Reproduced by kind permisssion of Practical Performance Car

I never could understand the mentality that requires the messenger with bad news to be shot. I sometimes do power runs for people with competition cars and when they don't make the power they're supposed to it's somehow my fault. It's even worse when the engine is a pro built one and not living up to the quoted power. The thing to remember is that there's no such thing as two identical engines. Manufacturers typically quote a 5% tolerance on standard engines, so on a 100bhp engine you could be 5bhp up or down. On a 200bhp that becomes 10bhp plus or minus. The problem starts you are missing multiples of tens!

The 2-litre Vauxhall XE engine normally makes about 180bhp with a set of throttle bodies and a decent exhaust. Steve Broughton at SBD sells a kit with bodies and an exhaust for the stock 2-litre XE engine called the '208' which made 208bhp on an engine dyno. The story is that they never make that power figure and I have to say in the past that has been my experience; until now.

I had a very tidy Westfield in with a 208 kit where the original ECU had failed (quite an old conversion it has to be said). My task was to map the engine and the owner wasn't looking for anything special by way of power output form the otherwise standard motor. Our rolling road cell has correction facility for barometric pressure and air temperature. I always use this facility and honestly try to get an accurate figure (as accurate as the rolling road kit will allow). This is the only way to measure power by correcting to standard air temp and baro pressure, the figure you then get is the power that the engine would have made at 20 degree air remp and 1010 millibar atmospheric pressure (observed bhp can obviously be up or down on that depending on cell conditions).

After finalising the mapping a power run on this Westfield showed a peak figure of 201bhp. That's damn close to the quoted SBD 208bhp figure and allowing that my result is from the rolling road (with its built-in rolling loss correction) it's not inconceivable that this engine was about right for the quoted engine dyno figure. So the 208 kit will make the power but if you don't see it then you probably need to look at your engine, not the kit.

View the 2.0L Basic Taper Throttle Kit (formerly called TP208 kit)