Whats the deal with MBC
Guest
Posts: n/a
Whats the deal with MBC
I want to get a MBC for my WRX and I am getting mixed opinions. Some people say go for it and others say no its a bad thing to do. I am just looking for a reliable one that can lower my 1/4 times by a couple tenths, what brands do you recommend and is there such a thing that I can adjust, you know raise it up at the track and keep it stock driving around? Thanks
VIP Member
iTrader: (1)
Joined: Nov 2002
Posts: 2,518
From: Plymouth, MN
Car Info: 94 T-Leg Sedan and a 00 M5
Most MBC's are all the same. I would recommend a Joe P or Dawes device. Unless the MBC is total crap, or made by blind monkeys, it should work just as well as any other. Just MAKE SURE YOU GET A BOOST GUAGE TO GO WITH IT. And don't put it over 16psi unless you have engine management. The n00b has spoken.
-Etch
edit: Oh yeah, about the adjustment. Every MBC I have ever seen is adjustable. Usually there's a little twist screw on top that you turn to raise/lower the boost. Sometimes requires a screwdriver or wrench, but real easy to adjust, and so easy to install that I could do it myself without supervision.
-Etch
edit: Oh yeah, about the adjustment. Every MBC I have ever seen is adjustable. Usually there's a little twist screw on top that you turn to raise/lower the boost. Sometimes requires a screwdriver or wrench, but real easy to adjust, and so easy to install that I could do it myself without supervision.
Guest
Posts: n/a
I installed the Turbo XS Dual Stage Boost Controller at about 10,000 miles and haven't had any problems...yet. The reason why I chose a this particular model is so that I can drive at stock boost levels during my daily commutes and have the second stage set at a higher boost level for occasional racing. Before I say anything else, I must state, with great importance, that you must be very careful and conservative when using a manual boost controller.
Before making any adjustments to your boost controller, make sure you've installed and are using an accurate and calibrated turbo boost gauge to measure your boost levels. Remember that boost levels vary depending on what gear you are in and the amount of load you put on your engine. For standardization, most posted or published boost levels are measured with the car driven in a gear that's closest to having a 1:1 ratio. For a 5 speed manual transmission, that would usually be 4th gear and for 6 speed manual transmissions, it could be either 4th or 5th gear, depending on which one has the 1:1 gear ratio. If the engine is stock and everything is working properly, you can expect a maximum boost level between 0.095 MPa (13.8 PSI) and 0.097 MPa (14.0 PSI) in 4th gear.
With the Manual Dual Stage Boost Controller, you will notice that when you adjust the boost level in the Stage 1 chamber, the boost level is effected in the Stage 2 chamber. DO NOT set the boost levels for Stage 2 before setting the boost levels for Stage 1 first; otherwise, you'll have a greater chance of overboosting and detonating.
I have my Stage 1 boost level set to about 0.097 MPa (about 14.0 PSI) and my Stage 2 boost level set to about 0.113 MPa (under 16.5 PSI). There's about a 2.5 PSI difference between the two stages. I'm usually driving in Stage 1 most of the time and only reserve the use of Stage 2 when I race every 3 to 4 months.
Here's how I set the two stages of my Turbo XS Dual Stage Boost Controller:
1) Set booth boost chambers to their most "minimum" positions;
2) With the toggle switch set to Stage 1, slowly increase the boost level in the Stage 1 chamber first. To be on the safe side, initially set the boost level to 0.090 MPa (13.05 PSI). (Note: After each adjustment, make sure to check and verify your boost levels while driving in 4th gear);
3) Next, check the boost levels when the toggle switch is set to Stage 2. Because you pre-adjusted the Stage 2 chamber to its "minimum" setting, you shouldn't see any significant change or increase when switching between Stage 1 and Stage 2;
4) With the toggle switch set to Stage 2, slowly increase the boost level in the Stage 2 chamber until you reach 0.100 MPa (14.50 PSI);
5) Check and verify your boost level settings at this time. When the toggle switch is set to Stage 1, the boost gauge should show 0.090 MPa (13.05 PSI) and then the reading on the boost gauge should jump up to 0.100 MPa (14.50 PSI) when you throw the toggle switch into Stage 2;
6) Set the toggle switch back to Stage 1 then slowly increase the boost level of the Stage 1 chamber up to and no more than 0.100 MPa (14.50 PSI);
7) Recheck the boost levels for each stage again. This time when going from Stage 1 to Stage 2, your boost level should go from 0.100 MPa (14.50 PSI) to 0.110 MPa (15.95 PSI) respectively.
8) From this point, I continue making a few more adjustments for fine tuning.
