- Joined
- Jan 30, 2008
- Messages
- 18,708
- Reaction score
- 909
- Points
- 113
- Location
- Glenrothes, Fife, Scotland
Ok i've had this posted up on RS246 but hopefully posting here will get a bit more coverage.
Been doing some vagcom logging runs on craigs S4 and noticed it seems to be cutting throttle once it gets up the revs.
Thats the last log we did (full throttle 3rd gear), which shows throttle angle as well as boost pressure, well at least its supposed to show boost pressure...
As you can see the throttle closes down once the RPM's reach about 4800, the feeling from googling seems to be that throttle cut like that is caused by overboosting, so we want to look into that next, however with the logs not showing boost properly it leaves us a bit blind.
I'm going to try it again, theres another few channels i can log, which are supposed to show boost pressure (117 and 118) so i'm going to try those first to see if it gives me any more sensible readings...
Any ideas on what would be causing the overboost on a stock car? i'm thinking along the lines of a faulty N75 valve or a split vacuum pipe somewhere...
Original post is here: http://www.rs246.com/index.php?name=PNphpBB2&file=viewtopic&t=73850
Been doing some vagcom logging runs on craigs S4 and noticed it seems to be cutting throttle once it gets up the revs.
Thats the last log we did (full throttle 3rd gear), which shows throttle angle as well as boost pressure, well at least its supposed to show boost pressure...
As you can see the throttle closes down once the RPM's reach about 4800, the feeling from googling seems to be that throttle cut like that is caused by overboosting, so we want to look into that next, however with the logs not showing boost properly it leaves us a bit blind.
I'm going to try it again, theres another few channels i can log, which are supposed to show boost pressure (117 and 118) so i'm going to try those first to see if it gives me any more sensible readings...
Any ideas on what would be causing the overboost on a stock car? i'm thinking along the lines of a faulty N75 valve or a split vacuum pipe somewhere...
Original post is here: http://www.rs246.com/index.php?name=PNphpBB2&file=viewtopic&t=73850