[e.n335]

Hi everybody

I am curious why nobody discussed about replacing all OEM cat's with metal cat's / 200 cpsi in their original OEM housings. Wouldn't this be a feasible and sustainable solution offering good power gains without compromising in emissions and sailing close to the wind ? Are there any downsides I didn't consider ? What would be the estimated price for such a mod ?

Thank you for feedback.

Cheers
Eugen

[Terry335]

It's easy to remove the 2nd cats and its impossible to do much with the primary until someone makes an aftermarket downpipe.

[bnj]

Originally Posted by Terry Burger

It's easy to remove the 2nd cats and its impossible to do much with the primary until someone makes an aftermarket downpipe.

Why not just having a local custom exhaust shop to make downpipes. I would not have cats in downpipes. I would prefer cats after the downpipes.

[jon@themshop]

Supersprint is the only company that I know that sells a turbo downpipe for the 335i which eliminates the primary catalytic converters. However it ain't cheap.. retail is $2735.00.

There's also the issue of the service engine light coming on because the post cat o2 sensors will detect no cats are present.

[leftcoastman]

Wait, does the SS system remove the primary cats or simply relocate them? Removing it would be incredibly bad for passing emissions, open yourself up to serious penalties and not to mention smell like crap.

[Terry335]

Originally Posted by bnj

Why not just having a local custom exhaust shop to make downpipes. I would not have cats in downpipes. I would prefer cats after the downpipes.

Good option also but I'm sure in 6-12 months someone will make a bolt in downpipe for a reasonable price (around $500-$800)

[CASHBY]

Originally Posted by leftcoastman

Wait, does the SS system remove the primary cats or simply relocate them? Removing it would be incredibly bad for passing emissions, open yourself up to serious penalties and not to mention smell like crap.

Not sure about the rest of the states, but when you buy a new car like the 335, you have i belive 5 years before you have to smog it again. So as far as passing emmissions you wouldnt have to work.

However yes if you get caught their are penalties, depends how the cop writes the ticket.

I would love to get down pipes on this car... just my A4 it made 19whp and 43wtq....i can only imagine what it will do with this car. I havnt seen the DYNO's from SS yet with downpipe and software.

However someone needs to figure out how to bypass the CEL you will throw due to the 02's like every has mentioned.

[BoostedBMW]

Would you be able to use simple spacers (two spark plug non-foulers and drill out one of them to fit the sensor inside) for the o2 sensors like every other car can or is the 335 different for some reason? I have this on my s2k and my bro has it on his 350z, both cars have no cats and no CELs.

[jon@themshop]

Originally Posted by leftcoastman

Wait, does the SS system remove the primary cats or simply relocate them? Removing it would be incredibly bad for passing emissions, open yourself up to serious penalties and not to mention smell like crap.

Yes the Supersprint turbo downpipe eliminates the primary cats. It does not relocate. Supersprint offers a racing metallic cat that replaces the secondary cats but that's also most of our budget.

[jon@themshop]

Originally Posted by BoostedBMW

Would you be able to use simple spacers (two spark plug non-foulers and drill out one of them to fit the sensor inside) for the o2 sensors like every other car can or is the 335 different for some reason? I have this on my s2k and my bro has it on his 350z, both cars have no cats and no CELs.

I am sure the SS turbo down pipe will have 4 O2 bungs to accommodate all pre-cat and post-cat o2 sensors but if the post-cat sees the same signal as the pre-cat then it'll think the cat has failed and check engine light will show up.

The only fix for a BMW is either software (turning off post cat o2 sensor monitoring) or O2 simulators.

[e.n335]

I understood that the SS metallic race cat's relocate the primary cats. Look at the pictures (o2 sensors). So no issues with the SS downpipes. Hmmm ... well, the price is an issue

Cheers
Eugen

[jon@themshop]

Originally Posted by eugen.niederreiter

I understood that the SS metallic race cat's relocate the primary cats. Look at the pictures (o2 sensors). So no issues with the SS downpipes. Hmmm ... well, the price is an issue

Cheers
Eugen

Eugen,

Not sure if the Euro models are different but for the US models the N54 engines has the primary cats integrated with the turbo downpipe. Secondary cats are in the middle of the vehicle.

