It is a fact that the MCS boost sensor has a limit of nearly 22psi and when it hits that number it dumps pressure to nearly 10psi.
My car has that exact problem and I can tell you that is very frustrating when you drive the car.
I assume a solution is to lower the target boost pressure and subsequently loose torque and power through the whole rpm range.
My question is if the JCW boost sensor has an altered limit and what limit is that? Can I use it as a bolt on solution to avoid the dumping of boost pressure at 22psi?
Can Alta or anyone help me on this?
What is the best way to deal with it?

 

Please explain exactly which boost sensor you are referring too!

 

I mean the boost converter which regulates boost pressure.

The part number for the MCS is here
http://www.realoem.com/bmw/showparts...82&hg=11&fg=45

And the part number for the JCW is here
http://www.realoem.com/bmw/showparts...82&hg=11&fg=45

What I was wondering is if there is any difference between them and if the JCW can fix my problem

 

There is no difference between the S and JCW pressure converters after 09/2009 for the S, I can only assume that the pressure sensor up to 09/2009 could hold the key to your pressure drop off issue!

That said I have not had a problem holding this amount of boost in trials, and my Clubbie is a 04/2009 build.

The part numbers are for the S model:

02 PRESSURE CONVERTER 1 up to 09/2009 11657566781 $128.76
02 PRESSURE CONVERTER 1 11657595373
02 PRESSURE CONVERTER 1 11657599547

And here are the part numbers for the JCW:

02 PRESSURE CONVERTER 1 11657595373
02 PRESSURE CONVERTER 1 11657599547

Also, are you running a stock S turbo ?

If so, your stock turbo won't last long with this amount 20ish psi boost abuse, your asking too much of the stock S turbo.

 

My initial suspicion was that my pressure converter 11657566781 is causing the problem and that if replaced by the 1165795373 or the 11657599547 would fix my problem. But having said that the following question has to do with the difference between those two after 09/2009. Which is the right one?

The turbo is brand new because I already blew one apart...
I swear it was not my fault, the car was totally stock until then. I also changed the exhaust manifold as well, as it is a part of the JCW kit (here in Europe) together with a brand new turbo with different part number than the factory fitted (after 03/2010). I drove the car for some months, trying to find the extra power that the JCW promises. I never did...
Then I went directly to stage 3 and all the mods that my signature says. The turbo is really working hard and since it has been only two weeks with my stage 3 mods I really feel that it shouldn't work with so much boost. 19-20psi would be enough to get me into the game.
But after all, since there is no turning back from the tuning way, I think I will try the new pressure converter first to bypass the boost cut and if something bad happens to the turbo again then I will replace it with the modified JCW one, to go one step further. What is your opinion about that and how short do you think is the life of the stock turbo working this boost?

 

Regarding the different pressure converters, I will do further research this coming week, and how long your turbo will last, will determine how much abuse you give it, over and above it's correct working parameter!

 

Mine dumps the boost at 22psi as well...(with JCW turbo)

The part that you are referring to is simply the diverter/by-pass valve though, isn't it?

If so, I do not think that is your issue. I think the issue lies in the MAP sensor which is post-turbo. There is one MAP sensor, and then another smaller temp/pressure sensor on the intake manifold...the JCW has different part numbers for both.

 

Yes there is the temp/pressure sensor which is on the rigid plastic hose on the top left of the engine bay and then there is the main map sensor on the intake manifold which I tapped with alta's boost thief to take a reading for my boost gauge. I have searched them as part numbers and surely they are different than the MCS. The question is, if replacing them with JCW's sensor will do the job?
Has anyone here done that?
Please enlighten me...

 

Although these sensors you are talking about are different on the S to the JCW, they both have 3bar working pressure sensory limits!

If you put either of these two sensors from a JCW into a S, you will get a CEL light.

 

So what you suggest here, is that the cause of the problem are not the map sensors?
I am trying hard to find a logical explanation about the boost cutout and I can say I am a little confused. After all I am just a Civil Engineer.
Maybe it is the software itself to blame then or does the chance of the pressure converter to be the key is higher?

 

Like I mentioned earlier, I will do some research and trial testing of the pressure converters, I am not into guessing or giving misguided information.

But I will say this, you don't need to run as much boost as 22psi to produce good amounts of power!

 

Thank you in advance for your interest. I really appreciate it. I will be waiting for your feedback...

