Cat converter option

[engineermike]

But can any one confirm the bank 2 header from an s197 fits the s550? That's another good option if it does

I don’t know if it does, but the 2-bolt flange is 90 deg off from gt500 cats.

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[WildHorse]

FMEM response is different depending on what the sensed failure is.

Yes I know all about that when I had and electrical gremlin that killed all my o2 / evap / cam position sensors .

When my 2018 car and 2020 truck throw a p420/30 it definitely turns on a wrench light. Not sure why yours doesn’t.

Mine will throw a CEL, but it won't throw the wrench.

 

[Robottrainer]

I don’t know if it does, but the 2-bolt flange is 90 deg off from gt500 cats.

Saws all fixes that

 

[SnowFox]

FWIW, I had GENSi cats on my 13 Shelby for 4 years without spacers or defoulers, rear sensors enabled and it never threw a code.

I have no doubt the defoulers keep the code away (I used one in my previous EcO) But if I'm understanding Mike correctly though, even if the Code is not thrown, the Trims are still potential run richer give or take 10% based on his/their testing.

 

[K4fxd]

It's sounds like @K4fxd has done this on an S550. Is this correct?

Yes, it works

 

[Robottrainer]

Yes, it works

I'm edging toward this and the Mak Performance and just re orienting the flange on the cat

 

[engineermike]

The market for used gt500 cats seems to have dried up. Though, I do wonder about retrofitting hellcat converters. I looked up the part number and it appears dodge used the same ones in everything from the 6.1 na to the demon and redeye. They’re $2000 a piece new but eBay has a used pair for $800. These should be much more common due to the production numbers.

 

[GregO]

The market for used gt500 cats seems to have dried up. Though, I do wonder about retrofitting hellcat converters. I looked up the part number and it appears dodge used the same ones in everything from the 6.1 na to the demon and redeye. They’re $2000 a piece new but eBay has a used pair for $800. These should be much more common due to the production numbers.

That’s a great idea.

 

[WildHorse]

re: downstream o2. @engineermike is correct. They do keep the upstream o2 calibrated, in a sense . Narrow band O2's do not need to be calibrated as they are continually oscillating from full rich to full lean and the average is very accurate, but only when near Stoich, so Ford uses the Rears to re-calibrate Stoich of the Front O2's.

Rear o2 are meaningless at WOT, or at any range other than at stoich.

So if the downstream are deleted via tune, the upstream will drift out of calibration.

Mike says 10%. Could be more, could be less. Depending on the condition of the upstream o2.

But here's the rub, it's an easy fix. Just periodically replace the upstream and voila ,
back into calibration.

How often that's the only question. Guess you just gotta watch the LTFT.

 

[Angrey]

re: downstream o2. @engineermike is correct. They do keep the upstream o2 calibrated, in a sense . Narrow band O2's do not need to be calibrated as they are continually oscillating from full rich to full lean and the average is very accurate, but only when near Stoich, so Ford uses the Rears to re-calibrate Stoich of the Front O2's.

Rear o2 are meaningless at WOT, or at any range other than at stoich.

So if the downstream are deleted via tune, the upstream will drift out of calibration.

Mike says 10%. Could be more, could be less. Depending on the condition of the upstream o2.

But here's the rub, it's an easy fix. Just periodically replace the upstream and voila ,
back into calibration.

How often that's the only question. Guess you just gotta watch the LTFT.

I'm running the crazy expensive NGK's because Motec insists on them, so I'm not keen on the idea of swapping them frequently. I'm curious as to how the aftermarket tunes address the issue.

Is there just not enough physical space to combine wide and narrow band in the same sensor/bung location?

 

[Angrey]

That’s a great idea.

If you buy Dodge cats used, they'll even through in a harbor freight sawzall with it if you buy 2 or more. You're buying them from Teeter the meth tweaker in Stockton, but he may have to change his profile in a couple weeks so referrals to your friends aren't going to work.

 

[engineermike]

Rear o2 are meaningless at WOT, or at any range other than at stoich.

Are you sure of this? The ford patent doesn’t seem to mention excluding corrections at non-stoich lambdas.

 

[K4fxd]

I wonder if it needs the cat to perform the calibration? I would think it wouldn't.

 

[Robottrainer]

I wonder if it needs the cat to perform the calibration? I would think it wouldn't.

Pretty sure it does. The aft sensor is measuring oxygen in the cat after the reaction. Without the reaction things would be messed up.

 

[WildHorse]

Are you sure of this? The ford patent doesn’t seem to mention excluding corrections at non-stoich lambdas.

99.9% positive that the narrowband ONLY calibrates the wideband at stoich. Then the wideband goes from there for everything else.

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