Anyone replaced the catalytic converter with straight Y-pipe

Guest · Post by **Guest** » Mon Jul 11, 2005 10:55 pm

Hi, this is my first post here, glad I found the board.

I took my cat off of my 2003 r1150r and replaced it with a straight Y-pipe and I did not notice any sound differnce but a big power difference. I really like it and I am getting a little bit better mileage with it. Anyone else do this mod?

1150RINSOCAL · Post by **1150RINSOCAL** » Mon Jul 11, 2005 10:59 pm

this is "1150rinsocal", the above post logged me in as "guest" - I'm getting used to the board

Post by **Ed K** » Mon Jul 11, 2005 11:12 pm

FYI. . .a reputable source that races indicated to me that the Y pipe makes shows little difference in power on the dyno without other mods. . .

fnfalman · Post by **fnfalman** » Tue Jul 12, 2005 12:46 pm

You don't change out the Y and the can for a great show of power gain. You do it for better throttle response.

darthrider · Post by **darthrider** » Tue Jul 12, 2005 1:25 pm

You don't change out the Y and the can for a great show of power gain. You do it for better throttle response

Well yeah, and dropping close to 25 lbs. and some "tunes"...

Post by **Deans BMW** » Tue Jul 12, 2005 2:02 pm

And removing a lot of heat from just below the tranny

BreadMan · Post by **BreadMan** » Tue Jul 12, 2005 6:38 pm

So i have an R1100R, can I do the same thing without any sort of modification or re-coding to the engine? Will it adapt?
Can I just run a complete straight pipe with no cat and no muffler?

Post by **bikermeow** » Sat Oct 15, 2005 8:15 am

Some buddy of mine did it, and reported that response wasn't quite the same.

More feedbacks?

Cheers

Cat

Post by **jm1515** » Sat Oct 15, 2005 4:07 pm

Not a Y-pipe, but a StainTune collector box. Did this on my new 04 R bought this past May....here are some observations.

http://www.r1150r.org/board/viewtopic.p ... highlight=

Post by **boxermania** » Sun Oct 16, 2005 6:10 am

Y pipe removal will reduce the restriction of the cat converter and allow the cylinders to fill up more. The Y pipe and the can that typically come with it will provide ~ 3hp increase to the rear wheel.

The increase will be mostly noticeable on the low end grunt and the roll on of the throttle. It will also make the throttle crisper.......normally there is a slight loss of MPG associated with this mod something in the 1 to 2 MPG.

And like Darth so stated the almost 20 pounds lost is a welcome relief to those like me that are "marketing size"

Straight pipes decrease the engine's output because one of the functions of a well desigbed exhaust is to use the sound waves to assist with the clearing of the spent gases from the cylinder, the process is called "scavenging"

Straight pipes have reduced internal voloume as opposed to a muffler and do not support the bouncing and expansion of the sound waves well....hence the loss in performance. On the other hand they do make a hell of a noise......can you hear me now.

Straight pipes do not all

BobFV1 · Post by **BobFV1** » Sun Oct 16, 2005 9:17 am

Deans BMW wrote:And removing a lot of heat from just below the tranny

Dean -

You have a full Remus system, right? Did you go with a Power Commander or other chip modification too?

Post by **bikermeow** » Tue Oct 25, 2005 11:06 am

How much is a Y-Pipe anyway, and from who?

Thanks for the info.

Cheers

Cat

Post by **Beemeridian** » Tue Oct 25, 2005 6:35 pm

berniej · Post by **berniej** » Tue Oct 25, 2005 8:57 pm

Changed to the Y pipe, K&N filter, and the Techlusion. Much improved throttle response, eliminated the surge BMW said I never had, not much different in sound. Gas milage? Never checked it but about the same miles/tank. Much less heat on feet and ankles in the heat of stop & go traffic. Have two r's, a 2002 & 2004 (both ABS), liked it so much did mod on both

Guest · Post by **Guest** » Tue Oct 25, 2005 9:50 pm

Cant I just open the cat, remove internals, re-seal cat, keep my money and get most of the benefits???

Post by **new2BMW** » Tue Oct 25, 2005 10:41 pm

Cant I just open the cat, remove internals, re-seal cat, keep my money and get most of the benefits???

Probably. I've not heard of anyone doing this, but sure it could be done.

You will need a good welder (machine) and a good welder (person) as carbon contamination in stainless steel welds will cause inclusions in the heat affect zone which will cause cracks. You could overcome this issue by passivating the material prior to welding.

The second problem is that this material has been heated and cooled so many times that is has heat treated itself into a very brittle crystal-like form of stainless steel with properties that can't be defined without a nice lab and lots of cash. Welding on this material might be successful, but heating and cooling it again (during use) would most likely cause more cracks unless you anneal it first and heat treat it again afterward.

In the end, the labor and "pain in the a$$" costs will probably outweigh the price of a new Y pipe or collector box.

Post by **Beemeridian** » Wed Oct 26, 2005 7:39 pm

dilligaf · Post by **dilligaf** » Thu Oct 27, 2005 2:30 am

Wow, i never would have thought the outer "shell" to be that thick, looks like you got your work cut out for you.

My guess is that because of the wall thickness your project cat won't have that "tinny" sound that the Staintune collector is said to have, allthough i'm sure it'll weigh a bit more. At any rate keep sending the pics, it looks like a good project.

Post by **bikermeow** » Thu Oct 27, 2005 9:28 am

dilligaf wrote:Wow, i never would have thought the outer "shell" to be that thick, looks like you got your work cut out for you.

haha ... "work cut out for you" .. get it???

Cheers

Cat

Doug T · Post by **Doug T** » Thu Oct 27, 2005 3:58 pm

I was going to gut my cat as well. I do a lot of welding and such so I thought no big deal. But when I pulled the cat I noticed some plug welds on the sides of the cat . About 4 I think. Made me think that the internals are pretty well secured to the inside. You can't see anything looking in the openings so you can't just torch it out. It would require cutting the cat in half top to bottom, and then hopefully be able to cut the plug welds, gut it and weld back together. It could be done but it could also get ugly. So for now I'm positively not sure what to do. Hope this helps

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Anyone replaced the catalytic converter with straight Y-pipe

Anyone replaced the catalytic converter with straight Y-pipe

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