Turbo Boost Creep Creeping T25 14B 16G [Merged]

[kenamond]

I need to play around with this (as I have some in the garage)... but the thing that bothers me is that I think you run the risk of air locking the WG. That's one of the reasons the ball/spring types have a small hole in them; to help bleed excess WGA pressure when you cut boost and the ball re-seats.

This Turbonetics MBC is nothing more than a standard air pressure regulator. It will regulate pressure in one direction under constant flow, but I'm not sure it provides a bleed path for reverse pressure with it hooked up the way you guys are talking about. It will reverse flow, but not very well.. at least that's the way the ones I have work.

Thoughts on this Mack?

Bleeder MBCs get hooked up completely different than ball-spring MBCs. The ball-spring models go in-line between the compressor and WGA. Bleeder types get T-ed into the line from the compressor to WGA (like the stock BCS). So the bleeder type just bleeds off some of the air from the compressor so that the pressure before and after the T changes, and the WGA gets less pressure. The more air you bleed, the higher boost you get. If you close off the bleeder, you get 9psi.

Also, this air that's being bled off should get recirculated back into the intake pipe (like the stock BCS) or it's a boost leak (that air is metered air). If you have an intake pipe equipped with the bleeder fitting for the stock BCS, you can re-use that. Or you can tap the intake pipe and add a nipple.

Let's see if I can do a text drawing of it:


(j-pipe)--------(T)----------(WGA)
.................|
.................|
.................|
...............(VBC)
.................|
.................|
.................|
...........(Intake.pipe)

Ignore the periods...it won't let me put in extra spaces.

 

[nfernotalon]

Im gonna try hooking it up like that tomorrow.. sick of this POS MBC

 

[kenamond]

Ummm.. why is it recommended to drain coolant and oil if you are pulling just the turbine housing for porting?

I just took apart a spare turbo I've had laying around (first time I've been in one), and it looks like I could just leave everything hooked up on the compressor side, remove the 4 mani-turbo bolts, band clamp, and drop the downpipe... and pull the turbine housing/O2.

What am I missing here?

Forgot to reply to this.

I think you're right. I've heard of folks dropping just the hotside. Just make sure you scribe marks on the turbine and CHRA before you loosen the band clamp so that you can get the CHRA and turbine housings clocked properly when you reinstall. Also, I'm not sure if it would put any extra stress on the oil feed, oil drain, or coolant banjo bolts if you let them carry the weight of the rest of the turbo. Normally, the turbine housing lets the whole turbo hang on the exhaust mani. Probably not a problem, but worth considering.

 

[90tsidude]

ok get this, I was just out on the highway. was really making some long hard pulls on it. was holding around 5k in 5th somewhere around 115-120. up to this point ive had to back off the throttle to keep the boost below 15psi, then i hit it and boom boost stays at 10-13psi then few more miles its holding 10-12 in every gear, i was hitting fuel cut by red line but thats either due to lack of fuel management, or boost leak. so i get home and the exhaust side of the turbo is glowing alone with most of the manifold, everything except the bolt heads and about 2 inches off the head in the runners wasn't glowing, could the lack of creep be caused by the increase in heat making the intake air hotter and less dense? im confused, i will have to conduct more tests tomorrow morning when the car is cool, on a good note my FMIC is working great, first end take was hot the other side ice cold! so im not soaking it too much!! i <3 ebay intercoolers.

 

[dsm-onster]

You need to log a run and come back to get the most help.

If you have a boost leak, then yes can get fuel cut. But your turbo can also supply less because the pressurised air is escaping and the turbocharger compressor cannot make up the difference in flow. This also causes severe over -spinning of the turbocharger and could lead to sudden turbocharger failure.

So you have a boost leak. This is why you don't seen as much boost as you used to see.

 

[nfernotalon]

Ok kenamond I hooked up the MBC how you had it on the diagram and it did keep my boost at 10psi all the way to redline.. but it wont go any higher, I turned it up all the way and nothing, stays at 10psi... any suggestions? Im just gonna hook it up the regular way so I can at least leave it at 15psi...

 

[Calan]

Forgot to reply to this.

