bfisher wrote:Sooo.... How does this mod differ from the gains from those through Lennies induct (
http://boxer-performance.com/bmw-inlet-ducts/)? Would you consider do this mod in combination with the Lennies (if not why not?).
Brad
When I got my 11S, a riding mate with an 1150 RT told me the first thing I had to do was to fit the GS tubes, and to go to the 1100RT forum to see dyno results of fitting GS tubes to an RT. Saw the dyno numbers and said "rightio - this is for me
", and since the tubes were cheap and they could be easily removed if they didn't work out I had nothing to lose and a lot to gain.
So away I went (as above), and from the moment I hit the starter the bike felt different. Better idle, crisper exhaust note, less clutch slipping uphill out of my driveway. On the road - crisper throttle response from 2000 rpm - and when the tach went past 4k it was just "in yer face" full on better.
I had this big ear to ear grin and went off to have the bike dynoed.
I overlaid my dyno result over the factory dyno charts, below:
I can tell you that the seat of the pants result is every bit equal to what you see in the dyno comparison.
You know when your testing some new power gizmo and if you squint really hard you can feel a bit more 'here' and some more "there" ...?
Not with this. It's a pie-in-yer-face type improvement. No joke. If you can't feel the difference then you're next in line for the morgue. LOL
I've got nothing to gain by telling ppl about this. I don't own a shed full of black market GS tubes or anything like that. It's just that I've never got so much bang-for-buck from anything I've done to an engine.
To your specific questions:
- Lennie's Induct: I had already fitted this and felt that it improved breathing above 4000 - 5000 rpm (I have a 2000 ft test mountain range nearby
)
- then I fitted the GS tubes (whoohoo), so I can't quantify and difference made by the Induct BUT ... it has to have helped with high rpm breathing when you look at the minimum x-section (around the battery box) of the OEM snorkel (below):
Intuitively I would say that by fitting GS tubes you would achieve the same gains below say 5k rpm (because it's an issue of better ram filling using available air, rather than needing greater air volume). Remember that great gobs of low to mid-range torque are far more exciting most of the time, so I'd say you'd still have lots of fun fitting GS tubes but using the stock intake snorkel.
When I first posted all this a couple of years ago there was a chap, who had already fitted Lennie's Rocket Sprockets and Induct, fitted the GS tubes to his 11S. His reaction was "Ohhhhhhhhhhhh f************k", or words to that effect, but shortly after he sold his 11S and disappeared.
Look - all I can say is this:
firstly, it's not like you're making a few hundred quid of irreversible changes, putting your trust in the claims made by the bloke flogging whatever it is.
secondly - I'm not flogging anything so I've nothing to gain.
thirdly - to find out, it will cost U what U might spill on the bar on a Saturday night trying to get laid yeah? (= price of second hand GS tubes).
fourthly - if U don't think they work then U can take them out just as easily, and yer now worse off than U were on that Saturday night when U were in bed before 11 o'clock. LOL LOL
fifthly - you won't have to worry about 'fourthly' - cos they flippin' well do work.
Anyway Brad - over to you mate - but here's a thought - "over analysis" of a situation: look - your talking about investing a couple of hours of your time and a few bob's worth of plastic for what is, anecdotally, a good gain.
Fer heaven's sake man - get some perspective will ye! It's not like yer deciding on a nuclear submarine contract. G'wan - splash out. Take a risk!
Having said all that, let me know how the GS tubes work out, won't ye?
.
Real torque curves don't have a first derivative. :-^)
, or buy a pair of GS tubes from a bike salvage yard for a few quid and throw caution to the wind, with bugger all to lose?