Scott Posted October 30, 2009 Share Posted October 30, 2009 Wrong Have a go MBC +2 hoses Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 Nice diagram Some EBC have extra ports to assist with measurements and response times, they are basically more intelligent but they are doing no more than an MBC. The wastegate controls boost, this is done with a manifold pressure feed, to be able to raise boost all you need to do is limit the manifold pressure being applied to the wastegate, you can do this two ways, block it or bleed it off, its simple and nothing complicated about it at all. Cheap MBC just tend to bleed air, ie bleed valves, the more expensive MBCs use a ball and spring design so you can tension up the spring to crack at a given pressure and then bleed the rest. EBCs do exactly the same but in a much more controlled/intelligent manner. Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2009 Share Posted October 30, 2009 (edited) Nice diagram Some EBC have extra ports to assist with measurements and response times, they are basically more intelligent but they are doing no more than an MBC. The wastegate controls boost, this is done with a manifold pressure feed, to be able to raise boost all you need to do is limit the manifold pressure being applied to the wastegate, you can do this two ways, block it or bleed it off, its simple and nothing complicated about it at all. Cheap MBC just tend to bleed air, ie bleed valves, the more expensive MBCs use a ball and spring design so you can tension up the spring to crack at a given pressure and then bleed the rest. EBCs do exactly the same but in a much more controlled/intelligent manner. I never said they didn't do the same thing. The guy asked a question about how to plumb in an MBC, the diagram for an EBC was given as a solution. I said it wasn't any good, the reply was that they were both the same. I said they weren't, an MBC requires more inputs & outputs to be plumbed in. This renders the diagram useless. I know how a boost controller works In conclusion, are they the same? No, he is wrong and now so are you Edited October 30, 2009 by Scott (see edit history) Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 Doesn't matter though does it? The MBC is doing the same job as the EBC surely? As long as the +ve pressure is pushing against the ball/spring. I may be wrong, it has been known! Your wrong You told this guy he was wrong Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2009 Share Posted October 30, 2009 You told this guy he was wrong They work in a similar fashion, they are not the same. Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 They work in a similar fashion, they are not the same. He asked if they are doing the same job, which they clearly are Quote Link to comment Share on other sites More sharing options...
jevansio Posted October 30, 2009 Share Posted October 30, 2009 I'm with Wez, one bleeds via pulsing a solenoid, the other via opening a hole pushing against a spring, the method for connecting them up is the same (unless controlling an external wastegate with 2 ports) Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2009 Share Posted October 30, 2009 He asked if they are doing the same job, which they clearly are Not in the context he asked the question in though. "doesn't matter though does it?" Yes it does. Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 Not in the context he asked the question in though. "doesn't matter though does it?" Yes it does. OK OK OK, we can agree to disagree, but I am right and you are wrong Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2009 Share Posted October 30, 2009 Ok I need a beer Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 beer already flowing freely here Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2009 Share Posted October 30, 2009 I'm with Wez, one bleeds via pulsing a solenoid, the other via opening a hole pushing against a spring, the method for connecting them up is the same (unless controlling an external wastegate with 2 ports) All 3 of you are wrong then. MBC doesn't remove the wastegate VSV, EBC does. *ding ding* Round 2 Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 An MBC can remove the VSV though, why would you leave it in place Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2009 Share Posted October 30, 2009 If thats the case then it wouldn't need to be there in the first place? All the MBC does is splice between the actuator and the compressor housing. The VSV is connected to the other end of the actuator. If you can take out the VSV when the MBC is on there then you can take it out when its not on there, can't see what difference it would make. I'm ok now, got beer AND wine Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 The stock VSV is an EBC just that its controlled by the ECU. This is why when you upgrade the ECU to an AEM or Solaris etc you do not need an MBC or EBC as you can control the VSV using the ECU boost control strategy Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2009 Share Posted October 30, 2009 The stock VSV is an EBC just that its controlled by the ECU. This is why when you upgrade the ECU to an AEM or Solaris etc you do not need an MBC or EBC as you can control the VSV using the ECU boost control strategy EBC is variable though and can control the boost. MBC once set doesn't vary. I can't see the MBC controlling the boost properly if it doesn't have the wastegate VSV controlling it properly. Basically the MBC and the wastegate/VSV do the same job that the EBC does. MBC ups the boost, wastegate VSV controls any fluctuations. EBC does that all on its own. Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 EBC is variable though and can control the boost. MBC once set doesn't vary. I can't see the MBC controlling the boost properly if it doesn't have the wastegate VSV controlling it properly. Basically the MBC and the wastegate/VSV do the same job that the EBC does. MBC ups the boost, wastegate VSV controls any fluctuations. EBC does that all on its own. Yes the EBC is more intelligent as already stated but they do the same thing and both can work without the VSV and to work they function in the same way, just one is more crude than the other. MBCs can and do work on there own. Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2009 Share Posted October 30, 2009 Yes the EBC is more intelligent as already stated but they do the same thing and both can work without the VSV and to work they function in the same way, just one is more crude than the other. MBCs can and do work on there own. As far as boost control at a certain boost setting goes.... EBC = MBC + Wastegate VSV EBC > MBC Can't do the therefor dots but.... They aren't the same The obvious advantages of the EBC are the on the fly adjustments that can be made from the cabin. Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 The obvious advantages of the EBC are the on the fly adjustments that can be made from the cabin. Not an advantage, its the only difference Quote Link to comment Share on other sites More sharing options...
