GSX-R 1000 04 model

Discussion in 'Australian Motorcycles' started by Fraser Johnston, Nov 16, 2008.

  1. Anyone here pulled the exhaust control valve off one? I'm looking at
    doing mine.

    Fraser
     
    Fraser Johnston, Nov 16, 2008
    #1
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  2. Fraser Johnston

    BT Humble Guest

    You'll have to do more than that to get it passed as LAMS restricted!


    BTH
     
    BT Humble, Nov 16, 2008
    #2
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  3. Fraser Johnston

    JL Guest

    No but it's just an electronically controlled valve in the exhaust
    pipe - what exactly do you need to know? You'll need to replace the
    collector pipe IIRC to remove it out of the system altogether if
    that's what you mean.

    JL
     
    JL, Nov 16, 2008
    #3
  4. After a bit of googling I have found the info. Basically the valve is
    there for emmissions reasons and for low end torque. Most people on
    forums can't tell the difference. The reason I want rid of it is they
    are a complete pain in the arse to set up. By getting rid of it you get
    a ecu error and the bike goes into limp home mode. But by pulling a
    wire on the ecu you get rid of the error. Result!!! A kilo of crap off
    the bike and one less thing to go wrong.

    Fraser
     
    Fraser Johnston, Nov 17, 2008
    #4
  5. Fraser Johnston

    JL Guest

    <sigh> You didn't do a lot of research if you think it's a kilo of
    crap. (and I'd be very surprised if it weighed that much)

    Most racebikes remove it because it doesn't add much value on the
    track. On the road it's a different story. The Yamaha EXUP valve and
    the later Suzuki equivalent (I forget their acronym - SRAD ?) create a
    benefit for surprisingly little cost.

    The benefit is a significant increase in low and mid range power
    without costing much if any top-end. This is more important on a road
    bike than a track bike and hence race teams will of course often
    remove it usually in favour of an exhaust that will allow even more
    gas to flow and give them even more top end.

    Exhaust tuning has to balance peak power against low end grunt. The
    low end is particularly useful on the road and allows you to not have
    to do the gearbox shuffle you do on say a 250 2 stroke. A wide
    powerband is more usable in the real world. The shape of the torque
    and power curves are always a trade off - you take a little from down
    here to add a bit up the top here etc. So in conventional tuning you
    can get more mid range by taking a bit off the top - how ? In simple
    terms you reduce the diameter of the exhaust pipe (yes it's more
    complicated than that). A narrower pipe gives higher gas velocity and
    prevents the gas slowing too much and hence not flowing out quick
    enough to clear the cylinder. That's great at low rpm but obviously as
    the rpm climb you end up putting a limit on how much gas gets out.

    That's where exup et al come in - you basically get two exhausts for
    the price of 'one plus a valve' - you get one optimised for low rpm
    (valve closed and hence narrower pipe) and one optimised for high rpm
    (valve open and hence bigger pipe).

    If you take it off you basically take away a chunk of mid range to
    absolutely no benefit. The only way you will get a benefit is if you
    replace the exhaust with a full race system.

    At least one manufacturer (MV Agusta) and I think a couple of others
    (Yam and Aprilia IIRC) have the same thing at the intake side -
    variable length intakes - which does exactly the same job - maximises
    air flow at lower velocities(1) and then opens out to let more air
    through at high velocities. It's somewhat common on cars.


    JL
    1 low velocity is a combo of both rpm and throttle position - think
    about opening a carbed motor wide open at low throttle and the way it
    bogs down - that's because the velocity gets slow - big orifice and
    not much pre-existing movement to suck it along
     
    JL, Nov 17, 2008
    #5
  6. Seen dyno charts and it basically does **** all. It is there for noise
    and pollution regs. There is a TINY bit of low end torque lost by
    removing it but on a 1000cc sports bike it is bugger all. Heaps more
    info here:-
    http://www.gixxer.com/forums/showthread.php?t=87741&highlight=set+valve

    Not sure if you need to register.

    Fraser
     
    Fraser Johnston, Nov 17, 2008
    #6
  7. Fraser Johnston

    Nev.. Guest

    If all this info is available on a gixxer forum, why didn't you just ask
    the original question there?

    Nev..
    '07 XB12X
     
    Nev.., Nov 17, 2008
    #7
  8. Fraser Johnston

    fred.kroft Guest

    I used to have a 2001 model. The valve cables failed after 2 years
    and I did the mod.
    However, on billard board table roads like the NT, you wouldn't notice
    it, but on
    goat tracks like you have in SA, the 6k and 10k power peaks that
    appear without
    the value rev filtering become a bit dangerous when you hit big F.O.
    bumps. Can
    easierly result in a high side (the gixxers are notorious for side
    siding people in
    the hills). Those power peaks were pretty good fun though :)

    I ride a KTM SD now and go harder.
     
    fred.kroft, Nov 17, 2008
    #8
  9. Fraser Johnston

    jl Guest

    And you didn't read it either did you from this guys post, with chart

    ===========
    tank34
    Roll On Champion


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    Re: One Last Time...The final set-valve thread
    Maybe it's just me... but I'm a bit of a stickler for details.
    According to JeffW's chart, which he posted many moons ago, there is
    torque loss at 3k rpm (without a remap, from what I can gather).
    Now- maybe it's not useful, and no-one cares, but I think when people
    come here for explanations, we should try to be accurate in the
    responses. Gives the forum a better reputation.
    Now, I have no doubt that a decent exhaust and a good re-map would fix
    that hole.
    I just think it's a bit misleading to conclusively say the SET valve
    only reduces noise on a stock bike.
    (I dunno, some people think cucumbers taste better pickled.)

    Does someone have the sport rider results to refute this?
    ====================

    Obviously I can't attach the jpg (and I can't view it without
    registering which I ain't gunna do)

    Bottom line you get no benefit from removing it unless you change the
    headers and dyno tune for the higher gas flow. If you do that you'll
    prob end up with more up top and less down low (assuming it's a higher
    flow system which you would expect it to be).

    JL
     
    jl, Nov 17, 2008
    #9
  10. To annoy you and to slow the death of usenet. : P

    Fraser
     
    Fraser Johnston, Nov 17, 2008
    #10
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