55fanatic

Thought some of you might like to see and hear this... There was a noticeable amount of power increase from the butt dyno...

http://www.youtube.com/watch?v=SKG_dp_UaqI

Rebellious_AMG

+1 thanks for the post.

Would be nice though to hear it from the outside and again from the inside but with the windows up.

55fanatic

I am sure I can get them for you... The owner of the car is a good friend

AMS Performance

any pics of the underbody of the SLS while doing the upgrade? would be curious to see what it looks like exactly

55fanatic

nope didnt snag any shots of the piping up close... the headers needed to come out though to remove the cat as welding the top of the cat wasn't doable...

edit: I have one from a while ago when my buddy first got the car, this is from the nose of the car towards the back...

AMS Performance

thx for the pic, very interesting. It appears to have 4 cats & two resonators from the looks of it. whats interesting are the primaries & secondaries appear to be back to back instead of much further spread apart (the only AMG I've seen with this configuration). I'm assuming the rear two are resonators.

Whats even more shocking ... I do not see any crossover of any kind. The SLS may be an excellent candidate for a high flow X-pipe. Perhaps for improved power & sound quality you may want to put an X-pipe where the system narrows and becomes parallel, you could potentially pick up 20+ HP on a large displacement high revving 6.3L AMG engine.

Just a thought

55fanatic

My ML55 had a pretty similar set up on its cat layout... but these cats seem to be much further away from the manifold than I have seen in most cars.

There is an H pipe before the resonators(IIRC) and the two mufflers are inside the back bumper, looks like a PITA to even attempt getting them out. Thats all this car is going to be getting as it is destined for a plane to head to Dubai sometime soon

AMS Performance

You are correct the primary cats are much further back than on most MB AMGs, most likely due fitment reasons and to pick up a bit more power (moving the primaries back can usually add 10HP+ NA depending on the application).

I see, tough to see any crossover from that angle. Typically, however, the OEM crossovers benz uses (normally H-pipes) are purely for sound and not for power (simply too small). An X-pipe should still give you significant gains over the stock setup. You do not need to touch rear mufflers, usually there are zero gains to be had over AMG catbacks. All the gains are in the front half of the system usually.

If you were upgrade to high flow 300-cell metal core primaries on top of deleting the secondaries you should be able to pick up even more power and improve the exhaust note to a more race sound above 4000rpm without too much compromise in sound on the low end. 300-cell will ensure no CEL light and still provide plenty of backpressure to maintain & improve low end to mid range torque.

Hope that helps,