[umut335i]

Got a decat and a remap today however my cars smoking so bad its actually kind of embarressing. If i come to a stand still and idle there would be a cloud of white smoke... is it the turbo seals or should i get a 100/200cell high flow secondary cat?

[PR3CI5N]

You're catless man what'd you expect? You should've left your secondary cats in place

[umut335i]

Obviously didn't realise till it had been done!! Im just hoping its not a turbo issue...

[Blaster400]

Add back secondary cats or go with 100 cell race cats like I did. This will probably fix your smoke issue it did for me.

[umut335i]

Is there any chance this is just consealing a turbo issue?

[old grey steve]

When I dropped the primary CAT's for down pipes I had smoke with 30 miles, which seemed to disappear then re appear, depending on the journey done, car was re mapped correctly to suit the mod but not long afterwards I discovered this wonderful piece of news...















One partially seized secondary turbo due to carbon build up and one primary turbo failure due to the usual seal issue. I think with the CAT's in place they've helped mask the issue the smoke combined with oil traces on my offside pipe kind of gave the game away.

I have also addressed the cars notorious breather issues with a Rob Beck PCV valve



and a decent BMS catch can






It's difficult to be certain no CAT's in place will promote smoke I guess the thing to do is monitor what goes on over a short period of time, but at the same time don't leave it too long before getting it checked out, not only looking for turbo issues but also the cars breather system because if the car does shortish journeys this will be put under pressure, once mine was dine at work everything's been A1. But don't leave it too long

[umut335i]

I think its a turbo problem.

[BMWburger]

Get it checked by a proffesional, but I was always led to believe that which smoke was caused by burning water?

[umut335i]

this is burning oil smell... its quite a thick foggy smoke... it is apparent when stationary and in D/S or while driving and easing off the throttle then back on again... literally loads of it which surrounds the car!

[doughboy]

CATS don't stop smoke anyway.

If it wasn't smoking before the cats were removed then something's been damaged during the work. Is your oil level going down?

It will never pass an mot with no cats, you should have left*secondary cats in.

Old grey Steve: what do you mean by primary and secondary turbo? They're not sequential like a 335d.

[old grey steve]

Originally Posted by doughboy

CATS don't stop smoke anyway.



Old grey Steve: what do you mean by primary and secondary turbo? They're not sequential like a 335d.

Bank 1 Bank 2 turbo I call Bank 1 primary Bank 2 secondary i.e. cylinder 1-3 4-6 but the oil smell to help OP is what, likewise on trailing throttle etc I got the smoke. This eventually got worse and the end results lie in the pics above.

[umut335i]

I've ordered new turbos from vargas, bms oil catch can, RB PCV, just to rule everything out... have the VRSF fmic and vrsf chargepipe on the way too...

Hopefully this will fix the issue. Im going to a garage on saturday anyway so they should be able to help....

[umut335i]

Originally Posted by doughboy

CATS don't stop smoke anyway.

If it wasn't smoking before the cats were removed then something's been damaged during the work. Is your oil level going down?

It will never pass an mot with no cats, you should have left*secondary cats in.

Old grey Steve: what do you mean by primary and secondary turbo? They're not sequential like a 335d.

Im not sure mate but a lot of people on the forum say that the smoke can be masked by the cats.. also the same was said by powerflow and all the specialists i rang up... the oil levels are fine...

[doughboy]

All bollox mate. CATS don't hide burning oil smoke. They might help with condensing water vapour at cold start, but that's it. So you might get more steam at cold without CATS.

Cars without CATS don't smoke. Neither old cars made without CATS or new cars with CATS removed.

If it smells of burning oil then that's what it is, and the oil must be coming from your engine. And no amount of cats will hide it, in fact they'd be destroyed by it.

Numerous decatted 335i's on here, including me, and never a puff of smoke.

[umut335i]

Could it be because of the remap?

Are you completely catless? I do not have ANY cats... i.e. primary and secondary both gone...

[doughboy]

Does it smell of oil or fuel?

Put a white cloth over the tail pipes and rev it, is it spotted with oil ?

The map could affect fuelling, but not oil leaks.

[umut335i]

No it definitely doesnt smell of fuel, its a heavy oil smell, proper strong you can tell the difference. The smoke is thick and lingers. I'll try the cloth thing tonight...

[umut335i]

Also its coming out the left exhaust

[lolololol]

Why go catless ? Cat back with catless DP's is enough.

What Map doe you have ? Seems to have happened since map, doesnt it !

Could be over fuelling, could be over boosting and blown a seal ? Do you know what PSI you are running ? You would with a JB4 ;-)

All these mods you are running and buying and no way of logging and adjusting the maps.

I hope it isnt serious mate but you are asking for trouble the way you are going about this tbh.

[BMWChap]

Originally Posted by umut335i

Also its coming out the left exhaust

..you don't seem worried

[umut335i]

I've ordered new turbos along with loads of other bits... Im hoping that'll fix it...

[umut335i]

Originally Posted by omaragha

Why go catless ? Cat back with catless DP's is enough.

What Map doe you have ? Seems to have happened since map, doesnt it !

Could be over fuelling, could be over boosting and blown a seal ? Do you know what PSI you are running ? You would with a JB4 ;-)

All these mods you are running and buying and no way of logging and adjusting the maps.

I hope it isnt serious mate but you are asking for trouble the way you are going about this tbh.

I'll buy a JB4 if you can teach me how to use it.. lol!