I use this one in 850 also with m4.4

I have tried the standard round one, a Mac 3 port I made up, and this pierburg one.

The pierburg seems the better choice for me anyway, and works well with the M4.4

I temporarily replaced my 850R’s original round unit with one of those pierbergs in an attempt to isolate an erratic boost issue. A mate fab’d an aluminum bracket to mount it on the side of the air box using existing bolts.

I ended up reinstalling the original round unit. @VPT02 reckons the pierberg and m4.3 mightnt always play nicely at the upper end.

Might grab the pierburg box then, also does the CBV spring get weaker with time? Having some pretty bad boost fade problems even with an MBC. Wondering whether or not I should get the IPD kit with the springs or just try to find a diaphragm by itself.

The Forge units look swish but I opted for one of these Kinugawa kits

https://www.ebay.com.au/itm/263690802234

Hmmm, is that spring (assuming it's stock pressure) enough for 14-15ish psi, or doesn't it really matter?

Its probably unsuitable for pressure levels much above stock

More here

https://ozvolvo.org/discussion/11729/blow-off-valves-and-compressor-bypass-valves-for-the-850-turbo

Yeah I might go with IPD and run the blue spring, seems like the best option.

I use the kinugawa cbv kits, I currently have a blue spring in it, but have a red spring ready to go in when I can find the time. They are cheap and ship very quick.

If your diaphragm is original there is a very good chance it has pin holes in it too.

    I ran the oem round tcm then the ipd hd one

    but was noticing spikes , so went with the Pierburg

    Now waiting for this instead

    I did find the Pierburg better than the IPD HD item , stopped the spiking

    Running Forge actuator and Forge recirculation valve as well and all running very good

      hamsandwich

      I use the kinugawa cbv kits, I currently have a blue spring in it, but have a red spring ready to go in when I can find the time. They are cheap and ship very quick.

      If your diaphragm is original there is a very good chance it has pin holes in it too.

      Yeah original 365,000kms, probably nothing left of it although the wastegate actuator still holds vacuum surprisingly, will most likely need to be calibrated however.

        rado

        I ran the oem round tcm then the ipd hd one

        https://cdn.ozvolvo.org/uploads/656/BKWNCFJ497RI.png

        but was noticing spikes , so went with the Pierburg

        https://cdn.ozvolvo.org/uploads/380/1VQNNS4HIAWC.png

        Now waiting for this instead

        https://cdn.ozvolvo.org/uploads/908/DD887V6IIKMS.png

        I did find the Pierburg better than the IPD HD item , stopped the spiking

        I currently have a MBC installed but it builds boost too quickly. Looking at the logs the ecu is pulling quite a bit of timing, even with richer fuel maps and retarded timing. Boost goes way up to 15 psi in 1st somehow and then falls to 10psi in second which then dwindles down to 5 by around 4800 rpm or so.

          Went ahead and bought the kinugawa repair kit, green spring (5-15psi) and a mac solenoid for $120 shipped. Probably should have gone with the pierburg solenoid but $47 for the mac was just too good. Pretty sure that's what IPD uses for their "HD" TCVs anyways. I'll use the MBC in parallel to manage any spikes.

          If you got the Mac without the plug like I did it's just one of these.

          If you can log with tunerpro then you can tune boost spikes out and ditch the MBC altogether, after you get rid of the timing pull, if you can be bothered it is quite time consuming, but good fun and great learning curve

          Yeah I was wondering what connector it used, that'll save me from messing with the wires. Not sure if my neighborhood would approve of any more tuning, I'll just take to where all the old farts have their 5 investment properties. Car doesn't have a cat and it's quite loud under load, never realised that the cat did so much muffling, thought that was the mufflers job.

          7 days later

          Does the polarity matter for the MAC solenoid? Can't seem to find anything that distinguishes the wires so I'd assume not but want to make sure so I don't fry anything.

          Nvm, haltech claims that their BCS isn't sensitive to polarity, looks identical to the MAC. Didn't even bother to slap a sticker on it like IPD.

          Car's doing the same thing, jumps to 15psi then gets stuck at 10 psi with lots of noise but no power almost as if someone is applying the brakes mid-pull. Tried different fuel, ignition and tcv pilot maps, looked at the logs nothing out of the ordinary except air mass is significantly lower, before it was 710, now it doesn't seem to want to go over 400 even during 16 psi spikes. TCV is getting a signal. Does the same thing thing with no line to the waste gate (i.e closed), even at higher pressures. Might switch back to the MBC had better luck with that but it only seems to cover up the underlying issue. Starting to give up hope on getting any proper boost control working on this car. Not sure if it's a failing fuel pump, bad MAF, bad waste gate, seriously don't know anymore.

          Edit: Car starts and idles fine too with normal fuel trims. Upper intercooler hose is pretty squishy too, but shouldn't affect anything when under boost pressures.

          What bin are you running?

          The later available m4.4 revisions out there will flash the MIL light when it pulls timing past a certain threshold, are you sure it's not pulling a bunch of timing?

          If you have another maf to try would be good, but you could also look at the logged maf voltage and maf readings to see if it's playing up a bit.

          The original rubber boost hoses can be problems, can hide cracks or holes until boost is built, but a major boost leak would also show up with erratic fuel trims in the logs.

          Torn cbv diaphragm can leak boost.

          Too much plug gap can cause problems.

          I have also had problems with bin files, which were fixed by loading up a fresh, unedited bin and starting tuning again.

          I took me ages and tons of logging to get smooth boost and load with tunerpro, and hours of looking thru logs.

          I don't know man, I just chucking ideas out there based on the time I spent tuning m4.4, but if you want to send me a logged drive where it plays up and I'll have a look thru it if it helps? Won't be home till tomorrow night anyways.

          The fact that it won't build boost with wastegate disconnected makes me think cbv or piping is leaking? A 15g should build 18psi then taper off as it runs out of puff pretty easily

          What pipe are you using from the air filter to turbo? As you are in the long shot range atm I have seen in the past these pipes compressed/collapse under load but look totally normal when you are looking at them at idle, worth a go ?

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