Warning! You can overboost and trigger the Check Engine Light (CEL) if your boost levels exceed 0.115 MPa (16.67 PSI). Try not to run at higher boost levels for long periods of time; otherwise, you will shorten the life of your turbo and engine. Always watch your turbo boost gauge, be aware of your boost levels and make conservative adjustments to your boost controller.
--------------------
2002 Subaru Impreza WRX
1/4 Mile: 13.83s @ 96.85MPH (as of January 2003)
http://members.cardomain.com/uncle_dan
Dan
Before making any adjustments to your boost controller, make sure you've installed and are using an accurate and calibrated turbo boost gauge to measure your boost levels. Remember that boost levels vary depending on what gear you are in and the amount of load you put on your engine. For standardization, most posted or published boost levels are measured with the car driven in a gear that's closest to having a 1:1 ratio. For a 5 speed manual transmission, that would usually be 4th gear and for 6 speed manual transmissions, it could be either 4th or 5th gear, depending on which one has the 1:1 gear ratio. If the engine is stock and everything is working properly, you can expect a maximum boost level between 0.095 MPa (13.8 PSI) and 0.097 MPa (14.0 PSI) in 4th gear.
With the Manual Dual Stage Boost Controller, you will notice that when you adjust the boost level in the Stage 1 chamber, the boost level is effected in the Stage 2 chamber. DO NOT set the boost levels for Stage 2 before setting the boost levels for Stage 1 first; otherwise, you'll have a greater chance of overboosting and detonating.
I have my Stage 1 boost level set to about 0.097 MPa (about 14.0 PSI) and my Stage 2 boost level set to about 0.113 MPa (under 16.5 PSI). There's about a 2.5 PSI difference between the two stages. I'm usually driving in Stage 1 most of the time and only reserve the use of Stage 2 when I race every 3 to 4 months.
Here's how I set the two stages of my Turbo XS Dual Stage Boost Controller:
1) Set booth boost chambers to their most "minimum" positions;
2) With the toggle switch set to Stage 1, slowly increase the boost level in the Stage 1 chamber first. To be on the safe side, initially set the boost level to 0.090 MPa (13.05 PSI). (Note: After each adjustment, make sure to check and verify your boost levels while driving in 4th gear);
3) Next, check the boost levels when the toggle switch is set to Stage 2. Because you pre-adjusted the Stage 2 chamber to its "minimum" setting, you shouldn't see any significant change or increase when switching between Stage 1 and Stage 2;
4) With the toggle switch set to Stage 2, slowly increase the boost level in the Stage 2 chamber until you reach 0.100 MPa (14.50 PSI);
5) Check and verify your boost level settings at this time. When the toggle switch is set to Stage 1, the boost gauge should show 0.090 MPa (13.05 PSI) and then the reading on the boost gauge should jump up to 0.100 MPa (14.50 PSI) when you throw the toggle switch into Stage 2;
6) Set the toggle switch back to Stage 1 then slowly increase the boost level of the Stage 1 chamber up to and no more than 0.100 MPa (14.50 PSI);
7) Recheck the boost levels for each stage again. This time when going from Stage 1 to Stage 2, your boost level should go from 0.100 MPa (14.50 PSI) to 0.110 MPa (15.95 PSI) respectively.
8) From this point, I continue making a few more adjustments for fine tuning.
Warning! You can overboost and trigger the Check Engine Light (CEL) if your boost levels exceed 0.115 MPa (16.67 PSI). Try not to run at higher boost levels for long periods of time; otherwise, you will shorten the life of your turbo and engine. Always watch your turbo boost gauge, be aware of your boost levels and make conservative adjustments to your boost controller.
--------------------
2002 Subaru Impreza WRX
1/4 Mile: 13.83s @ 96.85MPH (as of January 2003)
http://members.cardomain.com/uncle_dan
Dan
Guest
Posts: n/a
another option, cheap, easy, and reliable is to do what I did. I bought a boostvalve mbc for $40, some vaccuum tubing, and two small brass valves from home depot (an additional $13). The way I have it hooked up I'm running the mbc when both valves are closed and the stock boost controller when both are open. The nice thing about my setup is that it is very easy to hook up, very reliable, and when you aren't running the mbc you are running the boost controller completely stock, not merely an mbc with the boost turned down to stock levels (such as a duel stage mbc), and it's easy to tune since you only have to set one mbc. It is also easily removable. The only downside to my setup is that you can't change the boost while sitting at a stoplight. It takes about 30 seconds to switch over under the hood. It is also completely foolproof, there is no way you can have the valves in any combination that would damage your car. If you are primarily interestsed at switching over for the track or you know you will be driving aggressively its a great way to go. If you have any questions let me know.
