Balancing Caterham Roller Barrels

[TeflonT]

My car has a habit of kangarooing at very low throttle openings - appears to be only at the very initial throttle openings. (for those who spoeak the lanugae of MBE - load sites 1,2, 3) PITA in traffic. the car is perfect at all other throttle levels.

Putting an air flow meter on the roller barrels reveals an imbalance between the two barrels in each body. i.e cycls 2 and 3 are the same, but 1 and 2 are different as are 3 and 4. The imbalance is 1 to 1.5 kg/hr on the AFM.

Is there an air bleed screw I cannot see, or is the only way to get perfect balance to set about modifying the lower flowing barrel with a file?

Ta

[DVandrews]

AFAIK there are no air bleeds. Just ensure that the overall airflow via the front is the same as the overall flow on the rear.

You should be drawing around 5.5-6 KG/hr on each barrel at idle, make sure you align the TPS correctly too.

That should sort it.

Dave

[TeflonT]

So Dave,

I get the following readings on the AFM:

Cyl 1: 4.5
Cyl 2: 5.75
Cyl 3: 5.75
Cyl 4: 4.5

The TPS is set at 0.43v (Load site 0 in the Throttle Index Map)

Its all set up as well as I can get it. The only other thing I suppose I could look at is fuelling maybe its running a bit lean.

The only area where the issue occurs is at the initial load sites, below 2000rpm.

[DVandrews]

Overall airflow looks a bit down on the recommended value.

Dave

[BSA]

When were they last re built ? I think the ones on your car are about the same age as mine 2002,The springs can stretch over time , When my car was on the rollers last month we noticed an oscillation at low revs creating very poor throttle response


Matt