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Old 02-25-2006, 12:02 AM   #1
un_focused
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Default Possible stupid Question. AP and BC?

Ok so im still new to the subi thing and here is another possibly stupid question to prove it. I looked and was unsuccesful in finding a thread on this specific question. Is it possible to safely run a boost controller with a Cobb AP? Completely honest question so if you must flame please(1) first walk to the nearest mirror. (2)Think about the stupid a$$ comment your about to post. (3)Now this is the really important part......Hit yourself in the balls for me and dont post it. Thank you however, to all those who have legitimate input on the subject.
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Old 02-25-2006, 12:23 AM   #2
wrxdrvr
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I have a MBC and am using it as an adjustible restrictor pill instead of the factory one that is in the first vac hose off turbo nipple before wastegate actuator. Seems to allow turbo to spool up faster as the actuator starts to activate slightly later than before but still allows the ECU full control so that theres no part throtle full boost problem. Basically I get 16.3 PSi with the Cobb stage 2 93 octane map. Had it like that for the last 6 months and no problems. Now i'm not saying its compleatly harmless, But i'm willing to take the risk for the faster spool and 16.3 PSi instead of the slightly slower spool and 15.7 PSi. ...EDIT;... I did think twice about posting this so... If you don't know what to look for and how to avoid the associated risks with MBC's don't even think of doing this... especially in '04, '05 and '06s... It works on my car is all I can say.

Last edited by wrxdrvr; 02-25-2006 at 07:22 PM.
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Old 02-25-2006, 12:49 AM   #3
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....playing with matches.....while soaking in gasoline
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Old 02-25-2006, 11:04 AM   #4
wrxdrvr
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Quote:
Originally Posted by Uncle Scotty
....playing with matches.....while soaking in gasoline
Quite right, I am, and so is every one that mods their car ... in any way. I now have over 128,000 miles on my '02 wrx and it's never been in the shop exept for rear end and driveline problems. My car has had a MBC on it for 3 out of the 4 years i've owned it, the first 2 1/2 years was driving with the MBC only, the 2nd year was Cobb stage 1 no MBC, and the last 10 months was Cobb stage 2 with the last 6 months with the adjustible "restrictor pill". Again... I agree with the playing with fire comment and that's why I don't recomend the MBC for any one, I happen to be able to control myself and not crank it up, I changed my driving habbits for the first 2 1/2 years. Now with the ECU controling the boost its the best of both worlds no more PTFB as long as you don't over do the MBC control. Again you need to know what to look for and control youself and it can be done... Uh...Where did I put the matches???
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Old 02-25-2006, 11:22 AM   #5
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i agree with wrxdrvr. Depending on how you setup your AM BC, if you eliminate the stock ECU's ability to cut/control boost you HAVE to know what you're doing and what to watch for.

See with Cobb's EM, the stock ECU controls boost, and if for some reason you overboost it will cut and let you know in a hurry. If you bypass this you could risk overboosting your engine and PTFB is something to be careful of, again you will need to be educated about it.

unfocused-what is your motivation for using an AM BC? You could simply get a protune and not have to mess with any of it. . .
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Old 02-25-2006, 12:34 PM   #6
un_focused
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My motivation is I simply want to pull the most i can from my engine without blowing it up. To be honest Im only looking for about 16lbs compared to the stock 12 or so. A protune is a good idea except and im not positive on this but i dont think there is one within an hours drive. And That is really uncharted territory for me. How does the protune work? Is that something where i can set specifically for my mods and what amount of boost I would like to run?
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Old 02-25-2006, 01:42 PM   #7
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Quote:
Originally Posted by un_focused
My motivation is I simply want to pull the most i can from my engine without blowing it up. To be honest Im only looking for about 16lbs compared to the stock 12 or so. A protune is a good idea except and im not positive on this but i dont think there is one within an hours drive. And That is really uncharted territory for me. How does the protune work? Is that something where i can set specifically for my mods and what amount of boost I would like to run?

a protune is a custom of your car, done for your car/mods. Boost can be raised to whatever is deemed safe for your car/setup/gas. I would recommend this route personally.
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Old 02-25-2006, 01:53 PM   #8
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^^^

