In gear performance issue

[5cylinderman]

My ABY S2 is standard spec (bar a de-cat).
If I floor it from 1500RPM in second and third gear she starts to spool at 2500 rpm and comes on hard from 3000 rpm revving cleanly to the red line.
BUT
If I cruise at 4000rpm in third, fourth or fifth and then floor it there isn't that much urgency in acceleration. I have no fault codes and have checked for boost leaks (none).
I'm borrowing a boost gauge this weekend to see what's what under the bonnet but until then are there any words of wisdom from forum members?

[mcandmar]

Sounds like you have discovered the overboost functionality, WOT in 3rd, 4th, 5th from ~2000rpms is required for it to work, and i think that gives you ~1.2bar in the midrange vs .8bar-1bar. Its a daft system as you have to drive in such an un-natural way for it to work.

Get a homefry, 1.4bar all day long

[5cylinderman]

Hi Mark,

Interesting idea that explains the problem.
Should my throttle switch "click" on WOT or does the ecu just go on resistance value?

P

[UrS4boy]

Should my throttle switch "click" on WOT or does the ecu just go on resistance value? P

No click on WOT, just at idle:

More info including resistance tests: http://forums.quattroworld.com/s4s6/msgs/20405.phtml

[Rusty]

Get the boost gauge on there and check you're getting over 0.4 bar first. Should see 0.8bar non overboost and 1.0bar overboost dropping to 0.6bar at the red line, give or take some inlet air temperature and altitude variations (see www.s2central.net).

[UrS4boy]

Sounds like you have discovered the overboost functionality, WOT in 3rd, 4th, 5th from ~2000rpms is required for it to work, and i think that gives you ~1.2bar in the midrange vs .8bar-1bar.

Here is the factory overboost graph (2.15 Bar max for 15 seconds) (with boost showing as absolute pressure (atmospheric pressure = 1.01 Bar).

[mcandmar]

No click on WOT, just at idle:

More info including resistance tests: http://forums.quattroworld.com/s4s6/msgs/20405.phtml

The fully open value varies from car to car, measured with vagcom i've seen anything from 96 degrees to 101. As per the pic anything over 86 degrees is enough for the ECU to know your intent.

[mcandmar]

Here is the factory overboost graph (2.15 Bar max for 15 seconds) (with boost showing as absolute pressure (atmospheric pressure = 1.01 Bar).

Nice diagram, i was seeing 1.2 bar peak and .8 bar upto 6000rpms on mine but thats well within the variation of boost gauges, and user error trying to read them at WOT.