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TD04HL-16T CBV and wastegate

Fretka

New member
Joined
Dec 22, 2013
Hey guys!

So lately I've been messing around my 16t powered B200FT. I noticed there is something wrong when tried upping the boost above 1bar not long ago. Completely closed my MBC and realised, that it does not boost more than 1bar (~14psi) which was suspicious, since I've heard that this turbo can hold up at least a little more. While we are here, question 1 - how much boost can 16t actually hold?

Anyways, then I thought that my old wastegate actuator has gotten weak through years and tried adding external spring and for a little while there was a significant improvement, boosted about 1.4bar for a while and afterwards it fell down again to about 1.1bar (heat releasing external spring?). After track driving at the same day, turbo boosts only about 0.7-0.8bar and that's it.

Another thing is that boost builds up slowly and through out whole rev range (max boost basically at the redline).

One guy on fb suggested it could be blown CBV diaphragm, which sounds possible. Should I swap both - original wastegate and CBV with some aftermarket parts? Any suggestions?

And when I am repairing/swapping CBV or/and wastegate to different, what to look for? Looking for about 1.4-1.5bar (20-22psi) right now.

Thanks in advance.
 
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If your CBV doesn't have a hole in it or isn't torn put a washer or quarter behind the spring to get more holding power before it lets the boost out of the bag. Put the shim on the outer side of the rubber. Take spring out put washer then spring then rubber CBV.
 
Thanks for answers guys.
MadDog_945 - it's a straight flange. What's wrong with that?

sbabbs - thanks for suggestion, will keep this in mind.

Actually there is an update after yesterdays checking. Took wastegate actuator and CBV apart.
CBV diaphragm looks great, no problems with that and spring does the job. Did not measure how strong it is, but I think it works good.

Good news is that the problem looks solved thanks to working out wastegate actuators problem.
Since I rotated my cold side about 2 years ago and did a poor bracket for actuator from not thick enough material, actuator was flexing. I noticed that after looking how bent it was. Fabricated bracket from much thicker steel, put everything back together with a good preload on actuator and now it works like a charm. Boosted way over 1.5bar without MBC on, so I installed that back on, lowered it to about 1.4bar and now boost builds up quick and holds like that until the end. Very happy with result.

One more question since we are on this - what harm can be done if preload on actuator is too big? I have heard that the preload should be approximately half of legs diameter (about 3mm) but right now it is definitely bigger.

Everything works well but maybe it is doing some harm for turbocharger with such preload.

Thanks again.
 
You can set it to say 10 pounds of boost should be okay before you then use your MBC to set it where you really want. The whole point is to get that boost up fast as you can.
 
Nothing wrong, just wanted to know.. sometimes the internal wastegates are outflown by the pressure in a conical with a very good flowing exhaust.. but that would be 180? to your Problem ;) So.. you are from latvia? :)
 
Thanks guys. I just read somewhere that adjusting preload is not recommended. If it is not doing any harm, then I am more than happy with the results. As mentioned before - boost pumps up pretty quick to about 1.4bar and stays there until redline thanks to MBC.
Solenoid boost control would be the next step, but for now it looks good.

Yes, I am from Latvia! :)
 
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