Especially on an 05, mess with an MBC on an 04-05 without engine management and careful monitoring and you will regret it later.
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Old 02-25-2006, 03:49 PM   #9
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Quote:
Originally Posted by wrxdrvr
Quite right, I am, and so is every one that mods their car ... in any way. I now have over 128,000 miles on my '02 wrx and it's never been in the shop exept for rear end and driveline problems. My car has had a MBC on it for 3 out of the 4 years i've owned it, the first 2 1/2 years was driving with the MBC only, the 2nd year was Cobb stage 1 no MBC, and the last 10 months was Cobb stage 2 with the last 6 months with the adjustible "restrictor pill". Again... I agree with the playing with fire comment and that's why I don't recomend the MBC for any one, I happen to be able to control myself and not crank it up, I changed my driving habbits for the first 2 1/2 years. Now with the ECU controling the boost its the best of both worlds no more PTFB as long as you don't over do the MBC control. Again you need to know what to look for and control youself and it can be done... Uh...Where did I put the matches???

.......Wakie-Wakie.

The '02-'03 ECU is totally different from other ECU's and if ya DON'T know what you are doing ya gonna break something, in any event.

And posting things that may or may not be specific to a particular model year vehicle is, again, playing with fire for those that don't KNOW.

....so, in closing.........posting the above thing may induce kidie ricer racer to blow it up 'cuz he read it here and YOU did it and nothing bad happened-----but you and he drive COMPLETELY different cars----the ECU makes them different, RIGHT.
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Old 02-25-2006, 04:35 PM   #10
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It's important to realize that with a tuned vehicle, or even the stock tune, the fuel and ignition curves are built around vehicles with a particular volumetric efficiency and a particular boost curve. Playing with modifications that change either of those (such as different exhaust characteristics, intakes, turbos, boost controllers, etc.) allow the engine to reach areas of the maps that the original tuner had no intention of it reaching, often resulting in bad driveability.

This can range from spots that are, at best, too rich or retarded, to very lean and over-advanced... and it's usually the latter. For instance, with "stage 2" hardware, the turbo will spool up substantially sooner than with stock parts, and as a result, even a stock tune will run dangerously lean in low-RPM areas. Same goes for a boost controller that changes the boost curve... you'll be going into places that the tuner didn't account for, and are not likely to be safe for your motor.

/Andrew
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Old 02-25-2006, 08:20 PM   #11
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KhaOs, ok so how do i keep from running lean. Because as soon as my AP comes in the car will officially go stage2. Would it be a good idea to install a 255 fuel pump? And by they way thank you all for your imput. Please keep it up.
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Old 02-26-2006, 03:00 PM   #12
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Quote:
Originally Posted by un_focused
KhaOs, ok so how do i keep from running lean. Because as soon as my AP comes in the car will officially go stage2. Would it be a good idea to install a 255 fuel pump? And by they way thank you all for your imput. Please keep it up.

...ya do NOT deviate from what Cobb says to do....ya do NOT add intakes or MBC/EBC's or anything that is not SPECIFICALLY intended to be run with their maps
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Old 02-26-2006, 03:30 PM   #13
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First, if you want the safe answer listen to the uncle, he knows!

Second, I'm a gambling man and will run a mbc on monday with my ap.
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Old 02-26-2006, 06:51 PM   #14
wrxdrvr
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Quote:
Originally Posted by desert pirate
First, if you want the safe answer listen to the uncle, he knows!

Second, I'm a gambling man and will run a mbc on monday with my ap.
Well put... But I sure hope you also know what you are doing. I don't wan't to read on tuesday a new thread about ... what is this knock knocking sound ... my engine never made it before??? ...Uncle Scotty will want to whack my wee wee with a stick and that would suck.
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Old 02-26-2006, 07:02 PM   #15
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Quote:
Originally Posted by desert pirate
First, if you want the safe answer listen to the uncle, he knows!

Second, I'm a gambling man and will run a mbc on monday with my ap.

...d00000000d....I have 2 or 3 MBC's laying around......in fact----I have a GFB one right here on my desk......but NOT on MY car....which runs RIGHT with a modded STi(at 20psi) to ~90 mph....so does it NEED a MBC----nah...not
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Old 02-27-2006, 12:08 AM   #16
un_focused
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thank you all for your input. I think ive decided i will take the car to get a protune done. I think in the end the long drive is worth it. As well as the money for getting me what i want out of my car.
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