Hey all,

 

Hopefully someone here has experienced this before, but have a BKD engined 2007 Octavia which seems to have some oddities in its running and charge pressure control since having a new turbo fitted under warranty.

 

Can anyone advise what the turbo duty cycle should be at WOT at 4000 rpm? The car seems to desperately be trying to lower boost as it climbs the revs. On one of the runs the duty dropped to single figures? If anyone can offer any help I'd really appreciate it. I've graphed the act/req boost and duty cycle but I must admit I was looking more than one block on this run so perhaps I need to do it again to get more readings in a given time. Maybe this looks normal and if so that's great - but it seems to be constantly over its spec boost?

 

Thank you

 

 

 

Edited 10 September, 201510 yr by -mike-

I should also add, the timing is currently retarded -2.9 which will hopefully be corrected next week when it has a new timing belt and water pump fitted. Not sure if its relevant information, but furthermore the current IQ is according to what I've read showing a rather lean mixture at idle?

 

Have done the VCDS output test on the turbo and I believe it may be making too much boost when the solenoid is cycled to on. Will report back with figures for that tomorrow.

I would say the actuator is too short as I would aim for a duty cycle of around 30% at 4000rpm.

Thank you for the reply! Is that something my mechanic could have a quick fiddle with when he does the timing belt? I'd have a go myself but don't have any ramps for ease of access to the actuator. Would the overboosting be doing any harm?

I would say the actuator is too short as I would aim for a duty cycle of around 30% at 4000rpm.

I'd lengthen the actuator 1 full turn and log again. If it's too short then it causes overboost.

I'd lengthen the actuator 1 full turn and log again. If it's too short then it causes overboost.

 

Will get him to do that. Can you tell me the effects of it being too short besides overboost? Does it cause faster/slower spool?

Two more seperate runs here if they are of any help

Another question for anyone else that may know if you don't mind - where should the car be making specified boost? It feels laggy low down compared to the old 1.9 PD lump I'm personally used to driving - just wondering if that is a characteristic of the 16v lump?

 

Thanks

Had the actuator rod turned once, car meets requested boost much earlier now and feels more eager low down but still behaving oddly higher up and desperate to shut down at high rpm -

 

Does it need more turns in the same direction?

You've gone the wrong way Needs to go the other way. You want around 30% duty at 4000rpm.

You've gone the wrong way Needs to go the other way. You want around 30% duty at 4000rpm.

 

It was giving me 4.7% on runs before, I realise one showed 10% but I've had 4.7's before now. This car is becoming a headache fast :(

Should also add - I have used approved warranty on this thing but the dealership are useless. It has a lovely lumpy judder going on that they can't pinpoint as the computer isn't showing faults - apparently I have to wait for it to get worse first!

You've gone the wrong way Needs to go the other way. You want around 30% duty at 4000rpm.

 

I should have asked you - I need to shorten the rod not lengthen it then? The guide is (I believe for an edc15 based car which all seems turned on its head compared to the BKD lump!) which may be throwing me a little bit.