[ironic]

For those of you who've been following my previous reviews, this IS a performance enhancer and still a bit of car upkeep as far as maximizing potential goes.

I previously had a muffler shop delete my secondary cats and had ran this set up for months but after getting the car up on a decent rack I saw just how poor a substitution it was for mandrel bent piping. Although the cats were gone the crush bends in the stock pipe are VERY restrictive, but even more shocking than this was the substantial bottle neck created by the muffler shop when they had welded on new flanges. They had used piping that looked like it was originally part of a bend and when they cut it they didn't bother to remove all the bend so that looking down the flanges into the pipes the mouth of the opening resembled a ( () crescent shape instead of a 2.5" circle ( ). Also not only was their major restriction still, but the welds leaked and you could see where exhaust gas was escaping by the black marks on the pipe. The non-stainless pieces of metal tubing also had a little bit of rust by the welds. The lesson of the story is you get what you pay for.

So I went and bought myself a set of Borla Secondary Cat Deletes, which are all you can ask for on paper. They're mandrel bent, 2.5" dual piping, made of stainless steel, but when they arrived I discovered that they tapers to 2.25" at the flange to the downpipes. To this I was confused and shocked and I'm still unsure why it tapers to 2.25" instead of being 2.5". But I had them installed anyways because no matter the restriction they were far superior than the muffler shop caveman creation. My flange to flange link from downpipes to secondary pipes now looked like (( )) although not as bad as the muffler shop's restriction I just wanted full 2.5" pipes.

Riss Racing's Secondaries were the answer. They're reasonably priced, come in a VERY attractive polished finish and are a true 2.5" secondary cat delete replacement. There's no if and or buts about it's diameter. It's just what it's advertised to be and that's all I ever wanted. The welds are top notch and the units are very sturdy and well put together see for yourself in the photos below. I also ordered a set of new gaskets as it's always good practice to swap gaskets when you change out pipes and they too look great and are a true 2.5" diameter.

The verdict is simple, better flow = true 2.5" diameter pipes = better performance = Riss Racing secondary pipes. I only wish I had discovered the truth behind secondary cat deletes sooner

[M3to335]

Good write up. When I first saw the title I was hoping it was someone with catless DPs and catless mids with a stock muffler. A bunch of us are still waiting to hear what that sounds like.

[ATSR]

Nice review!

What about the install? I know they bolt on directly to the DP's, but what about the other end?

I'm guessing you cut the stock exhaust and just weld the RR pipes? I really dont like that part since you are exposing yourself to a poorly done job by a muffler shop and you end up with the same problem you mentioned before (weld leaks). This will also make it a PITA to go back to the stock ones.

Am I correct? Please let me know as I've been thinking about getting these but the installation/removal is what keeps holding me back.

[Sniz]

Originally Posted by M3to335

Good write up. When I first saw the title I was hoping it was someone with catless DPs and catless mids with a stock muffler. A bunch of us are still waiting to hear what that sounds like.

+1, me included.

I was thinking of having all the piping from the downpipe to the stock muffler replaced and have a set of resonators in place of the 2nd cats.....smooth it out a bit.

[Malek@MRF]

Originally Posted by Sniz

+1, me included.

I was thinking of having all the piping from the downpipe to the stock muffler replaced and have a set of resonators in place of the 2nd cats.....smooth it out a bit.

That's a good idea, especially for cars that have cat-less downpipes. Resonators don't act as mufflers, but they do control tone and reduce some rasp.

1 thing I don't understand.. what was BMW thinking by making the piping and muffler all one piece??

[ironic]

Originally Posted by M3to335

Good write up. When I first saw the title I was hoping it was someone with catless DPs and catless mids with a stock muffler. A bunch of us are still waiting to hear what that sounds like.

Well I did have this set up for a while. It simply sounds louder all around but the tones and pitch are about the same. I wouldn't say there's any real variation in sound except that it's louder.

Originally Posted by alejotrujillo

Nice review!

What about the install? I know they bolt on directly to the DP's, but what about the other end?

I'm guessing you cut the stock exhaust and just weld the RR pipes? I really dont like that part since you are exposing yourself to a poorly done job by a muffler shop and you end up with the same problem you mentioned before (weld leaks). This will also make it a PITA to go back to the stock ones.

Am I correct? Please let me know as I've been thinking about getting these but the installation/removal is what keeps holding me back.

Well this might be something that you should contact Riss Racing about as I already have a full exhaust, but you might be able to simply slip the Riss Racing pipes over your stock pipes and clamp them. If not,even if you have a muffler shop weld them the welds that they create shouldn't be TOO bad since this is just straight sections of piping, unless they really don't know what they're doing. As for leaks - that's just what happens when you go to those kinds of muffler shops. I've been taking my exhaust to Turbo Hoses, who do fabrication and their welds are absolutely top notch but they're going to cost at least 3 times the muffler shop.