I think you're right. I've heard of folks dropping just the hotside. Just make sure you scribe marks on the turbine and CHRA before you loosen the band clamp so that you can get the CHRA and turbine housings clocked properly when you reinstall. Also, I'm not sure if it would put any extra stress on the oil feed, oil drain, or coolant banjo bolts if you let them carry the weight of the rest of the turbo. Normally, the turbine housing lets the whole turbo hang on the exhaust mani. Probably not a problem, but worth considering.

Just thought I would give an update for future reference...

This worked great and was a piece of cake. Here's what I did:

1. Dropped the downpipe (didn't even unbolt the hanger)

2. Unbolted the turbo oil return line at the oil pan so I could wiggle the turbo downward a bit without stressing it

3. Removed the band joining the CH and TH

4. Pulled the 4 bolts holding the TH to the mani (I didn't have a stud; if you still have the silly stud, this method won't work).

That's it. The hardest part was knocking the turbine housing loose from the compressor. I used a wooden "bar" and tapped it with a hammer, and it popped loose. Pulled the TH and O2 right out...took maybe all of 15 minutes, working slow.

Leaving the compressor hooked up wasn't a problem, because most of the weight is in the turbine housing and O2. Once they were removed, there was very little strain on the compressor. Besides that, my lower IC pipe sits real close to the motor mount, so I just stuck a rag under it to help support a bit.

Went back together just as easy. Actually easier, because I rotated the band so that I could get to the nut from the top-front instead of underneath at the back where it was when I removed it

As for alignment, the E316G has a small pin, so you can't mis-clock it putting it back together, unless you lose the pin. Even then it would be hard to do because with the mani still in, it'll only go one way

From the time the car was turned off to running again, including a full port job on the turbo housing and some on the O2 (flapper clearance), swapping mani's (I had a ported one waiting to go on), and some other maintenance (repiped my MBC and made a new breather catch can setup)... was probably 6 hours or so. And I wasn't in a hurry.

Dropping only the hot side and a good carbide bit saves a LOT of work and time

Now I'm off to the other thread to post some results...

EDIT:

Here's a few pics:

Before

http://www.jcsautomation.com/temp/IMG_5524.jpg


After

http://www.jcsautomation.com/temp/IMG_5541.jpg
http://www.jcsautomation.com/temp/IMG_5536.jpg


Only the hot side is removed

http://www.jcsautomation.com/temp/IMG_5535.jpg

 

[Calan]

Ok.. did some porting and testing on my E316g. (BTW - It's my first turbo port job.. so be gentle )

Before:

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After:

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Before the port job, I was creeping like mad. With the flapper disconnected, it would start around 3.5-4k and climb rapidly until I had to let off somewhere around 6k. Was topping out around 20-22psi when I bailed.

After porting and with the flapper disconnected, I still get some creep but nowhere nearly as bad. It starts around 5.5k and maxes out at around 14-15psi at redline. Huge improvement... but would still be nice to have only 1-2psi by redline

I tied the flapper fully open thinking maybe it was causing some resistance. If it was, it's minimal. With the flapper closed, creep dropped by maybe 2 psi, but it was hard to tell. Personally I think tieing the flapper open has little or no affect compared to letting it flop as it desires.

With the flapper hooked up and the MBC set at stock (ball and spring basically running with no pressure), it creeps about the same. In all tests, boost maxes out around 15psi at redline.

I haven't turned up the MBC yet to see what happens... I'm debating on tearing into a couple of spare WGAs I have and have a look at them. I'll probably get one of Peeper's creations, but I'm a curious guy and kinda wanna tear one apart just because

 

[slowgsr]

boost creep is very common with factory internally gated turbo's, or all internally gated turbo's for that matter.

especially when trying to run lower boost pressures, upgrade to a externally gated turbo, a well designed tubular manifold and a 44mm wg and you should have less troubles running lower boost pressures.

 

[dsm-onster]

If you're discussing MHI only then yea. Considering GN, urbfrd, sr20/rb26 and 1/2jz stock setups, we're the only boostcreep prone with just opening up the exhaust. It's a small-turbine-housing MHI thing.

