wastegate and bov hookup
06-24-2012, 09:55 PM
#11
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Wastegate bottom port goes on the boost side before the TB and the top port is for the boost controller. The bov can use either before the TB or after the TB.
06-24-2012, 09:57 PM
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My mp76 has a flat spot you could drill and tap for a fitting. Take another look at your 70 I bet its got one to. I believe the gate responds faster hooked to the housing. Someone correct me if im wrong.
06-24-2012, 11:05 PM
#14
No. Wastegate should reference manifold pressure (after the tb) and BOV must certainly reference the manifold after the TB. The line to the BOV is there to help open the valve when you let off the pedal when under boost. In this case the engine is pulling a lot of vacuum and there is positive pressure in the cold pipes, both of which force against the BOV spring opening the valve. If you were to hook it up before the TB, the same pressure the BOV is meant to relieve will be holding it shut effectively making it useless.
06-25-2012, 08:55 AM
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You can drill and tap near the outlet of the housing. Ideally it shouldnt make a difference if you reference the compressor housing, or the intake. However, if you have an undersized or crappy intercooler and there is a large pressure drop across it you may have problems. What you really care about is the pressure in the intake, ie what the engine sees, as opposed to the compressor housing which is just what the turbo sees. Ideally they will be the same but there is always some degree of pressure drop across an intercooler, so I would reference the intake.
No. Wastegate should reference manifold pressure (after the tb) and BOV must certainly reference the manifold after the TB. The line to the BOV is there to help open the valve when you let off the pedal when under boost. In this case the engine is pulling a lot of vacuum and there is positive pressure in the cold pipes, both of which force against the BOV spring opening the valve. If you were to hook it up before the TB, the same pressure the BOV is meant to relieve will be holding it shut effectively making it useless.
No. Wastegate should reference manifold pressure (after the tb) and BOV must certainly reference the manifold after the TB. The line to the BOV is there to help open the valve when you let off the pedal when under boost. In this case the engine is pulling a lot of vacuum and there is positive pressure in the cold pipes, both of which force against the BOV spring opening the valve. If you were to hook it up before the TB, the same pressure the BOV is meant to relieve will be holding it shut effectively making it useless.
06-25-2012, 09:21 AM
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I'm sry I was quite drunk when I wrote that last night haha. You are correct. I have my bov after TB and I know wastegate "should" go after TB as well but mine is coming straight off the turbo.
You can drill and tap near the outlet of the housing. Ideally it shouldnt make a difference if you reference the compressor housing, or the intake. However, if you have an undersized or crappy intercooler and there is a large pressure drop across it you may have problems. What you really care about is the pressure in the intake, ie what the engine sees, as opposed to the compressor housing which is just what the turbo sees. Ideally they will be the same but there is always some degree of pressure drop across an intercooler, so I would reference the intake.
No. Wastegate should reference manifold pressure (after the tb) and BOV must certainly reference the manifold after the TB. The line to the BOV is there to help open the valve when you let off the pedal when under boost. In this case the engine is pulling a lot of vacuum and there is positive pressure in the cold pipes, both of which force against the BOV spring opening the valve. If you were to hook it up before the TB, the same pressure the BOV is meant to relieve will be holding it shut effectively making it useless.
No. Wastegate should reference manifold pressure (after the tb) and BOV must certainly reference the manifold after the TB. The line to the BOV is there to help open the valve when you let off the pedal when under boost. In this case the engine is pulling a lot of vacuum and there is positive pressure in the cold pipes, both of which force against the BOV spring opening the valve. If you were to hook it up before the TB, the same pressure the BOV is meant to relieve will be holding it shut effectively making it useless.
06-25-2012, 09:35 AM
#17
Most wg manufactures won't recommend putting the signal to the manifold, they aren't meant to see vacuum (also a slower response, as atomic said).
On diaphragm style wastegates, the diaphragm may deform under vacuum (causing creases or pinched diaphragms).
On all wastegates, non have a valve stem seal, causing a vacuum leak (and possibly a little exhaust diluting the intake charge if your backpressure is too high).
On diaphragm style wastegates, the diaphragm may deform under vacuum (causing creases or pinched diaphragms).
On all wastegates, non have a valve stem seal, causing a vacuum leak (and possibly a little exhaust diluting the intake charge if your backpressure is too high).
06-25-2012, 09:59 AM
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You can reference the wastegate between the compressor and intercooler, between the intercooler and tb or in the manifold with different results, none are wrong, just 3 different results and different reasons for each. BOV must use manifold pressure as said above.
06-25-2012, 11:32 AM
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I would reference it to the manifold. That way the gate will open via the actual pressure seen in the intake, rather than at the compressor housing. Pressure at the intake is what matters.