And for the history I should say that I did not ask for excess boost pressure from my tuner. He actually did not tune it to run 22psi. He gave a target boost pressure of 19psi but for some reason, which is not known to me, the engine hits a boost pressure of 21-22psi causing the boost cutout. And that is happening after 4250rpm. Maybe the software is wrong. I do not know...
The only thing I know though for sure, is that I really love my Mini and I have spent time and money into making it better in many different ways. It will be a shame destroying it.

 

I can confirm that the pressure converter with the part number 11657566781 has been superseded by part number 11657595373 but this is no longer available and has been superseded by part number 11657599547 this now fits all S and JCW models including the LCI N18 engines.

Now as I have a countryman all 4 S fitted with the N18 engine, and a friend has JCW, I did a vacuum test this morning, and sadly the pressure converter is not the issue to the boost regulation drop off at 22psi.

 

My S has the .......781 part number. Is Your friend's JCW using the same converter?

 

My tune is also running 19lbs... but however keep in mind when your ecu goes into overboost, it usually runs ~3psi more while you're WOT. Thus, giving you the 22psi figure. I have the same issue... when I'm driving the car hard and either go from cruising throttle position to WOT, (thus activating overboost) the car feels like its running in limp mode, aka no boost and the car doesn't move anywhere. Also sometimes when I go through the rpm band and shift high at high revs, when i release, shift, and mash on the throttle again (again wide open throttle), it is still trying to get into overboost mode, and again it will dump all the boost.

I also notice the boost dump when the car gets hotter, aka sitting in traffic for a while then getting into open road.

There technically should be a way to edit the map sensor, as its controlled by the ecu. They may set it at 22lbs since they don't expect to see the stock turbo ever hit that high. I also read someone found out that a warning (CEL possibly?) doesn't come on until the car sees 28 psi. How you'd get there bypassing the MAP sensor, is still beyond me. I'm not sure I'd like to find out either.

All I can say is 19psi in 1st gear is more than enough unless you have wide grippy rubber, and at that point probably a stronger axel too =\
I'm happier spinning my tires in 1st right now than it gripping... cuz sometimes I do fear my axel snapping in half

 

Sorry I forgot to add this to my original post this morning.

My S also has the 781 pressure converter, and I checked this too, and in my vacuum tests, there was no difference

So I have tested the 781 and the latest 547, and there is no difference from a vacuum pressure test, point of view.

 

My tune does exactly the same as yours and since I have a boost gauge I can see that when the boost cutout happens the boost pressure drops at about 12-13psi but the difference from 22psi is so big that it seems that there no boost at all!

I have not noticed yet any dependency from the heat soak, since I have the tune for two weeks or so and the temperature is not that high.

The most important thing is to fix it as soon as possible because it is not healthy for our engines and secondly it is very annoying when you want to drive the car as it is designed for.

Czar thank you for your valuable time and feedback. I appreciate it.
Maybe it is wiser to loose some boost pressure from the software after all.
Investigation not done yet...

 

Here is an interesting article about the pressure converter Mini uses.

http://www.etuners.gr/en/index.php?s=12&t=247

Discussion continued...

 

The ECU runs more boost as the car gets warm. As temps increase it allows the turbo to run more boost. My car is set around 20psi and hits it pretty consistantly, but as it gets warm it begins to try and run 22+, and that's when the cuts start happening. There is a specific map in the ECU which deals with boost vs inlet temps, but I don't think that map is the issue. Something is preventing it from going past 22. Personally I want to be able to run 22-23 psi with the JCW turbo, as it still makes power running that much boost. And the difference in numbers from running 19-21psi vs 22-24psi on it is quite dramatic.

And as far as the high boost limp mode that you are talking about @ 28psi...I was the one that said that. A while back with my old tune and stock turbo, it would go into limp mode and when the data was pulled it said the car saw 29psi....but I don't believe it actually did (I was running around 17-18psi consistently with that tune). It is on that fault memory data sheet straight from BMW/MINI that says 1875 mbar was the setpoint in the ECU which would trigger the 2884 DME fault code "Charge-air pressure control deviation....control deviation too great, upper threshold exceed." The upper threshold being the 1875 mbar (which is ~27.2 psi). Again though, I just think it was reading boost wrong...theres no way the car saw that much boost (and it certainly didn't sound like it either). Completely a separate issue than what we're having now, but just thought I'd respond to what you mentioned in your post.

