Pierburg Valve

**corriedw** · 15-09-12, 21:55

Sorry if I repeat something discussed before.

I think you miss some of the advantages of the Pierburg valve. Lancia was just the first car to use the concept, now all new turbo cars does. As a turbo's waste gate has the turbo pressure working against a spring there are always an amount of leakage through the waste gate, even from very low rpm. Now the waste gate is kept closed by the spring pressure, the boost from the manifold will work against the spring and open the waste gate at the adjusted boost. The Pierburg is a 3 way solenoid one of the first 2 legs can be open to the 3rd. Pressure tapped from the turbo outlet goes through the open channel of the Pierburg and help the spring of the wastegate to keep it closed. Now there are no leakage and have a little boost pressure, way lower than before. When the planned boost is reached the ECU switch the Pierburg's solenoid, the channels change and now the boost from the manifold work against the spring to open the waste gate, keeping the boost pressure at the planned level. This gives a much more linear power supply without the huge shove in the back at 3500 rpm and it is much more usable on a track. The waste gate actuator used with the Pierburg, then will have a tube on either side of the actuator's diaphragm. I am not the electronic expert but the ECU do not just open and close the Pierburg but rather pulse it to open or close the channels a little. This stops the solenoid from chattering, due to open an closing on the boost limit.

An external waste gate have a larger diaphragm and the spring is then stronger to counter the larger force the pressure now supply. The larger spring allow less leakage and the control of a boost controller will be more accurate.

The only possible advantage to go without the Pierburg is to have less power below 3000 rpm, saving fuel in town.

The bleed valve is the crudest form of boost control and are only work satisfactory in some cases where the waste gate is set to a lower everyday setting and by opening the bleed valve the pressure will go to a higher boost pressure before the waste gate are opened.

**wrinx** · 15-09-12, 22:20

Thanks, very interesting.

Trouble is, I think a lot of the Peirburg valves are faulty and it's cheaper to remove and install a MBC....plus finding them in the UK was/is hard.

I know one ex-owner had to buy one from the States but the car was reported not to run well with it and a subsequent owner took it off.

wrinx

**AlfaJack** · 16-09-12, 08:16

Interesting. Thanks, and welcome to the forum. I remember contacing you a couple of years ago on AO.
I like the MBC as it is the simple way to get a higher initial boost pressure. Crude but easy.

**Steve Webb** · 16-09-12, 08:22

Originally Posted by AlfaJack

Crude but easy.

Just how I like my women.

I'll get my coat, I've nothing more to add here.

**wrinx** · 16-09-12, 20:05

Well...that was a thread stopper

wrinx

**Steve Webb** · 16-09-12, 20:31

Sometimes I worry that the forum is just too highbrow. Or maybe its just that I'm too childish!

**corriedw** · 16-09-12, 21:33

Originally Posted by wrinx

Trouble is, I think a lot of the Peirburg valves are faulty and it's cheaper to remove and install a MBC....plus finding them in the UK was/is hard.

The Pierburg is not the only solenoid that can perform this function. You could use the equivalent part used by VW/Audi or by Focus ST. According to the tuner I use, the VW part is popular and freely available.

**wrinx** · 16-09-12, 22:31

Interesting...do you have a link?

wrinx

**corriedw** · 17-09-12, 05:47

Unfortunately not at this stage

**AlfaJack** · 17-09-12, 09:54

Found this:
http://www.jbubu.com/index.php?id=36700

**SteveNZ** · 17-09-12, 23:43

My Pierburg seems to work fine but I have a MAC valve to use inplace as suggested by Xavier. This is a common solenoid used with many electronic boost controllers, mine is from a Gizzmo IBC. Once installed I have the option to control it like a Pierburg valve or off the Gizzmo IBC too.

http://www.lanciahf.eu/

**Alfa Patch** · 18-09-12, 13:32

There are two Q4 Pierburgs on German Ebay. I was tempted to get one but there seem to be mixed opinions on how effective they are. Having never had one on my car i can't comment but if they work well i can't see why you'd waste cash on EBCs.

**wrinx** · 18-09-12, 16:00

The difference is controllability; with an EBC you can change the boost characteristics whereas you're stuck with the factory settings with a PV...unless you go for a remap of course. but even then, the settings are static.

The argument about whether the controllability is good for the engine is another matter...

wrinx

**hf hpe** · 18-09-12, 20:19

http://www.ebay.com/itm/MERCEDES-W12...9a5341&vxp=mtr

http://www.ebay.com/itm/Mercedes-Ben...898c5d&vxp=mtr

**Steve Webb** · 18-09-12, 20:26

Can't see the number of the one in the first link, but the one in the second link is a different part number to the one fitted to the Q4.

