Anybody running DPs with N54 mids?

[TheRuss]

As the title says really - is anybody running catless downpipes with N54 mids?

Somebody mentioned that you shouldn't/couldn't do this because running a stage 2 tune would kill the cats in the N54 mids. Is that right?

Only, I installed some AR downpipes at the weekend and have N55 mids on and the BMW Performance axle back, but it's just far too loud and raspy. Sounds like a truck when I load the throttle. As such, I'm considering putting the N54 mids back on, whilst I look at options for sports catted midpipes.

Currently the worst of the noise is when I start the car from cold. I'm pretty sure nothing is rubbing because I ensured that all my clearances were good, but because it's so straight through I think at start up it sounds like it's rattling anyway.

FWIW it doesn't rattle when driving, even when I get on it or go over speed bumps, so I'm pretty sure it's not rattling at start up. (I friggin hope.)

Here's a cold start vid.

[SGJB135i]

I put my n55 mids and vrsf downpipes catless with my stock axel back and it sounded soooo bad, full of rasp! Took off my midpipes and my car sounds amazing! No rasp or anything!

[TheRuss]

So you're back on N54 mids? Can the mid cats handle the heat of a stage 2 tune?

[Colt]

Hate the N54 mids with DPs and axleback. Ordering Berk in the next day or so to change it out

[Miko226]

Im running this right now with a muffler delete with no problem also i could really care less if it ruins the cats on the secondary worst case scenery they breathe better. i plan on swapping them for n55 mids anyway

[1911A145]

I have VRSF DP's, N55 mids (cats cut out), and stock axle back and i love the sound. sounds stock when cruising until i get on it.

[TheRuss]

Hmm, I might consider swapping the N54 mids back in then, but I don't want to fry the cats in case I ever want to go back stock.

Angerman, what do you hate about your setup? I notice you have different downpipes and axle back to me, so I guess mine would sound different with the N54 mids back in anyway.

[TheRuss]

Originally Posted by 1911A145

I have VRSF DP's, N55 mids (cats cut out), and stock axle back and i love the sound. sounds stock when cruising until i get on it.

Another good option, but I'd think it would still sound quite raspy at times? Do you have any vids of the sound?

[1911A145]

Originally Posted by TheRuss

Another good option, but I'd think it would still sound quite raspy at times? Do you have any vids of the sound?

The ONLY time it really "rasp" would be on the 1st to 2nd gear shift (automatic) but other than that it always sounds very deep and throaty.

I dont think you will have any issues "melting" the rear cats on the cobb tune.

[TheRuss]

Hmm, I might try switching the N54 mids back in then and see how it sounds. Has anybody actually run stage 2 with N54 mids and killed them?

[MIAblu1]

Im running 3" AFE DP's kittyless with my N54 mids and the golf-T mod to keep the flap open on the muffler and the car sounds good. Has a nice deep tone but not raspy at all either. Heard it for the first time this week from the outside while my buddy drove my car and I followed in his and of course as soon as he got open highway he opened her up. I heard the car's exhaust over the music i was listening to in his car and saw a quick puff of smoke and he was gone... sounded great for nothing but DP's and that flapper mod.

[Colt]

Originally Posted by TheRuss

Angerman, what do you hate about your setup? I notice you have different downpipes and axle back to me, so I guess mine would sound different with the N54 mids back in anyway.

Preferably the noise. Really droney at about 1900-2650RPMs and after that it's silent. Yes, it probably will sound different to your current setup one way or another... I think my current main problem is bottle-necking. The aftermarket DPs and axleback don't align correctly to the stock n54 midpipe (in diameter), which I believe is causing an increase in throttle lag and sound quality...thus making me want to get the 2.5" berk midpipes to correctly line up to the rest of my exhaust components

[TheRuss]

What is the diameter of the stock mids then?

[Dmacc]

Just FYI the cats in the n54 mids don't do S$&!, I smogged my car in CA at the hardcore state referee station with my stock downpipes, catless Agency power midpipes, as well as the stock axleback. I passed both visual and the sniffer with flying colors.

I'd say throw on the n54 mids if you are looking for a less raspy set up, and don't give a rats ass about the secondary cats and heating them up or blowing them out because they truly are pointless, run stage 2 or 3 or 4, they may as well just be resonators. They do add a nice tone to the exhaust with catless dps but to each their own.

[TheRuss]

Thanks for that. I'll give that a go this afternoon (if it doesn't rain).

I think it's going to go from a very raspy setup to a very deep, bassy one though, as I have the BMW Y-pipe (resonator delete) fitted to my N54 mids!

I'll try to get a video after I've done it and I'll throw it up here.

Are the N54 cats very restrictive? My main issue with not wanting to kill them is if I ever wanted to go back to stock. New N54 midpipes are pricey, so I'd rather not obliterate the cats.

Does anybody know of anyone that has actually killed the cats though? I've not seen any posts about it, but one member told me they couldn't stand the stage 2 temps via PM.

I'd have thought that eliminating the downpipe cats would make the turbos run cooler anyway, so surely the temps to the mid cats would be fine?

[yawn]

If my understanding is right (for n54), catless dps are installed much more frequently than catless mids due to the higher gains in performance. That being the case, I haven't read too much in these forums about the cats in the mids getting fried.

So how do you know whether or not the cats in the mids have been killed?

[Dmacc]

Originally Posted by sharkatron

If my understanding is right (for n54), catless dps are installed much more frequently than catless mids due to the higher gains in performance. That being the case, I haven't read too much in these forums about the cats in the mids getting fried.

So how do you know whether or not the cats in the mids have been killed?

Exactly, there really isn't an easy way to tell if they are fried. That's why I wouldn't worry about it at all, no one has ever mentioned frying their cats in their mids as far as I can remember on here.

I've ran upwards of 21psi on my stock downpipes and put a lot of stress on the cats, but they seem to be okay, would I recommend it on the stock downpipes? No I would not.

[1911A145]

Originally Posted by Dmacc

Exactly, there really isn't an easy way to tell if they are fried. That's why I wouldn't worry about it at all, no one has ever mentioned frying their cats in their mids as far as I can remember on here.

I've ran upwards of 21psi on my stock downpipes and put a lot of stress on the cats, but they seem to be okay, would I recommend it on the stock downpipes? No I would not.

:raises hand:

I have actually mentioned a few times on these forums about my N54 cats in the mid pipes being fried.

At 44k miles the car was bone stock when I decided to start modding. I added a COBB AP on the stage one tune. drove around a little bit until I bought the VRSF DP's. I installed the downpipes and at the same time cut the rear cats off before going to the stage 2 tune.

My drivers side rear converter was partially clogged. So... it is possible and I would not recomend anyone to run a tune with the mid cats at all. resonators, yes.

[Dmacc]

Originally Posted by 1911A145

:raises hand:

I have actually mentioned a few times on these forums about my N54 cats in the mid pipes being fried.

At 44k miles the car was bone stock when I decided to start modding. I added a COBB AP on the stage one tune. drove around a little bit until I bought the VRSF DP's. I installed the downpipes and at the same time cut the rear cats off before going to the stage 2 tune.

My drivers side rear converter was partially clogged. So... it is possible and I would not recomend anyone to run a tune with the mid cats at all. resonators, yes.

Ahh I gotcha, I didn't know it was such a problem, my agency power midpipes have two resonators in place of where the cats were, it adds to a nice sound imo, I enjoy it, if you are looking for another alternative to n54 mids.