Swirl flap actuator needed or not??

[ep1centre]

Hi all,

Quick couple of questions, I've searched and read just about everything on the forum and i can't seem to find some definitive advice or make my mind up based on the advice available.

I've got the usual issues everyone complains about with the swirl flaps and so i decided to replace the whole manifold with a new (upgraded / revised) one.

In the how 2 it recommends replacing the swirl flap actuator and linkage, some people say not to bother if it works, other people still say something needs to be done with tech 2 (which i don't have) if the actuator is replaced.

My questions are;

1) if my actuator works, do i have to replace it?
2) if i don't have to but "should" replace it, why?
3) if i do replace it, are there any special things i need to do / take into account just because i'm replacing it?

Thanks in advance.

[Steel]

If you are replacing the inlet manifold with a welded/blanked one just leave it connected and you should be error code free.

If you are replacing it with a new manifold complete with swirl flaps as I did then I would replace it. I fitted my new manifold with the old actuator and kept getting fault codes as apparently they develop a memory on the arc of movement. Fitted a new actuator and no codes since, but it's easier to do the job once.

[ep1centre]

Does that mean the actuator have clever electronics built into it?
Normally the actuator would be either a solenoid (on-off) or a stepper motor (anywhere between fully open to fully closed), there shouldn't be any part of it that would be able to "develop memory" as such...
Sorry if i seem dubious about this but it's not the first time i see the advice to replace it but i see no logical reason to do so and at the cost of around £130, it's not trivial...

And yes, i'm replacing the manifold with a new one with brand new swirl flaps.

[Dog_Book]

Forget the new manifold it will leak again anyway.
Get the old or another manifold welded up then either leave as is or have it mapped preferabley by @Teapot
In either case leave the old actuator in place and plugged in but disconnect the arm that drives the flaps.

This info I found when I did mine years ago in the modifying section or the swirl flap info in the sticky

Or do it the hard way and fit new and get mapped so flaps stay open and do not move, above is better as until you map out and blank the egr your going to have soot build up issues on everything inside anyway.

[Steel]

When I did mine I made the decision to keep it standard and fit a new manifold with swirl flaps. Conscious of the problem of soot build up I also fitted an EGR restrictor plate with a small hole rather than the fully open hole that they have, similar to some Alfa models which have a gasket with a small hole rather than fully open one. I know eventually it will get sooted up again, but my opinion is that they are there for a reason which besides the official explanation of 'swirl' causing better combustion at lower engine speeds also in some schools of thought has a similar effect to lengthening or shortening the inlet tract.

Having raced modified saloons in the past, I know that shorter trumpets (closed flaps/shorter inlet tract) improve torque and longer trumpets (open flaps/longer inlet tract) improve power, this is called pulse tuning.

I can't say one way or another whether it is noticeable or not as I have never driven a Vectra with a welded inlet, but pulse tuning is a fact and I don't think they put the flaps in for the laugh.

I am not in any way rubbishing welded inlets as I know for a fact I would never have a problem again and I have accepted the fact that I am likely to need a new inlet at some point in the future (currently on 212,000 miles) but just a personal choice.

[Dog_Book]

But remember this is a forced induction engine and a diesel so work even more differently

[Steel]

But remember this is a forced induction engine and a diesel so work even more differently

Fair point, but why in that case do the put a trumpet in the air box? Also back in the day some drivers even made up ram air systems similar to the German touring car BMW M3's which gave them forced induction of a sort as well. A big collector box behind the frill funnelled into a fabricated plenum chamber over the trumpets, it worked quite well.

[Dog_Book]

Fair point, but why in that case do the put a trumpet in the air box? Also back in the day some drivers even made up ram air systems similar to the German touring car BMW M3's which gave them forced induction of a sort as well. A big collector box behind the frill funnelled into a fabricated plenum chamber over the trumpets, it worked quite well.

Could be noise, but if you remember the pics when I upgraded to a 80mm maf my air box lost the trumpet yet still made stupid power. But don’t compare NA to forced induction it’s 2 different principles.
A turbofan is forced induction but they still have a trumpet like inlet don’t they?

[ep1centre]

Just like all other threads on this subject... it quickly goes off subject!
I appreciate the advice, but as i said in the OP, after reading just about everything i could find on the subject I decided not to weld up manifolds or map anything out, I accept it will leak again but the car has 180k now and it has only started causing me some trouble in the last 10k or so, given I don't have the time or contacts needed to go about modifying it I'd rather concentrate on just getting it repaired using standard manufacturer's parts and procedures, there's economy in standardisation.

So, the question was; what is the explanation for replacing a working actuator?

Assuming the actuator is just a "dumb" solenoid or stepper motor, as long as it works, and all it's parts and linkages are in good condition I can't fathom the reason behind replacing it, and seemingly neither can anyone else. People seem to either shelve the whole thing and weld their manifolds up based on some general forum advice or replace it anyway due to some other general forum advice... does anyone know how they actually work?

[Dog_Book]

My opinion on the z19dth inlet manifold is clear and has been stated so that’s all I’m going to say.