Is this combo a good idea?

Or is the DP & exhaust best if all (with stage 2 tune) or nothing?

I currently have a K&N intake & Stage 1 tune. Planning on putting on a Riss racing 2.5" catless DP but rest of exhaust is stock.

Stage 2 tune is for full 3" and I don't plan on changing the exhaust from stock. There's no tune (at least preloaded) that fits.

I did a quick search but haven't found a definite answer. Your input is appreciated.

 

I have a DP and stock exhaust with 4" tips and I make great power 250whp and 270wtq. The stock is great, just remove your cat and the second one if your car has one.

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^You have a GP2 N18, he won't get nowhere near that

 

True but my stock exhaust is perfect. I added a resonator where the second Cat was. It's very mellow till you get on it. DP makes power and exhaust is only for looks and sound. The 4" tips help it look more aggressive

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Stage 1 would continue to be appropriate. The AP map will suppress the DP cel. Going to a catless dp will allow for slightly quicker spooling. The power/load/torque will still be dme controlled through wastegate modulation.

 

Excellent. I just wanted to make sure there wouldn't be any negative effects.

And that's darn good power. I'll take those stock GP2 tips if there still around

 

The exhaust is stock, but I welded on 4" double walled tips.

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So upon realizing the misfire codes were not a result of carbon buildup or HPFP, I changed the tune to stage 2.

It got fewer codes but seemed confused. So the resonator and 2nd cat are now out; replaced by a straight thru resonator and a bit of piping. Rest of exhaust is stock.

CEL stayed off for a longer period this time, but it's back. Got 3 codes.

I figure this may be a result of using the secondary O2 extension...? For those of you with no cats, do you use an O2 extension/defouler with the stage 2 tune? Doesn't the sensor get burnt up since there's no cat?

 

P2773
P2ac2
P2a75

I have these codes even with stage 2 tune and O2 extender.

About to rage quit back to stock cat.

 

I'd be more inclined to say its the tune. There is too many people out there with catless DP with no problems for me to think its that. And on a similar note, there are too many people the AP tune with random problems here and there for me not to think thats the problem.

My advice, sell the AP and get a real tune from a tuner. Battle, Evolve, JZW and RMW to name a few. You'll get personal service and they can adjust the tune as needed. Trust me, you'll be alot happier you did.

 

Thanks. I'm gonna give no O2 extender a try (if the sensor will reach; bung is placed lower than stock). If it doesn't work I'll follow your advice.

 

I have heard of someone relocating the O2 sensor to after the secondary cat on a 335i, after doing a catless downpipe I believe. Apparently the second cat was enough to keep the light off. Just some food for thought!

 

+1 on this I run a cat less dp and have no CEL. I run the JZW tune.

 

Anyone tried running a high flow cat while tuned? I want a bit more power but don't want the stinky smell of going catless. I hear the power gains are similar.

 

Sneaky sneaky trying to make your car faster without me knowing. I see you now lol. You got http://www.pawmotorsport.com/ down the street from you. You should go to them or renntech here in lake park. I'll even pick you up if you need to drop your car off over here.

 

I barley have a smell, and that's only if I'm going 100% and redlining it. I have no cats and there is no smell if II don't race it. Also, if there is smell, it's only on the outside. Never in the car.

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PROBLEM SOLVED! Don't run stage 2 tune with an O2 extender. Car will think it's running lean.

Also don't delete the primary cat on a stage 1 tune with or w/o defouler. It gives missfires and may run lean.

It really doesn't stink much. My Miata with a high flow cat smells worse than this w/o cats. Try having an exhaust shop delete your secondary cat for an easy slight jump in power

Thanks man, I've heard good things about PAW. But I'm doing things on the cheap. Kind of a sleeper stage 2 since most of the exhaust is stock. We still need to run; you do have an intercooler on me.

 

Basically don't use o2 extender if you have AP?

 

Yes, never run one a O2 extender with the AP, especially on the front O2, it's not needed, and will cause CELs! Running an extender on the front O2 is especially bad.

 

Correct. It didn't do it's job in any of my previous scenarios.