BMW R1200R R1150R/T F800 K1200R R1100R/T R1250R RnineT Message Board

Hi there, I've just bought a 2003 Rockster, my first, but my 3rd BMW.
I'm in Derby, Midlands, UK.

I've just sold my Kawasaki ZZR1400, which to be fair is an awesome bike, but too much so if you can understand, I was only using half the available power, it's restricted to 186mph!.
So I decided to get another 1150, I've had an 1150GS and a 1200GS and really wished I hadn't traded up to the 1200 as I had loads of problems with the diff and our local BMW dealership were nonscalent and unhelpful.

So I bought the Rockster, so far so good, I'm enjoying the character and familiarity of the Boxer engine, the power delivery... to a point.
But, with the standard can on it's a bit tame, I am wondering what is the effect of adding the popular Remus exhaust?
Apart from the sound, is there a performance gain? Do you have to rechip / reprogram the ECU?

Hello and welcome.
I can tell you from my experience that running without the muffler does nothing for engine speed and very little for the sound. I think on these bikes when it comes to exhaust you might as well remove catalitic go with y-pipe and then probably have to richen the misture and end up with 88hp In my case I left the exhaust alone and removed airbox and put UNI filters on. I dont think it did anything about the performance but the bike has sound. I did it mostly for ease of maintenance. I actually got the idea from one of the people here boxtermania.So far not too bad of a burble on the intake side. You can cruise comfortably but on acceleration it has that deep "BOOOOAH" if you catch my drift.
https://drive.google.com/file/d/0BzKrzJ ... sp=sharing

a little better picture.

https://drive.google.com/file/d/0BzKrzJ ... sp=sharing

Exhaust alone does not yield any power increase.

Remove the OE can, save some weight, get some growl, show off your wheel.

Folks here have used aftermarket car exhaust tips to dress up the cat collector outlet. Or do like this guy:

And running without a silencer does not burn out the valves or hurt the engine?

I have the cat removed already (I think) as the collector is much smaller than the standard 'ribbed' cat, but it isn't the normal Y pipe either.
If I just removed my silencer would it not hurt performance? Would I need to adjust the fuelling?

Running without a silencer would allow me to fit the RT full size left hand pannier too!

Ribcracker wrote:Hi there, I've just bought a 2003 Rockster, my first, but my 3rd BMW.
I'm in Derby, Midlands, UK.

I've just sold my Kawasaki ZZR1400, which to be fair is an awesome bike, but too much so if you can understand, I was only using half the available power, it's restricted to 186mph!.
So I decided to get another 1150, I've had an 1150GS and a 1200GS and really wished I hadn't traded up to the 1200 as I had loads of problems with the diff and our local BMW dealership were nonscalent and unhelpful.

So I bought the Rockster, so far so good, I'm enjoying the character and familiarity of the Boxer engine, the power delivery... to a point.
But, with the standard can on it's a bit tame, I am wondering what is the effect of adding the popular Remus exhaust?
Apart from the sound, is there a performance gain? Do you have to rechip / reprogram the ECU?

The best performance enhancement is the throttle. Twist it, hard.

I've run Rocksters with OE, full Remus system, cat and Remus can, Y-piece and OE can (not recommended btw), and just the cat. Damned if I could tell any actual performance differences though. Currently my 93,000 mile bike is running just the Cat, it will still pull to 135 indicated with enough time, gets to 125 with ease, and allows me a full size pannier on the left. I think the best way to get good performance is to ride it like you stole it and get those Nickasil liners worn in. Oh - if you have it - take out the CatCodePlug. None of my 3 Rocksters have ever had one.

Ribcracker wrote:And running without a silencer does not burn out the valves or hurt the engine?

nah - the closed loop Motronic adjusts itself.

Ribcracker wrote: I have the cat removed already (I think) as the collector is much smaller than the standard 'ribbed' cat, but it isn't the normal Y pipe either.

Can you post pics yet? helps a lot

Ribcracker wrote: If I just removed my silencer would it not hurt performance? Would I need to adjust the fuelling?

As said - as long as the lambda sensor is plugged back in then the Motronic is closed loop (afaik) and will adjust. Also - remove the CCP and get the standard fuelling map.

Ribcracker wrote: Running without a silencer would allow me to fit the RT full size left hand pannier too!

Yup!

What is a CCP? Cat Code Plug?

Ribcracker wrote:What is a CCP? Cat Code Plug?

yup.

