PhiDeltBeers

Forgive me for this as I'm looking for a quick explanation on this subject. I don't own a C63, but I'm asking on behalf of a friend that just picked up a 2013 p31 sedan. I've have a GT-R tuned, a 335i tuned and currently have an IS-F with deleted 2nd cats and mufflers. I'm putting on my headers this weekend which puts our cars around 400rwhp. There is NO tune available for the IS-F, but its my understanding that the IS-F's ECU "learns", if you will. Anyway, he loves the sound of my car right now and wants to do exhaust and headers on his, but doesn't want to jeopardize his warranty with tuning. So my question is, will the A/F be fine with the boltons only and is the tune simply to maximize the potential of the boltons.

If the boltons are fine without the tune, what numbers can he expect. I suppose if a tune IS, in fact needed, then he'll most likely stick with exhaust only.

Again, sorry for the newb question and I did do a header search but was bombarded with threads. I know how it is with newbs as I'm a really active member on the other car boards.

PaulWdz

Probably more likely to have warranty issues with headers than with a tune. Unless there is an ECU problem requiring the dealer to connect to it, the tune is not visable at all. But, the headers are very apparent and a dealer could deny any driveline issues because of the headers.
And to get the most out of the headers, a tune if 100% required if not a must to make sure the car is running properly.

PhiDeltBeers

Thanks for the quick answer. After reading a bit on the tuning process of the C63, it's sounds identical to the GT-R as its simply a flash that can reflashed back to stock. Sounds like he'll most likely just stick with exhaust, since he's stuck on the warranty. With the IS-F, headers don't really seem to be a warranty issue at all. Are there known issues with headers on the C63? Denial,of warranty work etc....? I'll send him a link to this thread and maybe he can follow along as well.

PaulWdz

No known issues with headers but the engine bay on the M156 cars is tight so making sure they are good quality and fit correctly is a must. The factory log manifold on the M156 is the major limiting factor - with heads that flow really well, intake and headers are the best for picking up big hp gains. But, without a tune the motor will not run properly and it could also be dangerous and most likely trigger the CEL. Personally I would not run headers without a tune. You can get away with removing secondary cats and/or resonators...but with headers, you really have to tune the ECU for the additional air being pushed through it or will have all kinds of problems. I'm sure others here will chime in and agree.

Merc63

You can't run headers without a tune. It will run dangerously lean.

You have way more flow with no fuel to go with it.

Headers will void the warranty.

PhiDeltBeers

Thanks for the info guys....looks like we're just going to play with exhaust for now.

VaclavSV

If he just want better sound replace the resonator with straight pipes!

PhiDeltBeers

He's looking at deleting the 2nd cats and going with the ipe innotech valvetronic exhaust. The x-pipe (which replaces the resonator) and the mufflers. I'm assuming there are no O2 sensors after the 2nd cats? Hard to tell from pics. He was going to lift the car and look but can't get to it until tomorrow.

PaulWdz

O2 sensors are before and after the primary cat. Secondary cats do not have O2 sensors after them. I would replace the secondary cats (with straight pipes) and keep the resonators. You want to keep the resonators in case you ever decide to go with long tubes.

PhiDeltBeers

Looks like the x-pipe replaces the stock resonator using the IPE exhaust. I guess if he wanted to go headers down the road he could pick up IPE's headers and straight pipe to complete the system?

freefall

Why? I have LTH and deleted the res and the sound is absolutely insane in the most wonderful way possible...

PhiDeltBeers

Yeah, I think for him, deleting the resonator will be fine if it's just a noise thing. Going with the IPE exhaust and having the ability to "tone" it down is something I wish I had on my F. Here's my car and what he's after. I think it's funny that a C63 guy wants it to sound like an F, when we all drool over the C63 sound...


Should be interesting what it does after this weekend with the headers being installed.

rory breaker

If your cars' sound is what he aims for, he should probably just get an aftermarket exhaust and not touch the headers/resonators/etc. Some aftermarket exhausts for the C63 remove that bark/growl the car is known for and replaces it with a higher tone like on your car. If thats what he wants, to me it's literally toning down the stock exhaust, but thats his way of getting it.

johnnyblaze

Talk with a service advisor in your area about modifications. Long tube headers are the single best modification you can do to a M156 motor. Or just find a good local independent shop that can swap them out when you need service.