Originally Posted by Sniz

+1, me included.

I was thinking of having all the piping from the downpipe to the stock muffler replaced and have a set of resonators in place of the 2nd cats.....smooth it out a bit.

I think this is a pretty good option, but if you're worried about drone I'm honestly not sure if I encountered any with the secondary cat delete. Also, the car has a resonator further down after the secondaries anyways. So you could simply replace the cats and leave the resonator.

[oddjob2021]

Originally Posted by Sniz

+1, me included.

I was thinking of having all the piping from the downpipe to the stock muffler replaced and have a set of resonators in place of the 2nd cats.....smooth it out a bit.

+2, stock muffler but riss to the engine, im worried about the sound as is everyone... do you think you'll pick up any power leaving the stock muffs in? even if 5 whp

[AV9]

thanks for sharing!

[ironic]

Originally Posted by oddjob2021

+2, stock muffler but riss to the engine, im worried about the sound as is everyone... do you think you'll pick up any power leaving the stock muffs in? even if 5 whp

you should but with any exhaust it'll be more pronounced with a tune. you're removing restriction and that's always a good thing on a turbo car. also your restriction will have been pushed further back the exhaust which is also a good thing.

[midlife]

Originally Posted by oddjob2021

+2, stock muffler but riss to the engine, im worried about the sound as is everyone... do you think you'll pick up any power leaving the stock muffs in? even if 5 whp

i believe terry of BMS ran total catless (both catless dps and exhaust).

as i remember it, he said that the exhaust smelled really bad, and it was too loud....he also said that our secondary cats and muffler were not very restrictive.
his conclusion that if you have catless dps, there is not very much gain to be had with secondary cat delete.

he went totally catless like this for just a little while, and then reinstalled his secondary cats.

[Mr. 5]

Originally Posted by midlife

i believe terry of BMS ran total catless (both catless dps and exhaust).

as i remember it, he said that the exhaust smelled really bad, and it was too loud....he also said that our secondary cats and muffler were not very restrictive.
his conclusion that if you have catless dps, there is not very much gain to be had with secondary cat delete.

he went totally catless like this for just a little while, and then reinstalled his secondary cats.

I was there when Terry ran the 11.89 second 1/4 mile with catless DPs and complete stock DP back exhaust.

[midlife]

Originally Posted by Mr. 5

I was there when Terry ran the 11.89 second 1/4 mile with catless DPs and complete stock DP back exhaust.

I believe he proved his point with an exclamation mark !!

[oddjob2021]

sweet then ill keep my exhaust the way it is! thanks for the advice!

[midlife]

Originally Posted by oddjob2021

sweet then ill keep my exhaust the way it is! thanks for the advice!

not sure if the OP has catless dps....if not, the secondary cat delete could give him some horses.

certainly, i do not intend to rain on his parade.

[ironic]

I have catless downpipes.

To be honest, it just really depends on what you're looking for. I'm sure the car is plenty fast even without deleting the secondary cats, but if you ask any tuner - even Terry, any kind of restriction removal that'll let the car breath easier is going to help. Now, by how much and in relation to what is another story.

If you buy a tune it'll give you 50hp/50tq, the pipes are substantially less. But if say, you're trying to get to 400whp/wtq then even the 10odd hp/tq will help, especially if you get the car tuned for it.

If you value a clean running car, and more bearable daily exhaust then it might not be for you. Everything is a trade off and there are very few mods out there that are going to be comparable power gain wise to throwing on another piggyback or larger turbos. With that said and going back to one of my recurring motifs in my posts: it's about creating a well rounded car. If you want gains the exhaust including the secondary cats are something to address and if you're willing to get a custom tune for it more power to you.

[midlife]

previously, i did just a quick read of your thread and did not notice your car pics or your sponsors...looks like u r going all the way!

god bless you man
(note that the last mod i am waiting for are larger turbos)

Originally Posted by ironic

I have catless downpipes.

To be honest, it just really depends on what you're looking for. I'm sure the car is plenty fast even without deleting the secondary cats, but if you ask any tuner - even Terry, any kind of restriction removal that'll let the car breath easier is going to help. Now, by how much and in relation to what is another story.

If you buy a tune it'll give you 50hp/50tq, the pipes are substantially less. But if say, you're trying to get to 400whp/wtq then even the 10odd hp/tq will help, especially if you get the car tuned for it.

If you value a clean running car, and more bearable daily exhaust then it might not be for you. Everything is a trade off and there are very few mods out there that are going to be comparable power gain wise to throwing on another piggyback or larger turbos. With that said and going back to one of my recurring motifs in my posts: it's about creating a well rounded car. If you want gains the exhaust including the secondary cats are something to address and if you're willing to get a custom tune for it more power to you.