MBC how could i get it wrong ?

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MBC how could i get it wrong ?

Postby kaymar » Thu 02.06.2005, 22:40

After reading about MBC on this site i decided it was well within my limited capabilitys. Purchased pipe and bleed valve, fitted, tested ok, i dont think my BSV is operational as my boost is constant on .5 bar under heavy acceleration so didn't touch that. Adjusted MBC to boost at .7 bar but couldn't tell any noticable difference, even tested acceleration against stop watch with and without MBC.<br>So what have i done wrong ?<br>Any suggestions gratefully recieved.  Ken.
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Re: MBC how could i get it wrong ?

Postby Nige » Thu 02.06.2005, 23:17

Have you disconnected the BSV (pressure tubes not electrics, although you should do this as well)?  An MBC replaces the BSV.<br><br>Nige
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Re: MBC how could i get it wrong ?

Postby Doug » Thu 02.06.2005, 23:35

well, it's all in the adjustment.  You may want to try and slowly adjust it until it overboosts and hits boost cut, cause that way you know it is working and then back down from there to where you want it.<br><br>If you change from stock boost to, say, 0.9bar, you should feel about twice the turbo oooomph as stock!!<br><br>The gauge could be wrong and is not too precise.<br><br>Engine timing has a lot to help with performance under boost, so setting the base timing to correct could help a bunch too.<br><br> 8)
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Re: MBC how could i get it wrong ?

Postby kaymar » Sat 04.06.2005, 19:28

Thanks Nige for advise but i don't understand why i would disconnect pipes on BSV i don't think it's working because it makes no difference if i unplug electrics.
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Re: MBC how could i get it wrong ?

Postby kaymar » Sat 04.06.2005, 19:31

Thanks Doug for advise i increased boost to cutoff then set it down to .9 if anything the car performs worse at this setting. Booked in at Chris Foulds on 20th for service i'll leave any further experiments until after then.
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Re: MBC how could i get it wrong ?

Postby Nige » Sat 04.06.2005, 22:01

Kaymar,<br><br>An MBC replaces the BSV, (both are bleeds to fool the wastegate) so the pipes that normally connect to the BSV should now be connected to the MBC instead.  If you still have the BSV connected and an MBC you'll end up with a confused ECU (when I had an MBC on mine I removed the BSV from the car and bagged in in the garage to keep it crud free).  You may well be right that its not working, did it work ok before you fitted the MBC?  If so then there's no reason for the BSV to suddenly stop working.  If it's disconnected electrically and still in the system then your boost will be limited to the .4 bar the wastegate allows (gauge may well read .5 bar).<br><br>From your last post if you can hit fuel cut I assume you get an increase in boost when you adjust the MBC?  If so it might be base timing or a restricted exhaust?<br><br>Nige
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Re: MBC how could i get it wrong ?

Postby kaymar » Sat 04.06.2005, 22:31

Cheers Nige. I have connected my MBC between turbo and wastegate actuator as per drawings on this site, only had car 2 weeks and never seen above indicated .5 bar boost, makes me think BSV not working. <br>Points to exhaust or timing as you suggested.<br>Ken
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Re: MBC how could i get it wrong ?

Postby Candles » Sun 05.06.2005, 10:09

Do the know the boost gauge is accurate?
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Re: MBC how could i get it wrong ?

Postby kaymar » Sun 05.06.2005, 22:16

No i don't but i do know when it indicates .5 bar it performs ok and when i install MBC so it indicates .9 it does not perform as well.
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