Very strange boost control issues...

[90 GSX]

My car struggles to spool up under 3500 rpm and above 5500 rpm is creeps to about 21 psi. The car did not used to do this, and I have not changed anything.

If I floor it at 2500 rpm in say second gear, it will spool SLOWLY to about 14, then drop back down to 12 and hover for a little while. Then, once it passes about 5000rpm, it has not problem spooling, in fact, it creeps to 21. The boost controller should be set at 17 psi but there is not one single point that the car holds 17 psi. It's like the turbo has a mine of its own.

There NO boost leaks at 25 psi, so don't tell me to check. I have put a lot of time into boost leak testing and fixing, so DO NOT TELL ME TO DO A BOOST LEAK TEST.
The actuator opens at 13 psi.
The MBC is a joe p tapped into the outlet elbow of the turbo.
The turbo is a big16g, it has very little shaft play and spins smoothly.
The turbo is heavily ported in the turbine housing and wastegate areas.
See my profile for full mod list.

The car started doing this randomly one night while I was driving. I didn't do anything or change anything when it happened. Also when it starts to creep I get 15-20 counts of knock on the high end that used to NEVER happen. The way this car is right now in this exact configuration, I used to be able to hold as low as 14 psi all the way to redline because of the porting I did to the turbine housing and the wastegate area and it would spool INSTANTLY! Now it lags, stumbles, struggles to spool, and then creeps up top. What could cause a problem like this? What part of a car can just degrade like this?

Please don't respond by saying porting or boost leak test because that's not the problem.

 

[JBDdsmer610]

What size exhaust do you have?

 

[pooker]

I had boost control spikes and problems, look inside your turbo if you have a chance I am betting money on a hairline crack somwhere in the exhaust housing around the wastegate.

 

[MyÜberFastGSX]

I wish I had some sort of an answer for you, this is a very strange problem. I'm interested to find out what it is.

 

[oldman]

I think you should port your turbo and perform a boost leak test.

I honestly have nothing for you right now but it's late, I will see if something comes up tomorrow.

 

[93_tsi_fwd]

sound like its your MAFs. start the car, go outside and while idling remove the mafs plug. the idle should mess up if its not pluged. if it stays the same, then thats your problem.

 

[romeen]

Timing may be off.

Consider examining plugs to get an idea of what's going on in the cylinders.

 

[MarkAngelo05]

Hey bro.. Check your MANIFOLD TO TURBO BOLTS! MAKE SURE THEY ARE TIGHT! That can cause it to lag, and all sorts of weird stuff. Also, check your HOSE from your boost source to your boost controller, and to your waste gate.. you may have a slight tear or crack... Also, Usually if you are boosting more than 15psi, Its been said that it is more accurate to tap the boost source from the Intake manifold.. That way, YOUR WASTEGATE SEES THE SAME BOOST PRESSURE YOUR MANIFOLD and ECU SEES, PLUS, Having it tapped from the compressor cover, and you are at partial throttle acceleration, and you are tapping from your compressor cover, and your set at lets say, 18PSI, since the Throttle plate is only slightly open, it could already be around 18psi at the compressor cover, and after the throttle body will be less, and your waste gate would already be open... Good luck! But Check those bolts, take your cotter pin or whatever that's holding the wastegate arm onto the wastegate off and see if your wastegate opens and closes freely as well.. it may be getting stuck open which would cause HUGE LAG, or may take a lil longer to open which would cause you TO CREEP UP THERE... By the way.. where is your boost controller set at?? Is it a ball and spring type, or ball and spring and BLEEDER valve type??

To eliminate your HOSES and BOOST CONTROLLER as the culprits, TRY USING A FRESH LINE FROM YOUR BOOST SOURCE, STRAIGHT TO THE WASTEGATE, and see if you're gettin the same symptoms!

Alright man.. Take care, and good luck!!!!

Mark Padilla

Mark

 

[StR8sPo0Ln]

How do you have your MBC set up. Is it from the actuator to the mbc to the hot pipe or no. You could have it setup wrong, if it is connected to the bov which would allow your BOV to stay open a little under wot.

 

[MarkAngelo05]

How do you have your MBC set up. Is it from the actuator to the mbc to the hot pipe or no. You could have it setup wrong, if it is connected to the bov which would allow your BOV to stay open a little under wot.

Hey... Forgot to mention this aswell... but I'm sure you already knew NOT TO TAP the boost source for the boost controller to your BOV....


Mark

 

[90 GSX]

The exhaust is what I listed in my first post.

There are no cracks in the turbine housing especially since I ported it. I took the manifold off last weekend because I thought my turbine wheel disintegrated or something but everything looked perfect to my disappointment.