 

[AlaskanDsm]

I don't mean to steer to a different turbo, but I was following the FP 18g thread and it sounded like they were using older small compressor housings. Seeing as i was reading through this thread that some of the E316g turbos creep, would that also mean that the 18g would also have the same chances for the creep issues? I'm looking at needing to replace my turbo soon and was looking at these two turbos.

 

[layzie12g]

I ALWAYS had boost creep with my Evo 3 with a 3inch turbo back exhaust even with the cat. Who ever rebuilt my car before i owned it used non turbo pistons like an idiot. If you plan on upgrading you should just go with the external wastegate. I spent 200 on the 38mm and then 100 bucks on a manifold off ebay with the flange welded on. 20 psi all day long and the wastegate misses the radiator but the fan has to be removed on driver side.

 

[slowgsr]

If you're discussing MHI only then yea. Considering GN, urbfrd, sr20/rb26 and 1/2jz stock setups, we're the only boostcreep prone with just opening up the exhaust. It's a small-turbine-housing MHI thing.

I think opening up the exhaust on ANY turbo setup makes it more prone to boost creep, it just makes it worse if their prone to boost creep to begin with. The SRT4's creep and spike badly, i was in my friends with 'stage 2' upgrade, and i couldn't believe the way the gauge moved all over, if that ever happened in my honda i would have some serious problems, but then again hes not spooling at gt35r.

i agree, i still have yet to understand whys so many members of the dsm community swear by porting stock manifolds instead of upgrading to tubulars, running stock turbo's way out of their efficiency (even after upgrading). I just dont get it, even spending a good chunk of money on a turbo with an internal gate. Maybe their heads are full of hot air, just like their motor when they run them way out of the efficiency range.

however, everyone on this site has been more then helpful. I had limited knowledge about these cars, no i feel i need to get more personal experience from people who have tuned/built the type of setup im attempting right now to gain anymore experience, real world knowledge < ALL.

 

[dsm-onster]

I think opening up the exhaust on ANY turbo setup makes it more prone to boost creep, it just makes it worse if their prone to boost creep to begin with. The SRT4's creep and spike badly, i was in my friends with 'stage 2' upgrade, and i couldn't believe the way the gauge moved all over, if that ever happened in my honda i would have some serious problems, but then again hes not spooling at gt35r.

Again, you two are discussing an MHI unit and boost creep issues. It's an MHI think. Not very prevailant in the rest of the oem turbo world.

 

[kenamond]

i agree, i still have yet to understand whys so many members of the dsm community swear by porting stock manifolds instead of upgrading to tubulars, running stock turbo's way out of their efficiency (even after upgrading). I just dont get it, even spending a good chunk of money on a turbo with an internal gate. Maybe their heads are full of hot air, just like their motor when they run them way out of the efficiency range.

A ported stock 2g mani is dirt cheap and works very well. I agree with some of what you're saying, but I see a lot of unfounded opinions as well. There will always be people who do unwise things with their cars, but there are also a lot of successful setups using internally gated, medium-sized turbos (within their efficiency ranges) on ported cast manis that don't crack.

What I don't get is why folks have to mix insults into posts rather than just contribute what they know or think they know or debate what they suspect in a constructive way.

 

[kenamond]

Ok kenamond I hooked up the MBC how you had it on the diagram and it did keep my boost at 10psi all the way to redline.. but it wont go any higher, I turned it up all the way and nothing, stays at 10psi... any suggestions? Im just gonna hook it up the regular way so I can at least leave it at 15psi...

Whatever setting makes it so you can blow more air through the valve is the direction you'd turn it to *increase* boost. And if you can blow through one way but not the other, make sure it is such that the "T" in the cartoon connects to the nipple you're able to blow through. If you can blow through it, the boost pressure should also be able to blow through it. If all of this doesn't work, you can try disconnecting the vaccuum line that returns to the intake pipe and just leave it free, but be warned...that's a boost leak...only do this to test out the setup and see if that makes a difference. Make sure all of the vaccuum lines aren't clogged, and double and triple check everything.

