hello there, the above graph is of my turbo corsa, i asked timrud to post it for me see if anyone could make any sense out of it.

the car was tested in 5th gear and i was informed that they always test them in the gear below the top gear.

now, me and tim worked out that the 257 was made at a little under 4900rpm. on the graph, in my eyes, the power was still building and the boost was still tailing off evenly like its supposed to.

the reason why i have doubts is another corsa turbo there at the same day made 265bhp and 340+ nm of tourque. that car was peaked at 0.8bar of boost, whereas from the above graph mine peaked at 1.3.

the rolling road opperator said my loss of tourque was due to the fact that the engine runs low compression pistons. the pistons are je 87mil instead of the std 86mil. as far as im aware they only lower the compression from 9:1 to 8.5:1 which isnt reall a great lot.

also told me id loose tourque due to the drag of the 6 speed box. the other corsa ran an f20 5 speed which has the same ratio's as the f28 6speed, so i can understand why mine wasnt tested the same in 4th????

when i was sat in the car on the run for the graph above, the clocks in he car didnt show 5000rpm, whereas the other corsa went to over 6700rpm.

maybe i shouldnt worry too much and look at it that my car makes 257bhp below 5000rpm and probably would have made a lot more as it started to spin out the rollers when they had another few goes. the rpm figure on the graph above is wrong. totally wrong. i think he gave up on the run as the red light on the cumputer started flashing like mad as it was reading nearly 9000rpm.

sorry for the long, long, first ever post ive made.