Bike 2005 R1200GS It is a well known fact that removing the catalytic converter from the GS exhaust system will open up a whole new dimension to the way that the bike performs. Better mid range performance and sharper throttle response being the two key benefits. A BMW Akrapovic can was already fitted to mine in conjunction with the OE headers. There was certainly an increase in throttle response together with a much throaty exhaust note utilising this configuration. To uncork just that little power rider friendly power I decided to fit the Remus headers as a replacement for the BMW OE headers. There are three subtle differences between the OE headers and the Remus ones: - 1) Remus headers do not have the catalytic converter fitted. 2) Remus omits the connecting balancer pipe between the two cylinders. 3) Overall diameter of the Remus headers is approximately 4mm larger than OE. It is a very straightforward installation to do and one that should only take about 1½ hours from start to finish. It is advisable to fit new header gaskets in the replacement process. That said, if you have the Touratech bash plate extension and or the Touratech main stand plate fitted, these should be removed in order to make it a header replacement process a whole lot easier! The difference in performance is quite remarkable to be honest, the throttle response is now so much quicker and instant, also the low & mid range hook up is totally transformed. The whole power curve seems to be evened out to be a more rider friendly advantage. There is still however a very defined power surge when you get towards the upper rev limits. Personally I quite like this, as its like having a secondary kick when you most need it. The engine runs and performs very smooth indeed with no apparent fuelling issues in any apart of the entire rev range. The bike has now covered just under a 1000 miles since the Remus headers were fitted and I have nothing but praise for the set-up and would have no hesitation at all in recommending it. Dependant on your point of view, but a consequence of removing the catalytic converter is the exhaust will now cackle & pop when the throttle is closed and the engine is on over run. Once again personally I quite like this, but others might find it annoying? Despite having no issues regarding the performance and the running, I was still a little concerned about the possibility of the engine running lean? I contacted my local BMW dealer who suggested that the bikes ECU would figure out any fuelling concerns. The Remus headers were a recognised retrofit and as such would not create any adverse fuelling conditions. The main advantage is the removal of the catalytic converter, this allowing sub standard quality fuel to be used for those travelling in remote parts of the world. The BMW Arkopovic can is also a recognised and approved BMW aftermarket part, and will also not have any adverse effects on the fuelling. As was pointed out to me, a main BMW dealer would simply not supply these parts if there were ANY concerns at all regarding the performance of the engine or any possible warranty claims. But being a compulsive tinkerer I just had to explore the next tuning stage, this is in the form of the Wunderlich Power Controller. I am also very lucky enough to have been given a Power Controller and also K&N air filter in order to conduct my own tests. The fitment of the Power Controller (PC) could not be any easier, simply unplug the two OE fuel injector plugs and also the two oxygen sensor plugs located in the headers and then just plug in the corresponding leads in from the PC. Finally connect a black wire from the PC to the earth post on the battery earth and thats it done! No need to remove the fuel tank, just the removal two small plastic side covers and the both the seats, total installation time around about 1/2hr. Now follow the simple instructions regarding the reprogramming the ECU. Ignition on, but engine note started, open throttle to fully open to closed three times, switch ignition off. The instructions included in the kit show two base setting for the PC, one for a standard bike and one for a modified bike, i.e. Remus headers, high air flow air filter, open exhaust can. The bike was started and the PC set to the latter base setting, the exhaust note was certainly a deeper sound, due to the increase in the supply of fuel. On a road test over 80 miles the throttle response appeared to be more responsive and the engine certainly spun up a whole lot quicker. So much so, that pulling away aggressively in first & second gear will see you hitting the rev limiter very quickly indeed! Changes that have been noted are the tick over speed has increased and so to has the fuel consumption. Plus any popping or cackling from the exhaust on throttle over run has now ceased. I think that the throttle response has improved low to mid range but it is very difficult to measure by the seat of your pants. That said when you are travelling at high speed in sixth, the throttle response could only be described as a bit woolly, certainly not as clean as it was pre-PC fitment. But I do know that there is no increase on the overall top speed though. The power surge mentioned before is still noticeable towards the upper end though, I did expect to see this smoothed out? At a constant lowish road speed, such as 30mph in a built up area, I was aware of what can only be described as a minor amount fuel surging. This condition was also noticeable pre-PC fitment? That said, with some minor tweaking on the PC mode + & - buttons I expect that this could be ironed out? At the end of the day every bike is different and as such there has to be a certain amount of fine-tuning required in order to gain optimum results. But personally I would suggest that the bike is set up on a rolling road to determine exactly what the fuel mapping is doing across the whole rev spectrum. Gauging performance by the seat of your pants in an uncontrolled environment is not really acceptable to me as I am a figures on a chart person. I also conducted the road tests with a standard air filter and also a K&N filter. To be perfectly honest I could not notice or feel any particular benefits in performance what so ever? I would love to see the dyno chart differences though? Pre-PC fitment the bike ran 100% perfect with no running issues at all. Post PC fitment, overall pleased with the results but IMHO a session on a rolling road could possibly see more advantages .maybe? But at what cost, £300 Remus Headers, £500 BMW Akrapovic can, £250 for the PC, £40 for the K&N air filter, and then £40 per session on a rolling road? Its an awful amount of money to spend; especially taking into account that its a heavy old GS and not a lightweight sports bike? Perhaps the old saying is the most suitable: - If its not broken, then dont fix it I would however certainly recommend the Remus headers and the BMW Akrapovic can, but I am not entirely convinced about the rest, would like to see hard data to support the claims.
Thanks for the write up! I am considering the Wunderlich PC as I have already fitted a Remus can and Y pipe along with a foam style air filter. Like you, I did not notice a huge jump when adding the filter but who knows. I have never seen the Remus header sold in the USA. Have you ever had a Y pipe fitted? If so, would you consider the header a big performance difference over the Y pipe?
