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Discussion Starter #1
So, I tried fitting a manual boost controller today - using the center and right lines (turbo inlet and wastegate actuator lines)

no dice - wasn't limiting boost at all. Am I doing something wrong?

I've seen somewhere on here you should install it with the turbo input side of the MBC fitted to the end leading to the APC solenoid, and the other end to the wastegate actuator. Anyone running an MBC have some advice to lend?
 

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the apc can be bypassed in order to have higher than normal boost limits. you can use a MBC, or an EBC. both work the same way as the apc, and open the waste gate at a set amount of boost. im not exactly how you have to plumb it, but there ar eonly 3 lines, jsut play arroudn til it works:cheesy:
 

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If I recall correctly, the apc has to be full disconnected in order for a mbc to work correctly, due to the fact it retards timing if there's knock, so theorically a mbc is more dangerous, but you receive cleaner boost(no spike and fade) as for a knock signal I believe if you disconect the apc completely the knock sensor doesn't work then, I may be wrong, also I think its pin 17 on the apc if you wanna do a knock led best 1dollar mod ever, but again it might be rendered useless if you disconect. Not 100 percent on this though hope someone else comes thru and clarifies a little more on this.
 

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the APC system controls boost, calculated by engine knock, RPM and boost pressure. it only controls boost, not ignition timing, unless it is a DI/APC system.
if the apc is to be disconnected you will have no knock sensing/protection whatsoever. if you want to get a higher boost pressure then the easiest way is to mod the APC.
 

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Mbc= have to diconnect apc,no knock protection, more stable boost. However wind mbc in too much and no engine, unless your gearbox goes first.
 

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I forget where but there is a way to disconnect the apc and have the knock sensor still work by using a warning led or light, I'm a mbc/ebc fan my self, I guess it really depends on what kinda power you wanna make what the cars used for, if it a DD that never or rarely sees track time then apc is the better option, if its a performance car or track car go the mbc/ebc route way more stable boost without spike and fade. You just have to make sure your tuned right. The other thing you need to keep in mind is that the stock knock sensor isn't super affective about 1.5bar and high revs, there's just too much rotational noise, I maybe wrong about. This my info on that was from several standalone tuners, more modern sensor I guess are better not sure about all this, I just go by my gauges, and sound/feel, I guess some have this talent and others don't I notice things like that but I have friends who don't even notice things like valve noise
 

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Discussion Starter #9
well I've tried the MBC in two different setups (hooked to turbo inlet and wg actuator as well as inline with the WG actuator) and neither seems to work. Diagnosis: piece of crap MBC. I think i'll leave this alone for the time being until I can get my APC working, and enjoy the joys of not blowing up my gearbox due to base boost. I'll revisit this topic later if my need for power continues to grow...

-James
 
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