Daphur280 Posted September 10, 2010 Share Posted September 10, 2010 So I adjusted my afm lastnight, runs a little better than previously, so I decided to turn the boost up from 5psi - 8psi, turn the manual controller up a full turn. No boost increase. Turned it another full turn. No boost increase. Just for curiosity turned it another full turn and it was maxed out. No boost increase. I read the surging thread a little bit to see if this was what my problem was, but I'm not sure if I understand after reading, that the two are related. I would like to avoid picking up another MBC to see if it was the boost controller that was the issue, instead to find a way to diagnose where the problem area is. Would my wastegate be my first place to check? Quote Link to comment Share on other sites More sharing options...
Nigel Posted September 11, 2010 Share Posted September 11, 2010 So I adjusted my afm lastnight, runs a little better than previously, so I decided to turn the boost up from 5psi - 8psi, turn the manual controller up a full turn. No boost increase. Turned it another full turn. No boost increase. Just for curiosity turned it another full turn and it was maxed out. No boost increase. I read the surging thread a little bit to see if this was what my problem was, but I'm not sure if I understand after reading, that the two are related. I would like to avoid picking up another MBC to see if it was the boost controller that was the issue, instead to find a way to diagnose where the problem area is. Would my wastegate be my first place to check? Did your MBC ever work? What kind is it? How do you have it hooked up? Is it a stock external wastegate actuator? FYI, surge has nothing to do with no boost increase. Nigel '73 240ZT Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted September 11, 2010 Author Share Posted September 11, 2010 Did your MBC ever work? I assumed so. But it doesn't seem to affect the PSI. What kind is it? eBay brand How do you have it hooked up? it comes off the "Y" of the compressor, into the MBC, then into the wastegate Is it a stock external wastegate actuator? Yes FYI, surge has nothing to do with no boost increase. Oh, thanks Update: I routed the vacuum hose from the "Y" back into the wastgate... No change, still at 5-6psi. Perhaps a leak at the BOV? Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted September 20, 2010 Author Share Posted September 20, 2010 Bueller? Bueller? Quote Link to comment Share on other sites More sharing options...
LamboZ Posted September 21, 2010 Share Posted September 21, 2010 A leak would mean you have no boost or boost falling off. Sounds like a bad MBC. Quote Link to comment Share on other sites More sharing options...
goodoldjam Posted September 21, 2010 Share Posted September 21, 2010 (edited) A MBC is nothing more than a bleeder, it reduces the pressure that the wastegate sees. Thus making it open at higher pressures. Now if it didn't bleed at all then you would see no change. If it were to bleed to much you would see alot of boost. So considering that you can run at stock boost with no issues, then I think it's more than likely not bleeding at all. Chinese Ebay parts are not even close to reliable. So test the new part and make sure it actually works before you start looking at the oem parts. Chinese BOV is the same, when I pulled mine apart after a little use 2 pieces of spring fell out. My cheap adjustable FPR, didn't even hold pressure. The Chinese probe fan controller that you can pick up from Summit didn't even work out of the box, luckily that one wasn't mine. Edited September 21, 2010 by goodoldjam Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted September 21, 2010 Author Share Posted September 21, 2010 A leak would mean you have no boost or boost falling off. Sounds like a bad MBC. The MBC has been removed and I'm still only at 5.5 psi... I'm guessing I should be checking the wastegate, but WHAT on/in the wastegate sould I be looking for? Quote Link to comment Share on other sites More sharing options...
goodoldjam Posted September 21, 2010 Share Posted September 21, 2010 (edited) The MBC has been removed and I'm still only at 5.5 psi... I'm guessing I should be checking the wastegate, but WHAT on/in the wastegate sould I be looking for? 5.5 is exactly what you should be seeing. There are no issues as far as boost. Only problem your having is the MBC has no effect on the stock level. Even with a leak it would be odd for it to have Zero effect. Edited September 21, 2010 by goodoldjam Quote Link to comment Share on other sites More sharing options...
Nigel Posted September 21, 2010 Share Posted September 21, 2010 A MBC is nothing more than a bleeder, it reduces the pressure that the wastegate sees. Not all MBC's are bleeders. Some use a ball and spring valve that blocks the signal to the WG actuator until the spring pressure is overcome. Nigel Quote Link to comment Share on other sites More sharing options...
goodoldjam Posted September 21, 2010 Share Posted September 21, 2010 (edited) Not all MBC's are bleeders. Some use a ball and spring valve that blocks the signal to the WG actuator until the spring pressure is overcome. Nigel Now that you point that out it's the exact opposite. No pressure getting past is high boost and to much is low boost. None the less the ebay controller, leaks pressure to control. Unless I'm totally misunderstanding how it works.This is a good source for it's operation http://forums.nicoclub.com/generic-ebay-manual-boost-controller-install-on-sr20det-t346138.html For the generic ebay controller. Edited September 21, 2010 by goodoldjam Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted September 23, 2010 Author Share Posted September 23, 2010 so if I were to test that I would need to run compressed air through IN and have a pressure gauge on the OUT to adequately see if it A) holds pressure; Accurately holds the correct PSI... ? Quote Link to comment Share on other sites More sharing options...
goodoldjam Posted September 24, 2010 Share Posted September 24, 2010 (edited) I guess a basic test would be to put a regulated amount on the Vacuum/pressure side and making adjustments with the controller. Something like 10psi and if adjusting it has no effect on the wastegate feed then it's bad. It should be reducing how much pressure the wastegate sees when you turn it up. Probably better to use a pressure gauge on the wastegate side. Edited September 24, 2010 by goodoldjam Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted September 24, 2010 Author Share Posted September 24, 2010 you wouldn't happen to be able to make a quick diagram on paint or something to indicate where i would be need to test? Quote Link to comment Share on other sites More sharing options...
goodoldjam Posted September 25, 2010 Share Posted September 25, 2010 (edited) You need to put some pressure to the side of the T that is coming from the turbo. Then you want to see what comes out the side the arrow is pointing (the side the wastegate connects to). While you adjust the boost dial, if it doesn't change when you adjust it then it's bad. Just hook it up like the diagram out of the car. Minus the turbo and wastegate obviously. Pressure out <--- Pressure in Edited September 25, 2010 by goodoldjam Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted September 27, 2010 Author Share Posted September 27, 2010 Wow, thats is a great diag. Now I noticed that I had my MBC routed wrong, I didn't include that "T" , I believe I just had it routed straight to the wastegate, wonder if that was the problem all along. Thanks! Quote Link to comment Share on other sites More sharing options...
motoman Posted October 6, 2010 Share Posted October 6, 2010 The way that system works is crazy. I would make it so the flow from the boost would be at a 90° angle, with the path to the waste gate. Instead of the path to the boost dial. Quote Link to comment Share on other sites More sharing options...
Daphur280 Posted October 6, 2010 Author Share Posted October 6, 2010 then where would yuou have flow from the dial? Quote Link to comment Share on other sites More sharing options...
Nigel Posted October 7, 2010 Share Posted October 7, 2010 The way that system works is crazy. I would make it so the flow from the boost would be at a 90° angle, with the path to the waste gate. Instead of the path to the boost dial. then where would yuou have flow from the dial? Yeah, I also can't follow your explanation. Can you elaborate? Nigel Quote Link to comment Share on other sites More sharing options...
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