[carholic]

Anyone has done high flow catalytic converters? Like a 200 cell cat? Is a tune necessary afterwards? I want to buy sport cats but do not want a tune right now. I am buying the sport cats for a bit more sound and also a bit more performance.

Thoughts?

Thank you.

[M_Power Rob]

Originally Posted by carholic

Anyone has done sport cats? Is a tune necessary afterwards? I want to buy sport cats but do not want a tune right now. I am buying the sport cats for a bit more sound and also a bit more performance.

Thoughts?

Thank you.

What are sport cats/who makes them?

For the most part, a tune is not required for exhaust modification. Changing downpipe, different story.

[Squidget]

Yeah, not sure what a sports cat is either. Like, would it be some kind of low-backpressure catalytic converter?

Or?

[carholic]

200 cell catalytic converters.

[mike@x-ph.com]

The tune is not required, but you will get a check engine light; you can ignore it as the car will drive normally.

If you wish to avoid the CEL, get the active autowerke downpipes with GESI cats, it won't trigger the light.

[M2siast]

Originally Posted by mike@x-ph.com

The tune is not required, but you will get a check engine light; you can ignore it as the car will drive normally.

If you wish to avoid the CEL, get the active autowerke downpipes with GESI cats, it won't trigger the light.

From which generation has the car been driving normally with a CEL? F-series?

OP, it makes no sense for you to replace your downpipes without a tune. Why do you not want to tune it? You’ll be missing out on performance gains with the new setup.

[mike@x-ph.com]

Originally Posted by M2siast

From which generation has the car been driving normally with a CEL? F-series?

E, F, and G chassis generations all run normally with high-flow downpipes.

[M2siast]

Originally Posted by mike@x-ph.com

E, F, and G chassis generations all run normally with high-flow downpipes.

That’s incorrect.
From experience, I owned an E82 for 6 years+ and had a sport cat (200-cell) and without a tune it went into a “soft limp” mode of sort, it lost power demonstrably when the light went on. I’m wondering if the same is true for F/G.

It certainly affected the E82.

[mike@x-ph.com]

Originally Posted by M2siast

That’s incorrect.
From experience, I owned an E82 for 6 years+ and had a sport cat (200-cell) and without a tune it went into a “soft limp” mode of sort, it lost power demonstrably when the light went on. I’m wondering if the same is true for F/G.

It certainly affected the E82.

I don't know about your specific case but no, getting a CEL from downpipes did not lead to limp mods on any chassis.

[Info@mad-us.com]

You will need this https://mad-us.com/mad-bmw-s58-catte...-flex-section/

and this M18 X 1.5 Bung 32mm O2

[r33_RGSport]

Originally Posted by carholic

Anyone has done high flow catalytic converters? Like a 200 cell cat? Is a tune necessary afterwards? I want to buy sport cats but do not want a tune right now. I am buying the sport cats for a bit more sound and also a bit more performance.

Thoughts?

Thank you.

Evolution Racewerks do make it, but you’ll need a tune.
With CEL on, based on my testing on my F97 X3MC, S58 loses power when CEL is on.
It has been discussed many2 times in F97 X3M sub-forum, but many downpipe manufacturers doesn’t post the actual dyno result to show the power loses without a tune. They all shows power gain with flash tune and E30 mix, etc.
For guaranteed no CEL, you’ll need to spend more money for ActiveAutowerke that is using 400 Cells GESI Cats.
Seems like you are in California, your best bet is to run a midpipe for more sound.

[mike@x-ph.com]

Originally Posted by r33_RGSport

Evolution Racewerks do make it, but you’ll need a tune.
With CEL on, based on my testing on my F97 X3MC, S58 loses power when CEL is on.
It has been discussed many2 times in F97 X3M sub-forum, but many downpipe manufacturers doesn’t post the actual dyno result to show the power loses without a tune. They all shows power gain with flash tune and E30 mix, etc.
For guaranteed no CEL, you’ll need to spend more money for ActiveAutowerke that is using 400 Cells GESI Cats.
Seems like you are in California, your best bet is to run a midpipe for more sound.

Why don't you post your dyno showing the power loss and prove the manufacturers wrong

[r33_RGSport]

Originally Posted by mike@x-ph.com

Why don't you post your dyno showing the power loss and prove the manufacturers wrong

Sure Mike. Here it is.

Stock vs Catless on 2020 BMW F97 X3MC.

[M2siast]

Originally Posted by r33_RGSport

Sure Mike. Here it is.

Stock vs Catless on 2020 BMW F97 X3MC.

Attachment 3260096

Thank you.

[mike@x-ph.com]

Originally Posted by r33_RGSport

Sure Mike. Here it is.

Stock vs Catless on 2020 BMW F97 X3MC.

Attachment 3260096

1- Given that they are a month apart, what was the ambient temp for each run

2- Do you have the full run for each? Im assuming you did three runs for each setup and got the average, not just picked, the high of one and the low of the other.

3- Assuming the downpipe had no leaks or bad fitment, what, in your opinion, could lead to the loss since it's better to flow than stock?

[M2siast]

Originally Posted by mike@x-ph.com

1- Given that they are a month apart, what was the ambient temp for each run

2- Do you have the full run for each? Im assuming you did three runs for each setup and got the average, not just picked, the high of one and the low of the other.