Since 1999 the BMW North American models have the cats integrated on the exhaust manifolds on the NA engines.

[e.n335]

Originally Posted by jon@themshop

Eugen,

Not sure if the Euro models are different but for the US models the N54 engines has the primary cats integrated with the turbo downpipe. Secondary cats are in the middle of the vehicle.

Since 1999 the BMW North American models have the cats integrated on the exhaust manifolds on the NA engines.

Please read:

Supersprint Italy has just released the first full turbo to rear muffler performance exhaust system for the 335i with excellent performance results. Product will be available in approx. 3-4 weeks. Below is a product development write up by one of the engineers in the R&D department. For more information on the product check out our web site at supersprintna.com simply enter your year and model and see the entire system. The photos below are the actual components involved. The system achives maximum gain as a complete system since the tubing size is upsized to 60mm for maximum flow capacity. However the rear mufflers include a step up sleeve if you're only wanting to install rear mufflers.

Supersprint has developed a new, stainless steel full exhaust system, from turbo-back, which includes a set of special 65mm down pipes, a set of metallic cats with 100cpsi, a mid section wit a built-in X-pipe, and a set of rear mufflers with bolt-on tip kits, available in quad or dual design. The increase in performance is astounding, as the peak power jumps from 324 Hp to 348 Hp! But most importantly, the torque curve is way above the stocker, from 1500 rpm all the way to redline. In some places the difference is + 26 Hp (5000 rpm). The power build-up remains as smooth as stock, only much stronger throughout the range.The stock engine puts out 324 Hp instead of 306 Hp. These are impressive numbers to start with. There has been rumors rampant among the German tuners about this new BMW turbo engine. Some of them are aware that the factory tuned it to a higher degree, compared to what the brochures claim, but few of them actually expected that the full Supersprint exhaust system would instantly make the 335i faster and quicker than BMW's own E46 M3! Driving the 335i with the Supersprint exhaust is a new experience, as the sound may seem soft, when compared to the excellent, high revving M3. However, stealth sometimes is compatible with immediate throttle response and quick acceleration.Supersprint achieved this result without using the popular exhaust flapper valve gimmick, found on the stock system, as well as on several other aftermarket exhausts. By using its tried & true method of studying the engine flow characteristics, and determining the best pipe diameter, the perfect tube layout and the ideal silencer canisters' design and volume, Supersprint has again done an excellent job, building a state of the art exhaust system, perfectly suited for everyday use, which offers unmatched, race car performance.

1) Turbo down pipes. The stock down pipes cause a major restriction in the exhaust flow, partly because of the limited room available in the engine bay, as the crushed tubes design and the built-in cats, located next to the turbos' outlet ports, make the exhaust gas backpressure to rise to less-than-ideal levels, at all rpm and engine loads. This design retains a lot of heat in the engine, and it's no surprise that the Lambda (Air/fuel ratio) breaks the low 0.7 barrier. This is probably necessary for the engine own durability, however it definitely affects performance in a negative way. On the contrary, the design of the Supersprint down pipes takes advantage of even the smallest space available, and frees the exhaust gas flow dramatically. The SS pipe cross section remains constant all along the down pipes, and the pre-cats are totally eliminated.

2) Metallic cats. After the down pipes' outlet flanges, the cross section shrinks down to 60mm, and it is maintained constant all the way to the tail tips. In place of the stock, quad cat design, Supersprint uses 2 high volume, high flow, HJS metallic cats, placed further away from the engine, for the lowest restriction and the best results. This design has been borrowed from the popular SS E46 M3 exhaust system.

3) Mid-"X" pipe section. The stock Mid pipe has an unbelievable number of crushed sections, for added clearance. The result is that the flow rate is negatively influenced by the crooked design and the shrunk-down cross section of the tubes. Supersprint made its mid pipes with a real "X" section for balancing the exhaust flow, and most important, without having a single crush. The needed clearance is guaranteed, nonetheless. Again, a major improvement over the stock exhaust.

