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Discussion Starter · #1 ·
I am taking my Spyder in tommorrow to have the high flow main cats installed (from Formula Dynamics) as well as the Larini X Pipe. I would like to remove the packing from the pre-cats (the ones at the front integrated with the headers).

Has anyone had the packing removed from these pre-cats (MaseratiBoy - I seem to remember that you did??).

If so, are there any issues with the senors (CEL coming on due to falsing)? My mechanic has cautioned that this might be a problem.
 

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flash gutting those cats integrated into the headers will cause CEL light issues unless you can get some O2 sims and bypass the sensors...but then you will lose the fuel correction functionality from those sensors as well.
 

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grt lake those pieces you posted are for the euro spec headers and pipes...the euro pipes do not have a cat in the header that one unit is the pre and main cat system also most likely that first cat being gone will be a problem as the o2 sensor is right behind it...maybe relocating it to behind the other cat would assist it in not throwing a CEL as long as it doesnt look at EGT as well that would not be an issue
 

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grt lake those pieces you posted are for the euro spec headers and pipes...the euro pipes do not have a cat in the header that one unit is the pre and main cat system also most likely that first cat being gone will be a problem as the o2 sensor is right behind it...maybe relocating it to behind the other cat would assist it in not throwing a CEL as long as it doesnt look at EGT as well that would not be an issue
interesting. I wonder if anyone has any more input. It wouldn't be too difficult to extend the o2 sensor wiring and weld in a o2 bung.

If I did this, I'd probably buy an aftermarket air/fuel gauge to keep an eye on the mixture.
 

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Discussion Starter · #7 ·
The ones from Jeff are weld in main cats (they replace the second set) so they will still cause the CEL issue as the senors are on the first set of cats only.

I thought about relocating the sensor as well (to downstream of the main cats) - that is probably the preferred route but will involve running new wire or splicing the existing to make it longer.
 

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Discussion Starter · #8 ·
interesting. I wonder if anyone has any more input. It wouldn't be too difficult to extend the o2 sensor wiring and weld in a o2 bung.

If I did this, I'd probably buy an aftermarket air/fuel gauge to keep an eye on the mixture.

Ace: Can you elaborate on this?

My main driver here is that I do not want to have the pre cats keep overheating and the packing fall apart and end up downstream (e.g. clogging up the main cats). The last time they heated up the CEL came on and the car went in to limp mode.
 

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Ace: Can you elaborate on this?

My main driver here is that I do not want to have the pre cats keep overheating and the packing fall apart and end up downstream (e.g. clogging up the main cats). The last time they heated up the CEL came on and the car went in to limp mode.

Well I don't see a problem extending the o2 sensor wiring properly, meaning using solder and high temp heat shrink. Most exhaust shops will being able to fill the old bung hole and add a new bung hole (that sounded funny). They pull the o2 sensor and find a bung that has matching threading. I'm guessing its a pretty standard metric Bosch o2 sensor.
Now I don't know what the ECU is calibrated to actually expect to see from the sensor. I don't know if the rear cats would put out a similar reading. This is the info we need to find out.
If I really had the balls, I'd rip out the factory ECU and install a complete stand alone engine management system. I've done a ton of VW/Audi standalone installations.....just not ready to rip apart the Maserati.
 

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I presume you are not in Calif.

It is a huge problem here. The State has mandated OEM cats only now from what I understand, and the pricing has skyrocketed on them here.

How about $750.00 being a good price now for a cat for a 2000 Mazda 626?

BMW's are in the thousands!
 

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I presume you are not in Calif.

It is a huge problem here. The State has mandated OEM cats only now from what I understand, and the pricing has skyrocketed on them here.

How about $750.00 being a good price now for a cat for a 2000 Mazda 626?

BMW's are in the thousands!

no emissions here in Florida. No checks. Nothing.
 

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I wonder if Formula Dynamics has ever done an o2 sensor relocation behind the 2nd cats.
I'm really curious if this gives a proper reading and prevents a CEL.
 

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You could switch to the AEM UEGO unit...it has a narrowband output as well which if memory serves would have the correct voltage sweep to cover the cel issue and give us a metering point for mixture as well.
 

