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| quote: | Originally posted by VERTiG0
No, no no no. The turbocharger itself provides backpressure that the engine needs, that an exhaust would provide for a normally aspirated car. If you could, you'd be best off running no exhaust straight out of the turbo which would allow for the freest flowing turbine wheel. More backpressure from the exhaust makes your turbo very efficient. You should read some of Garrett's technical writeups 
As for the BOV, that wouldn't help at all becuase the BOV is before the throttle. If it were, say, in the cylinders or something sure that'd help, but since it isn't, that doesn't work at all. Not all cars have BOVs anyway, or can even make real use of them. Twin turbo 300ZXs are usually much more efficient with recirc valves than BOVs because of the silly "do-everything-twice" design of the VG30DETT. However, some of the newer BOVs out there can open faster than recirc valves and therefore keep the turbo spoooled up marginally longer. It's not much, but any performance gain is good.*
*all from my hardcore 300ZX TT buddy |
I stand corrected, my apologies. I guess my understanding was based on the fact that you're going to have to rely on the NA portion of the engine's power band until you can get your turbo to spool up to proper speed, which would require some backpressure to have decent response. But you are absolutely right that at the higher rpms, high amounts of back pressure would be completely detrimental to the turbo's performance and safety.
With the BOV, even though it's stationed before the exhaust, pressure, if excess pressure is in the housing, wouldn't the blow off valve still engage, regardless of which way the pressure is coming from? The valve is still linked to the pressure in the housing isn't it? Or is it am I missing something here?
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