Hello people,

I have driven about 1,000 miles on the new clutch and flywheel now, and so far, I don't think I have a problem with the new parts. You might remember I did a write up on a new intake system, on making a custom made intake from stock parts, but unless I can be proven wrong, I don't think that has added anything to my new problem. Though I agree that the intake was a goofy project, it works, it seals around the throttle body, and there are no leaks. So here's my problem - yes, another one.

For some reason, the power I once had with my 19% pulley upgrade (ALTA) is gone. My boost gauge proves that considering I cannot get over 6lbs of boost no matter what - and the 19% allowed me to hit 10lbs as soon as I instructed the MCS to perform wide open throttle. Theoretically, the S/C system is nothing like a turbo when losing boost, boost loss on a turbo system could be due to hundreds of reasons, but the S/C is always creating boost. The 19% pulley will create the boost, but the ECU will control how much of it is being fed into the engine from the butterfly valve, so something is wrong and the ECU will not allow full boost to be created.

The thought I had about this problem surrounded the stock injectors. I figured that since the 19% comes close enough to full duty on the stockers, the ECU was limiting boost so as to get the A/F ratio back in check. I was wrong, however, when I was told that if the car ran for almost 5 months with full boost emitted by the reduction pulley and the ECU had not changed the setting within the first few miles, it wouldn't just 'eventually' limit boost. Next thought was on weather - the colder weather we experienced in the Carolinas may have caused too much dense air to be fed into the system, and created the same situation with the ECU and stock injectors, but that too was proven false since the weather started getting hot again last week (highs in the mid 70's), and the problem continued.

The first recommendation I had was to check the intercooler boots to see if one had 'popped off,' which a friend had told me was common. Common, I suppose, to those who had not tightened their boots down to near-superhuman strength. I removed the intercooler somehow and found no leaks, even underneath the part on the stupid end-tanks that are almost impossible to correct once installed incorrectly. But now I'm stuck - what's causing the ECU to 'blow off' the extra boost and only allow for stock boost? Why am I subject to -45hp as was the case when I first bought the car? Vacuum lines not connected - even though the car was inspected by the service department at the dealership, and if so, which lines need to be inspected? Anything????

Thanks in advance!

 

Do you have a link to your previous mod post?


Have you checked your by pass valve? Is it stuck open?

 

custom intake:
https://www.northamericanmotoring.co...ad.php?t=31832

current mods list:
http://www.thenewfastlane.com/project.asp
(note - A'PEXi electronics have not yet been installed)

the butterfly valve is not stuck open either - forgot to mention that. I had a friend rev the car and watched the valve open and close.

 

Are you referring to the butterfly valve on throttle? I'm referring to the by-pass valve which you can't observe in action.

 

yes you can see it depending on what type of intake you have

 

Help me out here cause I'm confused Isn't the bypass valve in between the intake plenum and the TB. How can you see this thing working? Plus it's butterfly valve is only 1 inch in diameter and hidden inside it's body.

 

you might be able to see the external lever moving. a surer test is to zip tie it closed then see what you get.

 

I don't think you can blame this on the ECU.

If you read Ryphyle's explanation of how the bypass valve works, you will see tht the ECU can not control the boost levels. It is set by the size of your pulley. The bypass valve opens based on the pressure in the intake manifold.

When the throttle valve is closed, the manifold goes negative and the bypass valve opens.

If your throttle valve servo motor or its controls have gone bad, the throttle may not open all the way, and that would deffinetly limit your boost. The ECU does control the throttle butterfly, and it thinks it knows where it is because there is a sensor (potentiometer) on the throttle to report its position. If it is reporting the wrong position, the ecu may think it has the throttle wide open. I would expect an error code to tell you that the engine is not developing the expected power. I have seen other posts where this error was corrected with a new throttle body.

If your accellerator pedal potentiometer has gone bad, the ECU may not know you have your foot to the floor.

Good Luck.

John

 

Interesting.

I was thinking about trying the zip-tied butterfly valve trick, but considering I have a customer's turbo Civic Si coupe (99-00) at the shop with a crankshaft that can be moved BY HAND after flooding the motor with too much boost too soon, I was kinda nervous about doing it. I know, our 1.6L motor is built up a good bit more to withstand the boost, whereas his was built for near 10.0:1 compression..... BUT STILL! I was told that there was a problem with the 02 model butterfly valves and they needed to be replaced - I was instructed that mine COULD be affected by this "recall," but most likely was not.

