CAT bypass pipes with no CEL's ? (5.2)

The factory Ferrari 355 primary main catalytic converters and secondary "wishbone Y pipe" catalytic converters use weak ceramic cores. On regular lightly driven street cars these cores are often found shattered and broken apart inside thereby throwing a CEL light and P420 P430 codes on OBD 2 cars

The cores are very dense and 700 cells per square inch.

A super quality 200 cell tri metallic directional sports racing catalytic converter like an HJS Germany Emitec brand catalytic converter flow 94% of a straight pipe and will add significant power and sports car sound while never ever breaking apart.

These Ferraris should only get the latest HJS catalytic converters and in particular the directional catalytic converters and not cheap metallic catalytic converters that are a $100 or less apiece for the weld in cores that are available on EBAY.

HJS catalytic converters are manufactured in Germany utilizing Emitec metallic cores
. Emitec is OEM for Ferrari and many other OEM major exotic car manufacturers like McLaren Mp4 12 C and others. I have detailed files and photos on all these matters.

There are many no name no engraved generic catalytic converters are over North America and often these catalytic converters are cheap and unravel unwind and fall apart.

Many many years ago I tried many of these non HJS catalytic converters on Porsche twin turbo cars and other high performance cars and all these special usa sourced brazed metallic catalytic converters fell apart or set of MIL CEL lights despite full manufacturer guarantees. The manufacturers back pedaled and later said you have to have a software tune to eliminate the check engine light.

You still see tuners and others selling sports race cats on forums, eBay and elsewhere stating emphatically that a software retune is mandatory for a good running engine and no cel light. That's 100% bull**** as the software is a mask or trick to simply turn off the cel light for catalyst efficiency fault codes and readiness codes.

Furthermore, when the cheap discounted catalytic converter explodes and gets sucked into your engine, blows down the exhaust pipe, and I clogs the rear muffler and rattles inside the rear muffler you will still not be able to pass emissions and then have to cut open the rear muffler fish the garbage out of the rear muffler and rewelding.

There are detailed videos showing all of this on my website caveat emptor.

 

It will not. It will be telling the ECU exactly what the front sensor is telling it. That's what trips the CEL.

Remember, the CEL isn't tripped by emissions - there's no sensor for that - the ECU uses an indirect method to determine cat condition, the oxygen storage and release capacity of the catalyst. A big part of the reactions used to reduce NOx, HC, and CO involve storing and releasing oxygen. As a cat degrades, it's ability to store and release oxygen does too.

How do the O2 sensors help determine that? The cat, storing and releasing oxygen, acts like a low past filter damping oscillations in the O2 content of the exhaust. Upstream, the O2 sensor is switching very fast (rich,lean,rich,lean). Downstream, it switches more slowly (rich...lean...rich...lean). The ratio between the two is calculated and the deterioration of it (the downstream rate approaches the upstream) is what triggers the CEL. The OEMs determine the threshold. Some let you get away with nearly anything, others are more strict.

You can see how straight pipes are a problem. No O2 storage means no difference between the two measurements. Spacers work well for some people (not for me in my 360 w/no pre-cats and Kinetix secondaries!) by creating a trapped volume of gas, which slows down the switching of the second O2 sensor.

 

According to the owners manual the secondary cat is metallic core.

 

You have taken my comment out of context..

I don't know the exact algorithm in the ECU but one scenario might go like this. Pre cat sensor switches rapidly between rich and lean, based on O2 content the exhaust, in an attempts to keep the A/F ratio near 14.7 on average. The post cat sensor looks at the O2 coming out of the cat. It tells the ECU that the mixture should be either a little richer or leaner than what the pre cat sensor is saying. It's also comparing pre and post cat O2. If it can not achieve the correct difference or ratio between pre and post cat O2 it thinks the cat is bad. But this doesn't necessarily preclude the ECU from making additional mixture adjustments based on the post cat sensor. That would depend on what the ECU fuel trim algorithm does if it senses a bad cat. If it just throws the cat CEL and keep on using the post cat sensor to adjust trim, it would seem this would push the mixture to rich. Thus, w/o cats it would seem that the ecu would tend to move toward a richer mix. Again, I don't know how the ECU reconciles this and it could be that once the cat cel is thrown it ignores the post cat sensor in the fuel trim loop.

 

Joe/Fabspeed crew,

I know you have posted some dyno results on the cats and bypass, but do you have any flow numbers for these vs stock on the 355/348? Specifically, what is the quantifiable variance between flow of stock vs aftermarket vs aftermarket premium vs open pipe, with no other mitigating factors (i.e. same temp, same exhaust)?

No agenda. Just legitimately curious how large of a factor these are to exhaust backpressure.

Thanks.

 

I'm not an ECU calibrator but I'm repeating what I was told by an OEM calibration engineer. They just don't work the way your imagining. The service manual cite earlier in this thread supports that. The ECU only references the secondary sensor for fueling when the first is dead.

The smell with straight pipes is from unburned hydrocarbons which the cat would otherwise convert to water and carbon dioxide.

