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HY35 Boost Management Issue


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Hey Hybrid Z-er's,

 

I have a small issue with the boost control on my HY35.

 

I currently run a stock L28ET with an HY35. The manifold has an adapter piece welded to the turbo flange with a Tial 32 mm MVS wastegate hanging off it. The turbo is an open 4" down pipe at the moment.

 

Currently, I have a 7 lb spring in the waste gate, but I can't seem to keep the boost below 15 psi. I do have a 5 lb spring I will install later this week to see if this clears up the issue, but I'd like to get your guys' opinion beforehand.

 

For some reason, I had the idea that a 7 lb spring in the wastegate is equivalent to 7 lbs of boost on the compressor side, but that can't be right. 7 lbs of pressure doesn't correlate with 7 lbs of boost, correct? I had this idea in my head for the longest time, but after trial and error that clearly isn't the case.

 

What spring do you guys run in your wastegate for an HY?

 

I am tapping a boost reference from the compressor housing using a good sized brass fitting (1/4" I believe) straight to the wastegate. I have yet to plumb my boost controller due to the fact that I need to be able to achieve a base boost pressure on spring. I will then worry about controlling boost thereafter.

 

Thanks guys!

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If I were to remove my boost signal, the gate would not open at all. I don't see the advantage of running a line from the intake manifold rather than the compressor housing, it would facilitate the same function. See diagram below.

 

Just for the record, the top port is un-capped to vent.

 

externalwastegateopen.jpg

Edited by jacob80
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Try taking the spring out or locking it open some other way and seeing how much boost it makes. If it makes any significant amount, I'd say you need to reposition the gate for better priority.

 

A good friend of mine has a scion with some sort of precision turbo, his gate is at a 90* angle feeding from half of a merge collector, he has a 7lb spring in it and it makes 11-12psi.

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Try taking the spring out or locking it open some other way and seeing how much boost it makes. If it makes any significant amount, I'd say you need to reposition the gate for better priority.

 

A good friend of mine has a scion with some sort of precision turbo, his gate is at a 90* angle feeding from half of a merge collector, he has a 7lb spring in it and it makes 11-12psi.

 

Unfortunately, if it is an issue of the position of the wastegate, I'm limited as to what I can do. I welder the adapter onto the manifold, so the wastegate won't be moved anywhere. However, I could attempt to port the hole to improve the flow of exhaust to the wastegate if this is, indeed, the issue.

 

I'll see what happens when I leave the spring out. If it makes a significant amount of boost (something over 15 psi), I may be in trouble!

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Don't know about ur springs but u should'nt have to worry too much about the 15lbs.... I ran mine at 25lbs when showing out and 15 or so all the time... All on it's internal wg ported and a AEM electronic boost controller... Mine was a NA motor before finding a turbo motor...

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Turns out I didn't have all ports closed on the bottom half of the diaphragm, which meant all the boost that was trying to push the valve up was simply dumping out the open port. I closed up the port and now the boost is under control completely.

 

Thank for your help guys!

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