If you remove CCP then AFAIK there is no closed loop adjustment but the map should be richer to begin with. I am currently running a jumper that simulates CCP for "regular" with CAT. I might play with it later to see if it makes any difference

Suggested reading regarding R1150** Motronic tuning:
http://www.advrider.com/forums/showthread.php?t=749080

We haven't had anyone dig so deep here on Roadster board, specific to fuel injection, but the info is directly applicable.

vwdoctor wrote:If you remove CCP then AFAIK there is no closed loop adjustment but the map should be richer to begin with. I am currently running a jumper that simulates CCP for "regular" with CAT. I might play with it later to see if it makes any difference

As I understand it, the closed loop is the way the Motronic works, with a built in default map - the CCP basically just applies a different fueling map - kinda like applying a different 'theme' to a Windows desktop - same data, just handled slightly differently. That way BMW could have a very restricted map for California/USA, and then slightly different mapping for different markets (eg Australia would probably be mapped differently to Europe).

Closed loop operation is when one part of the output is fed back to the input of the system to accomplish control. Hence closed loop. In this Motronic implementation the only feedback to the system is the O2 sensor (or lambda sensor for you Europeans). With the CCP you can select different maps, however some of those maps are "open loop" where the system is no longer looking to the O2 sensor to provide feedback, it is always running in open loop. This would be the map for "no catalyst, no O2 sensor". If we assume that without catalyst which could have been the default for some markets (need confirmation), the engine is breathing a little better, ie more air out, more air in, we could assume that this default map would be richer for this reason. It is also a common practice to design open loop maps to run a little on the rich side since the power is about the same and the "safe window" is wider before lean burn damage can occur.
Open for comments.
So to the original question, main restriction is the CAT, therefore engine performance and mixture is not really affected by the muffler.
This is theory, in practice many people have been running various mufflers (or none) with no adverse effects on the engine.

So what about running a Y-piece and shorty pipe (no cat)?

I haven't tried it personally. I think sound would be too loud for me. I wouldn't know if the mixture would be too lean, or would the Motronic still have enough range to adjust, but as a try, a Y pipe with a stock muffler would be a good experiment, especially since I think the sound would probably be the best out of all the options. If I had a Y pipe I would try it but right now it is just speculation on my part. I was interested in the Y pipe myself and I might revisit that option in the future but for now I am on CAT + shorty, tried and true. If I was going that route I would install wide range O2 sensor and monitor the mixture, but that is whole another project.
Ultimately return on invested time and money is not worth is unless something is wrong with your CAT (clogged).
BTW if there is a picture of the "short" catalyst I would love to see it just to see what it is.

Short answer: I dont know.
Anybody else?

vwdoctor wrote:I haven't tried it personally. I think sound would be too loud for me. I wouldn't know if the mixture would be too lean, or would the Motronic still have enough range to adjust, but as a try, a Y pipe with a stock muffler would be a good experiment, especially since I think the sound would probably be the best out of all the options. If I had a Y pipe I would try it but right now it is just speculation on my part. I was interested in the Y pipe myself and I might revisit that option in the future but for now I am on CAT + shorty, tried and true. If I was going that route I would install wide range O2 sensor and monitor the mixture, but that is whole another project.
Ultimately return on invested time and money is not worth is unless something is wrong with your CAT (clogged).
BTW if there is a picture of the "short" catalyst I would love to see it just to see what it is.

Short answer: I dont know.
Anybody else?

one thing - Y-pipe with OE can makes the exhaust gases VERY hot - much hotter than normal. Hot enough to do this : http://www.flickr.com/photos/rockburner ... 110357035/

The CAT traps and concentrates a lot of the heat from the exhaust gases, the y-piece won't - so a restrictive can (ie the OE one) will catch more heat than usual and will concentrate it (because it's not a straight through flow).

CAT with a tip is the way ahead.

That is where I ended up. I am happy with it. ID of the pipe you need is 1 3/4" just for your reference.
eedit. Assuming your CAT is the same size as mine

I have an r850r mu, i fitted y pipe and remus can no baffle, cut off most of the air intake so it is more like a scoop and removed the tubes inside the airbox, I fitted a high flow filter and used a jumper for the cap, in my opinion it pulls stronger and harder thoughout the rev range, sounds great and has no noticable flat spots.

i tried the chrome end on the y pipe with a VW baffle but it sounded to vintage and ran rough.

Ribcracker wrote:So what about running a Y-piece and shorty pipe (no cat)?

That would probably be very noisy and most likely wouldn't give too much performance - worth a try though.

San Jose BMW/CC Products makes a replacement Intake sytem larger snorkel, larger K&N Filter, and new Air box Lid.
http://www.sjbmw.com/parts.asp?bid=4#s= ... 1&pid=1068
Several different exhausts manufactures make complete systems
A set of Lennie's Rocket Sprockets
After all that you might see about a 7-10 hp gain or about $200 per hp gained.

Where is the Cat Code Plug? I'd like to try it without. I am running a Staintune mid (Y pipe) and an Akrapovic can, no db killer. The sound is perfect.. not to loud.

JB