MBC and our MS3 ECU...

[borderline]

Hello,
Does anyone have an anwser to this (sorry for my bad english!):

-If we raise the boost level (with a MBC), it is supposed that the ENGINE will throw a code to the ECU saying that the boost level has been raised over the factory limit BUT this is done without throwing a CELL! (so you won't notice it) The code is stored somewhere in the ECU and disconnecting the battery won't erase it at all.

Apparently, the dealer can see that "stored" code with their diagnostic tool.
But I don't know how! Someon know if a CAN-BUS code reader can see and erase that code?
(Guess NOT, Mazda engineers are not imbeciles like that)

Someone know more about this?
Cuz this is not a clue, if the dealer see this you can say GOODBYE to the warranty!!

This is what my local MAZDA tech said to me, but it is true?

[TX Speed 6]

Yes, a cleared cel will still be stored, and the dealer can see even after its gone. If it reads that the boost was altered, more than likely whenever you have an issue with your car they will try and relate it to that and not do any warranty covered work.

[borderline]

Is there a solution for that? is it still possible to erase that STICKY code?
There is no tool available on the market to do this?

[fourthmeal]

I think overboost closes the throttle-by-wire. Thus wasting your efforts. Call me on it if I'm wrong.

[mrlilguy157]

yall are silly. i run 20psi on the stock turbo daily.

Manual Boost Controller, and ATP boost cut killer. its $75 dollars, well worth it, and what it does is bleed off the pressure that goes into the MAP sensor (which senses boost levels) and retains it at 15.6psi at the sensor, although its higher in the actual manifold.

buy a Joe P manual boost controller (they're super simple and easy) for about $50.

enjoy the added power, get no fuel/boost cut whatsoever, and no CEL

call me for questions.

Jonathan Martin
214.957.0461


edit: also - i've been to the dealer 3 times and they've plugged in everytime and never have said anything.

[Jays07MS3]

I think overboost closes the throttle-by-wire. Thus wasting your efforts. Call me on it if I'm wrong.

I'm curious as to what would happen if a boost controller was used and set at the stock 15.6 psi. Would an over-boost condition occur in 1st and 2nd gear? If not, then it could be a way to overcome the limitation in those gears while still maintaining stock boost levels.

[tru-boost]

yall are silly. i run 20psi on the stock turbo daily.

Manual Boost Controller, and ATP boost cut killer. its $75 dollars, well worth it, and what it does is bleed off the pressure that goes into the MAP sensor (which senses boost levels) and retains it at 15.6psi at the sensor, although its higher in the actual manifold.

buy a Joe P manual boost controller (they're super simple and easy) for about $50.

enjoy the added power, get no fuel/boost cut whatsoever, and no CEL

call me for questions.

Jonathan Martin
214.957.0461


edit: also - i've been to the dealer 3 times and they've plugged in everytime and never have said anything.that mod does work, but i can tell you this. at 20 psi the turbo is WAY out of its efficiency range. after 18 psi you actually lose power. i showed less power at 20 psi than at 17psi on the AMS dyno. the motor is good for it, but the turbo isnt ! you are actually slower now !

[oskinosmee]

what do you dyno at 18 psi

[jhowey]

Stupid question. If your computer thinks your spooling 15.6psi but your really spooling 18-20 psi, how does that give you power, wouldnt you need more fuel, and your computer not know it needs to give it to the car?

[Jays07MS3]

Stupid question. If your computer thinks your spooling 15.6psi but your really spooling 18-20 psi, how does that give you power, wouldnt you need more fuel, and your computer not know it needs to give it to the car?

The amount of fuel the ECU calculates is based off of the MAF reading not the MAP pressure readings. So it only cares how much air is entering the engine not the pressure in the manifold. I believe this is the case but I could be wrong.

[itzl0l]

that mod does work, but i can tell you this. at 20 psi the turbo is WAY out of its efficiency range. after 18 psi you actually lose power. i showed less power at 20 psi than at 17psi on the AMS dyno. the motor is good for it, but the turbo isnt ! you are actually slower now !

i remember when people said that about the srt-4 turbo. Peeps also said that you could never get 300whp out of the stock turbo and it was not effecient above 17 psi. Bout a year later folks were running 20+ psi and making 300whp without too much trouble...it was all in the tuning...and keeping the charge cool (either water/meth inj. and or a big ass intercooler)

[itzl0l]

yall are silly. i run 20psi on the stock turbo daily.

