1M has high flow cats in downpipe???

[Gtrain]

Does the 1M have high flow cats in the downpipes?
I have read elsewhere that the 1M had high flow cats but was wondering if there was any data to back that up.

From looking at realoem, the 1M cats versus the 135 n54 cats, they have different part numbers for sure.

1M
01 Rmfd primary catalytic converter ZYL. 1-3 1 18307980403
02 Rmfd primary catalytic converter ZYL. 4-6 1 18307980404

135 N54 Engine
01 Rmfd primary catalytic converter ZYL. 1-3 1 18307553594 $957.00
02 Rmfd primary catalytic converter ZYL. 4-6 1 18307553595 $957.00

[Dackelone]

Yes, the 1M has higher flow cats - so it has been reported before.

[MDORPHN]

And it's interesting that there was not even a whisper of this difference during all of pre-production hype generated by BMW, while other suggested differences (piston rings, etc) proved not to be.

Neil

[p66]

A tuner shop dyno'd the AR dp's with race cats and generated insignificant gains over stock. With and without a tune. Would support the evidence that 1M has higher flow cats than 135i.

Don't ask me for graphs, or names, places and dates. I don't have them. I was considering getting the AR's and was advised to save my money. Coming from the tuner himself, that sells the product, made an impression on me.

[OrangeCrush]

I have smelled the non cat/ high flow cat smell on numerous occasions. I have also heard this and though it was caused by this. Either that or my car is fucked up.

[OrangeCrush]

Originally Posted by p66

A tuner shop dyno'd the AR dp's with race cats and generated insignificant gains over stock. With and without a tune. Would support the evidence that 1M has higher flow cats than 135i.

Don't ask me for graphs, or names, places and dates. I don't have them. I was considering getting the AR's and was advised to save my money. Coming from the tuner himself, that sells the product, made an impression on me.

I think it was GIAC, they said we didn't need to update the downpipes for one of thier more aggressive tunes because of the highflow cats of the 1m

[Zuzu]

Originally Posted by Gtrain

Does the 1M have high flow cats in the downpipes?
I have read elsewhere that the 1M had high flow cats but was wondering if there was any data to back that up.

From looking at realoem, the 1M cats versus the 135 n54 cats, they have different part numbers for sure.

1M
01 Rmfd primary catalytic converter ZYL. 1-3 1 18307980403
02 Rmfd primary catalytic converter ZYL. 4-6 1 18307980404

135 N54 Engine
01 Rmfd primary catalytic converter ZYL. 1-3 1 18307553594 $957.00
02 Rmfd primary catalytic converter ZYL. 4-6 1 18307553595 $957.00

Its here..

http://www.1addicts.com/forums/showthread.php?t=691143

and here..

http://www.1addicts.com/forums/showthread.php?t=702209

[Gtrain]

Thanks for all the info. I was wondering if there were any hard facts on this, that's all.

Thanks again

[flzrider]

Never knew this. Learned something today.

[richb811]

Good stuff to know! I guess I know why I haven't sold a set to a 1M driver yet!

[1Mpressive]

Good info! a

Not to thread jack but i had a question for those with Akrapovic... Do you get the same or similar sound as heard on the Alekshop Akra video without the aftermarket cats? More specific do you hear the turbo spool up like in the video with the factory cats and say the akrapovic mid and rear sections? ...with wireless of course

[bdaddylo]

In order to hear the turbos spool up on any exhaust, you have to go catless.

[-Z-]

Originally Posted by bdaddylo

In order to hear the turbos spool up on any exhaust, you have to go catless.

in many cases it also means raspy sound I hate... and gas smell.

[MDORPHN]

I had the opportunity to to a side-by-side comparison of 1M downpipes and other N54 downpipes this weekend.

Other than different numbers etched into the cat, externally they are identical. And no difference was obvious looking through the pipe at the cat substrate.

However, we put them on a scale and the 1M cats weighed less than the other (7.6 lbs v 8.0 lbs).

This difference may be related to the much higher mileage of the "regular" N54 downpipe or it may be the the 1M cat substrate is less dense and, for that reason, higher flowing. I'm guessing it's the latter.

Neil

[sparoz]

Originally Posted by MDORPHN

I had the opportunity to to a side-by-side comparison of 1M downpipes and other N54 downpipes this weekend.

Other than different numbers etched into the cat, externally they are identical. And no difference was obvious looking through the pipe at the cat substrate.

However, we put them on a scale and the 1M cats weighed less than the other (7.6 lbs v 8.0 lbs).

This difference may be related to the much higher mileage of the "regular" N54 downpipe or it may be the the 1M cat substrate is less dense and, for that reason, higher flowing. I'm guessing it's the latter.

Neil

Thanks, that's good information. Advan in Sydney has confirmed that too. However, GIAC's work indicate that it is higher flow.

[PunjabiM3]

Good info! Any figures for how much catless DP's would add power wise with tune over the stock DP's?

[ADVANT123]

So if the 1M has higher flowing cats, does this mean we can run the Cobb Stage II/Stage II+ mods if we have all the other mods?

[ozinaldo]

Originally Posted by ADVANT123

So if the 1M has higher flowing cats, does this mean we can run the Cobb Stage II/Stage II+ mods if we have all the other mods?

GIAC was saying that stock DPs are enough (though a catless alternative would be the better solution) for their Stage 2 tune so should be others.

[HP Autosport]

We only saw 8-12 whp with high flow cats vs stock.

[m3dragon]

Originally Posted by HP Autowerks

We only saw 8-12 whp with high flow cats vs stock.

I came back from UK a few weeks ago and had a chance to talk to one of the tuner's there. Their test on a UK 1M showed using DP and using the stock catted section gave positive gains as well as allowed the turbos to spool faster.

Any testing with that combo? Would like to compare notes and see on a US car if it did do anything different.

[cbl117]

I've searched and this was the only thread I could find on this question...

If I have a N54 135i, is it worth swapping my downpipes for 1M downpipes to gain performance, not have a CEL and pass emmisions?

[HP Autosport]

Originally Posted by cbl117

I've searched and this was the only thread I could find on this question...

If I have a N54 135i, is it worth swapping my downpipes for 1M downpipes to gain performance, not have a CEL and pass emmisions?

If you can find them cheap. You will likely gain about 10 hp by the switch. The alternative is just to save the money and put it towards a cat-back exhaust, intake of a proper software flash for the car.