VIP Member
Joined: Feb 2003
Posts: 488
From: 12.9 / 105+
Car Info: black my03 5mt wrx s/w
hackjar,
i'd be interesting in seeing a layout of your scheme. also, if you've got the part #'s, or whereabouts in home depot you found your brass valves, i'd be interested.
i'm also wondering if there would be interest in a GB of grainger 12vdc actuated solenoids. they go about 20 bucks, but they don't sell to the public (afaik)--you need to have a commercial account.
ken
i'd be interesting in seeing a layout of your scheme. also, if you've got the part #'s, or whereabouts in home depot you found your brass valves, i'd be interested.
i'm also wondering if there would be interest in a GB of grainger 12vdc actuated solenoids. they go about 20 bucks, but they don't sell to the public (afaik)--you need to have a commercial account.
ken
2006 Mt Hammy Car Show Winner
iTrader: (11)
Joined: Dec 2002
Posts: 2,730
From: Danville, CA
Car Info: Black 03 WRX, White 04 E46 M3
do a search on nasioc for mbc. This has been discussed alot. The main problem with mbc's is partial throttle full boost. Meaning if you are giving 1/4 throttle you will have full boost. This is bad of course since the turbo is constantyl spooling and you will get REALLY high egt's. Also theres ball/spring vs bleed. I wont go into detail but to have a "safe" mbc peopel have used both combined. Or the ball spring type with a restrictor to bleed off excess pressure.
2006 Mt Hammy Car Show Winner
iTrader: (11)
Joined: Dec 2002
Posts: 2,730
From: Danville, CA
Car Info: Black 03 WRX, White 04 E46 M3
when checking for boost you normally want to check for it in 3rd gear and go all the way to redline. This will give you an accurate reading of your boost. You might want to go test this oin freeway though because by the end of 3rd you will be going pretty fast.
VIP Member
iTrader: (2)
Joined: Nov 2002
Posts: 3,639
From: Longing for my ol' white '02 WRX :(
Car Info: 2016 Acura RDX ... meh. Um, nice subwoofer?
MBC are fine to use. I had one. You just need a boost gauge first and don't go stupid gung ho.
But, I'd recommend not wasting your time. Anyone who wants to have more boost and do it safely and really get the best bang for your work and $ eventually gets an EBC anyhow.
Save your $ and put it towards an EBC.
jason
But, I'd recommend not wasting your time. Anyone who wants to have more boost and do it safely and really get the best bang for your work and $ eventually gets an EBC anyhow.
Save your $ and put it towards an EBC.
jason
Last edited by mmboost; Apr 17, 2003 at 02:50 PM.
Guest
Posts: n/a
Originally posted by P5Shawn
A quick question about setting the boost level. Someone said to check the boost in 4th gear but at what RPM should you check the boost in 4th?
A quick question about setting the boost level. Someone said to check the boost in 4th gear but at what RPM should you check the boost in 4th?
--------------------
2002 Subaru Impreza WRX
1/4 Mile: 13.83s @ 96.85MPH (as of January 2003)
http://members.cardomain.com/uncle_dan
Dan
Last edited by Uncle_Dan; Apr 22, 2003 at 12:27 PM.
Guest
Posts: n/a
Originally posted by tk5dan
when checking for boost you normally want to check for it in 3rd gear and go all the way to redline. This will give you an accurate reading of your boost. You might want to go test this oin freeway though because by the end of 3rd you will be going pretty fast.
when checking for boost you normally want to check for it in 3rd gear and go all the way to redline. This will give you an accurate reading of your boost. You might want to go test this oin freeway though because by the end of 3rd you will be going pretty fast.
Also, if you down shift into 3rd gear from 4th or 5th gear and at WOT, you can overboost in 3rd gear because your MBC isn't set correctly.
In general, boost levels in 5th gear are higher than in 4th gear and boost levels in 4th gear are higher than in 3rd gear when using a MBC. The reason for this is because the boost levels vary based on the load the engine is under. Electronic Boost Controllers (EBC) are able to do a better job of setting, controlling, managing and stabilizing boost levels consistently from gear to gear and at various throttle positions. A negative characteristic to take into consideration with MBC's more so than with EBC's are "Spikes" in boost levels when shifting.
--------------------
2002 Subaru Impreza WRX
1/4 Mile: 13.83s @ 96.85MPH (as of January 2003)
http://members.cardomain.com/uncle_dan
Dan
Last edited by Uncle_Dan; Apr 22, 2003 at 12:27 PM.
Thread
Thread Starter
Forum
Replies
Last Post
FuturistiK_STI
NorCal Classifieds
9
Jun 30, 2011 08:45 AM
bartolommeff
Subaru General
24
Mar 22, 2005 04:25 PM
huck
Dumpster
5
Dec 1, 2003 09:29 PM
Zoeb2s
Engine/Power - EJ20T (pre-2006 WRX and JDM)
11
Feb 10, 2003 11:41 PM
