annoying MBC problem
 

I purchased a ball/spring type MBC from ebay for 10.50USD. It hold 7psi up to 8000rpm excellent, but i couldn't thread the bolt in the coupling more than 2-3 turns. So, i "refreshed" (I don't know the right English word for this method) the threads of screw. Since then i can turn the thread full, but it makes no difference in boost. Furthermore the boost (8psi) goes up to 5000rpm and then it falls to 4-5psi. I have tried 4 different thick springs, too. I have used some teflon tape on bolt and everywhere else i could to prevent air leaking (I thought this was the problem). No difference, it still can't hold the boost. But it could before !

What the hell can cause this problem? It's very frustrating, since this MBC looks very simple, so i have no more idea what can be wrong with it. I have no money to buy a branded one for 100USD.

Please, help me!

PS: This is the MBC i have purchased... DIY type: http://cgi.ebay.com/ebaymotors/ws/eB...spagename=WDVW

Re:annoying MBC problem
 

I would say to throw it away. Your best bet is to make sure there are no leaks (manifold/turbo) and then figure out a way to shorten the wastegate arm.
This would probably be a better way to raise the boost than to play around with that garbage MBC. :-\

Re:annoying MBC problem
 

i fby "refreshing" the threads on the bolt you mean you used a tap and die set then you probly used the wrong thread or took too much off and now air is leaking. you can always take it apart and goto home depot and retap a new piece for about 3 bucks. there is a link to how to make a MBC in the FAQ

Re:annoying MBC problem
 

I don't think he's from the US...so no Home Depot for him.

Re:annoying MBC problem
 

Yes, I'm from Europe :)

Jeffsciv23 may be right, i may took off too much of the thread as it is too light to turn now. That is why i used some teflon tape. I already wanted to replace the bolt, but we have different measurement in Europe (mm and not inch) and no compatible bolt available for the female coupling. Anyway if you also think (as i do) the air leaking is the problem i use 3times more teflon tape and it might help... I'll see...

Re:annoying MBC problem
 

where do you have the MBC hooked upto for vacuume? maybe you need a stronger vacuume source.

Re:annoying MBC problem
 

i used a MM bolt for mine and it worked fine but you may be able to goto any hardware store and find it if you have one of those over there.

Re:annoying MBC problem
 

buy a real mbc like turboxs or hallman

Re:annoying MBC problem
 

I have put it to PCV vacuum line, but tried on FPR source as well. No difference. The vacuum port on the top of intake manifold is sealed in EDM B16A2. :(

Re:annoying MBC problem
 

dont turn your internal wastegate in to far cause they will have shitty spool time and drop real fast.