A Major Breakthrough!

After missing out on racing at Snett, I thought I'd attack the performance problems, and first on the list was getting the thing re mapped on a rolling road.  When I'd fitted the CBR engine fourteen months or so ago I just down loaded from the Internet a high performance fuel map for my Power Commander USB3.   I wondered if the problems with performance were due to this being slightly out.  In particular I wanted to Iron out the power delivery issues that had been so evident when Testing at Snetterton.

So I dispatched the car off to Power-Tec In Peterborough for a mapping session, they had some staffing issues due to people being absent at trade shows... so I left the car with them for a week or so.

On the Friday I got a call and the result of the conversation was that they couldn't map the car!

Why?.. Because it was running dangerously lean.  Their AFR sensor was showing a best ratio of around 17 but was mostly off the scale at 18+.... Bejesus! I've run it at Brands, Mallory and Snetterton like that  it's a wonder I haven't blown a piston. It is so lean in fact that they immediately stopped the rolling road session.  These CBR1000s are really bomb proof!

(Bing!... the big lightbulb goes on above my head) Running lean, also explains the lack of power, poor power deliver and the general overheating problems I've been experiencing since putting in the CBR1000RR. The root cause was low fuel pressure which I tested when I got the beast home.   The pump was delivering 2.5 BAR at idle, dropping to 2 bar under load.  The CBR specification is 50 PSI (3.5 BAR).  aargh!

I have a fuel pressure test guage and a wide band lambda sensor and If I'd had time to fit either of these diagnostic tools I would have seen the problem straight away.  But the focus on Diffs for the last 6 months or so meant that it had never entered my head.  Still hindsight is an exact science I suppose. At least we've found it now

The problem is that the in tank pump is for a zx12R, I had reasoned (erroneously) that this would output the same pressure as the dedicated CBR pump, plainly it does not.  Well I'm not about to change the tank and in tank pump... both are a right pain to get at and even bigger pain to seal correctly.  

The solution was to get a billet CBR pump mount CNC machined by Andy Bates at AB Performance (Series Sponsor for RGB). and then get this fabbed into a supplementary fuel tank along with a proper CBR1000rr pump.  That way the existing in tank pump acts as a low pressure lift pump to the tank and the CBR1000RR feeds the injectors at the right pressure.  I finished this in the final hours before going to Brands Testing.  I also fitted the Wide band Lambda sensor to see if it had any effect.

and so it was off to Brands Hatch for the first race of the season.