1.5 bar spring wastegate boosting 1.2 bar ????

[poweradeTSI]

i got a1.5bar spring in tial 38mm wastegate drove for a bout a week then one day im only boosting 1.2bar i get my vaccum source from the i.c.pipe any suggestions to get me back to 1.5bar without using a mbc.i also opened the wastegate nothing was broken

 

[Mikelb]

Vacuum from the IC(intercooler) pipe?
I would suggest pulling it from the intake manifold. That will be the fastest source of vacuum right there, as it is closest to the engine.

Have you checked for boost leaks? This may not be a problem with the wastegate functioning, but maybe a leak.

 

[poweradeTSI]

i'll give it a try tommorow but why allof a sudden i stopped boosting 1.5 bar

 

[Mikelb]

Do you know for a fact that it is the wastegate opening that's causing you to only run 1.2bar?

 

[poweradeTSI]

anyone have this problem before car was running 1.5 bar last week getting vaccum source fromthe i.c. pipe now it seems it wont go past 1.2bar

 

[oldman]

Vacuum from the IC(intercooler) pipe?
I would suggest pulling it from the intake manifold. That will be the fastest source of vacuum right there, as it is closest to the engine.

Have you checked for boost leaks? This may not be a problem with the wastegate functioning, but maybe a leak.

Bad idea, especially running without a MBC as the diaphragm is not design to see vacuum. Compressor housing is the best and fastest (less chance of boost spike) boost reference for boost control.

anyone have this problem before car was running 1.5 bar last week getting vaccum source fromthe i.c. pipe now it seems it wont go past 1.2bar

BOOST LEAK TEST!!! And it boost source not vacuum, there are no vacuum in the IC pipes.

 

[Mikelb]

Bad idea, especially running without a MBC as the diaphragm is not design to see vacuum. Compressor housing is the best and fastest (less chance of boost spike) boost reference for boost control.


BOOST LEAK TEST!!! And it boost source not vacuum, there are no vacuum in the IC pipes.

Sorry, I was thinking of boost pressure for hte MBC, and not the wastegate. You are correct

 

[oldman]

Sorry, I was thinking of boost pressure for hte MBC, and not the wastegate. You are correct

Regardless, compressor housing is still a better option than manifold pressure (especially in your case since you own a TurboXS MBC), BOV line especially, is never to be used as boost reference for the MBC.

 

[Mikelb]

Ok, I must be faulted in my thinking (this is how it was explained to me, I'm fairly new to forced induction). The IM would be the best source, as it is the first to pull the vacuum, therefore it would relay the IM pressure to the MBC and allow the BOV to react faster when you let go of the throttle. The Wastegate also hooks into my MBC.

On the 14B, there is no hole to use for boost pressure, am I correct? Are you suggesting to tap into the compressor housing?

The 50-trim I have does have a port on the compressor housing to use for the wastegate (though I've never heard of hooking the MBC to it).

Could you please correct me and elaborate, Thanks

-Mikelb

 

[oldman]

Ok, I must be faulted in my thinking (this is how it was explained to me, I'm fairly new to forced induction). The IM would be the best source, as it is the first to pull the vacuum, therefore it would relay the IM pressure to the MBC and allow the BOV to react faster when you let go of the throttle. The Wastegate also hooks into my MBC.

Are you saying your MBC is hooked up to the BOV line? A turboXS MBC or any bleeder type MBC on the BOV line is the worst possible combination one can have. Who ever gave you that experplanation couldn't have been more wrong.

On the 14B, there is no hole to use for boost pressure, am I correct? Are you suggesting to tap into the compressor housing?

Either the compressor housing or the turbo outlet (stock)/J-pipe (aftermarket).

The 50-trim I have does have a port on the compressor housing to use for the wastegate (though I've never heard of hooking the MBC to it).

That is exactly the purpose of that fitting.

 

[Mikelb]

Ok, Here's how my vacuum lines are hooked up:
I've blocked off the nipples on the TB.
I have a vacuum line for the FPR running from the IM.
I have another vacuum line from the IM to the MBC, from the MBC a line runs to the BOV and another to the Wastegate.
The outlet on the turbo is blocked off (never thought of using it).

This is the way the car was setup when I bought it.
The BOV is also stock and vented (with a hacked 1G MAF; I know, not the best idea, but I didn't have the hose to reroute it into the intake).

IIRC, this is how mine is setup.

You must be logged in to view this image or video.

 

[oldman]

Ok I will take back my previous statement of "TurboXS on the BOV line being the worst combination one can have" and rephrase it properly to "TurboXS (or any bleeder type MBC) on the BOV line along with a vented BOV is the worst possible combination one can have".

Again, that Taboo diagram was the old way of doing things, I will give you a list of what not to follow on that diagram along with explanation on why, I will also add this list to the tech article in our tech section where you got this diagram and hopefully put this to rest for good.