Andy Blyth Posted October 30, 2009 Share Posted October 30, 2009 Jesus christ girls! Dave, have you got a ball and spring type MBC or a bleed valve MBC? Regardless of type, you plumb it in-between the compressor housing feed and the wastegate. If it's a ball and spring type, you need to ensure that the "ball side" is connected to the compressor housing. Both types (including EBCs) will work with or without the downstream VSV removed. The VSV is there in the stock setup to speed up the spooling by holding the wastegate shut (by bleeding pressure) until the nominal boost pressure is reached. If the VSV wasn't there the wastegate would start opening slowly, proportional to boost pressure, as soon as boost was available. Some people prefer to block off the feed to the VSV when using a boost controller because it can make the tuning of a controller easier. If you're using a ball and spring MBC, I wouldn't bother blocking off the VSV, because it wil have closed long before your MBC lets boost pressure through to the actuator. Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2009 Share Posted October 30, 2009 As far as boost control at a certain boost setting goes.... EBC = MBC + Wastegate VSV EBC > MBC Can't do the therefor dots but.... They aren't the same The obvious advantages of the EBC are the on the fly adjustments that can be made from the cabin. Not an advantage, its the only difference As i said.. EBC = MBC + Wastegate VSV EBC > MBC The wastegate VSV fine tunes the boost to keep it linear at the start. Well, thats how i understand it from reading how the sequential system works. The actuator has a certain spring rate, the MBC tricks this into thinking its getting less pressure than it is, the wastegate VSV then controls the back pressure on the opposite end of the actuator to make sure it stays linear. The EBC does the job of the VSV on the fly by monitoring the boost pressure being created. This negates the use of the VSV. I agree that the VSV can be removed on both setups, but in that case the EBC will always have better control of the boost. If the VSV remains in place the only changes that will effect the effectiveness of the MBC are climatic. Quote Link to comment Share on other sites More sharing options...
Wez Posted October 30, 2009 Share Posted October 30, 2009 OK so now everyone agrees its all good EBC and MBC do the same thing : check Do it by doing the same thing : check Can work with/without VSV: check Right we are sorted, we all agree, we got there eventually Quote Link to comment Share on other sites More sharing options...
Scott Posted October 30, 2009 Share Posted October 30, 2009 Jesus christ girls! Dave, have you got a ball and spring type MBC or a bleed valve MBC? Regardless of type, you plumb it in-between the compressor housing feed and the wastegate. If it's a ball and spring type, you need to ensure that the "ball side" is connected to the compressor housing. Both types (including EBCs) will work with or without the downstream VSV removed. The VSV is there in the stock setup to speed up the spooling by holding the wastegate shut (by bleeding pressure) until the nominal boost pressure is reached. If the VSV wasn't there the wastegate would start opening slowly, proportional to boost pressure, as soon as boost was available. Some people prefer to block off the feed to the VSV when using a boost controller because it can make the tuning of a controller easier. If you're using a ball and spring MBC, I wouldn't bother blocking off the VSV, because it wil have closed long before your MBC lets boost pressure through to the actuator. This all came about because of the confusion of "between the compressor housing and the wastegate". Its between the compressor housing and the top pipe of the wastegate actuator. The wastegate actuator has 2 connections. I'm sure you know this but that is where the confusion was created. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.