In theory, what you're doing is leaking some of the j-pipe boost pressure out this VBC so that the pressure in the WGA is lowered. That means that you need higher boost in the j-pipe to actuate the WGA, which should result in higher boost. If the leak is larger, the difference in pressure between the j-pipe and WGA is even greater, and boost is even higher as a result.

If all else fails, I'd punt on this and get a ball-spring MBC. This is taking long enough that getting the ball-spring unit may be worth it just to spare everyone (mostly you) the hassle.

 

[nfernotalon]

Ok thanks Kenamond, I dont think anything is kinked or clogged, so I dont know.

Right now its just hooked up like a regular MBC and holding 15 to 16psi steady..

thanks for the help!

Oh and where did you get your MBC from?

 

[kenamond]

Ok thanks Kenamond, I dont think anything is kinked or clogged, so I dont know.

Right now its just hooked up like a regular MBC and holding 15 to 16psi steady..

thanks for the help!

Oh and where did you get your MBC from?

JoePMBC.com.. Performance Products for Turbo Cars.
I got the black anodized IL (in line) model. $50 shipped.
Here's the picture from their site:

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[nfernotalon]

Im gonna go with one of these, ive never seen an inline one before, im gonna go with the bling bling on this one too

 

[kenamond]

Im gonna go with one of these, ive never seen an inline one before, im gonna go with the bling bling on this one too

Just about every ball-spring MBC has two nipples. Usually one is in the end and one is on the side and the adjustment knob is on the other end. This one just rearranges where stuff is. The physics "under the hood" are exactly the same. You can also make your own for dirt cheap. I've been thinking of making one just for grins lately (and so I could tinker with multi-stage MBC ideas I've got).

Just be careful setting the MBC. Start out with it loosened almost all the way (it will come apart if you go too far..just don't lose any parts if you unscrew it all the way. Then start tightening, doing pulls, etc. If it's too loose, you'll hit 9psi. As you tighten, it will stay at 9psi. Eventually, the boost will start to go up...but one full turn will make a HUGE difference, so once it starts increasing the boost, start doing half-turns. I used the brakes in 2nd gear to hit full boost without risk of a speeding ticket when I was first adjusting my MBC. Just floor the gas and apply the brakes enough that you don't accelerate...and watch the boost gauge to see where it settles. Pull over, adjust, repeat.

And be careful where you mount it. I zip-tied mine to the top of the radiator shroud, but you have to minimize the length of the vaccuum lines to decrease boost spike...and you have to make sure the vaccuum lines don't get caught in the rad fan or other moving parts.

Good luck!

 

[90tsidude]

Ok reading through this thread all i have seen is people blame the MBC and repeat them selves over and over again then state what boost creep is or explain how a turbo works i don't get it, it looks like this just a race for post numbers. I posted about boost creep and it was over run with other questions and noone even botherd to read anything to begin with. Boost creep will not allways be the MBC. so i have one for ya maybe someone will read this boost creep issue, I have boost creep, i DO NOT HAVE A MBC! i have the WGA hooked right to a boost source. Im running a MHI E316G with a E3 o2 hosing and 2.5 catless back. I creep to around 15-17. When i do a few hard pulls or boost hard on the highway it goes away. Ive been told to take off my MBC which is hard to when i don't have one, Ive been told to port the WG, yes i should, Ive been told to port the o2 houseing, sure i can see that, The only person that has made any scence was mr peepers with his custom WGA to make the flapper open more. why is it when my turbo gets glowing red my boost creep goes away? could it be the air is way hotter so its less dence causing it to flow less? could it be when it heats up it causeing less or maybe more of a restriction in the exhuast flow? and i swear the next person that asks about a boost leak needs to stop repeating everyone else, if you have boost creep and a leak then you wouldn't be getting much of a boost creep becasue the turbo would be over spinning as it is to make boost! im tired of asking for help and getting 10 replys saying to check for a boost leak. so i ask the gurus of this site why is it my boost creep goes away when my turbo heats up after hard pulls? i know i need to open up the WG, im working on it, thank you kenamond for the site to find porting stuff that really helped but please can there be one thread about boost creep where people don't just repeat the newbie posting rules! Please for the love of cars and all that is boosting holy somone, anyone, post something original, ive stumped all my local dsmers which i turn to first i will leave there usernames unnamed as my rant will most likely be deleted and i do apoligize for it but noone is of anyhelp with the exception of mr peepers and kenamond