I have already tried two different 2g mas and they didn't make a bit of difference. The original wiring harness adapter I made ended up taking a shit because the epoxy I sealed the connections with had some moisture I guess and it was shorting in there. I cleaned it, and resoldered it and shrinkwrapped it perfectly. The mas is not the problem I guess would be the moral of this paragraph.

Timing is a 5* btdc. I have verified this numerous times as with my boost leak testing.

MarkAngelo, it's funny that you mention those manifold to turbo bolts because I ruined the threads on one of them trying to take my manifold off to look in side the turbine housing. I had to helicoil it but all of the bolts were tight before and they are tight now. I have tried running the car with a boost source straight to the actuator and still did the same creeping business. I even changed to another joe p mbc just in case mine was bad, even though it's just 2 balls and a spring. The boost source is tapped into the turbo outlet elbow. I just replaced the vacuum lines from the boost source to the mbc (about 8") and from the mbc to the actuator (about 10"). The nipples perpendicular to the control knob on the mbc goes to the actuator. The nipples in line with the control knob on the joe p goes to the boost source. During a boost leak test with the mbc bypassed the actuator opened at about 13 psi. The wastegate moves freely with or without the actuator hooked up.

I have had a revelation earlier today. There is something else my car is doing that it didn't do before that I didn't mention. Every once in a while, the car will sputter for a few seconds like its on 2 or 3 cylinders, then it will come back, and then sputter, and it will intermittently cycle between sputtering and normal. During this time, my stock o2 sensor which only reads unreacted oxygen reads dead lean, as if there is no gas coming to the car. The only point in my fuel system that could be at fault is the injectors. I am beginning to think it may be a problem with my injectors. Anybody know if the boost creep could be fuel related maybe?

 

[90 GSX]

I changed my mbc boost source to the intake manifold and holy shit what a difference!!! I can't believe that I have not read that on this forum until now. The car still knocks but the boost comes on faster and spools very quickly, especially after a shift, the power is right where I left it in the previous gear.

 

[MarkAngelo05]

I changed my mbc boost source to the intake manifold and holy shit what a difference!!! I can't believe that I have not read that on this forum until now. The car still knocks but the boost comes on faster and spools very quickly, especially after a shift, the power is right where I left it in the previous gear.

Hey, I'm glad to see you like that setup! I've been running all of my turbo cars that way because if makes "more sense" to me.

As far as your boost creep issue, I do not see how that could be related to your injectors. Could be how your "ported the turbo as well. Its been said that if you cut the divider between the turbine exhaust hole and the waste gate hole it will be less likely to creep. So you are saying you are all good on the boost leak test? where did you test from? TB to Turbo inlet? or what?

Oh, and your NB air fuel gauge reading red, it's kinda hard to trust those. When I first installed my 650cc injectors and had my new turbo put in it was misfiring around 4k or when 12- 14 psi of boost kicks in. My Narrow band a/f gauge also READ LEAN!! So I kept richening it! but I was wrong, it was actually pig rich and would cause that reading!

You can try checking the gap and regapping your spark plugs first.. mine seem to go from .028 to .032 in about 4k miles... at 15psi of boost... so that can be your problem as well.

Do you have any pics of your porting JOB?? sometimes "PORTING" can have a negative effect, specially around the waste gate area...can cause you to creep and all that good stuff..

Take care and good luck!

 

[Apeximprt2nr]

Edit.

 

[MarkAngelo05]

Sup Jesse, I sent you a PM on how to route your boost controller vac/boost source to your intake plenum!

mark

 

[oldman]

Also, Usually if you are boosting more than 15psi, Its been said that it is more accurate to tap the boost source from the Intake manifold.. That way, YOUR WASTEGATE SEES THE SAME BOOST PRESSURE YOUR MANIFOLD and ECU SEES,

Mark, that is just a myth, your boost gauge will always be at the intake manifold so it doean't matter. Compressor housing is the best boost reference for your MBC. Most Garrett compressor housings are shipped from the factory with provision for boost referece fitting.

PLUS, Having it tapped from the compressor cover, and you are at partial throttle acceleration, and you are tapping from your compressor cover, and your set at lets say, 18PSI, since the Throttle plate is only slightly open, it could already be around 18psi at the compressor cover, and after the throttle body will be less, and your waste gate would already be open

Isn't that a good thing? Why do you want to hit full spool during part throttle situations? Can you spell "compressor surge"?

I changed my mbc boost source to the intake manifold and holy shit what a difference!!! I can't believe that I have not read that on this forum until now. The car still knocks but the boost comes on faster and spools very quickly, especially after a shift, the power is right where I left it in the previous gear.

