Dyno

 My Caterham has been to the dyno and it's good news all around. The replacement lambda sensor is working correctly, and it's fuelling correctly.

Everybody is very pleased with the engine rebuild, and it's making more power than the advertised power when it was new.

In the top graph the blue line is power, the red line is torque. the bottom graph is air:fuel ratio. What's interesting is that it's enriched at low revs. This is probably to make it easier to drive in traffic, but it might be a childish ploy to make it pop and burble on the overrun so it sounds like a racing car. Or something to do with the way they're tuned the variable valve timing.

They think the most important bits of the process were skimming the head for slightly increased compression, 3 angle valve seats, and careful valve grinding.

Richard "chef's kiss" B

Caterham Lambda Sensor

 I have a Caterham Seven with the 1.6l "Sigma" engine.

The original lambda sensor was Ford 1351337 These are now unobtainable or fiendishly expensive. I have replaced it with Ford 1327547. The sensor and the plug are identical, it's just that the cable is a bit shorter.

I can now say with confidence that the new sensor is functionally identical too, because my car has just come back from the dyno and it's fuelling correctly.

Richard "I hope this helps someone" B

Dyno

 This week my car goes to the dyno to find out how it's running. As I understand the procedure they're going to strap it down on a rolling road and measure the speed and power at the wheels at various different throttle settings and loads. They're also going to do an exhaust gas analysis because there are some questions around the lambda sensor and the fuelling. If things don't go as I hope, then I'll be charged (handsomely) to find out that the engine rebuild (for which I paid the same people a king's ransom) hasn't solved all of my engine problems.

Richard "fingers crossed" B