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Remus set up with Bren Tune

24K views 70 replies 24 participants last post by  RichA 
#1 ·
Has anyone run a bren tune on a full remus pipe and header set up. Would like to go ahead and do the flash but no use in not going all the way if I am at the gate. Looking for any opinions from the peanut gallery if they know how the set up would effect or not the tune.
 
#33 ·
@Rider59, I added the exhaust solely because I'm vain. I usually ride with top/side cases removed and wanted to show off the BST Carbon Fiber wheels. Let me add I do have the Remus headers. Bought them when first released, e.g. I drank the Remus kool-aid, before it was known the headers and/or cans add literally nothing to the performance of the GT.

Duane
 
#35 · (Edited)
So Duane, it is a fact that headers and pipes don't change a bike that much - even on sport bikes. But losing the cats has to at least add some responsiveness to the engine? Also, if you took the headers to the next level with a less restrictive air filter and then map the bike for more power I think you could get at least 5-10 hp out of it, no? It's about air in air out, adding just the header isn't going to increase flow. I'm sure the ECU's automatic adjustment is mainly to maintain a safe situation for the motor (probably just adjusts the A/F ratios). But a tuner can do better than that. I think I see your interest in Bren now!


I was thinking with a header and race filter you would be able to step things up. But the long runners on the intake side are going to focus the output on torque, not much that can be done there without major mods. Sort of an interesting line of thought though.
 
#36 · (Edited)
@crazyarch , I do run a K&N air filter. But custom tuning to gain maybe 5 hp, one isn't worth the money and two would hardly be noticeable on such a heavy bike with +-120 hp. I 'thought' I was gaining 20 ftlb torque with the Remus headers but was later debunked.

Duane
 
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#37 ·
@crazyarch , I do run a K&N air filter. But custom tuning to gain maybe 5 hp, one isn't worth the money and two would hardly be noticeable on such a heavy bike with +-120 hp. I 'thought' I was gaining 20 ftlb torque with the Remus headers but was later debunked.

Duane
Wow, Interesting. Guess somehow BMW has locked the goodie box!


EDIT: These are good conversations. Thanks for putting up with my stupid questions!
 
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#42 ·
#43 ·
#44 ·
Added a set of Jet-Hot HTC coated Remus stainless steel headers to my K1600B. Here are the updated dyno results. A 2nd iteration from BrenTuning was already in the bike, so the results do not represent what one can expect by adding the headers to a stock bike. Also have no comparison of headers with/without the Jet-Hot HTC coating.


Enjoy.
 

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#45 ·
Interesting.....
The diff between rain mode and dynamic isn't as drastic as I would have expected.
Also interesting is the diff between stock and Bren 1 is marginal, 5hp I believe, but does smooth the curve out.
Nice gain with the headers and Bren 2.
Thanks for keeping us all posted.
More important than dynos, how does the bike feel and sound?
 
#46 · (Edited)
@evomind : I try not to add subjectivity to discussions


Based on the curves for my setup, I have calculated these optimum shiftpoints for maximum available power. The increases in power at lower RPMs, have lowered most of the optimum shiftpoints:



  1. 8258: shift --> 2nd
  2. 7535: shift --> 3rd
  3. 7307: shift --> 4th
  4. 7273: shift --> 5th
  5. 7214: shift --> 6th


Again: these are for the setup I am running and the power curves of that setup. I am not saying these are the optimum shift points for a stock, or any other bike.


Using these shiftpoints, above 45 mph, there is over 140 rwhp available at all speeds. I need to retrain myself to these numbers and stop running it up near redline before shifting.


Two things I did not expect, that I see in the results, and for which I have no explanation:



  • Dyno performance had been consistently, slightly better for Road mode, compared to Dynamic mode, through all previous runs. That reversed with the addition of the headers for some reason.
  • Although dyno performance improved throughout almost the entire curve with the addition of the headers, just below redline performance actually declined with the addition of the headers.
 
#54 ·
[LIST
[*]Although dyno performance improved throughout almost the entire curve with the addition of the headers, just below redline performance actually declined with the addition of the headers.
[/LIST]

That’s probably where the combination is reaching the limits of the long intake runners and/or throttle body. Weird that it affected the header set up more than the non header setup though. Maybe a little reversion or something?

Kind of a moot point though, since it appears that Remus has discontinued the headers for these bikes
 
#47 ·
@phat6, this is good info if I ever decide to put the K bike on the drag strip after installing a shift light. For running the twisties an rpm range is much more useful. I suck an interpreting data from a dyno sheet but I'm pretty good at judging the optimum torque. That's the beauty of these big 6 cylinders, anything above 6K rpm and you're good to go.

Duane
 
#57 ·
@phat6 , this is good info if I ever decide to put the K bike on the drag strip after installing a shift light. For running the twisties an rpm range is much more useful. I suck an interpreting data from a dyno sheet but I'm pretty good at judging the optimum torque. That's the beauty of these big 6 cylinders, anything above 6K rpm and you're good to go.



RPM ranges are nice, and simple. I am sure most ride with glee without needing the information I have presented. That is fine.



I am often looking for more, especially if that "more" is available for free, already in the bike, and unlockable simply through knowledge. Gearing does not make optimal as simple as a fixed RPM range. Example from my setup:



  • The powerband, in terms of RPM range, is ~6100-7250 RPM
  • But, if I were to simply use that, and shift from 1st to 2nd at ~7250, the RPM would drop below/out of the powerband in 2nd, down to ~5350.
  • On the other hand, if I simply run it up to redline in each gear, I run into suboptimal performance in the higher gears. e.g. if in 3rd and accelerating up beyond 110, shifting up to 4th is going to drop the RPM down to ~6100 and the powerband will be coming on hard in 4th. Staying in 3rd and running up to redline would mean losing up to ~8 hp as compared to being in 4th.


