phatmitzu

Planning on replacing my primary cats with high flow race cats and do the secondary cat delete and resonator delete. However, I do not want to deal with the CEL issue. What are my options??

Supersprint is too much for my blood, so that is out.
VRUS 100 cell race cats?

What else?

newton22

Whoa, back up, how many kittens do we have under there? I always thought it was a pair of primaries and secondaries (which are also called resonators) and then the muffs all the way back there. Or is it primaries, secondaries, and then resonators (and the muffs at the back)?

Evosport makes primaries I think.

Fast55

The big question is: Why bother? There is almost nothing to be gained. You might see a difference on the dyno, but honestly, do you really think you'll get anything for the money spent? If you've modded the car to the point you need to be looking at the exhaust, there really isn't much left after just going with the EVO headers and keeping the rest of the exhaust stock. The only real restriction is the manifolds themselves. After that, there's not a lot left to gain.

phatmitzu

Is that true?
I understand that removing the secondaries and resonators won't do much, but will gain with the primaries replaced with highflow ones. And while Im at it, might as well remove everything else after the primaries.

chiromikey

newton,

your second scenario is correct...primary cats, secondary cats, resonators, then mufflers.

phatmitzu,

if you keep the new primary cats in the same location i don't think you'll have a problem with cel's. if you're deleting cats for performance purposes but still need to have cats for emissions, you should be removing the primary cats instead of the secondary ones and replace the secondaries with hi flow cats. there's no real gain in performance or sound by removing the resonators so i wouldn't waste your money there.

jangy

You will get CEL issues if you remove the primaries. Simple as that. Also, replacing them with race ones is no guarantee of not having CEL come up as the actual heat at the sensor is key.

The exhaust is definitely not your bottleneck. Having said that, IF you have trully pushed the car to the point where it is pumping out lots of power, then yes doing what you are thinking will be added. I say spend the money on openning up the intake and manifolds, if you are really after power. Do the exhaust if you want sound.

By the way, the resonator delete is a mod I recommend. I think it adds just by not having the turbulence caused by the mixing pipes and it costs all of $60.

Fast55

It is true. You need a lot of other mods to see any benefit from hacking up the stock exhaust beyond just the headers. I do like the resonator (there is only 1) being gone since it 99% cured the 72 mph "drone" my car had, but as Jangy suggests, beyond headers, exhaust mods are more for sound than performance. The real power is in the pulley, ECU, headers, and throttle body, probably in that order. The cooling upgrades are there to keep the power available and prevent heat soak. Beyond that, Victor's air box, SLR cams and/or the heads he's working on are about all that's left to do unless you are considering nitrous.

jpohl402

https://mbworld.org/forums/w211-amg/...akes-best.html

Ali_E55

i replaced the primeries with racing ones but my headers are stock, their is a little extra sound which really is adorable.