X5M DIY cat gut

[Sylvan Lake V35]

I am noticing the smell a bit, my G35 had catless down pipes and I could smell the fuel on my clothes after i got out of the car. This is nothing like that but at stop lights with the windows up I do catch the smell, as of now I can live with it.

[spaniard]

Originally Posted by Sylvan Lake V35

I got the catless OEM pipes on last week, they did trip the CEL. So I went and got a tune as well, it is louder now for sure and you can really hear the turbos whistle now. If you like quiet, eisenmann and catless pipes are not for you. On the hiway I don't hear the exhaust but apply any amount of throttle and you hear it. It gives it more of a sporty feel vs the OEM luxury feel it had.

ECUProgram did a stage II tune and it is a different animal now it's crazy how fast it is for a 5,500lb unit. They stage II is 700hp and they offered a free upgrade to stage II+ which will be 730hp (94 octane only) he is just fine tuning the drivability on that map before he releases it. I want to get it on a dyno and see what it's putting to the wheels now!!

Ecuprogram did a tune (Stage 1) for my car too. It pushes hard and nice!

Damn I need downpipes... I like your DIY SylvanLAke. This will be my next plan for this Spring. Yes they dynoed my car last fall. I have to find the dyno chart somewhere then post it. It got about 645-660 HP with octane 94.

for ecuprogram!

[Leonelm3-X5M]

Originally Posted by Rob NY

Not to get the gas smell you have to install downpipes with race cats.

This is great info. Thanks for sharing OP

The smell is important detail to me as I still have young kids I don't want getting sick or high when I drop them off @school one day in the modded X5M

So I gotta find DPs wRace cats or a shop that can install small enough Race cats that would fit n work

[m5james]

Any updates on this? Someone is selling used Akropovic for $1900, eBay has AR Design for $1400 but free is always best. Just trying to determine a HP per cost ratio...like if gutted gets 650 but Akro gets 660, that's a huge difference and I'd settle on gutted.

[grayforge]

Some of us survived the days of catless cars. And I'm sure a catless modern car is way cleaner than a catless classic like my '65 Vette. :-)

[Toneaero]

Originally Posted by m5james

Any updates on this? Someone is selling used Akropovic for $1900, eBay has AR Design for $1400 but free is always best. Just trying to determine a HP per cost ratio...like if gutted gets 650 but Akro gets 660, that's a huge difference and I'd settle on gutted.

I can't imagine that there would be any noticeable differences between different manufacturers. Its just a hollow pipe that connects turbo to the exhaust system. A hollow pipe is a hollow pipe.

[m5james]

Originally Posted by grayforge

Some of us survived the days of catless cars. And I'm sure a catless modern car is way cleaner than a catless classic like my '65 Vette. :-)

I've deleted one set of cats on my Harley F150, but that's a different beast all together.

[m5james]

Originally Posted by Toneaero

I can't imagine that there would be any noticeable differences between different manufacturers. Its just a hollow pipe that connects turbo to the exhaust system. A hollow pipe is a hollow pipe.

I'm guessing the same, the biggest differences I'd guess is overall fitment...which I'm assuming means being able or not being able to smell the exhaust in the car.

[m5james]

Originally Posted by Cattivo

I went with the Ultimate Racing 3'' catless dp's for just over $1k...same gains as the other ridiculously overpriced brands

Even $1000 is still ridiculous, so I'm kinda waiting until they come down to sub $500 range, which even then is still a lot for 6' of pipe. At this point I'm more curious how well gutted cats perform from someone who's actually done it. A few have mentioned selling theirs, yet I've never heard anyone say how they performed, issues, etc. It's not exactly the cleanest outlet on the turbo anyways with that huge flap there (http://www.european**********/conten...pipes#comments), so I'm curious if the air feeding into a large, open chamber will create turbulence or if the air will just be rushing out so much that it doesn't really matter.

[Toneaero]

Originally Posted by m5james

I'm guessing the same, the biggest differences I'd guess is overall fitment...which I'm assuming means being able or not being able to smell the exhaust in the car.

I bought the ultimate racing catless downpipes and it fits like OEM did. I still experience fumes smell when the windows are down. It bolted flush and I even replaced the gaskets. Anyone remove cats and not experience some fumes? I think it's just the nature of the beast.

