My new 406 project....

[Doggy]

Kelv, the big pipe that goes from the vac pump to the servo has quick release coupling at both ends, (something like the fuel pipes at the fuel filter).

Each end has a tee-piece with a smaller vac pipe branching off, (two at the servo end).

If you remove the pipe and look carefully inside the tee, you'll find it's almost solid aluminium at the bottom with a 0.5 mm hole leading to the small vac pipe - these are the 3 'restrictors', designed to stop you losing servo vacuum in the event of a downstream leak.

[GingerMagic]

Thanks Eric, on my old car there is a tube fed directly off the pump ( no restrictor, I think ) to the servo and the original connector from the pump is used on the servo, single T ( with restrictor )

[GingerMagic]

Finally redone my vacuum system. My swirl flap opens and closes like it should when I suck on the pipe, so I hope it is okak...

Here is a basic diagram of what I have done.



As yet untested but I will find out in a day or so, when I refit the gubbins I removed to get to the pipework. It is the same layout as my other 406 so in theory it'll be fine....

[gumby6371]

Other than missing the reservoir out and going straight to the swirl EV that's how I did mine.
When you do the EGR blank I suggest you also change the turbo vac pipe as there should be plenty of access.
I say this as I neglected to do it on mine and its a lot more difficult to get at with everything in place

Mine had a very thorough MoT on Monday, it failed on a few minor things but the jobs worth inspector said nothing about my 'modifications' in the engine bay and it sailed through the emissions test

[Doggy]

Looks pretty much the same as mine, think I have one pipe from pump via restrictor straight to the turbo, with the swirl flaps via the reservoir, but it amounts to the same thing as far as I can see.

[GingerMagic]

What are the benefits of bypassing the reservoir? I can still do it that way but I assume the reservoir is a fail-safe thing...?
As for my egr, I have left it all in place but attached a small piece of pipe, with a screw in the end, onto to little spout on the top.

[Doggy]

Others have done away with the reservoir in the interests of less to go wrong, (which makes sense).

My logic was to try to separate the turbo actuator from the swirl flaps as I suspect the latter could temporarily deplete the vacuum available to give rapid turbo response / prevent transient overboost. I recognise this theory is unproven. My major bugbear was turbolag below 1500 RPM. It's much better now, but I realise this doesn't prove my version is better than anyone else's.

I think the 'fail safe' feature is the flow restrictors, which should ensure the brake servo gets first dibs at the available vacuum.

Is your servo behaving now, Kelv?

[nutski]

Others have done away with the reservoir in the interests of less to go wrong, (which makes sense).

My logic was to try to separate the turbo actuator from the swirl flaps as I suspect the latter could temporarily deplete the vacuum available to give rapid turbo response / prevent transient overboost. I recognise this theory is unproven. My major bugbear was turbolag below 1500 RPM. It's much better now, but I realise this doesn't prove my version is better than anyone else's.

I don't suppose you have a graphical representation of that do you Doggy?

[Doggy]

You don't suppose correctly, (but I'll see what I can come up with)....

[jonsowman]

There have definitely been a few leaky reservoirs! It only protects thing downstream of it -- i.e. it's not designed to give you braking assistance if your vac pump fails for example (restrictor in the way). But it will continue operating the swirl EV if your servo suddenly demands all the vacuum.

If you've got 2 EVs operational (swirl and turbo, i.e. car is de-FAP and de-EGR), you can definitely remove the reservoir. If you're on 3 EVs (de-FAP but not de-EGR) then I'm not sure. If you've got all 5 EVs then you definitely can't remove the reservoir.

[GingerMagic]

Well, I managed to get the car back together earlier - started up no problem.

By process of elimination I think the servo fault is still there..

I blanked the swirl flap EV, then just the turbo EV, then the reservoir, then everything apart from the servo.... Even with everything blanked off the servo is solid at first, then your foot slowly goes down on the brake pedal then there is a whoosh noise ( a bit like air brakes ) when you release the pedal.

As for the swirl diaphragm, the little lever on top is pretty much upright, and moves forwards very little when revved, but you can push the lever back so its nearly horizontal but it springs back up on its own - not sure if this is normal, I'll compare it to my other 406 in daylight. Maybe the possible servo fault is losing the vacuum to move the EVs - maybe I'll blank off the servo and feed the swirl directly and see if it moves better.

Regardless, I will replace the vacuum pipes with new stuff from somewhere and also bypass the reservoir. Its a bit of a shame as I was hoping to get the car off the ramps tomorrow so I can take it to get the DPF removed.

Pants....

[GingerMagic]

Well, time for an update.

I have bought a brand spanking new Servo from Peugeot, luckily using mates rates, which came in at less than £100 including the dreaded so thats not too bad.

I used the spare swirl flap that was in the glovebox of my old car when I bought it, which is a fairly straightforward job when the EGR piping was temporarily removed. Turns out the old swirl flap worked fine but its one less thing to sort out at a later date.The blanking plates kindly supplied by Doggy were fitted on Friday ( the EGR end was a pain in the arse to do ) and I also bypassed the vacuum reservoir as I reassembled everything, with random bits of pipework that were left over. I didn't fit the silly metal clips that join up the EGR pipework, didn't think it was important and I will only need to take it off again in the future.

The servo was much better when the reservoir was removed from the system but still not quite right. The car started bob-on and drove better than when I first bought it but still holding back a bit - probably binding brakes/handbrake where it hasn't moved for a few weeks, and possibly the Turbo EV which is a simple swap with one of the redundant EVs.

Car is now at the garage waiting for the servo to be fitted on Monday morning - and my friendly Peugeot mechanic is going to put the car on his ramps and remove the FAP for me to take it away and smash it in, because I didn't have enough leverage to undo the bolts when I was laying on my back with my nose just missing the exhaust....

When I get the car back I will test my Galletto and flash it with either the 180 or the 200 map to see how the car really performs. If all goes well I will start using the car on a daily basis to iron out other niggling bits before deciding what to do next...

[GingerMagic]

Here is my new vacuum layout.



The Turbo EV and the Swirl EV are plumbed straight from the pump which I hope makes the whole system more user friendly.

Seemed to work okay on the short drive to the garage..

[Doggy]

Good progress there, young man.

If you're struggling to undo the CAT/FAP bolts they're unlikely to be usable afterwards. (Count yourself lucky if none snap off and refuse to knock out of the holes).
Arm yourself with a spare set - originals are M8 x 35, but M8 x 40 work fine.

Another option, I took the entire CAT/FAP assembly off and refitted it just on axle stands by undoing the clamps onto the turbo and middle pipe.

Best of luck with the rest, keep up the good work!

[jonsowman]

Good stuff Kelv, that vac layout looks good