I've got an Akra can on my 07GSA and like it. Didn't get the Remus because I thought I'd try to be a little green by keeping the CAT. Plus, I suffer from the Italian disease "mafundsarelow". Thanks for the rightup - I'm reconsidering the Remus
Thanks for the excellent write up. I have a PC on order and hope to get it installed next week. Running a Staintune can on Remus headers and a Blue air filter, my plugs indicate that the bike is running very lean. The low/mid range change you report is encouraging but I hope the top end can be tweaked for better response. Mine feels like it flattens out a bit near redline. I hope to gain a bit of a top end bump as well. If you find that modifying the settings improve the top end, please post your changes. Harry
Don't get confused between the Y-piece and the headers. On the 1150, which I assume you have, you can fit a Y-piece to replace the cat without replacing the headers. However on the 1200 it is all one assembly. If you want to replace the cat then you have to replace the whole lot. So based on the above, your last question has confused me a little?
I am no tuning expert, but maybe it is running lean due to the Blue air filter? Personally, I would not even consider running a high air flow filter at all unless I had added some sort of engine management device at the same time. In saying all that, lean is that always that bad. But of course it all depends on how lean it is running. Only a quick session on a rolling road will determine that really?
Hi, thanks for the write up. What is very interesting is that I have seen graphs from a dyno that show that the Remus headers actually decrease power output on higher revs and that the air fuel, that should be a constant line, fluctuates very much.
OK, just done a long ride into work this morning and I have to say quite surprised at how well the std can and Remus headers work together. K&N air filter and Power Controller removed. Smooth clean delivery of power right across the entire rev range, and no feeling of the power surge towards the upper rev limit either. The exhaust note is quite a lot deeper with the Remus headers fitted, which is very nice too. In fact the whole thing responded very well, maybe not quite as pin sharp as with the Akrapovic can fitted, dunno? Very hard to identify really. In conclusion, if I did not already have the Akra can sat in the garage, I would certainly not rush out and buy a aftermarket can, if it was performance I was after. As I said in the first thread, removing the cat is the cheapest option that will afford you the most gains, anything else are just personal options and are very much dependant on how much dosh you are prepared to chuck at your bike. However, noise wise the Akra sure does rock, but it is very easy to confuse noise with extra performance. In fact, I will be keeping this setup on for a while or until the yearning for the nice sounding Akrapovic becomes to great. __________________
Luister Boereworsrol - Ek dink jy praat KAK! Show us them graphs as I believe I have seen graphs on this site proving the opposite. I can assure you that my 1200ADV with full Remus Headers, Genesis can, K&N, modded snorkel, and Wonderlick PC is the best thing since the slicede bread NO fluctuations (or flatulations for that matter) just smooth POWER right through
My butt Dyno is telling me that the Remus headers, Remus can, Blue filter, and Wunderlich P.C. are the source of my increased smiles--and my decreased gas mileage.:dog I just installed a ground interrrupt switch so that I can turn off the P.C. on the fly when I want to save gas and I can deal with some suring and backfiring.
I was wondering, I'm thinking about adding the remus header and keeping the stock exhaust, How does anyone know if all these changes don't damage the engine over time? That is my concern.
I don't think that is worth worrying about..The only thing I would at all be concerned about is that PC messing with the computer... It obviously does something..but no one can tell me excactly what..I know it adds fuel..but the GS's computer should recognize that and correct it..or are the oxygen sensors de-activated. All I know is my dealer said they would not warranty a bike if that controller was installed on it. I still want to try it..I hate the popping on decel
I've gotta add my 2 cents worth here. I now have an '07 GSA and I am considering these mods because I did them before on my '05 GS. I had a full Remus, K&N, and an intake snorkel. The biggest overall improvement, performance wise, I've ever had out of any boxer was from the snorkel. I've done this several times and it's always the same. I then added the PC. I tried several road tests and could never notice any difference at low to middle RPMs with the PC no matter what settings I used. Over 6,000 RPMs it's a different story. Where the normal GS runs fairly flat after 6,000 when you have the PC it keeps building power. It's very noticable. If you go to the Santa Cruz web site you will see a PDF file that shows the increase in power. It's all over 6,000 which was EXACTLY what I experienced. Low to midrange - no difference just like their graph. If you spend much time above 6,000 then the PC is worth it. Otherwise save your cash. If you want to feel an increase EVERYWHERE get the snorkel or the Remus headers.
OK..I bit the bullet and ordered the Remus Headers from BMW Santa Cruz..(cause they take paypal) and they are already in the mail So my question is does anyone know the weight savings, if any, between the stocker and the remus? Thanks
Hey NR, Do you have the Wunderlich snorkle or did you trim the stock snorkle? Since I just sprung for the PC, and now shouldn't have to worry about running too lean, I may as well finish the job and do the snorkle. Thanks
Great review! I have been kicking this can down the street for a while. I recently picked up a KTM 530 EXC-R (on the way to order a Remus system for the R12GS, ironically:huh) and the KTM throttle response has made me stop kicking the can. From the report and the additional contributors, I summarize that the order of priorities are: 1. High flow snorkle 2. Remus Header 3. Remus exhaust pipe 4. PC only if you are spending reasonable amount of time above 6K RPM Sound about right? I thought the engine management system would compensate for the higher intake/exhaust flow and fatten up fuel/air mix?
I have had the Wunderlich header and akrapovic end-cans on both my '07 GS and '07 Adventure. Power increase is instantaneous. My concern is all the backfire and am wondering if it will damage the engine in the long run. Didn't feel the ECU did any adjustments automatically to conpensate for the changes.