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Thread: GS throttle bodies on a RS?

  1. #1
    Registered User ANDYVH's Avatar
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    GS throttle bodies on a RS?

    Anyone ever try this setup? I think the GS throttle bodies from the 1100 Oilheads were different than the TBs from the RS, more more mid-range torque.

    Is this true or does anyone have specifc tweaking experience with this idea. I ask because I may replace my TBs on my 94 R1100RS, and I prefer mid-range strength over high rpm power.

    My bike already has the GS intake tubes installed for some mid-range boost. I have installed a Techlusion and also made my own muffler internals. All this resulted in better mid-range power. Now I just wonder if I go one step further can I gain a bit more.
    Get trained! The best "performance" upgrade you can get is YOU. Visit msf-usa.org for training info.

  2. #2
    A bozo on the bus deilenberger's Avatar
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    Andy..

    One way to determine if there is a difference (IMHO - can't see why there would be..) is to go to www.realoem.com - and look up the two part numbers. If they're different - go back to the page where you select your bike, and look down at the very bottom, there is an option to put in a PN. That will tell you what bikes the part was used on.

    Comparing the two should give a big hint if there is a difference..
    Don Eilenberger http://www.eilenberger.net
    Spring Lk Heights NJ NJ Shore BMW Riders
    '12 R1200R - I love this bike!

  3. #3
    Rally Rat
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    There is previous discussion on the subject you can search for. As I understand it, the GS tubes result in some minorly perceptible bottom torque with a slight loss in top end.

  4. #4
    Registered User ANDYVH's Avatar
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    Yeah, I have had the long GS intake tubes in mt 94 RS since spring of 95. I feel they do give a bit my mid-range, and I wonder if the higher intake airflow velocity has anything to do to minimze the dreaded "surging". Because I have never had a surging issue with my 94 R1100RS, and they were supposedly known for that.

    The GS intake tubes do cause more intake noise, that is for certain.

    Thanks for the tip about realoem.com, I will certainly check that out.
    Get trained! The best "performance" upgrade you can get is YOU. Visit msf-usa.org for training info.

  5. #5
    tudo beleza
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    This mod was all the rage back in the mid/late 1990's along with autolites and opening up the valve tappet clearances and fitting co pots.

    http://www.ibmwr.org/r-tech/oilheads/R11pwmod.shtml

    also down load this pdf
    http://www.ibmwr.org/r-tech/oilheads...ce_2-25-02.pdf
    '02 R1150RS
    '08 SAAB 9-3 AERO 'vert
    '08 Honda Element EX

  6. #6
    BOXERR
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    I think you will find that the computor program is the same for the RS, and RT.
    The GS, and R share the same figures.
    So, I think unless you reprogram the ECU, you are wasting you time.
    Only my thoughts, maybe no fact to this.

  7. #7
    Registered User ALIENHITCHHIKER's Avatar
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    Andy, I ran the long GS tubes on my 2000 RT for about 10,000 miles before switching back to the originals. The bike was also equipped with a R259 Techlusion; CP plug was stock. As mentioned, the RT and RS engines are the same.

    The GS tubes did provide a bit more low end power. However, I felt that the engine suffered in the 4 - 6,000 rpm range. It just didn't seem to rev out as cleanly. (This was all seat of the pants.)

    Initially I got off on the increased intake noise - they made a throaty honk. Over time though I found the noise began to annoy me. Eventually I switched back to the stockers and sold the GS tubes.

    The tubes are not that expensive, especially if you can find a used pair (Beemer boneyard?). I'd give them a try and see what you think. You can do a back-to-back comparison.

    I've been giving some thought to gutting the cat element from the premuffler. What was your exhaust modification?
    Steve
    Current Hottie: '00 R1100RT
    Old Flames: '85 K100RT, '80 Yamaha XS850, '67 Triumph Bonnie, '66 Honda 90 Scrambler

  8. #8
    Registered User ANDYVH's Avatar
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    Yeah, I agree on all counts. I wonder if there is some way to "dampen" the intake noise with the GS tubes.

    Here is what I did to my exhaust:
    http://forums.bmwmoa.org/showthread.php?t=19907
    Get trained! The best "performance" upgrade you can get is YOU. Visit msf-usa.org for training info.

  9. #9
    Registered User ALIENHITCHHIKER's Avatar
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    Andy, with your less restrictive exhaust system I'm thinking the short RS/RT intake tubes are definitely worth a try. You might just like the results.

    Next step - enlarge the airbox intake snorkle to increase the ram air effect?
    Steve
    Current Hottie: '00 R1100RT
    Old Flames: '85 K100RT, '80 Yamaha XS850, '67 Triumph Bonnie, '66 Honda 90 Scrambler

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