I've enjoyed following Montegue's tuning journey with Monty, I followed a similar pathway with a K series Caterham some years ago. Initially moving from a base 1.6 - 112BHP car, with all the correct drivetrain equipment. Initially through to 1.8 - 160BHP then onto 1.8 - 210BHP. We used a rolling road 3 times to get the setup right, but for me it was always the subjective "feel" of the car that instilled satisfaction with the end product (or not!).
What was very noticeable was how the cars character changed through each step, the 160BHP engine being horrible, all or nothing throttle due to roller barrel throttle bodies with a bad flat spot in the middle of the rev range. We smoothed it out some on the first rolling road session but the MBU ECU wasn't very programmable.
The final work, was undertaken by Dave Andrews, one of the go to guys for the K Series. This involved a big valve head, new cams, forged internals and an Emerald programmable ECU. This ECU was brilliant and gave 3 switchable maps, very handy as we did a security map that ticks but over won't drive, everyday map at about 180BHP and the full fat trackday map, which I have to admit I rarely used on the road. At this stage we were still running the standard 4:1 exhaust manifold and sports silencer, it ran so much better. But at the suggestion of Dave Andrews, I had a new exhaust made 4:2:1 with a 7 inch can, this further smoothed out the whole package with a small sacrifice of power down to 195BHP, but at a big improvement in torque and smoothness, it made it all so much more drivable.
There were times when I still missed the simplicity of the original setup, but bury the peddle and work the gears and oh boy that induction roar. So for me I would say the performance measurement is always, whatever the rolling road numbers say, going to depend how it makes the owner feel when driving.
