ZZZero Posted March 31, 2006 Share Posted March 31, 2006 Theeretically what would happen if one were to run without a wastgate?(plugging appropriate holes,and welding a plate over the flaper door),using only a pop-off valve to control boost pressure? Wouldnt engine response increase? Quote Link to comment Share on other sites More sharing options...
AK-Z Posted March 31, 2006 Share Posted March 31, 2006 boost surge-->decrease in bearing life on turbo. Possablely the compressor wheel shattering (ceramic). Edit: This is increased boost than stock. Quote Link to comment Share on other sites More sharing options...
mtcookson Posted March 31, 2006 Share Posted March 31, 2006 it would also likely run extremely rich as you would be releasing metered air. you would have to move the maf after the pov... but would still be pointless due to the reasons listed above. the turbo would likely spool much quicker, but you would see boost spikes and its likely that the pop off valve may not flow enough to limit boost where you want it. it'd be best to just stick with the tried and true method of using a wastegate. Quote Link to comment Share on other sites More sharing options...
ZZZero Posted March 31, 2006 Author Share Posted March 31, 2006 without going over stock boost do you still think there would be a problem? (assuming maf is moved after the popoff?) Quote Link to comment Share on other sites More sharing options...
BLOZ UP Posted March 31, 2006 Share Posted March 31, 2006 I believe back in the first days of turbos, people just used their right foot to control boost, since they didn't have wastegates. But I imagine it wouldn't take long at all for the turbo to destroy itself nowadays. Quote Link to comment Share on other sites More sharing options...
ZR8ED Posted April 4, 2006 Share Posted April 4, 2006 GM Corvair turbo cars had no wastegate. boost was controlled by rpm and throttle position... the faster you drove the more boost you made..the more boost you made..the faster you would go!..till it would go "pop!" Quote Link to comment Share on other sites More sharing options...
Guest Jason84NA-T Posted April 4, 2006 Share Posted April 4, 2006 They also controlled boost on some cars/kits by sizing the turbine and turbine housing so the car never made over X PSI, even at redline. That would be a very stupid idea. Overspinning a turbo will not always make it fail right away, but most commonly when big diesel trucks have a boost leak and over spin the turbine, the compressor wheel will come apart sending shards of aluminum into the intercooler and releasing the turbine wheel and shaft to head out the exhaust... not something you want to experience. Quote Link to comment Share on other sites More sharing options...
TimZ Posted April 4, 2006 Share Posted April 4, 2006 Two things - first, if you are controlling boost with a popoff valve then the engine response will not be any faster - the popoff valve will have the same 'early cracking' issues as a wastegate would. Second, by controlling boost this way (or by turbo sizing as Jason mentioned), you are forcing the compressor to run off the edge of its map, so you will be running the turbo in the most inefficient manner possible (i.e., the intake charge will get really hot, and detonation will be a much bigger problem than it normally would for a given boost pressure) Quote Link to comment Share on other sites More sharing options...
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