[James Cole]

Hello guys,

Looking to get into catless downpipes as for the tune am a bit nervous since there is some info that the dealer might flag my car easily even when going back to stock by just connecting Esys.

Has anyone been able to fool the ECU with O2 spacers of something similar to avoid a CEL?

Thanks!
JC

[GOLFFRR]

you will get a check engine light I would imagine without the tune. There was a valve controller unit that may be available for these that you can plug in that just removes the check engine light and also lets you close and open your valves for those times you dont want the loud noise which will come from the DPs. Contact iND or EAS see if the Macht Schnell unit valve controller plug in will work on these models.

[shemeld_135]

In the past I used this for my m2 and m2c. Mixed reviews on forum but I had nothing but good luck.


http://www.bigdaddiesgarage.com/mini-cat-cel-fix.html

[suby01]

Todays BMW DME is too smart for downpipes or catalytic converters. Even with a catted DP you will get a CEL and adding O2 sensor spacers last worked years ago not on todays BMWs.
If you want to get rid of the CEL while catless a tuner is your only option. Ultimately that will yield your full potential of the aftermarket DPs as well and give you biggest HP gains. Otherwise pretend that the orangish light on the dash is not there and enjoy your car.

[James Cole]

MMMM... Any word on BMW automatically flagging cars with tunes even if returned to stock?

[James Cole]

From what I read is not up to the dealership, apparently just by connecting the diagnostic tool it could flag the car... or am I exaggerating ?

[GOLFFRR]

I would suggest if you are worried about warranty at all, I would talk to your service agent and see what their view is on things for your specific situation. BMW has def tightened up the past few years.

[AlexFL]

Originally Posted by James Cole

Hello guys,

Looking to get into catless downpipes as for the tune am a bit nervous since there is some info that the dealer might flag my car easily even when going back to stock by just connecting Esys.

Has anyone been able to fool the ECU with O2 spacers of something similar to avoid a CEL?

Thanks!
JC

Another solution would be to get catless midpipes. Would improve the sound and it would not throw CEL. Ben will have such midpipes soon.

[GT500R]

Originally Posted by James Cole

From what I read is not up to the dealership, apparently just by connecting the diagnostic tool it could flag the car... or am I exaggerating ?

Yes it is flagged once connected. And even if you do a full eprom back up they can still look at other data (G force, etc to determine if there is a tune). Pay to play.

[to_riffic]

Well, I'm running catless downpipes and had O2 sims, which were useless. It worked initially, and then stayed on and would never go away. On top of that there were several times where I'd start up the car and it'd run like shit and throw a CEL and "engine malfunction".

The only way to alleviate the issue was get a tune and it has been running fine since.

[James Cole]

Originally Posted by to_riffic

Well, I'm running catless downpipes and had O2 sims, which were useless. It worked initially, and then stayed on and would never go away. On top of that there were several times where I'd start up the car and it'd run like shit and throw a CEL and "engine malfunction".

The only way to alleviate the issue was get a tune and it has been running fine since.

Thanks! this helps a bunch! what tune did you go with?

[to_riffic]

Originally Posted by James Cole

Thanks! this helps a bunch! what tune did you go with?

BM3! It has been solid but there seems to be a crop of different tuners. You can't really go wrong when you've already got 470hp+ to start with in the S58 platform.

[SuperSport]

Been talked about a bit but catless DP's on the X3M will yield minimal gains. I could see doing them for an all out build w/bigger turbos.

Can't go wrong with an OTS map from Bootmode3 or MissionPerformance for half the price of DP's and no CEL's. The tunes are fairly conservative, unless you start getting into the more aggressive maps. If you are going to mod it, I don't think a dealer will care if it is a tune or DP. If they are gonna toss the book at you, they will.

I am one opinion.. take your time and read up.

[AlexFL]

Originally Posted by SuperSport

Been talked about a bit but catless DP's on the X3M will yield minimal gains. I could see doing them for an all out build w/bigger turbos.

Can't go wrong with an OTS map from Bootmode3 or MissionPerformance for half the price of DP's and no CEL's. The tunes are fairly conservative, unless you start getting into the more aggressive maps. If you are going to mod it, I don't think a dealer will care if it is a tune or DP. If they are gonna toss the book at you, they will.

I am one opinion.. take your time and read up.

Yep. No dealer will ever believe you that you run a catless downpipe without a tune.

[LUISX3M]

You might as well get a tune if you go catless (my 2 cents)

[LimeRock]

At risk of stating the obvious, will high-flow catted downpipes trigger a CEL? Specifically considering the VRSF option, but wary to tune bc of warranty.

Edit — may have posted too soon. From what I gather any high flow cat will trigger a CEL eventually...sounds like the solution is to remove the secondary cats? More sound, same power?

[spuntyb]

Originally Posted by Weissach

At risk of stating the obvious, will high-flow catted downpipes trigger a CEL? Specifically considering the VRSF option, but wary to tune bc of warranty.

Edit — may have posted too soon. From what I gather any high flow cat will trigger a CEL eventually...sounds like the solution is to remove the secondary cats? More sound, same power?

Yup, as AlexFL stated above, if you want to skip the tune, just go with catless midpipes. Decent sound upgrade for the $. A few of them out there now I believe.

[LimeRock]

Originally Posted by spuntyb

Yup, as AlexFL stated above, if you want to skip the tune, just go with catless midpipes. Decent sound upgrade for the $. A few of them out there now I believe.

Got it, thanks for confirming. Any thoughts on resonated vs non-resonated? I have the comp exhaust and am curious about drone. Totally fine if there is drone with the valves open, but as long as it can be quieted down.