Y Piece and BB Chip

[Les Wassall]

Have read this thread with interest as I have just got a BB power chip, with the not so clear instructions was not to sure to disconnect the lambda or not so have sent a mail to BB, there response was-

Hello Les,

never disconnect the lambda probe.
Who did tell you that?


Kind regard,
Bernhard Bludau

I have a 02 1150 single spark, which I told him, so I'm not sure if the chips have changed over the years, the instructions seem to have, there is no mention of the probe on my instructions, but there is on Pigglet’s instructions.

 

[sproggy]

I'd seen the same 'unofficial' instructions about removing the lambda sensor. I also contacted BB Power to check and was told the same thing - leave it where it is! 2000 model single spark - same as yours, basically.

Never had any problems but setting the TPS correctly is critical for smooth power delivery otherwise there's a noticeable 'step'. I found something between 0.33 and 0.34v worked best on my bike with the chip.

 

[Les Wassall]

 

[Micky]

Tried that, loads of hassle, no noticeable gain. But then I changed to 1100RS intake tubes which are a larger diameter along the centre part of their length with no 'step' (otherwise a direct replacement) and the difference at the top end of the rev range is very noticeable - it revs far more freely. And despite a theoretical trade-off at low revs there is no loss of ridability whatsoever - I ride two-up into London in heavy traffic every day and at low revs from walking speed the bike still picks up better than it did with the standard chip and inlets.

The tubes are pretty cheap from a dealer - go for it!

We tried the larger intake stubbs off the 1100RS, maybe more power top end but a BIG drop in mid range. Bigger isn't always better...

The piston speed, opening valves, fills the combustion chamber with air... the narrower intake tube (within certain parameters) means quicker air speed going into the combustion chamber, which has a ram effect, and you actually get more air into the chamber than if the inlet tubes were larger but air travelling slower... if you know what I mean.

Again, I asked Bernhard B in Germany, who does the chips, said he had dyno'd bikes with and without... the larger air tubes sap power midrange. He did find usefull torque gains tho with cutting off the standard GS intakes inside the air box (so they don't extend inside) and rounding the edge off!

Hope this helps...

 

[sproggy]

I'm aware of the theory. But I am not talking theory - I'm talking reality. I tried removing the inner ends of the standard intake tubes and rounding off the ends and this made no appreciable difference to the way the bike rode. Absolutely none at all. I then fitted the RS intakes and this made a huge difference at the upper end of the rev range.

As I stated before there was no noticeable loss lower down, and since I do most of my riding two-up in town (i.e. at the lower and mid part of the rev range) I WOULD notice a "BIG drop in mid range" if there was one.

I never dyno'd the bike so I'm talking just about the way it rode, not in terms of figures.

Incidentally ram effect is gained when air is forced (usually by movement of a vehicle) into the airbox or intakes thus increasing pressure above atmospheric. The smaller diameter intakes do not produce a ram effect. What they do is increase the speed of the air compared to larger diameter intakes (since the flow rate is constant at a given engine speed/load, if the cross-sectional area reduces the speed must increase) thus improving atomisation and distribution of the fuel from the injector. Too slow an air speed and fuel can 'drop out' of the air stream. This is the theory behind the smaller intakes being better for low down torque.

What you are talking about (increasing the amount of air passing into the combustion chamber) is venturi effect. The BMW engine doesn't use venturis in the intakes to my knowledge and if it does, they wouldn't be affected by the intake tube diameter one way or the other.

What I'm saying is that theory and practise aren't always the same thing - it's worth experimenting, which is what I was recommending in the first place for the sake of about £25 worth of intake tubes.

 

[Micky]

I'm aware of the theory. But I am not talking theory - I'm talking reality. I tried removing the inner ends of the standard intake tubes and rounding off the ends and this made no appreciable difference to the way the bike rode. Absolutely none at all. I then fitted the RS intakes and this made a huge difference at the upper end of the rev range.

As I stated before there was no noticeable loss lower down, and since I do most of my riding two-up in town (i.e. at the lower and mid part of the rev range) I WOULD notice a "BIG drop in mid range" if there was one.

I never dyno'd the bike so I'm talking just about the way it rode, not in terms of figures.

Incidentally ram effect is gained when air is forced (usually by movement of a vehicle) into the airbox or intakes thus increasing pressure above atmospheric. The smaller diameter intakes do not produce a ram effect. What they do is increase the speed of the air compared to larger diameter intakes (since the flow rate is constant at a given engine speed/load, if the cross-sectional area reduces the speed must increase) thus improving atomisation and distribution of the fuel from the injector. Too slow an air speed and fuel can 'drop out' of the air stream. This is the theory behind the smaller intakes being better for low down torque.

What you are talking about (increasing the amount of air passing into the combustion chamber) is venturi effect. The BMW engine doesn't use venturis in the intakes to my knowledge and if it does, they wouldn't be affected by the intake tube diameter one way or the other.

What I'm saying is that theory and practise aren't always the same thing - it's worth experimenting, which is what I was recommending in the first place for the sake of about £25 worth of intake tubes.

Well I'd rather go with Bernhard B of www.bbpower.de who makes the chips and has dyno'd the 'bikes, and my own findings... which is loss of power midrange. Not 'just a feeling' but tested back to back! Oh yes, and I know the theory too... which agrees with my findings and those of BB

Tuning For Speed by P.E. Irving (8s 6d net.) first published in 1948, it's all in there and still current!

 

[sproggy]

I'm not arguing with the theories and principles. What I was trying to say is that with my bike, with the other modifications that I've carried out and with the way that I ride I find the larger intakes to offer significant advantages at the top end with no noticeable loss lower in the rev range. And this makes me happy, and since it's my bike that's all that matters, really. I don't care about figures - I care about the way the bike rides

So the larger tubes won't suit everyone - I was simply stating my experience with them. If people want to listen to the experts and not question thier findings that's fine - I like to experiment for myself

 

[Le singe]

You're both right. The laws of physics don't change, and engine performance tuning uses the laws, however, every type engine is different, and on many occasions the actual design of the engine imposes restrictions.
The 1100GS engine is a challange, there is an rpm limit due to the length of the rods, porting limits due to the size of the inlet ports, these pose restraints on cam modifications and timing, and hence dictate certain inlet valve sizes, and so on.
Although some off-the-shelf tuning parts work well, others are purely profit related.
Theory is always a good starting point, dyno readouts don't always give the full story, road-testing, personal preference and 'feel' are the final tests.
And the black ones will always be quickest

 

[Micky]

And the black ones will always be quickest

Well at least my lad will agree with that... 'Laughingas' has a Nitrous kit on his

But it's not as quick as a 650 round Der Nürburgring