It's most likely just your butt dyno talking. If you didn't re-adjust your mbc and changing to the manifold source resulted in a higher boost level and quicker spool, it's a clear indication that you have boost leaks somewhere in between. Where exactly are you tapping from the manifold?

 

[90 GSX]

Mark, that is just a myth, your boost gauge will always be at the intake manifold so it doean't matter. Compressor housing is the best boost reference for your MBC. Most Garrett compressor housings are shipped from the factory with provision for boost referece fitting.


Isn't that a good thing? Why do you want to hit full spool during part throttle situations? Can you spell "compressor surge"?


It's most likely just your butt dyno talking. If you didn't re-adjust your mbc and changing to the manifold source resulted in a higher boost level and quicker spool, it's a clear indication that you have boost leaks somewhere in between. Where exactly are you tapping from the manifold?

Believe me oldman, it's not my butt dyno. There was a MAJOR difference. Even if it is my butt dyno, my ass is pretty reliable. The resistance of the turbo, all the piping, the intercooler, and the throttle body are going to create a significant pressure differential between the compressor housing and the intake manifold at steady state and when the boost is rising. Even if the mbc is set by your boost gauge which is tapped into the intake, it is possible that since the pressure will be higher at the compressor housing than it is at the intake manifold, that the wastegate actuator will open earlier because it will see any boost level no matter how low or high you set it, before the intake manifold. Do you see where I am coming from? I don't know all the mechanics of this phenomenon, but I tell you it's real and it made a huge difference. The turbo spools like it should, and part throttle conditions are unaffected. The only other thing I changed was the routing for my blowoff valve upper/lower nipples. I used the compressor housing nipple to run the solenoid for my gus mod BOV and the throttle body boost port for the mbc. I don't see how the boost source for the lower nipple on my bov can affect spoolup so drastically.

Factory o2 sensors only read unreacted o2. They don't read anything about the fuel. You have to consider that when looking at narrow band o2 readings.

The park plugs are brand new gapped to .028", BPR6ES, used to run BR7ES.

I don't have a pic of the porting but when I change my turbo to manifold gasket I will take pics. All I did was smooth out the entrance and blend the lip into the turbine housing. I opened it up quite a bit. I also ground a path smoother than a baby's ass to enter the waste gate hole, as well as opening up the wastegate hole itself and notching behind the flapper so it can open all the way whenever I get around to moving the actuator attachment point on the flapper arm. I also ported the exit to the wastegate and turbo. The only thing left I could do is remove the bridge between the wastegate and turbine sections but I don't know if that is necessary. I tell you that this car in the exact same form it is now used to hold 14 psi all the way to redline. 14 psi!!!! That's as low as stock!!!

No boost leaks, 25 psi, turbo inlet.

 

[oldman]

Believe me oldman, it's not my butt dyno. There was a MAJOR difference. Even if it is my butt dyno, my ass is pretty reliable. The resistance of the turbo, all the piping, the intercooler, and the throttle body are going to create a significant pressure differential between the compressor housing and the intake manifold at steady state and when the boost is rising. Even if the mbc is set by your boost gauge which is tapped into the intake, it is possible that since the pressure will be higher at the compressor housing than it is at the intake manifold, that the wastegate actuator will open earlier because it will see any boost level no matter how low or high you set it, before the intake manifold. Do you see where I am coming from? I don't know all the mechanics of this phenomenon, but I tell you it's real and it made a huge difference. The turbo spools like it should, and part throttle conditions are unaffected. The only other thing I changed was the routing for my blowoff valve upper/lower nipples. I used the compressor housing nipple to run the solenoid for my gus mod BOV and the throttle body boost port for the mbc. I don't see how the boost source for the lower nipple on my bov can affect spoolup so drastically.

I have done so many tests on this matter (mine and other people's car) it's not even funny, not ones was performance noticeable either way. Did you re-adjust the mbc to the same boost level before test runs? It's true that some adjustments of the MBC is required becuae you will boost a little more with a manifold pressure due to pressure drop and long route but normally we are talking about 1-2 psi the most, any more than that and you have got serious restrictions in your intake tract. To be honest, as long as you don't have a bleeder style MBC like the TurboXS standard units or running an extremely efficient turbo with a bolt on housing (like my GT12) where compressor surge might be an issue in part throttle situations, I'm really not THAT against running a dedicated manifold pressure as long as it's not the BOV, FPR, PCV and brake booster lines. The only difference between a dedicated manifold and the compressor housing reference are.