Manual Boost Controller, and ATP boost cut killer. its $75 dollars, well worth it, and what it does is bleed off the pressure that goes into the MAP sensor (which senses boost levels) and retains it at 15.6psi at the sensor, although its higher in the actual manifold.

buy a Joe P manual boost controller (they're super simple and easy) for about $50.

enjoy the added power, get no fuel/boost cut whatsoever, and no CEL

call me for questions.

Jonathan Martin
214.957.0461


edit: also - i've been to the dealer 3 times and they've plugged in everytime and never have said anything.


I did wonder if the ATP boost cut elim. worked or not. How was the install? i have not even looked to see where the MAP sensor is....got any pics?

[Haltech]

You should be able to clear any stored code with this software:

http://www.therpmstore.com/product_info.php?cPath=122&products_id=146





http://www.therpmstore.com/images/ae-scantool_pic1.jpg

[MS3ICA]

when the turbo goes out of the efficiancy range does that over rev the turbo?, mine spikes to 20 any time i floor it in 5th or 6th gear, doease that ruin the turbo?

[mrlilguy157]

I did wonder if the ATP boost cut elim. worked or not. How was the install? i have not even looked to see where the MAP sensor is....got any pics?

yes it works, install took 10minutes, and its an amzing little piece of machinary.

map sensor is on the opposite side of the intake manifold that the throttle body is.... about the same location. its tucked behind an electrical connector. 1 bolt holds it in.

i suggest anyone to buy it - mad props to ATP, for they're the only company thats produced a product like this. i dont have pictures, but they'd look identical to what ATP has posted for the install guide.....

[tru-boost]

i remember when people said that about the srt-4 turbo. Peeps also said that you could never get 300whp out of the stock turbo and it was not effecient above 17 psi. Bout a year later folks were running 20+ psi and making 300whp without too much trouble...it was all in the tuning...and keeping the charge cool (either water/meth inj. and or a big ass intercooler)

with meth inl....OK, but that is the only way to get it cool enough to actually make more power. i dont have the stack of dyno sheetsa they gave me in front of me but i think it was like a 17HP 20TQ gain at 18psi compared to 16psi

[fourthmeal]

makes sense, rule of thumb measurements show that 11hp per psi is in the ballpark.

[itzl0l]

with meth inl....OK, but that is the only way to get it cool enough to actually make more power. i dont have the stack of dyno sheetsa they gave me in front of me but i think it was like a 17HP 20TQ gain at 18psi compared to 16psi

yea that sounds about right. I wonder if any1 has done meth inj on one of these yet...hmm. Another thing to think about is that no matter what, on a dyno you'll never get the same airflow across the IC as you do at normal driving speeds.

[borderline]

Does what I'm talkin about is called: pending codes?

mrlilguy157: This is a nice setup :), but you have no trouble with the CELL or the dealer at all with this setup?

[mrlilguy157]

Does what I'm talkin about is called: pending codes?

mrlilguy157: This is a nice setup :), but you have no trouble with the CELL or the dealer at all with this setup?


thanks. no CEL is caused whatsover, and I actually have my manual boost controller right next to the battery, clearly visible, with vacuum lines going to the wastegate and the vac. source down there. i went in for the motor mount recall and they pulled the battery for testing and what not, they never said anything, and then i went in for a rattle in the trunk, but always pop the hood, and they didnt say anything about my ziptie k&n intake, bov, or boost controller.

i found my mod friendly dealership :)

[CaSHMeRe]

thanks. no CEL is caused whatsover, and I actually have my manual boost controller right next to the battery, clearly visible, with vacuum lines going to the wastegate and the vac. source down there. i went in for the motor mount recall and they pulled the battery for testing and what not, they never said anything, and then i went in for a rattle in the trunk, but always pop the hood, and they didnt say anything about my ziptie k&n intake, bov, or boost controller.

i found my mod friendly dealership :)

mrlil guy seems to be responsible with his mbc and boost cut killer. i personally wouldn't recommend it. too many kids get the urge, turn that shit up and blow their shit sky high.

wait for a tuning solution!

[mrlilguy157]

mrlil guy seems to be responsible with his mbc and boost cut killer. i personally wouldn't recommend it. too many kids get the urge, turn that shit up and blow their shit sky high.

wait for a tuning solution!