Still, to go down the thought path, you could never reliably compare the sensors in the manner you suggest to make it a "little richer or leaner". First, that requires instant measurements, which is not possible because the cat, by design, stores and releases oxygen. Second, the voltage in the narrowband sensors used in these cars swings fully in an extremely narrow range of A/F. 14.45-14.85:1 in the case of a Bosch reference I found. The car hits 14.7 by oscillating back and forth, not by nailing a specific voltage, which absolves the ECU of trying to make accurate measurements in the millivolt range through many feet of random wires and connections.

Beyond all that, the operation of the catalyst reduces the O2 anyway. Some O2 is used converting HC and CO to H2O and CO2.

EDIT: It turns out some new cars actually use wideband O2 sensors upstream. In those applications, some OEMs use the downstream narrowband O2 sensor to learn an offset for the upstream sensor. I think that compensates for measurement errors that can be brought on by wiring/connectors.

 

Well yes and no. First the restriction in the cats contributes HUGELY to the heat especially as the flow of hot gases (and horsepower) increases, but an even bigger component in exhaust gas temperatures is A/F ratio and spark advance. Turbo guys know this, because the turbos are a HUGE restriction in the exhaust and cause massive rises in exhaust gas temps. These have to be controlled and are controlled with A/F ratios and spark timing. There is optimal expected EGT's which differ slightly for turbo and non-turbo engines. The aviation community figured all this out long ago and knows that high EGT's = low reliability.

True, the engine under load generating more power will generate more heat, but the question is where does that heat get dissipated. If I open the exhaust up, it will run much cooler than if I restrict the exhaust, simply because it's doing less work to get the exhaust out of the system and the hot gas is not there to transfer heat as long as it would be in a more restricted system.

Once again though, this misses the importance that A/F ratios and spark advance have on engine temperatures. In order for the cat's to be efficient they need a certain amount of heat and contact with the gases. Run the engine excessively lean and advance the timing and you'll see EGT's skyrocket, period... cats or no cats.

That's a little silly, because there should be no reason for the cats to fail other than poor design and overheating of the units.

Really, judge much, lol. I agree that it is better to have a car with lower emissions, but no one is running an F355 as a highway commuter box that I can see. It's not the same as removing the cats off a toyota corrolla. There is something wrong with the F355 that causes it to overheat the cats in a way that will destroy them.

Much of the emission control system on the F355 is a bit braindead anyway... seriously an air injection system?!? That went out of vogue in the 80's! Most modern cars from 95 on forward did not have an air injection system (which coincidentally causes increased EGT's).

Don't get me wrong, I am not against having a car that "runs right" and has cleaner exhaust emissions, but the Ferrari isn't doing it well.

By comparison, the Honda S2000, arguably, is similar in power output (118 hp/l is US trim), is slightly over 1/2 the displacement of the Ferrari with 1/2 as many cylinders, and achieves the same approximate rpm, yet doesn't suffer from catastrophic failure of it's emissions system, headers, or other components.

The Ferrari is not running right if it is eating itself and it's emissions equipment.

Well there is more to it than just the O2 sensors. First there is MAF, RPM, and TPS which are the primary contributors to the amount of fuel the engine is supposed to get as a result of the injector pulse. There is also the spark table which largely determine what the O2 sensor will be measuring, because the O2 sensor is not measuring the A/F ratio but is a proxy for A/F ratio based on the amount of Oxygen in the exhaust gas stream. Much of the time, the O2 sensors may be ignored especially over 4,000 RPM at WOT. Only when the ECU is in a closed loop condition does it listen to the O2 sensors.

That is generally true... Your post was the most accurate one.

 

This is what I have been running on my car with a full capristo stage three and gruppe intake. Originally a check engine light every three drives now not 1 in a year . Will see what happens over next year. Also four previous years had too replace rear o2 sensor twice to meet ca emmisions . Not sure why the old ones would stop working good enough to pass but every time I changed them I passed ca emmisions easily. 99f1

 

Not to rehash an old thread, but I called Tubi and they are telling me no lights with their delete pipes? What's the real friggin story!!!!

 

Just received this email from Tubi. Any thoughts? Anyone?

Hello Marcus,

I heard back from Tubi’s production manager and he assured me that they haven’t had any Check Engine Light issues.



Please give me a call if you would like to order them.



Thanks,

 

Is he referring to catbypass pipes?

 

I had Tubi test pipes on my car for 8 years and yes, the CEL was there the whole time.

 

Why would they tell me there's no issues!!!! That's very frustrating.

 

Yes

 

There must be more that we are missing. You can't put just test pipes on a car ( No sensor extenders or anything) and not have a CEL.

 

Tubi Style - Ferrari F355 5.2L Test Pipes

 

Sent this follow up message to confirm............

RE: 335 Tubi Test Pipes...‏

Victor Ortiz
12:07 PM
Photos

To: 'Marcus'

[email protected]

Hello Marcus,

Yes those are the correct pipes.

Thanks,

Publication8





From: Marcus [mailto:[email protected]]
Sent: Friday, May 30, 2014 11:42 AM
To: Victor Ortiz
Subject: RE: 335 Tubi Test Pipes...


Just to be sure we are talking about the same pipes.

Tubi Style - Ferrari F355 5.2L Test Pipes

Thanks,
Marcus

 

Possible with 2.7 motronic, not possible to run cat delete pipes on a 5.2 motronic and not get CE light without further intervention


Sent from my iPhone using Tapatalk