1. Tapping the manifold pressure will reduce boost level variations between winter and summer. (advatage manifold)

2. Short route = less chance of boost spikes. (advantage compressor)

3. Possible surge at part throttle. (advantage compressor)

4. Prevention of overboosting the turbo (to death) when boost leaks suddently develop. (advantage compressor)

BTW, which TB port are you using?

 

[MarkAngelo05]

I used the compressor housing nipple to run the solenoid for my gus mod BOV and the throttle body boost port for the mbc. I don't see how the boost source for the lower nipple on my bov can affect spoolup so drastically.

The park plugs are brand new gapped to .028", BPR6ES, used to run BR7ES.

I tell you that this car in the exact same form it is now used to hold 14 psi all the way to redline. 14 psi!!!! That's as low as stock!!!

No boost leaks, 25 psi, turbo inlet.

So you are experiencing the same symptoms even if you just directly route the WASTEGATE Actuator line to a boost source??? you're not getting a consistent 13psi? or whatever your wastegate is set at?


and Bruce (Oldman) you're right about ; Short route = less chance of boost spikes. (advantage compressor)

Possible surge at part throttle. (advantage compressor),

To each their own. I'm running an 18G clipped TD05 Wheel in a EVO GT ported housing and so far, no boost creep, no compressor surge, and I my boost setting (15psi) from part throttle cruising above 3k rpm to full throttle Hits 15psi VERY VERY QUICKLY, since the turbo is "pre spooled" for lack of a better term..

When you think about it, Electronic boost controller WOULD THEN BE BAD for Compressor surge, and over boosting your turbo.. since the solenoid does not open till the desired boost level is hit. When I had my AVCR, I could hear my turbo spooling like crazy at partial acceleration above 3k.

When it comes down to it, it really depends on your own setup and how it works for you. If you tap from the intake manifold and it works fine for you with the benefits without harmful side effects, then go for it, if it works better for you to tap from the compressor housing, then awesome! I've tried both, and it all depended on my setup.

Take care!

Mark

 

[90 GSX]

Well I don't know what to say. When I had the mbc hooked up the turbo outlet, the total vacuum length to the wastegate was about a foot. I thought that was awesome, but I changed it just for shits and giggles and my goodness it made a huge difference. You can say whatever you want based on what you feel should be true, but I'm telling you that it made a huge difference empirically, in my car, on back to back drives within 5 minutes of each other. The car spooled up faster under all conditions, especially after a shift. I'm curious to know what kind of tests you did that allowed you to come to that conclusion because it seems that my car defies your results... I mean it's possible that my car is a freak or there are other factors, but to have results like that it's not a coincidence.

Also, even from the throttle body, the routing is not that long... less than the stock bcs routing I know that much. I will try changing it back to the turbo outlet and then back to the intake manifold again and see what happens just to be sure I'm right.

 

[oldman]

When it comes down to it, it really depends on your own setup and how it works for you. If you tap from the intake manifold and it works fine for you with the benefits without harmful side effects, then go for it, if it works better for you to tap from the compressor housing, then awesome! I've tried both, and it all depended on my setup.

Like I said, as long as the BOV line is left alone, I'm fine with it.

I'm curious to know what kind of tests you did that allowed you to come to that conclusion because it seems that my car defies your results... I mean it's possible that my car is a freak or there are other factors, but to have results like that it's not a coincidence.

A lot of test runs while watching spool and boost spikes. Can you apply pressure directly to the inlet of your JoeP? The only logical reason for better spool up that I can think of is that your JoeP is allowing pressure to leak to the other side of the ball before the spring is overcome. Also, did you adjust the mbc to the same boost level before test runs? 17psi is going to feel a lot faster than 15psi. Take a video tape of the RPM and boost gauge on both runs under the same conditions, psi and gear so we can more accurately guesstimate spool rpm.

 

[MarkAngelo05]

By the way.. did you get your boost creep issue taken care of? I'm curious to see what the problem was on that. Your car is not a "freak" ... your wastegate is actually "kept closed" so the spool is a little bit faster, until it hits the desired boost level(at the manifold/same area your boost gauge is tapped). The ball and spring style boost controllers tend to leak air into the wastegate line no matter how good that BALL AND SPRING TYPE controller is. lets say you set your boost controller to 15 psi, and it holds consistently at 15psi during WOT pulls, then you go and attach a air pressure hose w/ a regulator and regulate the air so that you bleed in about 10 psi of air into the Manual Boost controller, you will still see your wastegate actuator move just a TAD BIT.. which means, it's opened a tad bit, meaning its letting exhaust bypass the turbine causing it to take a TAD BIT longer to spool.