;) i've blown a motor before. it sucks so i don't mind keeping the boost down. i also know this turbo kinda sucks past about 20psi, if not before that. as does the intercooler. too many crappy parts to rely on. too hott = more possibilites for detonation = POP!:eek:

[borderline]

CaSHMeRe: You have the CB hood? Did you bought it at steetunit? Wondering if the fitting is really good...
you have some big pics?
you can send PM if you prefer, thanks dude!

[bast525]

I'm interested in doing this, not so much to raise overall boost levels... but more to hold more boost past 5500 rpm. I understand that boost drops down pretty bad by 6000 rpm and I want to bring some of that back. Overall i don't think i would go much above 17-18psi peak.

Also, I want to be allowed full boost in 1st and 2nd gear and get some of that power back as well.


So... if you have turned the stock boost up to 20 psi or whatever, what does it hold? by 6000 rpm? by redline?

[x'ed]

I did wonder if the ATP boost cut elim. worked or not. How was the install? i have not even looked to see where the MAP sensor is....got any pics?

Is this ATP boost cut a thing that lets it rev past 5700rpm with some actual power.

[Haltech]

Is this ATP boost cut a thing that lets it rev past 5700rpm with some actual power.


Nah, it keeps the wastegate from overboosting so it doesnt blow the motor.
Theres people here experiencing overboosting with CAIs on their cars.

[laloosh]

Hmm this is somethign i would also like to try. Run 18psi and pick up 20 to the wheels for 50 bucks is never a bad thing.

[bast525]

Boost controller = $50 (can make one cheap for about $10, ball and spring valve type)
Boost Gauge = ~$75
Boost cut defenser = $80


Just clarifying that. Either way... yeah not bad 20 hp for about $200 (less if you make the MBC yourself).

Can ANYONE comment on the MS3/6 having any part-throttle-over-boost issues? I know it's a small turbo... is anyone getting any surging after installing an MBC?

[mrlilguy157]

Boost controller = $50 (can make one cheap for about $10, ball and spring valve type)
Boost Gauge = ~$75
Boost cut defenser = $80


Just clarifying that. Either way... yeah not bad 20 hp for about $200 (less if you make the MBC yourself).

Can ANYONE comment on the MS3/6 having any part-throttle-over-boost issues? I know it's a small turbo... is anyone getting any surging after installing an MBC?

Buy the ATP boost cut killer along with a manual boost controller (I'll sell you a boost controller for $20 - Joe P.) and a gauge (I'll sell ya for 35$) and turn it up and watch the wheels spin.

No surging unless you turn the boost WAAYYYYYY up out of effeciency range.

Feel free to call with questions.

Jonathan Martin
214.957.0461

[speedi3]

Hello,
Does anyone have an anwser to this (sorry for my bad english!):

-If we raise the boost level (with a MBC), it is supposed that the ENGINE will throw a code to the ECU saying that the boost level has been raised over the factory limit BUT this is done without throwing a CELL! (so you won't notice it) The code is stored somewhere in the ECU and disconnecting the battery won't erase it at all.

Apparently, the dealer can see that "stored" code with their diagnostic tool.
But I don't know how! Someon know if a CAN-BUS code reader can see and erase that code?
(Guess NOT, Mazda engineers are not imbeciles like that)

Someone know more about this?
Cuz this is not a clue, if the dealer see this you can say GOODBYE to the warranty!!

This is what my local MAZDA tech said to me, but it is true?



I had this very thing happen this week. Infact the car is still at the dealer. the code is p0234. It happens but no light came on a while back. The dealer fortunately for me has been very cool fixed what he could but couldn't clear that code. I get my car back on Wednesday but your tech is accurate. They did try the old "if you mod you void your warranty" but completed the work that they could w/o touching anythign aftermarket. I think its all based on the dealer that you work with.

[mrlilguy157]

I had this very thing happen this week. Infact the car is still at the dealer. the code is p0234. It happens but no light came on a while back. The dealer fortunately for me has been very cool fixed what he could but couldn't clear that code. I get my car back on Wednesday but your tech is accurate. They did try the old "if you mod you void your warranty" but completed the work that they could w/o touching anythign aftermarket. I think its all based on the dealer that you work with.

I'm not buying into this. Boost spikes happen all the time at 20psi + on stock setup.