That's an interesting point you are making about the throttle body, Jdewey. Before I got the transmission back on (note to all - NEVER try to replace and reinstall an MCS tranny with the motor still in the car, no matter what our beloved Bentley manual says to do!!!), I did nick the cable connector that attaches to the throttle body - the only problem I have with considering that this incident puts the TB at fault is that the problem occurred prior to the R&R of the transmission.

Bottomline: What is a simple test to determine if the throttle body is not reading WOT? Now I wish I had my S-AFC II installed considering it has a reading on it that displays throttle percentage!! Furthermore, is this something that can be corrected considering it may not be opening fully, or replaced entirely? My guess would be to replace the unit, but then Lee at Century MINI and I will have to discuss how much that one will cost if it can't be done under warranty.......

 

here is a tip: I was able to r and r my S tranny solo without pulling the motor. I used an engine hoist to take the tranny weight from above through the engine bay.

 

I appreciate that, but....

I had a custom-made brace with a racheting cable hold the motor / tranny in place when I was working on the opposite unit. The motor, at VERY least, needs to be completely dislocated from the engine mounts before attempting to remove the tranny to provide enough room for the tranny to be pulled from the bottom. Either way, BMW mechanics do not leave the motor in the vehicle when removing the transmission, and I won't EVER make the mistake of doing so again!!!

It takes about 20-30 mins to get the front core support off, then removing all engine components takes about double the amount of time, then attach an engine crane (cherry picker, if you're in the south like I am), remove engine mounts, turn the motor sideways, and walk it straight out the front of the car..... SO much easier than going from the bottom and removing the front subframe in my opinion!!!

ANYWAYS...... what about this throttle body??? you have to have some input on this issue, jlm!

 

I'd suggest checking to see if your throttle opens fully:

 

The supercharger doesnt make boost, it displaces air. Its a purely mechanical system that the ECU has no control over. Your issues are most likely:

• Leaks in the intake path/system
• Faulty bypass valve
• Slipping belt

Less likey:

• Improper Cam Timing
• Your intake completely sucks.

You couldnt see the butterfly or the linkage move because the car would have to be under load in order for it to function... I dont think your friend can run that fast and I dont recommend you drive with the hood up!

 

when I reworked my first TB we put the car on the dyno at Helix with puny results, so that is a pic of my rig pulling about 165whp and truly WOT as only a visual would tell.


try the same if you can.

 

FastLane:

Sure they do. The standard practice is to drop it out from the bottom (while the car's on a lift). You have to pop off a bunch of parts, but it is the fastest way.

 

macncheese:

I think I might agree with the idea that there might be a leak in the intake system. It would not offend me to say that the idea completely sucks either - it was engineered to! I just wanted to create a way for the filter to be located in the same general area that the aftermarket filters are without setting people back $200 or so. Problem is, the boost loss occurred prior to installation of this intake system, which is why I was recommended to get a new intake because the problem could have surrounded the idea that I was not getting enough air into the system, for some odd reason....

The bypass valve and slipping belt might be more appropriate gremlins causing this problem - I did, however, purchase the correct NAPA belt for the 19% reduction pulley, so what would cause the slipping belt and how can that be checked without having to go through the pulley installation process only to learn that may not be the correct "gremlin?"

jlm:

I will try this, but you forgot to mention trying this in a completely CLEAN environment! hah....

helix:

standard practice? I had three BMW MINI mechanics at two locations (Lee and [can't remember his name] at Century MINI, SC // Kerry Conley at Sterling MINI, VA) all tell me that they did the transmission R&R the same way I did it the FIRST time and they have never done it that way again.... I guess things are different the further north you get on the east coast!!!!

 

you aren't getting any check engine light codes?

if you have a vacumm leak you will run lean at idle and that will usually throw a code super fast.

If you have no codes, then it is probably the by-pass valve. tie it in the full closed position (ie the lever is all the way out), this should clear your problem boost problem.

