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Discussion Starter · #1 ·
Hello everybody :p First i whant to apologise for my bad english and i hope you will understand what i am asking :roll: Special gratz from Bulgarian Saab forum :) So to the point.
For a time i have instaled MBC on my car, and first it was running very well (and fast :cool:) but after 2-3 days the problems began. The car was choking during accerelating (like loosing boost fo a 2-3 sec) ... the only way not to do this was to slowly press the gas pedal down. Then i decide to roll back some positions of MBC it was fine, but after 2 more days the same thing happend again :roll:
The only thing i supose that might be the problem is the Wastegate acutator spring ... and to be more exact this is how i explain this for me:
MBC is trying to close acutator very fast, but this spring cant hold up and it opens to relieve presure :roll:
Can i change my spring, and if i do that what type to use for my T25. Also i will be very grateful if you explain to me what else could make such problem. Oh and my car is 9-3t T5 sw. Again sry for my ENG ;oops:
 

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dont worry about your english... it was better than some natives to the language that are on this site
not too sure bout your problem
but i would say check your vacuum lines and your bpv just as a precaution
someone will chime in to give you some better guidance
 

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Discussion Starter · #3 ·
Ty for the replay :) I am wondering about the sparks plugs, cuz they are some model Bosch, and i didn't know if they are for my car :roll: Now i am going to buy NGK BCPR7ES-11 and put Stage 2 software, and after that i will try again with MBC :) I have checked all vacuum lines and they seems to be fine :roll:
 

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I wouldn't run the Stage II software with an MBC, the software is better at controlling boost and it's a bad idea to run an MBC with no fuel cut... you'll only start upping the boost more and more since it's so easy and that's asking for trouble (hey, we're only human, right?). The boost dialled into these software packages is already at the limit of what you should run, so there's no point in keeping the MBC after installing software. ;) Also, a good software map takes the turbo compressor's map into account, there's no point in boosting 1.5 bar at 2.500 rpm on this engine if the turbo can't do a good job there. You'll just heat up the intake air instead of making more power.

That said: does it feel like the engine suddenly hits a ceiling, like a rev limiter? If so, you're running into the fuel cut. This happens when the boost spikes above ~1.05-1.1 bar. It's a safety measure in the stock ECU, tuned software disables this effect because it also provides more boost.

The MBC is prone to being affected by the weather conditions. What level works today, may result in a boost spike the week thereafter if the temperature drops, for instance. I keep adjusting mine every week or so... it's cheap, but certainly not the ideal method.

Also, Forge Motorsports have an uprated actuator for our T25 turbos. It's anywhere between 125 and 250 euros depending on the shop and shipping costs. Money better spent elsewhere, IMHO.
 

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Discussion Starter · #5 ·
Well i agree with everything :) And yes its like hitting the rev limiter. First the MBC was at position 7 .. after 2 days - 5 ... and now 3 or 4 :confused: I also know about the forge acutators but 200 euro is too much (afterall my car is not goind to be 300hp to need this) Thats why i was wondering what type of spring they use to go buy just the spring and replace it :roll: I guess its better to spend this money for cooler :D Ty man ;)
 

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You're welcome dude! So that rules out the WG actuator, what you're feeling is normal and caused by the software. You can get the tuned software cheap (well, for free if you have the programming hardware) but with the risk of frying your ECU by using T5suite. JZW comes highly recommended on here, and a tune by him would cost you less than the Forge actuator would have. :)

As far as the actuator goes, I see where you're coming from, but our original actuators are not servicable unless you get very creative with cracking it open and putting it together again.
 
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