Quote:
Originally Posted by Pupbelly
Thank you JohnM 855 T5R Interesting to get some idea on boost figures there, that points to a certain boost loss as I thought. I've ordered some silicone pipework to do the vacuum hoses. How available are the turbo control values and turbo recirculating valves? Is there a way they can be checked before I purchase new / replacements?
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Opinion is divided as to whether silicone is the best way to go. The silicone pipes have a tendency to eventually slip off unless they are very well secured. I've put silicone hoses on mine and I purchased new stainless jubilee clips to secure them. I've had no problems.
The TRV has a diaphragm inside which can split or pinhole. A diaphragm and spring kit is freely available on eBay. Get one made by Kinegawa (they are the original manufacturers) and costs about £30 or so. Easy to fit (one of the bolts is a little fiddly). Just take out the bolts on top of the TRV, pop the new spring and diaphragm in (make sure to use the standard spring which I believe is green). You can get the whole Kinegawa unit for not much more. I replaced mine with a Forge piston type TRV at £150. Supposedly more reliable in the long run but as you see, expensive! You can get this from Forge Motorsports direct or via Parts For Volvos.
The original TCV can be ordered through your Volvo dealer via GCP and costs about £130 - ouch! Alternatively, I believe you can fit the Pierburg unit for the early V70 and is available online for about £40 ish. They are not, I believe, specific to each turbo model - the same part works on all 850/early V70 turbos.
You can strip the TRV and inspect the diaphragm but once you gone to that bother you might as well stick a new one in.
I don't know of any test you can perform on the TCV. I replaced mine because it was cracked and resulted in wild overboosting.
Regards
John