 

[kenamond]

Ok reading through this thread all i have seen is people blame the MBC and repeat them selves over and over again then state what boost creep is or explain how a turbo works i don't get it, it looks like this just a race for post numbers. I posted about boost creep and it was over run with other questions and noone even botherd to read anything to begin with. Boost creep will not allways be the MBC. so i have one for ya maybe someone will read this boost creep issue, I have boost creep, i DO NOT HAVE A MBC! i have the WGA hooked right to a boost source. Im running a MHI E316G with a E3 o2 hosing and 2.5 catless back. I creep to around 15-17. When i do a few hard pulls or boost hard on the highway it goes away. Ive been told to take off my MBC which is hard to when i don't have one, Ive been told to port the WG, yes i should, Ive been told to port the o2 houseing, sure i can see that, The only person that has made any scence was mr peepers with his custom WGA to make the flapper open more. why is it when my turbo gets glowing red my boost creep goes away? could it be the air is way hotter so its less dence causing it to flow less? could it be when it heats up it causeing less or maybe more of a restriction in the exhuast flow? and i swear the next person that asks about a boost leak needs to stop repeating everyone else, if you have boost creep and a leak then you wouldn't be getting much of a boost creep becasue the turbo would be over spinning as it is to make boost! im tired of asking for help and getting 10 replys saying to check for a boost leak. so i ask the gurus of this site why is it my boost creep goes away when my turbo heats up after hard pulls? i know i need to open up the WG, im working on it, thank you kenamond for the site to find porting stuff that really helped but please can there be one thread about boost creep where people don't just repeat the newbie posting rules! Please for the love of cars and all that is boosting holy somone, anyone, post something original, ive stumped all my local dsmers which i turn to first i will leave there usernames unnamed as my rant will most likely be deleted and i do apoligize for it but noone is of anyhelp with the exception of mr peepers and kenamond

Impressive post length, grasshopper!

First of all, the MBC has nothing to do with boost creep. Folks with faulty or improperly installed or configured MBCs may overboost, but that's not boost creep. It's 100% related to the wastegate...either the actuator or the wastegate itself or both are incapable of doing what you want them to do. Some turbos will creep even if you take the flapper out of the O2 housing, so it's not always an issue with the WGA throw.

As for why you creep until you've done hard pulls, I don't know for sure. It could be that the intercooler is heat soaking or you're otherwise getting higher temperatures in the combustion chamber, so at a given boost level, you're still flowing less air, and that's driving the turbine less than if you had lower intake charge temps, or maybe hotter exhaust temps flow better, and the WG flow doesn't have as much of a problem as when it's cooler. I'm guessing/speculating of course.

So if you haven't disconnected the WGA actuator arm from the flapper and done a test, try that. If it still creeps, the Peepers mod won't solve your problem and you need to either go external WG, port, or upgrade to support the boost the turbo wants to run. If it doesn't creep, maybe the Peepers mod will work for you (or you can still consider the other options).

Don't know if you only want to know why you creep cold and don't hot or what you should do to fix it...or both. So I tried on both.

 

[ricktb]

I hope my high tech drawing was of help to someone.. I didn't realize that was a valid way to connect a bleeder type mbc. And no, my current mbc is connected inline, maybe I'll try it the other way, to experiment.

Thats trippy to read one of my first threads, I actually understand all the terminology and acronyms now, before I'm like huh.

 

[nfernotalon]

Race for post numbersWTF are you saying that because like 20 posts

 

[Calan]

Ok reading through this thread all i have seen is ... <snip>

Unless I just missed it, I don't see any posts at all by you in this thread. It was started by nfernotalon and everyone has been discussing boost creep AND MBC's (and a few other things) almost from the first post.

So please explain... why are you jumping into THIS thread and complaining?

I'm just a little confused and was wondering is all ...

Matt... I had some ideas that I wanna try based on what you were mentioning in your PM. We should compare notes sometime.

EDIT:

err.. I meant Mack... I get my Matts and Macks confused.