[bast525]

Buy the ATP boost cut killer along with a manual boost controller (I'll sell you a boost controller for $20 - Joe P.) and a gauge (I'll sell ya for 35$) and turn it up and watch the wheels spin.

No surging unless you turn the boost WAAYYYYYY up out of effeciency range.

Feel free to call with questions.

Jonathan Martin
214.957.0461


How does this affect 1st and 2nd gear power? easy wheel spin in 1st now? Like... if you're already rolling, 5mph, and punch it, will the wheels spin? My SRT-4 used to do this... MS3 doesn't do it even with traction control off, unless it's wet out, then it will break them loose in first and second.

[mrlilguy157]

How does this affect 1st and 2nd gear power? easy wheel spin in 1st now? Like... if you're already rolling, 5mph, and punch it, will the wheels spin? My SRT-4 used to do this... MS3 doesn't do it even with traction control off, unless it's wet out, then it will break them loose in first and second.

yea you can break them loose quite easily.... although thats kinda dumb because i like when my car rolls forward with traction :)

[borderline]

mrlilguy157, do you think the ATP boost cut def. will prevent the ECU to "record" and store an overboosting condition? cuz I guess the engine won't even notice the turbo is overboosting (example: 19 psi) all the time.

This is what a guy from ATP said to me regarding the fuel cut defender: the extra pressure going into the MAP sensor that the ECU monitors is bled
off to atmosphere before it makes it into the sensor so the high value is
never sent to the ECU

speedi3: Thanks for sharing your experience, so my dealer tech is not a liar finally!

[fourthmeal]

P0234 -

This is a Wastegate System Monitor problem.

Not a code I'd want to have, for sure.

[bast525]

I want to do this but not in any way if it's going to affect or possibly affect my warranty.

I don't want to run big boost... 17-18 psi tops because I can plainly see on my dyno that there is extra fuel there, and I wouldn't turn the boost up til I was on the dyno and could make sure the air/fuel ratio stays safe.

I don't want huge power... I want the power limit lessened or removed in first and second gear, and I want the car not to run so damn rich.

But most of all I don't want Mazda to void my warranty.

Are we SURE this boost cut defenser will keep the ECU from seeing the increased boost and throwing some internal codes??

[mrlilguy157]

I want to do this but not in any way if it's going to affect or possibly affect my warranty.

I don't want to run big boost... 17-18 psi tops because I can plainly see on my dyno that there is extra fuel there, and I wouldn't turn the boost up til I was on the dyno and could make sure the air/fuel ratio stays safe.

I don't want huge power... I want the power limit lessened or removed in first and second gear, and I want the car not to run so damn rich.

But most of all I don't want Mazda to void my warranty.

Are we SURE this boost cut defenser will keep the ECU from seeing the increased boost and throwing some internal codes??

i've been 3 times to the dealer and ran the boost cut killer module 2 weeks after i bought the car.

no one has ever mentioned anything, but they did jokingly give me a hard time about the blow off valve :)

[bast525]

i've been 3 times to the dealer and ran the boost cut killer module 2 weeks after i bought the car.

no one has ever mentioned anything, but they did jokingly give me a hard time about the blow off valve :)

I am going to call you some time soon to discuss this a little further and possibly buy a gauge and MBC from you. If I can make ~20 whp for less than $200 and not hurt the warranty (or the engine!!!) that's hard to pass up.

[mrlilguy157]

I am going to call you some time soon to discuss this a little further and possibly buy a gauge and MBC from you. If I can make ~20 whp for less than $200 and not hurt the warranty (or the engine!!!) that's hard to pass up.

now would be a good time to call.

[laloosh]

now would be a good time to call.

pm sent(shady)

[tru-boost]

is your car still runnig 20psi and normal timing ?
on my car the cars ecu basically un-did any boost increases we did to it.
i also did not us the atp fuel cut device...... updates ??

[bast525]

Got the boost gauge and MBC. Boost gauge is installed, but running ECU controlled boost, won't get the MBC installed til maybe next week.

Boost definately spikes a LOT with stock boost control... I've seen it hit 20 psi a couple times. So I don't think the computer is 'recording' anything over 15.6 psi and keeping those records to use against you and void your warranty.

It shoots up quick, taps 19-20 psi, and drops right down to 16 psi.