There are similar cases when deciding when to downshift (or not). Some ride on the assumption that if there are revs available in a lower gear, downshifting will bring faster acceleration to pass that pesky truck in a short, closing window on a mountain road. That assumption may be false.



In the upper gears, the ratio changes gear-to-gear are close enough that just staying in the powerband (in my case ~6100-7250) works well. In 1st and 2nd it is a little different.


Yes, shiftpoints are not K.I.S.S. enough for most. Just sharing . . . and changing my behavior to upshift earlier, and not downshift as much, based on what I see in my setup.
 
#48 ·
As Duane points out, on the street, these bikes have so much torque they pull like freight trains if you're anywhere over 6,000 RPMs. Way, way overthinking it. Just my opinion, of course.
 
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#50 ·
@Vandaldog, couple of months after I bought the GPRs a buddy of mine, @FloRider, bought a GT. I found him a set of Remus, like NEW, for $350!!!! Talk about pissed. He was sitting with me when I found them online; otherwise I'd bought them for myself and sold him my GPRs. :)

Duane
 
#51 ·
@Gunnert As Dr. John said, "I been in the right place but it must have been the wrong time." :wink:
 
#56 ·
Just looking at the numbers, it looks like a 10hp or so peak gain so I am not discounting that, but one has to point out the cost/benefit side as well.
I know that full exhaust system isn't cheap by any stretch.
Would it be safe to assume it would cost parts and labor about 5-6k for a 10hp gain on an 800lb bike?
Again, not throwing shade on your efforts, just getting an idea what it costs to duplicate this.
 
#59 ·
Just looking at the numbers, it looks like a 10hp or so peak gain so I am not discounting that, but one has to point out the cost/benefit side as well.
I know that full exhaust system isn't cheap by any stretch.
Would it be safe to assume it would cost parts and labor about 5-6k for a 10hp gain on an 800lb bike?
Again, not throwing shade on your efforts, just getting an idea what it costs to duplicate this.



I do not have the full exhaust system, just the headers. I do not like the way the full exhaust system sounds, and the miniscule net performance increase for the price of the full system.


I spent ~$1900 total for the BrenTune + headers + coating. Labor I did myself.



To just look at peak horsepower is to ignore some of the other differences. For example look at ~6700 RPM. There is ~20 rwhp gained (~+16%) compared to stock. RWHP is gained throughout most of the curve. Out on the road, a bike with 5-20+ more rwhp throughout most of the curve, is going to pull away from a stock bike, rider willing, under just about any circumstances.



I am not selling anything. I have no vested interest in anyone doing, or not doing, what I did. Just sharing the data.
 
#58 ·
@phat6, what you write makes since, e.g. if you shift at max torque you'll drop too many RPM to be optimum. But , if you're shifting in a corner you've blown it. On the street this isn't a drag bike, it's all about handling and powering through and out of a turn.

Duane
 
#62 ·
Looking at that graph it looks like you had power gains throughout the curve and only a negligible loss down low. The bike already makes a ton of torque so I wouldn't be concerned with that low end loss. Improvement in air flow tends to result in some loss in the low rpm range -- same with cars.


These overall results are not negligible. Not only did you gain power throughout the mid-range and up top, but I bet the throttle response and overall tune make the bike a blast.
 
#64 ·
Speaking of shift lights, has anyone on the forum mentioned doing one already? I've got a nice one ready to go on the bike, but my dealer is hesitant since the bike is under warranty. They are worried about splicing into the coils. They said there is no other way with this bike, and I'm wondering if that's really true. Supposedly there's also no BMW harness that will make the job easier either.
 
#65 ·
Healtech makes one (model SLP-U01) for the K1600 and here's a screen capture of the wire connections that they claim will work on ALL motorcycles. Not really sure if it will work on the K1600 but I'd give the people you bought yours from a call and see what they think about an alternative to tapping into the coils.

Text Font Line Number
 
#66 ·
Healtech makes one (model SLP-U01) for the K1600 and here's a screen capture of the wire connections that they claim will work on ALL motorcycles. Not really sure if it will work on the K1600 but I'd give the people you bought yours from a call and see what they think about an alternative to tapping into the coils.

View attachment 126526
Thanks for that info and suggestion! Mine is called a Holley Sniper Standalone Shift Light. I did talk to support at Holley before I ordered it to confirm it would work with the bike, but didn't discuss installation as I thought it would be a piece of cake for my dealer to install. Not so much haha. I spent 3 hours at the dealer and left with no light installed... I guess they were researching the safest way to hook it up and never came to a conclusion.

I will give Holley a call.
 
#67 · (Edited)
Was analyzing some more data from the dyno runs. This time having to do with sound. I know what I think I heard from stock to as currently modified (BrenTuning II + Jet-Hot Coated Remus Headers + stock mufflers), but was looking for what the data showed. Ran a spectrum analysis of the audio from the different dyno runs to compare. Ya, ya, boring and geeky. Just sharing what I found.


Note: not run in a controlled, anechoic fashion




Update: ran and added the BrenTuning II w/stock exhaust analysis. Looks like most of the sound difference is from the headers, not the tune.
 

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#68 ·
Totally get it...On my K12LT I modified a K1 header attached to a supertrapp fishtail pipe! total cost about $450) I just fell in total style love with these Remus pipe for my K16B
 
#69 ·
Not to derail the conversation, but the reason I haven't pulled the trigger on these is because of the style. I really like the exhaust on the original Concept 101. I called Remus to see what they have planned. I was told they could build a custom exhaust if they could get maybe 100 orders. I for one would like to see the angled side exhaust.

 
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