 

Whoever told you that is ignorant. I could (almost) understand there be being no appreciable gains found with the stock induction system but you shouldnt have losses. You leaks have to be upstream of the supercharger in order for you to leak boost. My guess is that somewhere there is a sealling surface that didn't like 19% worth of boost. It wouldnt be the first time the factory didnt tighten a bolt.

The belt might slip because: its dirty, its stretched, its defective.

Why cant your 3 BMW buddies cant fix this problem?

 

Any chance the pulley has loosened up on the SC shaft and is slipping? I would think that would pretty quickly tear the hub apart, but I have never seen one so I don't know.

Boost gauge or sensor gone bad and you really do have boost?

Joker put a block of wood under your accelerator pedal, you think it is floored but it is not? (my nieghbors Dad put a block under the carpet under the pedal to keep him from using the muscle in his muscle car, the kid eventually found it.)

JD

 

Unless I'm mistaken, if you have an Alta Intake (like I do..maybe other CAIs/HAIs will allow you to see in there as well) you can see the plastic lever arm that comes out of the vacumn actuator (whatever that thingy is called) that connects to the lever that rotates the supercharger by-pass butterfly valve. This is the place you might apply the RyePhix #1 (zip-tie) to permanently hold closed the scbp valve.


Anyhow, another place to check for leaks is the rubber boots that connect the intercooler to the rest of the system. I know I had a hell of a time trying to keep the rubber boot from being kinked up into the oval hole while reassembling the intercooler section after applying RyePhix #2.

 

We have had three Factory trained MINI mechanics work at helix, including the most decorated wrench in the east (he drives a brand new 330xi wagon given to him by MINI for scoring the highest on technical tests). They all remove the trans in the same way: out the bottom with the motor in the car. That's how the factory manual instructs the techs to do it. Anyway, there are many ways to skin a cat, and if you've found a good way to do it, more power to you: you are one of the few that are actually doing the work.

 

ubercooper:

no check engine lights this go around.... I had one before and the system ran lean as you stated, but that had been cleared up, and the ECU was reset after one of the vacuum lines on the black plastic connector from the throttle body to the supercharger was replaced.

macncheese:

Agreed. Nowhere in my logic did I state that I had wanted to install an intake system JUST to attempt to remedy this problem, everyone needs one and I wanted to try something different.

As far as the belt slipping, this would be caused part of the time and not all the time, correct? One thing I thought about while driving the car today was that if the belt was slipping, it would not simply SLIP - if it were loose enough to slip constantly, it would not have enough tension to run the car perfectly normal with no check engine lights or codes being thrown. It would happen sporatically, and create momentary loss of boost, I believe.

The 3 BMW mechanics cannot help me with this issue for the following reasons: the two in SC that are 40 miles from my house do not even recommend doing a S/C pulley upgrade (reduction), let alone know what to do to troubleshoot any problem associated with it aside of replacing a water pump - they are not gearheads or speed-freaks, they are mechanics. The one in VA, on the other hand, is, but is also 500 miles from my house and cannot troubleshoot my problem readily.

dominicminicoopers:

See last paragraph of my first post about already checking that possible cause. It would be the most evident cause, but is not the reason.

helix:

Thank you for the compliment. In no way was I trying to say that your mechanics are not competent, but rather, as you said, there is more than one way to do the job, and thus, to each their own. It sounds like you have found a good way to steal BMW MINI mechanics away from the dealership, and the most common way to do so is with green paper - this proves you have a successful business, and my compliments to you for having accomplished such. I look forward to meeting you and visiting the shop someday!

 

i haven't pulled an engine yet but expect to in a few weeks. you can do it w/o dropping the subframe? any tips?

 

No, it would always slip under load, so the car would function normally just not make boost. I've had the belt slip constantly on an aftermarket supercharger that had a lousy system providing belt tension. Otherwise ran flawlessly.

 

jlm:

you have a PM!

macncheese:

Interesting. I figured that it would be one of those "sometimes on, sometimes off" situations with the slipping of the belt. I HAVE driven about 10K miles on the new belt, so it may be wearing down. Is this something I could visually see or do you suppose the belt would be spinning too fast to notice it slipping while idling? Either way, it looks like I'll be busy this weekend....