I'll be installing the MBC and turning the boost up to where it holds 18psi after the spike, and see what happens

[BoostedSpd6]

just to get my say in i showed up at the dealership with all my mods and my dealership actually loved it.. the owner wanted to take it for a ride to see how much faster it was...and all the techs were around my car checking it out..no hassle's for me!!.. and i have a front mount, intake, custom exhaust and a few others... too bad every other dealership isnt like mine.. sentry west mazda of shrewsbury MA...

EDIT: till i showed up with the front mount.

[mghunt]

One of the benefits of an MBC used in conjunction with the factory controls is for the purpose of limiting boost, not raising it. In ideal conditions, raising the boost might raise power output. However, high temperatures might offset this. Also, you definitely don't want to force the boost to be higher when the boost is tapering off at higher RPMs. This is happening because the flow map of the turbo is starting to get outside of its efficiency range. My 1.8t Passat was notorious for this with it's little K03.

I had a Dawes MBC on the 1.8t to restrict the boost of my chipped ECU to 15psi. It didn't run rich like the MS3 does, so restricting the boost was necessary in the hot summers here in Phx. I limited the car to 12psi when it was >100F and then turned up the boost during the winter. The chipped ECUs for the 1.8t would raise the boost in the turbo's efficiency range, but still rely on the turbos flow to limit boost. So, the additional power was at low and mid rpm, and it tapered off seriously. Using an MBC to raise the boost worked really well, as long as you didn't push the boost at high rpm's too much. Not sure what this level is on the MS3.

Another thing to be careful of is that the boost doesn't build too faster than the fuel can be delivered. I'm assuming this isn't as big an issue with the MS3, but still something to consider.

[speedi3]

One of the benefits of an MBC used in conjunction with the factory controls is for the purpose of limiting boost, not raising it. In ideal conditions, raising the boost might raise power output. However, high temperatures might offset this. Also, you definitely don't want to force the boost to be higher when the boost is tapering off at higher RPMs. This is happening because the flow map of the turbo is starting to get outside of its efficiency range. My 1.8t Passat was notorious for this with it's little K03.

I had a Dawes MBC on the 1.8t to restrict the boost of my chipped ECU to 15psi. It didn't run rich like the MS3 does, so restricting the boost was necessary in the hot summers here in Phx. I limited the car to 12psi when it was >100F and then turned up the boost during the winter. The chipped ECUs for the 1.8t would raise the boost in the turbo's efficiency range, but still rely on the turbos flow to limit boost. So, the additional power was at low and mid rpm, and it tapered off seriously. Using an MBC to raise the boost worked really well, as long as you didn't push the boost at high rpm's too much. Not sure what this level is on the MS3.

Another thing to be careful of is that the boost doesn't build too faster than the fuel can be delivered. I'm assuming this isn't as big an issue with the MS3, but still something to consider.


I thought that you had to remove the "factory boost controler" to put on a MBC. the solenoid has to be removed and then hoses rerouted to put on a mbc? How would they work together if they are removed?

[laloosh]

simply put, no. A mbc will work on this car just like any other car. Mine is going in monday. IM not installing the fuel cut defender im just turning it up untill the car cuts fuel at 18psi and backing it down a little

[mghunt]

I thought that you had to remove the "factory boost controler" to put on a MBC. the solenoid has to be removed and then hoses rerouted to put on a mbc? How would they work together if they are removed?

nah, you don't have to remove the factory control to install an MBC. Talk to some VW guys. There are tons of 1.8t guys that had to keep the factory control on there and bleed off pressure before it was sent to the MAP sensor. One of the big issues on VW turbos was that the boost could build too quickly causing overboost issues and lean conditions because the fuel system couldn't keep up. They would keep the factory controls in place to control the rate of boost buildup, but use the MBC to control the amount of boost and to bleed pressure so the MAP doesn't see the extra pressure.

They were also used in conjunction with the computer control to limit the amount of boost and eliminate boost spikes. In the extreme heat, where I live, boost spikes and surging are the enemy. The MBC was a good "boost insurance policy" to cap what the car could demand from the turbo system. It essentially forced the wastegate open early. The timing of the motor was much happier and my car actually ran better when I eliminated boost spikes.

I don't see why an MBC couldn't be configured in the factory wastegate piping to raise the boost and allow the factory systems to control the rate that boost builds.

