RT Aftermarker muffler

[podsobinski]

I am interested in an aftermarket muffler for my 06 RT. Nothing too loud as we run Autocom for intercom and music. Any ideas and comments.
Thanks all. . .

gpodzo

[Andy VH]

Just be aware that most aftermarket exhausts, especially those that claim "freer-flowing" can actually cause the fuel/aix mix to "lean out" even more than stock. That means even more "popping" out the exhaust on decel with a closed throttle, and more header blueing. In some cases, you could even decrease the mid-range power of the engine. But you will save some weight.

The fuel injection system cannot make up for the difference as it only senses Oxygen output as an open loop control system. I modified my stock RS exhaust and though it did perform ok, I got more popping sound on decel. I then installed a Techlusion and made the fuel adjustment to go with the easier breathing to get the result I wanted, and next to no popping on decel. My fuel mileage dropped only slightly, but I can occasionally get over 44mpg on the right conditions.

[BobFV1]

I have full Remus headers with a Remus graphite can. A little louder than stock, a little popping on deceleration, great power. I am using a stock chip and the bike has adjusted to the setup just fine.

[kgadley01]

My choice would be the Two Brothers system. but do your homework, not everyone wants the same thing.:bolt

[podsobinski]

Always get good advice and things I haven't thought about. I have a Two Brothers on my 02 GS and love the muscular sound and poping but it just would make the wife happy or fit the theme of the riding with the RT. I better stick with the stock one .

gpodzo

"When she's happy, everyone is happy!"

[kgadley01]

Always get good advice and things I haven't thought about. I have a Two Brothers on my 02 GS and love the muscular sound and poping but it just would make the wife happy or fit the theme of the riding with the RT. I better stick with the stock one .

gpodzo

"When she's happy, everyone is happy!"

I had the same problem till last Wed. night. I bought my wife her own trike. now I can do as I please on mine...:clap

[bimmerfreak]

I have the Remus slip-on. Great weight savings! Sound is just as I like. Very slightly louder than stock, but a very pleasing sound. The "popping" on deceleration is very minimal. I have an '06 R1200RT...Jim

[gulfcoastbeemer]

I have full Remus headers with a Remus graphite can. A little louder than stock, a little popping on deceleration, great power. I am using a stock chip and the bike has adjusted to the setup just fine.

My wife's '05 RT has the same Remus setup (with Titanium can) and it works great. With the Remus headers you have a measurable weight savings through the elimination of the catalytic converter.

[BobFV1]

My wife's '05 RT has the same Remus setup (with Titanium can) and it works great. With the Remus headers you have a measurable weight savings through the elimination of the catalytic converter.

I had a Remus titanium can crack on my GS after about 23K miles - cracked right in half. Remus replaced it for free. No probs with the graphite so far.

To be fair, I am one of the only cases of a cracked Remus can I have heard about.

Here are before and after pics:

http://BobFV1.smugmug.com/photos/64427946_DyFkQ-M.jpg

http://bobfv1.smugmug.com/photos/139072553-M.jpg

[136602]

So if I am hearing right :ear , installing a different exhaust sys. will not have a bad effect on my RT's valve tuning or MPG. Can the injection system be tuned to elem. the after fire when I let off the throttle.

[127768]

I think it runs better with the stock muffler.
Remus is a little louder (not bad) and a lot lighter.

[Andy VH]

136602, changing the exhaust/muffler never has any effect on the "valve tuning" as you refer to it. An aftermarket muffler can alter how the engine breathes, in that it can alter the power delivery of the engine. Depending on the system, it may make the engine breathe better at higher rpms, while actually slightly loose power in the mid-range. It all depends on what the mullfer/exhaust maker deemed was the performance point they strove to acheive.

The stock fuel injection system cannot be tuned any appreciable amount to eliminate the "after fire" (which I'm guessing you mean exhaust popping) when an aftermarket exhaust is used. To best suit that, a device like a Techlusion or power chip must be used to alter the fuel delivery and mapping.

[grasslander]

I think it runs better with the stock muffler.
Remus is a little louder (not bad) and a lot lighter.
I did an extensive test of the Remus system vs Stock winter 06/07. I used the Remus Revolution which has a removable core. My results R1200ST (RT uses the same system):

BMW brochure specification for the R1200ST:
110 HP - 84.81 Torque

Slip on test
Stock: 100.26 hp - 78.22 torque
Remus WO/core:101.91 hp - 77.09 torque
Remus W/core: 94.74 hp - 74.24 torque

Full System Test (header/muffler)
Stock: 100.26 hp - 78.22 torque
Remus WO/core:106.19 HP - 82.36 Torque
Remus W/core: 100.86 HP - 78.66 Torque

I tour with the core in and pull it for performance/track days. I'd like to try the new PC3 for kicks but the ECU did a pretty good job of handling things. (I want Ohlins first)

http://homepage.mac.com/jimdoyle/.Pictures/R1200ST-Images/R12STLrem.jpg

If you have the time the full story with dyno charts is here:
http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=145157&fpart=1

[deilenberger]

The fuel injection system cannot make up for the difference as it only senses Oxygen output as an open loop control system.
Andy,

Huh? What would be the purpose of the multiple O2 sensors? The system DOES go closed loop in any steady-state engine operation. It goes back "on-map" under acceleration - but I believe the newer faster computer on the hexheads may be using the O2 sensor for some fuel adjustment even during those conditions. Be hard to explain the exceptional fuel mileage they get otherwise. I modified my stock RS exhaust and though it did perform ok, I got more popping sound on decel. I then installed a Techlusion and made the fuel adjustment to go with the easier breathing to get the result I wanted, and next to no popping on decel. My fuel mileage dropped only slightly, but I can occasionally get over 44mpg on the right conditions.The 1100-1150 FI was really rather primative compared to the hexhead systems. Amazing what 10 years of computer advances can do. Better running more powerful engines with better fuel mileage to boot. Good stuff.

I do agree with you that most all aftermarket exhaust systems are about loosing weight. I tested quite a few on different BMW's - on a dyno - and never came up with one that provides more useable power. The best I saw was 1-2 HP at redline, usually at the expense of HP in the fat part of the curve (3-5k RPM). BMW's pretty good at designing exhausts for performance... (not so good for weight..)

[deilenberger]

If you have the time the full story with dyno charts is here:
http://bmwsporttouring.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=145157&fpart=1Jim, very nice work. I love when people actually have some data..

Question - did you do a stock system vs Remus full system on the same date?

Reason I ask - conditions (temp/humidity) can make a fairly noticeable change in what the curves look like, so I usually try to alternate STOCK/MODIFIED/STOCK/NEXTMOD sort of dyno runs. Advantage is - I have free dyno use, not everyone can do that if they're paying for it..

Dynojet tries to compensate for it with the sling-pysopwhatchamacallit.. (wet-bulb thermometer) - but in my experience - most dyno owners forgeddabout that after the first week..

It sounds as if the Remus works for you - without a big downside for everyday use - which is a wonderful thing compared to some other exhausts I've measured.

[grasslander]

Don, couldn't do that do to time schedules (Kent's dyno open slots). Would have been nice though. Thanks for the good word.

Stock first test was 11-17-06 - 10:37AM, temp was 82.6F and humidity was 17%. Second test for full system w/o core was 12-21-06 - 10:46AM, temp was 82.5F and humidity was 24%. When I do the PCIII Kent will do the dyno work again and build my curves. I think I will put on the stock system and do three pulls, then full open system and three pulls, then tune the PC. Question is do I dump the O2 sensors? I'm not so sure...

It'll be a while - I want Ohlins!