doing it the right way( EXHAUST)

[pinoyk20]

yup i have two race reso . i put in on the place where the 2nd cat used to be. SONNY: do you still have CATS? how many? and where did you place it?

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[greg12m3]

Hello!

High flow cats primaries + remove secondary cats + magnaflow x pipe to replace resonator + stock muffler ( all 2.5inch piping) = http://www.youtube.com/watch?v=zB0V7...eature=related , http://www.youtube.com/watch?v=WS_Hz...eature=channel

I miss my E55, especially the sound. As far as power, it felt a bit brisker after changing the exhaust.

[pinoyk20]

Originally Posted by greg12m3

Hello!

High flow cats primaries + remove secondary cats + magnaflow x pipe to replace resonator + stock muffler ( all 2.5inch piping) = http://www.youtube.com/watch?v=zB0V7...eature=related , http://www.youtube.com/watch?v=WS_Hz...eature=channel

I miss my E55, especially the sound. As far as power, it felt a bit brisker after changing the exhaust.

so you didnt lose tq with the exhaust diameter increase to 2.5inch? what size of priamry cats did you use? and what type of headers do you have? thanks

[Silver Logic]

greg12m3,
Where did you get your high flow primaries?

[pinoyk20]

hi guys! ill be having a new set up. ill update you guys after the mods.

btw im selling my kleemann headers!!! super cheap ehehehehehe

TQ here i come!!!!!

[greg12m3]

pinoyk20 - I didn't feel a lose in tq, the car definitely would break loose a bit easier after the exhaust was done.

Silver logic - I have no idea where I got my primaries, I'll ask my boss tomorrow at work and be able to tell you though. I do know they were metallic and emission legal, at least in md.

[AMS Performance]

Originally Posted by Esh

AMS Performance has expressed numerous times that our stock exhaust system is just about as good as it gets. Add an x-pipe, some high-flow cats, maybe pick up a tiny bit of tq, add headers, and you're good to go. There's not much else you can do to improve performance from the exhaust.

Hello Esh,

You are correct, The 3 main bottlenecks/weaknesses in our exhaust systems are:

1) Headers
2) Cats (primary and/or secondary)
3) Resonator (x-pipe)

Those are the ONLY 3 things that need/can to be done to maximize power on our cars; anything else will only hurt in the long run. Dual 2.25" piping is more than sufficient to flow 5.5Ls IF you design the system properly and target these key weak areas.

The explanation for this is due to the design of the front half of the stock system. The exit on the the exhaust manifold (lets say ours for example, 1.8" at the flange), matches the stock inlet to the midpipes. The pipe diameter going into the primary cats is only roughly 1.8" ID. This is done in order to increase back pressure and reduce pre-cat volume to ensure complete combustion occurs (for emissions purposes), it also "fires up" the primary cats quicker (ceramic cores take longer to fire up so this helps speed up the process). The higher pre-cat pressure ensures this complete combustion occurs and pushes the air through the primary cat at high velocity.

Therefore, going to a 2.25" post primary cat is already a significant increase in diameter up from 1.8". It is important to maintain the 2.25" piping throughout the remainder of the system to keep gas velocities as high as possible while at the same time removing as much restriction as possible (thereby keeping back pressures relatively high). When you jump up from 1.8" to 2.5" you kill back pressure almost completely post primary cat and as a result torque loss occurs (especially in your case where you have neither primaries nor secondaries).

In fact, all the recent dyno results from forum members who have done full primary & secondary cat delete almost without exception have shown torque loss in exchange for high end HP. It reduces low/mid range torque to provide high end torque ergo high end HP.

A properly designed 2.25" system will do wonders on our cars (and AMG knew this when they designed the car to begin with). They chose 2.25" piping many different reasons (ranging from relatively low 6000rpm redline, to torquey cam which doesn't need alot of high end airflow, sound qualities, easy of packaging, weight, etc). 2.25" is the best balance of all these criteria.

Furthermore, from a personal opinion stand point, 2.25s" actually sound better due to less resonance. Any time you start increasing pipe diameter, the sound becomes less & less refined as well as raspier w/ more resonance.

Address the front half of the stock exhaust system (in conjunction with X-pipe on the W210 E55s) and that is all the power you will need from the exhaust system NA. After you have done all that, then you can start to address in intake side of the engine more along with other components.

Hope that helps,
~AMS

[Silver Logic]

AMS,
So would you say that an exhaust set up consisting of high flow primary cats, deleted secondary cats, X-pipe/resonator delete, and stock muffler is a better set up than primary and secondary cat delete, X-pipe in place of secondary cats, stock resonator and stock muffler?

[Silver Logic]

Also, where can we get high flow primary cats that will fit our model?