Barry Posted March 3, 2003 Share Posted March 3, 2003 Ok, just taken this from the resources section.... When the manifold reaches 11psi of boost, the ECU sends a signal to the wastegate VSV, this allows manifold pressure to build in the wastegate actuator which opens the wastegate. ------------------------------------------- Now, why doesn't this happen when you remove the cats ? Am I right in thinking that all I need to do to get the wastegate to open is to restrict the pipe to this VSV to allow pressure to build, allowing the wastegate to open.? Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 3, 2003 Share Posted March 3, 2003 It does. But the flow of exhaust gas through the turbo is easier now than it used to be due to the decat. The wastegate isn't big enough, being a nasty old integrated one, to flow a comparative increase in exhaust gas through it, so the turbo gets it and boost creeps up. All that restricting the VSV pipe would do is allow the wastegate to ease open as boost builds, rather than pop open at a set pressure, which is a technological step backwards. You'll get boost buildup tail off as the wastegate opens, causing more 'lag' - but it will still creep. -Ian Quote Link to comment Share on other sites More sharing options...
Guest Terry S Posted March 3, 2003 Share Posted March 3, 2003 That about covers it. Ian how did you get on with that little project we were discussing??? Quote Link to comment Share on other sites More sharing options...
Barry Posted March 3, 2003 Author Share Posted March 3, 2003 I see. My hybrids have bigger wastegates than stock, so this will help. So then I need to get the VSV to close at say, 1.2 bar.? Surly a boost controller is able to do that.! Do you think it would be better to fit an adjustable actuator? Quote Link to comment Share on other sites More sharing options...
Barry Posted March 3, 2003 Author Share Posted March 3, 2003 Anyone? Quote Link to comment Share on other sites More sharing options...
JamesG Posted March 3, 2003 Share Posted March 3, 2003 I don't know about any other boost controllers but the Blitz DSBC installation doesn't connect to the wastegate VSV. That's capped off. The solenoid goes between the no.1 turbo inlet and the wastegate actuator. Don't know if that helps James. Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 4, 2003 Share Posted March 4, 2003 Once you install a boost controller, the stock system is removed from the loop, so it's irrelevant if it opens or not. Terry - I can't find the right bits of plumbing to fit it in a reversible fashion, so I haven't tried it out yet, but it's still lurking in the background. I know a couple of metal fabbers that I needs to talk to about it. I'm better at this sort of thing in the summer as it gets me out of the house -Ian Quote Link to comment Share on other sites More sharing options...
THOR Racing Posted March 4, 2003 Share Posted March 4, 2003 I think you are missing the point of the VSV. It's purpose is to make a non-linear actuator (the wastegate control actuator) more linear. (or binary!) Helping prevent a gradual bleed of the boost past the wastegate during boost build up. The VSV is OPEN for LOW boosts allowing any pressure build up on the wastegate actuator to bleed away to the air filter side. When the boost is high enough the VSV shuts (under ECU control) and this causes a large increase in the pressure on the actuator which snaps OPEN. This way you can get to the MAX boost quickly as you're not venting boost past a small opening in the wastegate valve during boost build up. This is all because you have a two port wastegate actuator. A lot of cars only have a single port one so hence most if not all the boost controllers out there only control the single inlet and cap the second port off on the actuator. You don't or cannot control the VSV to close later (well you could! but...). The Stock VSV is not built for pulsed operation and just delaying when the VSV closes would only serve to give you a spike in the boost. As soon as you shut the VSV the wastegate opens and dumps the boost, as the VSV cannot be pulsed (like a normal boost controller solenoid can) you now cannot pulse the bleed on and off and so the boost falls to the natural level. Whoopee. You got 18psi for 1s !! then back to 11psi I've experimented and you can (as I have done) put your boost controller solenoid in place of the VSV but I found a better degree of control was before the wastegate actuator, bleeding straight from the turbo. Probably the mechanics of the actuator that let me down there. Anyway. I've ranted on long enough..... Cheers Pete Quote Link to comment Share on other sites More sharing options...
Ian C Posted March 4, 2003 Share Posted March 4, 2003 Hurrah, someone has finally explained the point of the wastegate VSV better than I've ever managed -Ian Quote Link to comment Share on other sites More sharing options...
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