4) Rear Mufflers. The Supersprint rear mufflers are of the performance proven "flow through resonated design", rather than the baffled chamber design used by other manufactures. The internal tubing diameter is optimizes performance while the long strand rock wool sound deadening material provides the mature tone that Supersprint is so well know for.The stock, one-piece muffler system has a totally unnecessary, complex design, which includes a built in flapper valve, on one side of the system only, which has the sole purpose to alter the sound note at a certain, pre-set rpm. Not a performance related feature by any mean, as the Supersprint rear mufflers alone do increase the torque and max Hp by a significant amount, especially at low rpm.Regardless, the Supersprint system has absolutely no droning, even at low rpm and high loads.

Hope that helps.

Sorry for this long post.

Cheers
Eugen

[BoostedBMW]

Originally Posted by jon@themshop

I am sure the SS turbo down pipe will have 4 O2 bungs to accommodate all pre-cat and post-cat o2 sensors but if the post-cat sees the same signal as the pre-cat then it'll think the cat has failed and check engine light will show up.

The only fix for a BMW is either software (turning off post cat o2 sensor monitoring) or O2 simulators.

Isn't what I mentioned a mechanical o2 simulator? Then just keep the sensors in the same place as stock.

[jon@themshop]

Originally Posted by BoostedBMW

Isn't what I mentioned a mechanical o2 simulator? Then just keep the sensors in the same place as stock.

Sorry I didn't see you type in simulator. I never even heard of the spacer method you mentioned before. For the E36 and E46 models one either used an o2 simulator (black box connected to the wiring harness) or software.

[itsbrokeagain]

If you guys take a closer look at the SS midpipe pictures, you will see the rear 02 bungs welded into the backside of the cats. If they are thinking we will relocate the 02s to the rear of the car, I think not.

Id rather try an 02 simulator.

[e.n335]

Originally Posted by itsbrokeagain

If you guys take a closer look at the SS midpipe pictures, you will see the rear 02 bungs welded into the backside of the cats. If they are thinking we will relocate the 02s to the rear of the car, I think not.

Id rather try an 02 simulator.

Please read my latest post above. Thx.

Cheers
Eugen

[jon@themshop]

Originally Posted by eugen.niederreiter

Please read my latest post above. Thx.

Cheers
Eugen

Eugen,

On the Euro 335i models.. are the primary cats integrated to the turbo down pipe?

[BoostedBMW]

Originally Posted by jon@themshop

Sorry I didn't see you type in simulator. I never even heard of the spacer method you mentioned before. For the E36 and E46 models one either used an o2 simulator (black box connected to the wiring harness) or software.

No problem... this is they type of simple fix that I was referring to in the link below. I have run it on two of my cars without any problems, but I know that the BMW might be more complex when it comes to its sensors.

http://www.s2ki.com/forums/index.php...ic=229959&st=0

[e.n335]

Originally Posted by jon@themshop

Eugen,

On the Euro 335i models.. are the primary cats integrated to the turbo down pipe?

Yes, equal to your BMWNA cars.

Cheers
Eugen

[itsbrokeagain]

Originally Posted by BoostedBMW

No problem... this is they type of simple fix that I was referring to in the link below. I have run it on two of my cars without any problems, but I know that the BMW might be more complex when it comes to its sensors.

Yeah I was wondering the same thing. I wouldnt want to risk a few 02 sensors to avoid running without cats with sonme soldered in resistor stuff. I would love to run without cats and still be able to pass emissions, however at Almost $6,000 for a downpipe and midpipe setup, I'll wait, or make my own. I have friends in the right places who could help out in this situation, but wether they want to get involved in making them and selling them, I don't know.

Im sure someone will come out with something to fool the rear 02s soon.

[edgarj]

Originally Posted by CEA 3

Not sure about the rest of the states, but when you buy a new car like the 335, you have i belive 5 years before you have to smog it again. So as far as passing emmissions you wouldnt have to work.

However yes if you get caught their are penalties, depends how the cop writes the ticket.

I would love to get down pipes on this car... just my A4 it made 19whp and 43wtq....i can only imagine what it will do with this car. I havnt seen the DYNO's from SS yet with downpipe and software.

However someone needs to figure out how to bypass the CEL you will throw due to the 02's like every has mentioned.

You have to smog a new car @ 3 years in Oregon, but I think that they just hook it up to the OBDII port, so I don't know if that would turn up.

Why is the Super Sprint downpipe kit so expensive? It that on par with their other models, or just due to the exclusivity?