Vabene7

This is on a clk500...
First, I need to say I am trying to maximize the power of my 209.

The first photo are my cats and the 2nd are my (I think)resonators.....????
Can I increase flow and power by removing these? If so, do I replace with only 2 hi-flow cats, one on each side? (cats w/ O2 sensors are on both driver and passenger sides). With the correct cell count cat, I wouldn't trip the check engine light.
When I ran the after-market exhaust, I lost some low end. I don't want that happening again.....I need some good direction here.

redcoupe

There all four kats.

Supafly

if you remove your cat-converts, then you must get your ecu reflashed. Without a reflash, you will get CEL errors, and you car will run lean...
extracting power from our cars is like trying to suck mudd through a straw....its difficult and usually not worth it.

edit: if you run hi-flows, you can always trick the sencondary o2 with the washer extention trick..( having the o2 sensor sit further out in the exhaust path).

edit: the second picture is your resonators...its purpose to keep your car quiet.

suicidal4life

Those are all 4 cats. The front two have O2 sensors in front and behind them. Removing them would cause CEL's if you didn't move the O2's. The rear cats do not have O2's after them and can be removed without throwing CEL's. It may be illegal to do this in your area so consider that. It may be possible to remove all four cats and replace them with two "race" cats and not throw CEL's but this still may be illegal in your area.

unlukky

+1

Vabene7

All my research has been showing me that in a 500 series engine, removing the
stock cats (4) and replacing them with hi flow cats may decrease performance.... Has anyone had this experience with this engine and exhaust?

P.S...... has nothing to do with back-pressure......

MarcusF

For the exhaust, you're trying to increase exhaust velocity. This increases cylinder scavenging. Depending on it's placement, a true high flow cat that's properly sized will increase velocity. A true high flow cat that's improperly sized (too large) appears as a low pressure zone throughout most of the rev range (making the engine seem peaky). Low pressure zones kill velocity. That's why HyperFlow cats (one aftermarket cat distributer) are small in comparison to a JC Whitney "high flow" cat for a Mustang. Some people look at a cat and think if it's big, it must be good. The M113 doesn't rev very high, so it's easy for a mega-cat to have lousy flow throughout the entire rev range. This is why some exhaust systems cost so much. Tubing diameter, collector angles, cat size/design/placement and muffler size/design/placement can drive R&D costs through the roof.

suicidal4life

Nice! Whats the approximate cost on those?

MarcusF

That's not the exact converter you'd want. That's a Hyper Flow cat for a 308 QV / Testarossa (Both cars use the exact same part. The TR uses two, versus the 308, which uses one). Being a Ferrari, Hyper Flow retails the cat for $770. Hyper Flow (Bryan Performance out of Georgia) does not build their own converters. They're built to spec. Naturally, Hyper Flow won't say who builds their cats, but they look EXACTLY like a Random Technology 7000 series (metal substrate) cat with Ferrari flanges. The last time I checked, "full retail" on the Random Technology 7000 series is half what Hyper Flow gets. The RT cat flows 580 CFM at 1 bar (1 atmosphere).



For a lot less money, and almost the same performance, Magnaflow makes 599xx series metal substrate converters for $115. The Magnaflow cats aren’t polished, but I’ve spoken to the Magnaflow reps at press events and they claim their metal substrate cats can flow 500+ CFM at 1 bar. It would take a lot more engine or a lot higher RPM than an M113 to max out dual metal substrate cats.