Worth a try though for that price.

**AlfaJack** · 07-10-12, 00:03

I moved the inlet pipe for the boost controller today and put in a t-piece at the small bore plastic pipe which runs up the side of the battery and round the back to the inlet manifold.

As a result I seems to have a lot more stable boost pressure - I put my foot down from 50 to 90 and 1 bar all the way. I will need to do more testing on the airfield but so far I am impressed at the lack of drop off.

I won't go too nuts until I have an EGR gauge installed as I remember a problem a while ago of the engine feeling like it was hesitating when at prolonged full pelt.

Got many other issues to address though - this cars just loves to weep oil from everywhere!

**wrinx** · 07-10-12, 12:10

Where was it spliced in before?

Mine is the same area as yours now, but I'm not sure which run it cuts into.

wrinx

**Alfa Patch** · 07-10-12, 12:17

I fitted an old HKS electronic controller bought from ebay to my car on thursday, haven't had chance to configure it properly yet but it holds boost much better in it's 'manual mode' than the MBC i had did. It remains to be seen how ggod it is once it has 'learnt' the turbos characteristics but it seems like it was money well spent.

Originally Posted by AlfaJack

I moved the inlet pipe for the boost controller today and put in a t-piece at the small bore plastic pipe which runs up the side of the battery and round the back to the inlet manifold.

Thats the feed for the BOV isn't it? Will that create a problem for the turbo 'overspinning' when you close the throttle as the MBC will be seeing a vacuum? It probably won't as i assume there will be minimal exhast gas going to the compressor (so it won't spin that fast) but if i'm right the wastegate will remain firmly shut. Reading this back again god knows!! Sundays aren't my most switched on of days

**AlfaJack** · 07-10-12, 22:24

Originally Posted by Alfa Patch

Thats the feed for the BOV isn't it? Will that create a problem for the turbo 'overspinning' when you close the throttle as the MBC will be seeing a vacuum? It probably won't as i assume there will be minimal exhast gas going to the compressor (so it won't spin that fast) but if i'm right the wastegate will remain firmly shut. Reading this back again god knows!! Sundays aren't my most switched on of days

Nope, i'm not sure either. Seems OK though. That pipe is connected to the inlet directly so it simply sees the boost pressure from the last point possible - i.e way after the IC.

Wrinx, before the feed in to the MBC was straight off the connection on the turbo housing. That has now been blocked off.

**Alfa Patch** · 07-10-12, 23:18

Sounds like a very neat fix if it works though. The ebc I bought has 4 ports.

1. To wastegate actuator
2. To turbo boost feed as original
3. To inlet manifold
4. To nothing. I think this is where the solenoid vents the pressure.

It seems to work by reading the boost at the inlet through .3 and then trying to match it by adjusting the flow of boost from .2 to .1 using an electronic solenoid.

You have to wonder why the pressure feed isn't usually taken from inlet since that's the pressure we are trying to maintain and are reading from. It might be something to do with closed throttle behavior but i can't think what.

**corriedw** · 10-10-12, 15:20

Originally Posted by SteveNZ

Fit a larger turbo suitable for boost and flow at higher rpm and a basic internal wastegate will probably do the job fine.

Internal wastegates are pretty crude. They don’t flow well.

My opinion is the pressure drop at high revs is a function of boost leaks or the turbo is to small and can not deliver more air than the engine takes away. Fiat designed their turbo/engine combinations too get drop off at high rpm t protect the engine. Lancia's T3 should stay closer to the ideal but may not be perfect.

Steven is quite correct about the air flow through an internal wastegate turbo. A T3 with an external wastegate can deliver 25/30% more air than a T3 with an internal wastegate. The reason is with an external waste gate the exhaust gas run through a pipe with no obstructions through the down pipe into the exhaust. With an internal wastegate the gasses that are bled off mix with the gas flowing from the turbine in a non structured space. The turbulance cause much less gas to get out of the turbo and the pressure is higher at the outlet side than in the case of an external waste gate turbo. Then turbine wheel can not speed up more because it is turned by flow of gas and gas only flow from a higher pressure to a lower pressure.

For the same reason the down pipe is important, it must get the gas out of the turbo pronto. On high performance engines this is even more important, because hot gas that can not get out of the turbo, keep more hot gas in the engine. The combustion chamber temperature rise and the potential for detonation increase many times. A good down pipe and exhaust is very important.

On standard engines a turbo with an internal wastegate functions perfectly, the amount of gas coming out of the turbo is not more than the outlet of the turbo can allow.

The hole in the Pierburg do not leak boost it, only leak a little air in the system that open the wastegate against a spring. If it do not, then like an earlier poster said, there can be not wastegate adjustments.