[wj4]

Just a word of caution....at least in SoCal, if you get caught without a cat, the fine is hefty...nearly $2,000. I've seen cops personally get on their knees and look for cats under the car. There are also rolling smog stations that are linked to the DMV to smog "random" cars. Random pretty much equates to hooked up cars.

CEA3-just an idea for you and your muffler shop. What a local Evo shop did was made something called a Rally Cat. What is it? It is a test pipe with a false cat wrapped around it so it still looks OEM, but it isn't

[Hegemony]

I personally think it's the mufflers, crossovers, and the piping crimps especially. Next time your baby is up on a lift, take a look at the pipes under the plate just behind the secondary cats, yeesh..

I paid a little extra to have a set of high flow secondary cats put back in my setup, and I have much superior flow now. We parked two 335's next to each other, one with my setup and one on stock exhaust, and at idle you could feel air flowing freely and forcefully over 8 inches away from the tips on the upgraded exhaust. You had to put your hand nearly on the tips to feel the flow on the stock setup. It was night and day.

[wj4]

Originally Posted by Hegemony

I personally think it's the mufflers, crossovers, and the piping crimps especially. Next time your baby is up on a lift, take a look at the pipes under the plate just behind the secondary cats, yeesh..

I paid a little extra to have a set of high flow secondary cats put back in my setup, and I have much superior flow now. We parked two 335's next to each other, one with my setup and one on stock exhaust, and at idle you could feel air flowing freely and forcefully over 8 inches away from the tips on the upgraded exhaust. You had to put your hand nearly on the tips to feel the flow on the stock setup. It was night and day.

You should've got that on tape! It would be most definitely helpful.

[DrM]

Originally Posted by Hegemony

I personally think it's the mufflers, crossovers, and the piping crimps especially. Next time your baby is up on a lift, take a look at the pipes under the plate just behind the secondary cats, yeesh..

I paid a little extra to have a set of high flow secondary cats put back in my setup, and I have much superior flow now. We parked two 335's next to each other, one with my setup and one on stock exhaust, and at idle you could feel air flowing freely and forcefully over 8 inches away from the tips on the upgraded exhaust. You had to put your hand nearly on the tips to feel the flow on the stock setup. It was night and day.

One of the shops could easily test the flow of the stock and their aftermarket exhaust to confirm this theory. Perhaps CEA3 can ask his shop to flow test the factory versus aftermarket exhaust.

Until we see the flow numbers, it is all just speculation. However, given that cars have seen 10-20 whp increases, it is likely a correct speculation

[WilyB]

Very good thread. Yesterday I had a 80-series Cross Flow two chambers Flowmaster installed in my ML55 for $475. The shop welded back the original AMG tips, so the set up looks 100% OEM, but there is a more aggressive, deeper sound at full throttle.

When I picked it up with my 335, I asked the guy about a possible exhaust mod for it. I’ll let you know what he offers.

[CASHBY]

Originally Posted by DrM

Until we see the flow numbers, it is all just speculation. However, given that cars have seen 10-20 whp increases, it is likely a correct speculation

True.
I made quite a bit more power and tourqe than all the guys here in So cal on the PROcede tune day. It was because I was the only one with exhaust...so the exhaust for sure helps. and they will all make more power once they get it... well actualy probably more tq and a little more HP.

Good part about AWD with the fake cats is they would still pass smog since you cant hook an AWD car to the machine it is just a visual.

[CASHBY]

Also for so cal people.

A great place that is known for good quality custom exhaust is LA BREE.

They myight be more on the exspensive side, but its quality work they do.

[Terry335]

Does anyone have any really good pictures of the stock exhaust? Is it possible to unbolt and gut the rear set of cats?

[sitz]

the rally cat sounds like a great idea!

how about removing the cats, use an air chisel to remove the "insides" and mount them back? This would essentially give you the stock look w/out the restrictions. I've had some friends do this to their American cars with good results. Maybe start w/ the secondaries to avoid any O2 sensor problems?
Plus, "gutting the cat" has a nice ring to it

[e90335i]

cost me less than 700 mandrel bent and two magnaflow mufflers

[CASHBY]

Originally Posted by sitz

the rally cat sounds like a great idea!

how about removing the cats, use an air chisel to remove the "insides" and mount them back? This would essentially give you the stock look w/out the restrictions. I've had some friends do this to their American cars with good results. Maybe start w/ the secondaries to avoid any O2 sensor problems?
Plus, "gutting the cat" has a nice ring to it

yea, lots of people do this as well.... thing is we have to worry about is playing with the stock cats...gutting them, removing, or altering them in any way might throw a check engine light from the 02 sensors....but we will just have to see.

[nine4surfah]

I couldnt believe the prices the "name" brand mufflers sell for. $700 for a muffler!? and almost 3g's for cat back systems? I'm definately going custom.

[musc]

I wouldn't just gut out the cat. You'll end up with more a metallic sound that can get annoying. One thing you can do is gut it out then run a pipe inside the gutted out cat. Gives the outside appearance of having a stock cat.

The other thing to do is go with 100-cell cats, but that can get quite expensive.

[sitz]

Originally Posted by catm3

I wouldn't just gut out the cat. You'll end up with more a metallic sound that can get annoying.

Ah, that's a great point. Didn't think about the cats making much noise.
May have to mill a pipe to fit thru the cat.

[sitz]

Originally Posted by CEA 3

yea, lots of people do this as well.... thing is we have to worry about is playing with the stock cats...gutting them, removing, or altering them in any way might throw a check engine light from the 02 sensors....but we will just have to see.

Okay, i'm interested to see how your cat delete mod works. Will you delete the primary cats as well? What's the plan for the secondary O2 sensor?

[radgator1]

Originally Posted by CEA 3

whats a "good" exhaust?

I can get you a custom exhaust with what ever magnaflow mufflers you want for 350 bucks.....
Basicly the same exhaust that Shiv is running on his car. 2.5 inch piping with 2.5 inch straight through design magnaflow mufflers.

Honestly go custom and just buy stainles steel mufflers and tips... youll be under 350 bucks.... and make just as much power as all these other 1500 dollar exhaust systems.... and I dare someone to tell me otherwise becuase I have the prototype on my car right now and it makes/made just as much power as all these 1500 dollar exhaust systems and sounds just as good if not better.

ONlything you wont have is stainless steel piping....which i can care less since no one will be looking under my car....just the muffelrs and tips are stainless.

Guy is nto to far from SFV as well.

Still hoping to get the name and location of the shop you are talking about. I dont care if it looks like a pit, at this price if the welding is decent I'm there

[CASHBY]

sorry guys, waiting for my friend to email me the info on that shop...

its in torrance off of western street... im trying to get the name and number

[BMWPower06]

:werd: TBE or none at all

[edgarj]

And any info on similar shops in PDX/SEA would be greatly appreciated.

[WilyB]

Originally Posted by CEA 3

I can get you a custom exhaust with what ever magnaflow mufflers you want for 350 bucks.....

Basicly the same exhaust that Shiv is running on his car. 2.5 inch piping with 2.5 inch straight through design magnaflow mufflers.

Do you know the Magnaflow part number for those mufflers by any chance?

Thanks.

[turbocoins]

Anyone know of any custom shops in central FL?

[wj4]

I called a local exhaust shop myself. They were the guys I went to a couple of times when I had my Evo. He said that he will charge me roughly $700 for a customized catback. 2.5inch all the way around with deleting the resonators and second set of cats.
Apparently there is an e90post member who got his 335i done at the same place about 2 days ago, I'm trying to meet up with him to see how I like the sound before I proceed.