[Cattivo]

Now that I have dp's and a tune for the M on its way, I need to get another set of dp's and tune for the 50i

[Sylvan Lake V35]

Sorry I never did get any dynos or track numbers. However my tuner said my tune was pretty much the same as the tune on his personal X5M with AR down pipes. So the same boost and AFR as he ran, he said mine felt as fast as his too.

For a little bit of labour and no cash it was the best mod I did, of course it was paired with an ECUProgram stage II tune so the diffrence was night and day it was a beast after the tune and cat removal.

[m5james]

Thanks for not getting mad I hunted you down for a reply, Sylvan ;-) Seeing that the outlet of the turbo isn't' all perfect and smoother, a flapper valve in the path, etc etc I'm definitely leaning more towards free horsepower. I can understand what people mean about turbulence, but it reminds me of a video I saw about pickup trucks that do or don't use a tailgate...a pocket of air fills the voids and air flows freely and openly over the rest, hence why things don't fly out of the bed nearest the cab. Yes, I'm filling a small cavity of air before it flows out, once catless downpipes come down to reasonable prices then maybe I'll do a before and after, so until it can be proven that one will make huge gains over the other, free is free.

[m5james]

Drill motor, 12" long 1" paddle bit and 10 min later I've got a bucket full of precious metals and made myself some catless downpipes. Truck is down due to leaking PCV/oil return pipes so I'm thinking I'll get a tune while I wait...I was going to use Burger but after reading online, most everyone says you'll never get as much horsepower with a piggy back vs doing an actual flash.

Sylvan, where'd you recycle this stuff?

[xpl0sive]

the burger piggy back also doesnt turn off the rear O2's, so you'll have a check engine light on due to not having cats. I've been reading and it seems that either ESS or AA are the most reliable tunes to get

[m5james]

Velos, ECUProgram and other non-piggyback types all seem to have good reviews, even the underpowered and overpriced $$Dinan$$...be it people justifying what they paid to not knowing the wiser because they've got nothing to compare with. Until there's a tune to tune shootout, it's all a crap shoot with each tuner having different numbers from countless variables...car, conditions that day, dyno, etc etc. All of them offer customer service, all of them think theirs is the best, but prices are all over the highway.

[Leonelm3-X5M]

m5james hit it right on the head...

Here in Texas, me(DFW) and my Buddy Jose (Ft.Hood) both have 2010 X5Ms and will do exactly that.....similar Mods.....(Exhaust/Gutted OEM DP/K&N Filters/ charcoal filter delete)....different tunes......

I will go Velos stage 2, i think he will try Burger

we will them line them and go atleast a dozen times or until we experience heat soak and report back.

[m5james]

I've been torn between Burger (ease of installation but lacking the ability to shut off the CEL for gutted cats) or Eurocharged (seem to be the only ones on www.dragtimes.com with consistent trucks in the low 12's) while being decently priced and offering lifetime upgrades.

PS - I'm buddies with Derek, another HPF guy

[Leonelm3-X5M]

Originally Posted by m5james

I've been torn between Burger (ease of installation but lacking the ability to shut off the CEL for gutted cats, then having to buy a JB4, BCM, etc etc...it never ends) or Eurocharged (seem to be the only ones on www.dragtimes.com with consistent trucks in the low 12's) while being decently priced and offering lifetime upgrades.

PS - I'm buddies with Derek, another HPF guy

Awesome! yeah Derek is an Awesome guy! always helped me out. next time you talk to him, tell him Rico in Texas said whats up! God willing, I'm months from opening my own HPF in the DFW!

[m5james]

Yeah, he's a good guy. I met him and Brian when they broke down coming back from Bimmerfest '12...fortunately it happened in Oregon as well :-) I don't talk to Brian anymore but Derek's since sold the car, got dual lifted Jeep Unlimiteds for him and the wife and he's been looking into TT Lambo's now. I'll tell him you said hey!

[Dr.Duct_Mossburg]

Originally Posted by northern2020

Did this mod to my 2001.5 Audi B5 S4 downpipes...

They were named "piggie pipes" after the forum member whom first utilized gutting his cats...

Worked so well it was a phenomenon amongst those Audi owners!!

I remember the write up thread... Most of the fastest cars back then had piggies.

[Dr.Duct_Mossburg]

Im going to do this and have some high flow cats welded in to the exhaust... No way i'm paying almost $2k for downpipes. That's just highway robbery.

I also have a buddy with a Dyno so ill get before and after results.