 

i have a similar issue with my hybrid turbo... i'm currently set to 19 psi or around 210 load per cyl. (technically our cars run off load set points rather than a specific PSI and that subsequent load corresponds to a certain psi for each turbo/engine..) but when i get on the throttle in 6th gear, i'll get straight to 19.4 psi, around 4000 it rises to 20.9 or as high as 21.4 psi, then before i ever surpass 4500 i get either an instant boost drop to 8 or a P2885 code... which doesn't make sense, because back when my wastegate was the problem the 2885 code was saying that the boost wasn't being met (aka i'm making 11psi rather than the 16 i was aiming for at the time)... but now i'm getting 220 or 230 (20 21 psi) when i'm asking for 210 and what do ya know... a P2885 code... and yet the datalog clearly states that i'm at and/or above the target load request...

i've swapped diverter valve (that piece on the turbo) from stock (which failed) to WMWs upgrade which held fine.. and recently am trying out Ways new Forge BOV (not the spacer... see his post in vendor section) and that thing works like an absolute champ!!!! faster release, faster build, better all around than our pieces... being like a real bov really helps too :P (it's vacuum/boost activated but still connects to the wiring harness of the stock piece... i'll take pics of mine later once waylen tells me it's cool tod o so... )

one thing that MIGHt be an issue is the primary O2 Sensor... i know mine's going and throwing a code here and there... getting it replaced tuesday... but i too was going to look into JCW sensors on my 07 MCS, maybe combining MAP and MAF together to go with the hybrid turbo... but Czar and thumper will be FAR more knowledgable than me on that matter.

 

As I said...It's the MAP senor man!! Jan and Jeff will agree. It's been almost 2 months since we tuned my car with the JCW turbo, but its pretty obvious that's what the problem is. Like clockwork....when it hits 22 psi....boost is cut. And it only hits 22 when I've driven it hard or when its warm outside (which is everytime I drive the car, which is daily...its my only car)

MAF is not the issue...it's not being maxed out. And for that matter, neither is the MAP, but as Jeff said in another post...there is a voltage reading that is preventing it from seeing the most boost that it can see.

Also, as you said, boost is determined by load on this car. Boost is determined by requested torque values. Thus why in 5th and 6th gear you see more boost than you see in 1st and 2nd...there is more torque being requested thanks to the gearing.

Also, even though mine cuts boost at 22...I'm not seeing any codes. It cuts boost with no drama...you simply lift off the throttle and floor it again and it will accelerate with full boost. Not the best when your racing someone, but at least it doesn't send the car into a freak show. While you 02 sensor might be causing issues...it has nothing to do with boost. (As far as I know). 02 sensor will cause issues with AFR's though...which doesn't sound like a problem for you....

 

i was hoping not... only reason i think it might be is because of what i was seeing on my dyno readout vs my datalog from the car's OBDII port... read richer in one and not the other... basically flat where as datalog was a little jumpy... so i'm thinking that my O2 could be throwing the wrong AFR and ergo changing the tune parameters at times causing my CELs.... the ones aside from the ones saying that the sensor is basically dying :P

 

I am very glad that from this conversation we have specified which is to blame for the boost cutout.
And I think clearly is the ECU...
Correct me if I am wrong.
I value that until we, European people, get in our hands the Accessport tuning device, Jeff and/or Jan (not particularly in that order) would have found the coding to run higher boost pressure with various combinations. For instance let's say Hybrid turbos-completely forged engines etc.
But for now...because the car is my everyday ride and I hate reproducing the same unorthodox, frustrating effect (boost cutout) I want to ask you this:

-Did you try to lower the requested torque values ?
-And if you did, does the boost cutout disappears?

Your feedback is just great and I could not have asked for anything more.
I really appreciate it...

 

When dynotuning my car, we watched the AFR's for each run. The ECU likes to be "more fuel efficient" at first, for lack of a better way to put it, and runs the car leaner. (We all know our cars run VERY lean stock, 14-15 for AFR). However, as the car heats up, it pumps in more fuel to compensate, and thus you start seeing AFR's drop to 13-14. Once Jan tuned it, we watched the AFR drop down to ~11.5, which the turbo was much happier with. But yes, what you were seeing on the dyno I believe was the car getting hotter and actually running stronger because it was adjusting your AFR. Its ironic. Usually after more runs with cars, they start producing less numbers. The more runs you put down with the MINI the higher the power goes (till a certain point where heatsoak comes into play at least).

After about 7-8 runs, the car was definitely past the heat soak point. We sprayed down the front mount and instantly saw +9hp on the next run.
The ECU likes to o funky things.

 

Has anyone read this article?
Maybe the over boost phenomenon is so violent and this valve can not control it as it should and then the ECU detects excessive boost pressure and retards the boost pressure to protect the engine.
And of course all that happen without any cel or limp mode or anything.
Some tuners suggest to replace that converter every 60000km for safety precautions. Especially on heavily modified engines.
What do you have to say about this?