[Sparky2]

I have a 2014 335i with CAI, chargepipe, catless dp, JB4. Thinking about putting the stock cat back on because of overbearing smell. Would it be safe to run the S55 plugs? I'm under the assumption it would be ok if I keep the catless dp. Any help is appreciated.

[Wires]

Are you talking spark plugs? Not sure why you just wouldn't run the recommended ones for the N55 if this is the case.....

[insanecoder]

Hes looking to run a range colder which makes sense because of his tunes.. I think the N55 plugs are range 7 and the S55s are range 8

[Sparky2]

Thanks insane, I just want to know if it would still be safe if I go back with stock cat.

[Sparky2]

The car runs well as it is, but idles just a little rough, was thinking the one step colder plugs would help. May help burn a little extra fuel during combustion as well and help with the exhaust smell. I don't mind a little, but what I got going on is embarassing. Can't pull up to a drive through without gassing them out....lol.

[RoundelM3]

Try the N55 engine thread in this forum - much more information there.

[insanecoder]

Originally Posted by Sparky2

The car runs well as it is, but idles just a little rough, was thinking the one step colder plugs would help. May help burn a little extra fuel during combustion as well and help with the exhaust smell. I don't mind a little, but what I got going on is embarassing. Can't pull up to a drive through without gassing them out....lol.

I dont think a step colder plugs will solve your catless emission probs

[Wires]

Originally Posted by Sparky2

The car runs well as it is, but idles just a little rough, was thinking the one step colder plugs would help. May help burn a little extra fuel during combustion as well and help with the exhaust smell. I don't mind a little, but what I got going on is embarassing. Can't pull up to a drive through without gassing them out....lol.

Colder plugs will work against what you are saying though. You only need colder plugs if they are causing pre-ignition. If they are too cold, then they'll foul since they don't stay hot enough to keep clean.

They don't give more power, burn more fuel, or change the exhaust smell (you'll need to put the cats back on for that).

Check your JB4 logs. If you see timing being pulled under load, then colder plugs might help. If you don't see that, you're wasting your time/money swapping them.