Akra slip question for 2014 GSA - BMW R1200GS Forum : R1200 GS Forums
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post #1 of 13 (permalink) Old 06-Sep-2014, 03:59 PM (874) Thread Starter
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Akra slip question for 2014 GSA

I'm sure this is a tired topic and I have searched the forum but I couldn't find answers to my specific questions.

Is the Akrapovic slip on much louder than stock with respect to being heard in traffic (rpm 4-7k)? Does the Akra slip on for the 2014 model have an easily removable baffle (no cutting required)? Does the baffle seem to be "meant" to be removed if more sound is preferred? The guys at 2 local dealers had no experience with them and said the baffle isn't advertised in the literature as being removable.

My goal is more volume without having to install a full system or sacrificing low end performance. I'm not brand loyal but Akra and BMW seem to be linked. Coming over from Ducati, the Termignoni systems made an incredible difference over stock. Just wondering if there's a BMW equivalent (I realize they won't growl like a Duc).

Thanks in advance for any info!
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post #2 of 13 (permalink) Old 06-Sep-2014, 04:09 PM (881)
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The Akrapovic is louder than stock. It's very cleverly engineered so that it makes a real bark when you first fire up the bike - enough of a bark to turn the heads of kids in hot hatches in gas stations. However, it's obviously tuned so that with the baffles in place it meets the requirements of the CE regulations at the 4-4.5K rpm at which they're tested and then when the bike's pulling hard and WFO, it makes a very nice sound.

I've still got the baffles in mine because, especially with the Vario bags fitted and wearing earplugs, it's loud enough on long rides. Since it's a twin outlet, there are two dB killers which, I believe, are both removable by grinding out rivets but it's late here and I'm not going out to the garage to confirm that tonight.

In the meantime....

https://www.youtube.com/watch?v=P1hB9JS5B7M

You could, of course, also fit the Akrapovič or Remus headers as well and the full system sans cat' would give you a performance boost. However, are there not some legal difficulties with aftermarket exhausts in CA these days?

"A map is not the territory it represents, but if correct, it has a similar structure to the territory, which accounts for its usefulness".
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Last edited by Schtum; 06-Sep-2014 at 04:42 PM (904).
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post #3 of 13 (permalink) Old 15-Sep-2014, 05:44 PM (947)
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Hi. I have a 2013 GS. I have fitted the BMW / Akrapovic slip on muffler. there is good schematic diagrams and fitting instructions on the Akrapovic website. I was rather disappointed in the sound, it was not a lot loader than standard with the baffle's removed ( which is just a matter of removing a screw in each baffle ). Iam an engineer, so I started looking at the system. The item in the exhaust that controls the amount of noise that the bike makes is the butterfly just before the muffler. you can see how it operates by running the bike with the muffler removed. this butterfly is only there to control noise emissions at idle. if you look at the akrapovic website, they make titanium pipes for the bike. look at the fitting instructions for fitting these pipes, they do away with the exhaust butterfly completely and also the catalytic converter. this makes no difference to the tuning of the bike as the lambda sensors are retained and the bike self adjusts.
The easiest way to make more noise, which is what I have done. is to disconnect the control cables to the exhaust butterfly ( this is quite easy, and outlined in akrapovics fitting instructions for there aftermarket pipe system ). This leaves the butterfly in the open position, because it has a spring return on it to the full open position, the servo motor still operates as usual, but there are no control wires connected.
I have also cut open my exhaust and removed the internals of the catalytic converter and rewelded. this is really unnecessary!
The result is a throaty sounding bike. not the same as a Vee twin. but you can now hear the motor at riding speed, which is what I personally like. It has done nothing to hinder the performance of the bike, Akrapovic claims torque increasese, but I think these are small and maybe unnoticeable, as the engine / bike pulls like a train anyway.

Last edited by kiwi rob; 15-Sep-2014 at 05:49 PM (951).
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post #4 of 13 (permalink) Old 27-Nov-2014, 10:53 AM (703)
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Full Titanium Akrapovic system weight savings over stock 2013+ system

Anyone know how much in weight savings the full titanium akrapovic exhaust system has over the stock system on a 2013+ BMWR1200GS or Adventure?
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post #5 of 13 (permalink) Old 27-Nov-2014, 12:08 PM (756)
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Quote:
Originally Posted by kiwi rob View Post
this butterfly is only there to control noise emissions at idle.
That is a false statement. Actual back-to-back dyno tests were reported in Motorcyclist magazine a while back. Removing the flapper resulted in a LOSS of 3-5 ft-lb of torque between 2750 and 4500 RPM --- the exact area where most riders keep their bike most of the time.
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post #6 of 13 (permalink) Old 23-Dec-2014, 05:27 AM (477)
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fyi

Quote:
Originally Posted by marc View Post
That is a false statement. Actual back-to-back dyno tests were reported in Motorcyclist magazine a while back. Removing the flapper resulted in a LOSS of 3-5 ft-lb of torque between 2750 and 4500 RPM --- the exact area where most riders keep their bike most of the time.
Go to the Akrapovic website and read the fitting instructions for Akrapovics replacement header pipes. You will find that there pipes do not have an exhaust butterfly! They remove the cables from the servo drive motor controlling the original butterfly in the factory pipes. They also show power and torque diagrams before and after fitting. So you can make your own decision on who is correct, a motorcycle magazine or the actual manufacturers of the factory endorsed aftermarket systems!
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post #7 of 13 (permalink) Old 23-Dec-2014, 07:08 AM (547)
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Quote:
Originally Posted by kiwi rob View Post
this makes no difference to the tuning of the bike as the lambda sensors are retained and the bike self adjusts.
If I had $10 for every time I've seen this.....