3- Assuming the downpipe had no leaks or bad fitment, what, in your opinion, could lead to the loss since it's better to flow than stock?

Mike, do you have any dyno chart proving your claim that CEL doesn’t cause loss of power?

[c1pher]

[mike@x-ph.com]

Originally Posted by M2siast

Mike, do you have any dyno chart proving your claim that CEL doesn’t cause loss of power?

You claimed downpipes cause limp mode; RG claims it causes power loss. Unless you misspoke when you said limp mode and meant to say power loss, these are two different things.

Your claim of limp mode is not true and very easily proven. You can even check with your favorite vendor or manufacturer. plus 15 years of forum posts.

RG claim, on the other hand, is more interesting as he's got some data. I raised some questions I would like answered to understand better what is happening.

FYI i don't sell catless downpipes, and I don't use them on my car due to the smell, so it does not matter to me whether it loses power without a tune or not, but as an enthusiast, I'm genuinely curious to what is going on with RG dyno.

[M2siast]

Originally Posted by mike@x-ph.com

You claimed downpipes cause limp mode; RG claims it causes power loss. Unless you misspoke when you said limp mode and meant to say power loss, these are two different things.

Your claim of limp mode is not true and very easily proven. You can even check with your favorite vendor or manufacturer. plus 15 years of forum posts.

RG claim, on the other hand, is more interesting as he's got some data. I raised some questions I would like answered to understand better what is happening.

FYI i don't sell catless downpipes, and I don't use them on my car due to the smell, so it does not matter to me whether it loses power without a tune or not, but as an enthusiast, I'm genuinely curious to what is going on with RG dyno.

I think you got your timelines mistaken here.

OP asked about downpipes.
You, as a vendor, came in and said he could “ignore CEL as car would drive normally”.

I’m asking for proof of that claim. That’s it.

You seem to be on a rampage against facts, but have posted none yourself.

[mike@x-ph.com]

Originally Posted by M2siast

I think you got your timelines mistaken here.

OP asked about downpipes.
You, as a vendor, came in and said he could “ignore CEL as car would drive normally”.

I’m asking for proof of that claim. That’s it.

You seem to be on a rampage against facts, but have posted none yourself.

I see you are getting more aggressive with your responses; I'm sorry if my opinion offended you, but please do not take it personally, it's okay we can disagree on a car forum.

When you get a CEL, the car drives normally. Not in limp mode, regular shifting, everything operates as it should. Im not sure how you want me to prove that, go around the block and film myself driving?

Now if it loses some power as RG claims, then it could easily be proven by a consistent dyno and that's a lot more interesting.

And again, I'm not a vendor in this case as i don't sell catless downpipes.

[r33_RGSport]

Originally Posted by mike@x-ph.com

1- Given that they are a month apart, what was the ambient temp for each run

2- Do you have the full run for each? Im assuming you did three runs for each setup and got the average, not just picked, the high of one and the low of the other.

3- Assuming the downpipe had no leaks or bad fitment, what, in your opinion, could lead to the loss since it's better to flow than stock?

Given that it is still in the winter month, climate in the LA area not that much off. I wish I can jump into time machine and go back in time to remember the ambient temp. I guess Elon Musk need to hurry up on this project. lol.

I don't have it with me since it is not my own dyno machine. As you can see on the dyno sheet, it was SP-Engineering Mustang AWD dyno.
And as most know, Mustang dyno is one of the consistent dyno. Even if it off, it will be ~5whp IIRC. So, it still giving roughly a delta of 20whp.

Based on my discussion with knowledgeable tuners and guys who has been in the industry for decades like me, seems like BMW started to use secondary O2 reading for AFR.
Which makes sense since with flashtune, you can alter the secondary O2 reading.

I also tested with HFC downpipe, IIRC, the result was still lower than stock.
I don't have this data since I scrapped the dyno session after 2 pulls.

I have been waiting for years for others to proof me wrong, but no one ever posted a fair dyno reading. All I saw was baseline stock with after with catless w/ tune or E mix.
And IIRC this dyno result never been publicly shared until today since you asked.

[mike@x-ph.com]

Originally Posted by r33_RGSport

Given that it is still in the winter month, climate in the LA area not that much off. I wish I can jump into time machine and go back in time to remember the ambient temp. I guess Elon Musk need to hurry up on this project. lol.

I don't have it with me since it is not my own dyno machine. As you can see on the dyno sheet, it was SP-Engineering Mustang AWD dyno.
And as most know, Mustang dyno is one of the consistent dyno. Even if it off, it will be ~5whp IIRC. So, it still giving roughly a delta of 20whp.

Based on my discussion with knowledgeable tuners and guys who has been in the industry for decades like me, seems like BMW started to use secondary O2 reading for AFR.
Which makes sense since with flashtune, you can alter the secondary O2 reading.

I also tested with HFC downpipe, IIRC, the result was still lower than stock.
I don't have this data since I scrapped the dyno session after 2 pulls.

I have been waiting for years for others to proof me wrong, but no one ever posted a fair dyno reading. All I saw was baseline stock with after with catless w/ tune or E mix.
And IIRC this dyno result never been publicly shared until today since you asked.

Interesting find, I know on the F chassis there were some dynos posted with downpipes only, and the car made power.

Do you think this affects the X3M or all G chassis?