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We've not had a problem with a CEL light on these models. In theory it should be a problem. A few of our customers reported CELS initially and after a reset or two it stopped reporting a problem.

However if a CEL does seem to stay lit, you'll need to move the rear O2 sensor behind the CAT. These are standard Bosch O2 Sensors so it shouldn't be too difficult.

GrndLkNatv: Yes, you'll have the same concern with anyone's CATS. The solution is in moving the rear sensor so that one is before the CAT and another is behind the CAT. In this way the ECU can monitor the effects and efficiency of the CATS.
 

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Jeff, do you know if the rear o2 is only there to measure efficiency? is the front one to measure mixture?

If this is the case a pair of plug in o2 sims would solve the problem...we just need to find out the desired voltage output the ECU wants to see from the rear sensor so as not to trigger a CEL and you got it.
 

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Jeff..

Jeff's Quote:

We've not had a problem with a CEL light on these models. In theory it should be a problem. A few of our customers reported CELS initially and after a reset or two it stopped reporting a problem.

However if a CEL does seem to stay lit, you'll need to move the rear O2 sensor behind the CAT. These are standard Bosch O2 Sensors so it shouldn't be too difficult.

GrndLkNatv: Yes, you'll have the same concern with anyone's CATS. The solution is in moving the rear sensor so that one is before the CAT and another is behind the CAT. In this way the ECU can monitor the effects and efficiency of the CATS.

Response:

So if I go with the Larini, as I have planned, no worries.. That's what I needed to know.
 

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Not sure if anyone's still interested, but there is a way to remove both (pre & secondary) cats, w/o having to worry about any CEL issues...
My pre-cats were removed from the headers (not an easy job), de-cored, and then reinstalled. Next, Fabspeed cat bypass pipes were installed, along w/ an EVOMSit ECU reflash...the way it was explained to me, was that Evolution w/ their software, has the ability to "trick" the ECU into thinking that "all is well", regarding the CEL warnings that would've normally been displayed by removing the cats...in any case, my car is completely devoid of all catalytic converters, has passed emmisons inspection in my neck of the woods, and (knock on wood) I've never had an issue w/ a CEL warning light coming on.
 

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You can supress the light on the dashboard from displaying with a custom software tune that has programming to specifically ignore the efficiency threshold errors caused by removing the catalytic converters.

However, your car will not pass a proper emissions sniffer test (O2 Sensor in the tailpipe) without catalytic converters because there are no emissions control devices installed on your car that actually reduce the emissions levels. You may also still have trouble with the emissions monitors (not just the presence of a Check Engine Light) in states that check these through OBDII.

All in all, removing all of your catalytic converters isn't a great option for most owners since many states perform a sniffer test and / or a monitor test. If you're in a state that doesn't have strict emissions enforcement then you may be able to slip by.

In the end though, it's best to run at least a single set of catalytic converters. If they are High Performance, High Flow Sport Cats like our Tri-Core Metal Substrate models. You will pass the sniffer test in all states and they do not cause a restriction that robs you of power. If the rear O2 sensor is installed behind the active Catalytic Convertor, there will be no Check Engine Light to remove.

Best Regards
 

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I'm not quite sure if the emissions requirements here in DC are less prohibitive then most States are, but perhaps they are indeed (hey, who knows, maybe the 'tube in the tailpipe' gizmo @ the inspection station was on the fritz the day of my inspection, and the Gods were smiling on me).

But nevertheless, the car is running (for lack of a better expression) totally 'cat-less'...

It was inspected last Dec., a tube was inserted into it's tailpipe and the car passed DC's emissions test w/ no problem...that being stated though, if I EVER experience a negative issue due to their removal, or, move to a place that's more restrictive, then I will w/o a doubt install the high performance cats offered by Formula Dynamics (btw, Josh over @ ECS of VA was kind enough to install the DBWEM on my car last week, and I absolutely love it...albeit for some strange reason, my EVOMSit ECU remap, doesn't seem to always want to play nice w/ it.)!
 
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