It'll only "adjust itself" when the engine is running in closed-loop mode, ie at relatively low revs and small throttle opening and then only if the fuelling requirements are within the parameters of the ECU map + trims. It won't adjust itself when running in open-loop mode, ie large throttle openings and high revs and that's where an overly lean mixture presents the greatest risk to engine life.

To achieve what you think will happen, would require a wideband O2 sensor and an adaptive ECU. So that'll be a Power Commander V with Autotune module....

HTH

"A map is not the territory it represents, but if correct, it has a similar structure to the territory, which accounts for its usefulness".
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Last edited by Schtum; 01-Jan-2015 at 04:00 PM (916).
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post #8 of 13 (permalink) Old 23-Dec-2014, 11:51 AM (744)
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Kiwi Rob... did I perhaps push a button?

If you read closely instead of letting your emotions rule your response you'll see that I responded to this statement: this butterfly is only there to control noise emissions at idle. That statement is false. The valve does more than control noise. No where did I say anything good or bad about replacing entire exhaust systems.

The valve serves a purpose with the stock system and that purpose is more than controlling noise. This shouldn't be a surprise as Honda, Yamaha, Suzuki, etc. all have had a similar system for decades.

Happy Holidays
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post #9 of 13 (permalink) Old 26-Jan-2015, 02:31 PM (855)
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Marc

I'am not an emotional person. Don't know where you got that from.
I'am just relating my findings here. Rather than rubbishing what I have posted, obviously because you have nothing better to do. Maybe you should try it for yourself, and see what your findings are!
You obviously think you know more than Akrapovic, and as there parts are labelled HP and are endorsed and sold by BMW.
I have actually brought, read the fitting instructions and fitted the muffler and pipe to my bike! So why then is there no exhaust butterfly in the aftermarket Akrapovic Header Pipes, and Akrapovic tells you to disconnect and remove the drive cables to the servo drive ????
I actually ran / rode the bike with the Akrapovic Muffler with and without the exhaust butterfly connected, with the factory header pipes I noticed absolutely no difference, other than the exhaust being a lot noiser at idle with the cables disconnected, because the butterfly remains in the fully open position!
What I have said will be of interest to someone who is actually considering purchasing the BMW branded / Akrapovic aftermarket accessories.

For your imformation Marc. I have actually owned and raced Yamaha R1's that have the EXUP exhaust valve. Also Hondas VTR SP1 ( No exhaust valve, but with intake flapper restrictor ). A Honda CBR 1000RR which had both, this bike I fitted with a full Micron system which did away with both exhaust and intake valves, this bike had no exhaust oxygen sensing, but I fitted a ignition and fuel adjusting power commander and this bike was fully tuned.
I don't regard myself as a specialist unlike yourself. but I actually get out there and DO-IT ! Iam just posting my findings here, as they might be of interest to someone like myself who is also actually going to DO-IT!
I'am not on here to rubbish what others have posted. Its interesting to read others posts and then make your own informed decisions. Also if you don't experiment and try things, you never learn, then you just become a sad git that rubbishes others?
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post #10 of 13 (permalink) Old 26-Jan-2015, 02:38 PM (859)
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Marc

I'am not an emotional person. Don't know where you got that from.
I'am just relating my findings here. Rather than rubbishing what I have posted, obviously because you have nothing better to do. Maybe you should try it for yourself, and see what your findings are!
You obviously think you know more than Akrapovic, and as there parts are labelled HP and are endorsed and sold by BMW.
I have actually brought, read the fitting instructions and fitted the muffler and pipe to my bike! So why then is there no exhaust butterfly in the aftermarket Akrapovic Header Pipes, and Akrapovic tells you to disconnect and remove the drive cables to the servo drive ????
I actually ran / rode the bike with the Akrapovic Muffler with and without the exhaust butterfly connected, with the factory header pipes I noticed absolutely no difference, other than the exhaust being a lot noiser at idle with the cables disconnected, because the butterfly remains in the fully open position!
What I have said will be of interest to someone who is actually considering purchasing the BMW branded / Akrapovic aftermarket accessories.

For your imformation Marc. I have actually owned and raced Yamaha R1's that have the EXUP exhaust valve. Also Hondas VTR SP1 ( No exhaust valve, but with intake flapper restrictor ). A Honda CBR 1000RR which had both, this bike I fitted with a full Micron system which did away with both exhaust and intake valves, this bike had no exhaust oxygen sensing, but I fitted a ignition and fuel adjusting power commander and this bike was fully tuned.
I don't regard myself as a specialist unlike yourself. but I actually get out there and DO-IT ! Iam just posting my findings here, as they might be of interest to someone like myself who is also actually going to DO-IT!
I'am not on here to rubbish what others have posted. Its interesting to read others posts and then make your own informed decisions. Also if you don't experiment and try things, you never learn, then you just become a sad git that rubbishes others?
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