As for the exhaust I'm pretty sure I'm going to go with the 3" mainly because I'm pretty seriously considering a Radlite turbo in the future now. At that point I'd swap the DP as well.

Anyone here gone with a 3" exhaust and wished they hadn't?

Not sure if anyone on here has ever bought a performance exhaust and wished they hadn't.

The only thing I wish I would have done differently is bought the UR one before buying a Buschur exhaust and then just taking it off 3 months later and buying the UR. Now I have a Buschur exhaust sitting in my garage rotting away.

Smart idea going the Tactrix route. If you get into tuning yourself and editing your own maps, you can really start to learn your car and think the way it thinks. Also gives you quite a bit of control over everything engine related and some things transmission related. You won't get that control over your car with anything made by Cobb.

Oh and on a note, you should replace the crappy stock downpipe. It was my first exhaust mod and definitely made a difference. Spool up is quicker and smoother with a fat 3" pipe shoved on there instead of a stock crapper. You can pick up the shorty downpipes off EvoM for less than $100 bucks most of the time slightly used.

[ROMITON1]

Originally Posted by Jackal

FYI: I have the UR complete Turbo back exhaust and I have a test engine light on probably 5 out of 7 days of the week. I have gotten extensions and have taken it to dealership and checked code. P something or other. Description was Cat operating below minimum efficiency threshold.

Here is the funny thing about a 1/4 of the time when I fill up the car with gas it goes away then comes back when I get down below 1/2 a tank. Other times when I go out a play in sport mode and really heat up the exhaust it goes away only to come back on hours later if I drive it cold.

I believe it to be the 2nd O2 sensor the one further back and I think it is because it may have gotten damaged during one of my Rally Cross off road driving events. I got a quote from the dealer ship at over $600 for the sensor so I never did get it replaced.

I also have the full UR TBE, with the divorced wastegate long downpipe, and I have never thrown an O2 sensor...

[Rralliart09]

I was asking if anyone had gone with a 3" exhaust and wished they hadn't. Maybe would rather have gone with a 2.5" instead. Due to noise or for what ever reason. If I'm not doing a bigger turbo or a Radlite turbo would a 3" yield any noticeable gains over a 2.5"?