MBC issues

[moll88]

i cant get it to boost over 15 in third, then in 4th i get about 16psi, 5th and 6th i get 19psi i just dont understand it, how do i get 18 in 3rd ?

[AMS38U]

i see you have the forge wastegate if you dont mind me askin how do u like it and where there big gains

[Nutari]

i cant get it to boost over 15 in third, then in 4th i get about 16psi, 5th and 6th i get 19psi i just dont understand it, how do i get 18 in 3rd ?

unless you bypass the ECU control of the wastegate, a boost controller will not work properly.

[Cue]

unless you bypass the ECU control of the wastegate, a boost controller will not work properly.

Second that... The stock boost pattern is about 1st 8psi, 2nd 10psi, 3rd 12-13 psi, and 4th 15psi and over... an MBC will basically just add X amount to each gear.

[moll88]

soooo..... how do i go about bypassing the ecu WGA controller?

[Circle9]

I agree with what was said above, you really can't go wrong by going that way.

[Cue]

Ems..

[dread]

or a map clamp

[PCspeed3]

crank it an dont shift to 5th or 6th lol. MBC is SKETCH

[Cue]

Just turn it up about 3 psi and be happy with it.... You can't expect anything more from an MBC...

[moll88]

i have a map clamp i just havent had time to install it so when i do it will bypass the ecu controlled WGA ?

[AutoEuphoria]

boost "control" on this car is kind of a joke. Just something I've discovered over the months.

[dread]

i have a map clamp i just havent had time to install it so when i do it will bypass the ecu controlled WGA ?

yes

[Cue]

Yes.... but not bypass the WGA, fool it...

[NYSP33D3]

boost "control" on this car is kind of a joke. Just something I've discovered over the months.
You say that because of the effects of the stock ECU interfering with everything?

[mazdaspeed32007]

he says this because he had problems with his ms3 via his ap.

controlling the boost is fine. like said above, cant expect to much from a mbc. standback or the ap is all you can really do to fix it for real.

[Nutari]

he says this because he had problems with his ms3 via his ap.

controlling the boost is fine. like said above, cant expect to much from a mbc. standback or the ap is all you can really do to fix it for real.

There are more options that just those two.

http://siteground207.com/~protegeg/index.php?cPath=160_259

[mazdaspeed32007]

There are more options that just those two.

http://siteground207.com/~protegeg/index.php?cPath=160_259
i know. just saying a few options. if you got more your more than welcome to share them. im sure poeple would love to know all the options on the table right in front of them instead of searching.

[AutoEuphoria]

he says this because he had problems with his ms3 via his ap.



Not really true. I used two different MBCs before the Ap and still couldn't get CONSISTENT results. I hooked them up in every configuration mentioned on this board, also. A MBC will work fine if you're not looking to hit a specific target in every gear every time. To raise it roughly 2 psi, it'll work fine. I guess I am the only person on this board who is having issues getting consistency in boost patterns.

I've had a number of turbo cars in the past...7 or 8 at this point, I believe. I've used MBCs on at least half of them with no issues...a bit of playing around to find the right setting for the desired PSI, but after that I didn't have to touch it or worry. If I set it to 10psi, it'd run 10psi all day long in every gear. For some reason with this car I would set it to 17psi and have it run 17psi +/- 3 psi depending on what gear you're in and what the weather is like.

Boost control for me isn't about just raising the number...it's consistency. Just a different definition of the term, I guess. Again, it might just be me...others seem to have very little issues with this.

[mazdaspeed32007]

no weather and temperature play a huge roll in how your whole car will react to any situation. suspension in the 30's isnt going to work like in the 70's. same as your motor. cold air is way more dense than hot air so your vehicle is going to run differently, combust fdifferently etc... if your getting +/- 3 with roughly the same weather and conditions then....well....that sucks. lol. sorry to hear that. mbc's need constant adjustment and if you havent had to in [previous cars sweetness for you. also if you hit the gas from 2000 rpms or 4000 rpms your going to have different results with boost. if you run the car 3-4 times and stop inbetween it will effect your boost. im sure you know this and i hope your not taking offense to me stating some obvious things. boost isnt always the easiest thing to control. i think anyways.

[Nutari]

no weather and temperature play a huge roll in how your whole car will react to any situation. suspension in the 30's isnt going to work like in the 70's. same as your motor. cold air is way more dense than hot air so your vehicle is going to run differently, combust fdifferently etc... if your getting +/- 3 with roughly the same weather and conditions then....well....that sucks. lol. sorry to hear that. mbc's need constant adjustment and if you havent had to in [previous cars sweetness for you. also if you hit the gas from 2000 rpms or 4000 rpms your going to have different results with boost. if you run the car 3-4 times and stop inbetween it will effect your boost. im sure you know this and i hope your not taking offense to me stating some obvious things. boost isnt always the easiest thing to control. i think anyways.

I know what you are trying to say, but its just not correct.

Atmosphere has no effect on boost controls. In most cases, the wastegate alone governs boost levels. It has a spring that will open the wastegate once its spring rate is reached via the boost pressure venting the excess boost into the exhaust.

With the Ms3, there is the ECU that governs when the wastegate opens according to various condition, IE What gear you are in, traction, etc.
There is still the wastegate spring. It is set to open at 5psi.

With the XEDE, the computers control is totally bypassed for wastegate control. You are able to input exactly what boost you want at all times.

The best possible book to read on turbocharging is Maximum Boost - Corky Bell (http://www.amazon.com/Maximum-Boost-Turbocharger-Engineering-Performance/dp/0837601606/ref=pd_bbs_sr_1?ie=UTF8&s=books&qid=1233683714&sr=8-1)

[Cue]

I know what you are trying to say, but its just not correct.

Atmosphere has no effect on boost controls. In most cases, the wastegate alone governs boost levels. It has a spring that will open the wastegate once its spring rate is reached via the boost pressure venting the excess boost into the exhaust.

The MAP sensor reads temperature as well, and when this exceeds x degrees, the ECU boost maps change; lower.... and of couse, this is all influenced by the outside temperature, and length of driving, type of driving etc. When your temps are low, you will boost much higher.... when they're hot, you get 12, 11, 10 psi.

You're right when you say atmosphere has no effect on boost... the MAP temps have effect on boost... but the atmosphere influences big time the MAP temps....

[Nutari]

The MAP sensor reads temperature as well, and when this exceeds x degrees, the ECU boost maps change; lower.... and of couse, this is all influenced by the outside temperature, and length of driving, type of driving etc. When your temps are low, you will boost much higher.... when they're hot, you get 12, 11, 10 psi.

You're right when you say atmosphere has no effect on boost... the MAP temps have effect on boost... but the atmosphere influences big time the MAP temps....

I've never heard of our ECU changing boost due to outside temp. Then again, I live in Hawaii so I've never had to deal with that. :)

I do stand corrected. Thank you.

[Cue]

I've never heard of our ECU changing boost due to outside temp. Then again, I live in Hawaii so I've never had to deal with that. :)

I do stand corrected. Thank you.

Won't change due to outside temp.... will change do to engine temp.... I'm just saying that outside temp greatly influences the engine temps (temp of air coming in affects the engine temps)

[mazdaspeed32007]

ok well....in theory, we all ake a valid point. put them all together and get.....THE RIGHT ANSWER!!! WOOOOOOO!

[dread]

autoeuphoria, the problem with your car is that you have no cat's which is allowing for too much flow and your wastegate is maxed out. You can reduce boost in this situation by not opening the wastegate solenoid when boost is building and by limiting the throttle from opening completely. This way you will never build too much boost and the wastegate won't have to try and bleed off more air than it is capable of.