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Offline Patrick Bateman

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Exhausts, Filters, Tuning & Flashing
« on: June 10, 2018, 04:08:42 PM »
I've just spent a few hours watching a series Brock Davidson has done on the new Gixxer and found it really interesting. A little preachy and self promoting and anti-Akropovic (don't forget he is trying to run a business) but he takes the time to test and measure each mod incrementally, makes some mistakes, and makes some gains. When he's finished with it, the bike goes from 164hp to 204hp with nothing but tuning, bolt ons and race gas - which is astounding.

Interestingly, he mentions that the stock S1000RR air filter (same as the one used on the XR) is flows so well, he uses it on his 200+hp drag bike. Also, timing map changes (that can only be performed with ECU flashing) result in a loss of power, even when higher octane fuel is used - so tuning the fuel only with a power commander seems to be sufficient.

After watching the whole series, there are some questions about/comparisons with the XR...

  • Does the throttle valve angle taper off towards high RPM (even though the throttle is being twisted to 100%) on the XR as well?
    Brock found the Gixxer butterflies close back to 65% as the revs soar and, using a flashed ECU, is able to keep them open all the way to the limit and unlock a heap or extra power. Looking at the way some XR dyno graphs posted here taper off before redline - is this a result of the cam profile peaking too early or is there some electronic trickery going on? The RR is still ramping up significantly at 10,000rpm while the XR is choking.

  • WTF is going on with the link pipes at the headers?
    The RR has a valve under the muffler (same as the XR) and another valve in the link pipes between 1&4 + 2&3 (the XR has the link pipes but no valve). On the Gixxer tests, he finds that the link pipe valve opens at high RPM and provides a gain of about 3hp. Unfortunately he did not test it with the valve open at low RPM and what effect it has on power. This is relevant because the XR link pipe has no valve and the pipes are open all the time. Why do BMW feel they close it off in the RR at certain RPMs?

Guess we'll never know unless someone does the same type of step-by-step dyno testing on an XR. If I ever get a PCV for my bike, I will take it back to stock and try to find some answers.

If you have the time, start here and work your way thru.
I need to return some videotapes.

Offline Patrick Bateman

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Re: Exhausts, Filters, Tuning & Flashing
« Reply #1 on: June 10, 2018, 04:33:45 PM »
Its 1:30am and I should probably go to sleep, but I've been comparing the part numbers from XR to RR and found that the crank, pistons, head and conrods, exhaust valve springs and rockers are all the same part numbers.
The only differences are the inlet/exhaust cams & valves and inlet cam springs. Does this mean that with a top-end rebuild, rev extend and a tune, the XR should safely be able to reach RR power?
I can't think of a cheaper way to get a 40hp boost.


 :180:
I need to return some videotapes.

Offline BMW_XR_D

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Re: Exhausts, Filters, Tuning & Flashing
« Reply #2 on: June 10, 2018, 06:40:28 PM »
I'm with on the frustration , The best I've seen with XR is Headers exhaust , Air filter , tuning = extra 10-12 HP and for the cost , Noise its not worth it.
« Last Edit: June 10, 2018, 06:42:47 PM by BMW_XR_D »

Offline Belco100

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Re: Exhausts, Filters, Tuning & Flashing
« Reply #3 on: June 11, 2018, 04:28:19 PM »
Great Video - watching the rest now  :152:

Offline Winger

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Re: Exhausts, Filters, Tuning & Flashing
« Reply #4 on: June 11, 2018, 05:36:10 PM »
Well I started backwards!!! The stock headers and collector box were to me nothing short of visual tinnitus and a heat sync te-boot so I bought a secondhand set of Akra headers off this board for £400.

Simples I thought till I read the small print about needing a fuelling module 30 years ago i’d Have taken no notice but have been around the block more than once!!! And decided I would source such which wasted over well over a year and while it would interesting to tell the whole story it’s certainly not for these pages and finally bought a secondhand PC and had a custom map done as opposed to a generic version.

The final result was never going to be about HP even on my K1200 with many hours on a dyno with a Rexxer map I didn’t see double figures but what I did get with all the bikes that I have with aftermarket fuelling is a linear map from top to bottom.

If you ride one up and never have to filter in traffic then frankly you can avoid the glitches in the XR to the point it doesn’t have any but if you do those glitches will soon become apparent,I guess all in it cost me £700 and as I keep my bikes years an absolute bargain,but that is where I draw the line can you go further? of course but that’s for others not me.

Offline SAVAGEFOX

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Re: Exhausts, Filters, Tuning & Flashing
« Reply #5 on: June 11, 2018, 07:42:19 PM »
With the Akra headers is your bike road legal? If so how did you manage, as the headers themselves are not
2018 BMW S1000XR SPORT SE
Previous bikes:
2016 BMW S1000R SPORT ABS
2015 YAMAHA MT-07 ABS

Offline Winger

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Re: Exhausts, Filters, Tuning & Flashing
« Reply #6 on: June 11, 2018, 09:30:38 PM »
Can not even remember that far back when was the last time I ran a bike with a road legal system.

Offline SAVAGEFOX

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Re: Exhausts, Filters, Tuning & Flashing
« Reply #7 on: June 11, 2018, 09:32:01 PM »
No issues from police while in the U.K. or touring?
2018 BMW S1000XR SPORT SE
Previous bikes:
2016 BMW S1000R SPORT ABS
2015 YAMAHA MT-07 ABS

Offline Winger

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Re: Exhausts, Filters, Tuning & Flashing
« Reply #8 on: June 11, 2018, 09:57:27 PM »
Not in the slightest blimey i’ve Just had two weeks of bikers howling along the M6 which is close to where we live on the way to the IOM and now on the way home  :002:

Offline SAVAGEFOX

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Re: Exhausts, Filters, Tuning & Flashing
« Reply #9 on: June 11, 2018, 10:36:05 PM »
What about abroad like France or Germany?
2018 BMW S1000XR SPORT SE
Previous bikes:
2016 BMW S1000R SPORT ABS
2015 YAMAHA MT-07 ABS