Later!!

Mark Padilla

 

[90 GSX]

I'll play with my mbc another time, I still have knock and creep problems. My car just runs like absolute shit and I'm so sick and tired of it.

-It hesitates all over the place at all rpms and conditions especially when the turbo first spools up.
-It never idles right, my rpms never stay up when I come to a stop in neutral, the car has low vacuum at idle after warms starts, and it misfires and farts all the time.
-My decel vacuum goes from about 21-22 to 24 only after a long drive (>45 mins). It is never consistent and whenever I take my foot off the gas to decel it usually hiccups once or twice when it shouldn't be doing anything.
-It knocks like a SOB.
-There's the creep problem.

I could keep going on and on, but you guys will just think I'm some dumb amateur dsmer complaining about simple problems that I just don't know how to fix. The reality is, I know first gens and 4g63 motors like the back of my hand, better than the majority of people on this forum. I go to a local DSM shop after MONTHS of trying to fix this stupid car myself, and I try to explain to them everything I've done and that there is something severely wrong with the car and their only answer is for my to buy DSM link like that would miraculously fix my car that already had an awesome tune that took 5 or 6 chips to get right. I have checked and double checked everything I possibly could, even things that would have nothing to do with the engine. I even replaced the stupid ####ing wiring harness for all the good it did me. At this point, I'm ready to nuke my car to get it out of my sight and buy a ####ing honda. For all the money, endless hours in the sun, in the cold, at night, blood and sweat and tears, what do I have to show for it? Nothing but a modified DSM with a bunch of aftermarket parts that couldn't run half decent to save its life. I would rather have a 80's station wagon with wood panels on the side than my stupid dsm, at least I could probably get it to run good. If you search for my sn on dsmtalk or dsmtuners you will find posts going back months trying to solve the same issues. It is absolutely pathetic that the car is still ####ed up, just pathetic.

Sorry for that... I'm VERY frustrated with this car because I love driving it but my love only goes so far before I need some love back from this steaming pile of crap. Somebody help me before I go shaving my head like britney.

 

[MarkAngelo05]

ya man, i feel you on that! for the past couple of months, I've been battling my problems for my car, from stutter, knocking, weird erroneous information from the logger(which I finally found out was from EMI from the spark plug wires), and all kinds of other problems like bad Eprom ECU, NOW GRINDING 4th gear after clutch change, etc etc etc.

It does get very frustrating, and very addicting. It's pretty much a money bucket, even if it works, you always want to "make it better, faster" blah blah blah.


As far as your problems go, you may want to check your compression. You say that your vacuum is inconsistent, that could be a problem with compression, or EVEN A PROBLEM WITH A BOOST/VACCUUM LEAK from the INTAKE MANIFOLD! I know you said you've checked for boost leaks numerous times, but I don't recall if you capped it off at the upper charge piping, or if you set the engine to TDC checked your intake manifold for leaks as well.


You also said that you burn your own chips. Well, when I used to work on Honda's, I burned my own chips for my turbo setups. Sometimes, I guess it depends on chip quality, but I remember my car acting very funny and running like crap after a couple weeks of burning a new program. I try opening the file up, and it shoes up with erroneous information, which I thought should have triggered the CEL, but it didn't. I just was happy I saved all of my setups and re-burned the information.

I know if there is a problem with the file or the chip the CEL would come up, but my situation proved it doesn't.

Try using a new chip and burning your current setup. I'm sure you've checked your peak timing and what your a/f and timing readings were before knock comes up.

BEFORE YOU DO ALL OF THIS, CHECK YOUR KNOCK SENSOR. Those are known to go bad. I think mine is going bad because my keydiver chip gives me knock count, and sometimes at low rpms around 3.5k and up, specially if the car is cold, it and I keep my foot on the gas, KNOCK COUNTS KEEP ON GOING UP AND UP!! so I just let off the gas completely and press on it again, then no more knock..it's pretty crazy.. and I can feel a decrease and bog in power as well. I notice that it happens whenever it wants. When I first bought the car, UNMODIFIED, VIRGIN ECLIPSE w/ a Re-manufactured motor, etc, It ran very very well! but, I noticed the same intermittent bog and finally noticed that much more when I did all the mods, specially the eprom ecu w/ the chip which showed me knock counts. It all finally came to me, that the bogging/decrease in power that I feel was the ecu "THINKING" the engine was experiencing excessive amounts of knock.

Hope this helps, and good luck man! P.S. I may move back to California soon, (San Diego/Fallbrook/Oceanside area) How is SMOG and how hard is it to bypass all of those things..

take care!
Mark