-Mark

[speedi3]

nah, you don't have to remove the factory control to install an MBC. Talk to some VW guys. There are tons of 1.8t guys that had to keep the factory control on there and bleed off pressure before it was sent to the MAP sensor. One of the big issues on VW turbos was that the boost could build too quickly causing overboost issues and lean conditions because the fuel system couldn't keep up. They would keep the factory controls in place to control the rate of boost buildup, but use the MBC to control the amount of boost and to bleed pressure so the MAP doesn't see the extra pressure.

They were also used in conjunction with the computer control to limit the amount of boost and eliminate boost spikes. In the extreme heat, where I live, boost spikes and surging are the enemy. The MBC was a good "boost insurance policy" to cap what the car could demand from the turbo system. It essentially forced the wastegate open early. The timing of the motor was much happier and my car actually ran better when I eliminated boost spikes.

I don't see why an MBC couldn't be configured in the factory wastegate piping to raise the boost and allow the factory systems to control the rate that boost builds.

-Mark



AWESOME! That's how i want to set it up.

[bast525]

simply put, no. A mbc will work on this car just like any other car. Mine is going in monday. IM not installing the fuel cut defender im just turning it up untill the car cuts fuel at 18psi and backing it down a little


That's what I was going to do. Should be fine at that boost.

[tru-boost]

simply put, no. A mbc will work on this car just like any other car. Mine is going in monday. IM not installing the fuel cut defender im just turning it up untill the car cuts fuel at 18psi and backing it down a little

WRONG !! thats what AMS did to my car. it lasted about a week. then the car felt super slow. the car returned itself to stock boost levels, and even pulled EXTR timing. if you up the boost at all, you need the fuel cut defender...that is the key. without it you are waisting your time .

[laloosh]

if I leave it at 17 18 psi and don't hit boost cut what's the point of the defender. how can the ecu sense this if I'm not hitting boost cut. I have a hard time believing the ecu can physically turn down boost if its raised a mere 2 psi. I'm still doing it and watching the boost gauge if it stay at 17 it works

[shucky]

Laloosh, nice times (13.6) my man. If you leave the factory boost control solenoid in line with a MBC the ECU can still adjust and compensate to return everything back to stock levels. The VW ECU's did the same thing. Even when chipped on a VW, guys would run a MBC in line with the factory N75 (boost control solenoid) which I did as well, to get just a little more boost and to hold onto boost just a little bit longer and the ECU would still reduce this extra amount over time. Not totally back to the values specified by the chip, but it would keep trying to bring boost down each time you turned up the boost using the mbc. Tru is correct in that you need the ATP piece to fool your ECU into thinking no changes were made when in fact you upped the boost with the MBC.

[knowledge007]

I had this very thing happen this week. Infact the car is still at the dealer. the code is p0234. It happens but no light came on a while back. The dealer fortunately for me has been very cool fixed what he could but couldn't clear that code. I get my car back on Wednesday but your tech is accurate. They did try the old "if you mod you void your warranty" but completed the work that they could w/o touching anythign aftermarket. I think its all based on the dealer that you work with.


What is the description of that code?

[tru-boost]

if I leave it at 17 18 psi and don't hit boost cut what's the point of the defender. how can the ecu sense this if I'm not hitting boost cut. I have a hard time believing the ecu can physically turn down boost if its raised a mere 2 psi. I'm still doing it and watching the boost gauge if it stay at 17 it works

thats what the MAP (mainfold air pressure ) sensor does...reads boost.
it will see the car consistantly hold more boost, and it will play tricks with the throttle plate to actually reduce the boost. and if it continues to see that is being over rided it will then just pull out a ton of timing. even though at 17-18psi you wont hit fuelt cut, you still need the defender. it will hide the fact that you have more boost, and the ECU will not adjust.
just sharing my own experience.... if you want to learn the hard way... go ahead. the worst part is if you dont re-dyno the car you wont know that you are 25 HP short of where you started.

[laloosh]

hmmm, i guess i gotta order this stupid atp thing....oh well so much for being stuck at 17 psi, more like 18 19 now lol, yes yes i know the range of turbo is at its max, this turbo is a pos, the quicker it dies the quicker i have a reason to upgrade(glare)

[speedi3]

p0234 engine over boost.

[speedi3]

thats what the MAP (mainfold air pressure ) sensor does...reads boost.
it will see the car consistantly hold more boost, and it will play tricks with the throttle plate to actually reduce the boost. and if it continues to see that is being over rided it will then just pull out a ton of timing. even though at 17-18psi you wont hit fuelt cut, you still need the defender. it will hide the fact that you have more boost, and the ECU will not adjust.
just sharing my own experience.... if you want to learn the hard way... go ahead. the worst part is if you dont re-dyno the car you wont know that you are 25 HP short of where you started.

ok so how do you get it back? if you have already hit that point how do you get the hp back that was removed (uhm)?

[tru-boost]

ok so how do you get it back? if you have already hit that point how do you get the hp back that was removed (uhm)?

you have to reset the ecu, and drive it without any added boost. the ecu will re-learn the stock maps.
the stock turbo is pretty much dead above 18psi. it is ok to run more in short bursts. you would not want to run 20psi on a autox car. street driving and 1/4 mile use 19-20psi will work. the life of the turbo will be reduced...but who cares !

[knowledge007]

you have to reset the ecu, and drive it without any added boost. the ecu will re-learn the stock maps.
the stock turbo is pretty much dead above 18psi. it is ok to run more in short bursts. you would not want to run 20psi on a autox car. street driving and 1/4 mile use 19-20psi will work. the life of the turbo will be reduced...but who cares !

This is a great one. (hitit2)

[mghunt]

Tru is correct in that you need the ATP piece to fool your ECU into thinking no changes were made when in fact you upped the boost with the MBC.

For those that are interested... ATP said that this piece is basically just a pressure regulator. It allows lower pressures to pass and peaks at the regulator set point. So, the MAP sensor ends up seeing the capped value and anything below. I just hope the fuel system can keep up with the extra boost. Given how rich the car runs, I don't think that's a huge issue. But keeping an eye on a/f ratios is a good idea if you turn up the boost a little.

[tru-boost]

the car uses the MAF to determine how much fuel to add. it will still be getting proper readings and will maintain a stock like A/F .

[mghunt]

the car uses the MAF to determine how much fuel to add. it will still be getting proper readings and will maintain a stock like A/F .

This is only true if the injectors, the maximum injector duty cycle, and the fuel pressure can support it. In other words, the fuel maps in the ECU have to be able to support the added air. It is completely vehicle dependent. Some vehicles are more "tunable" than others.

My previous car had an injector duty cycle limitation. Basically the fuel maps were designed with the factory equipment in mind. If the turbo was replaced, than boost could be maintained at higher engine RPMs. However, the fuel system couldn't support the higher boost in this RPM range. The duty cycle limitation would eventually lead to the ECU trimming out the extra fuel when it was in closed-loop operation.

I don't think this is an issue with the MS3, but the reason I suggest keeping an eye on fuel trims and a/f ratios when you turn up the boost.

[laloosh]

Only if the injectors, the maximum injector duty cycle, and the fuel pressure can support it. In other words, the fuel maps in the ECU have to be able to support the added air.

My previous car had an injector duty cycle limitation. If the fuel pressure was adjusted for maximum boost during open loop operation, then the engine pulled fuel back at idle. In other words, no matter what was done to the fuel pressure, the motor would end up pulling fuel to stabilize the idle and would starve the engine of fuel at high RPM/boost conditions.

I don't think this is an issue with the MS3, but the reason I suggest keeping an eye on fuel trims and a/f ratios when you turn up the boost.


from what i read on here our injector duty cycles are nowhere near being a limitation.

[fourthmeal]

The bottleneck is all about the mechanical fuel pump on the engine block.

[mghunt]

from what i read on here our injector duty cycles are nowhere near being a limitation.

Good to know. :)

[nig3]

Stupid question. If your computer thinks your spooling 15.6psi but your really spooling 18-20 psi, how does that give you power, wouldnt you need more fuel, and your computer not know it needs to give it to the car?

yeah hes kinda retarded, the mbc actually bleed presure off to the wastgate not the map sensor.

[laloosh]

yeah hes kinda retarded, the mbc actually bleed presure off to the wastgate not the map sensor.

um no, the atp fcd defender bleeds pressure off the map

[mghunt]

Simply put, the "defender" is a pressure regulator. It "caps" the pressure so it doesn't exceed a set level. So, the car's ECU is happy because it doesn't see boost pressures that are too high.

jhowey, to actually answer your question, If we boost above the ECU's limit, yes, we need to add more fuel. However, the ECU will know how much fuel to add based on the mass airflow sensor (MAFs) readings. It is able to compensate, within reason.