1. Do not remove your FPS, Fuel Pressure Solenoid, if you're still on the stock fuel pump, doing so can cause hot start issues depending on where you live, the hotter the region, the higher the probability.

2. Do not disable and vent your PCV/breather crankcase ventilation system. Here is something I posted in the past.

For a PCV system (both PCV vavle and breather) to work effectively in ventilating the crankcase, they must work together as a team. While the system is under boost, PCV closes and ventilation is done through breather via vacuum in the intake pipe. While the system is under vacuum, PCV opens to relief pressure but more importantly, to remove blowby/contaminates from the crankcase then replace with fresh/metered air pulled in through the breather, this is the second part of crankcase ventilation that most seems to ignore, most only focuses on pressure relief.

Possible problems with other options:

1. Keeping PCV intact while venting the breather: Most running this setup will experience excessive crankcase pressure when under boost due to lack of vacuum coming from the intake pipe which can lead to dipstick pop out, leaky valve seals, tubo seal and gaskets. Less importantly, your AFR will go slightly leaner due to unmetered air.

2. Venting both PCV and brether: Pressure relief is not as big of an issue (provided that pcv is replace by a straight fitting) but because vacuum is completely removed, there are no ventilation and most blowby and contamintes will end up in your oil system. Less importantly your AFR will go slightly richer due to disabling the pcv vavle. Not a big problem for a track only cars but a DD is a different story.

You can easily maintain the integrity of your pcv system while keeping your intake tract clean as well as addressing the known leaky OEM PCV.

PCV side : IM -> heavy duty check valve -> inline/sealed catch can -> PCV valve -> VC

Breather side : VC -> 2nd inline/sealed catch can -> intake pipe.

3. Most important of the 3, DO NOT USE YOUR BOV LINE AS PRESSURE REFERENCE FOR YOUR MBC. Another quote from the past.

1. BOV line was previously thought to be better and more accurate because it's the pressure the engine sees when in reality it doesn't matter because boost gauge is already measuring manifold pressure regardless where you reference your MBC.

2. Long route vs short route, increased chance of boost spike.

3. Turbo protection. In a case of developed boost leaks in your intake tract, tapping BOV line will result in turbo spinning out of control while boost gauge till maintains full boost. Where as a compressor source will open wategate sooner while registering pressure drop on your boost gauge.

4. This is the most important one. Tapping your BOV line will result in a slightly opened BOV under WOT because of pressure bleed through the MBC's wastegate pressure relief hole. The situation gets worse when using a bleeder type like the TurboXS units because it's also a vacuum leak which can lead to idle surge, leaner AFR as well as compressor surge.

Just because the previous owner is the one to blame doesn't mean you don't have to fix them and continue down the wrong path. The most immediate issues you need to address is to restore your BOV line as a dedicated line from the intake manifold to the BOV, switch your boost reference for the MBC back to the turbo outlet pipe and recirculate your BOV back into the intake pipe.

 

[Mikelb]

Thanks,

that was very informative. I was completely unaware of most of this. I did know that venting the BOV wasn't the best option though... with my new project car, I'll try and put it together the right way.

Edit: oh, and sorry for jacking the thread. I like to learn.

 

[laserspeeddemon]

Good GAWD, oldman!!!

The more I read your post the more I realize I don't know CRAP!!! I got a related question, I got the old HKS EVC. I have the signal line tapped into the BOV line, the boost source at the turbo compressor elbow and the wastegate line going to the waste gate. This is how HKS instructions suggested. Should I change this around?

 

[oldman]

Good GAWD, oldman!!!

The more I read your post the more I realize I don't know CRAP!!! I got a related question, I got the old HKS EVC. I have the signal line tapped into the BOV line, the boost source at the turbo compressor elbow and the wastegate line going to the waste gate. This is how HKS instructions suggested. Should I change this around?

Regarless which type or brand of boost controller you have since all boost controllers (especially EBCs) functions based on pressure bleed, the BOV line should never be tapped because the proper/precise functioning of any BOV depends greatly on the pressure signal of this line. If you can link me to the instruction page of the HKS EVC, I will be able to better comment on what your other option may be, right now I'm a little confused about the later half of your setup.

the boost source at the turbo compressor elbow and the wastegate line going to the waste gate.

 

[laserspeeddemon]

Here is the instruction manual page for all HKS products.
http://www.hksusa.com/FAQ/?id=1647&rsku=0

This is what it says word for word.

1. MANIFOLD PRESSURE SENSOR PORT#1
This port when connected to an uniterrupted intake manifold source (compressor by pass signal line for example) will allow the EVC microprocessor to sample plenum conditions every 2.4 ns. Using this data the EVC can constantly feed the wastegate corrections.

2. CONTROL VALVE PRESSURE INLET PORT#2
Pressurized air, drawn directly from the compressor housing (discharge side) or compressor outlet pipe (before intercooler), is routed to the control vavlve pressure inlet port #2. This pressurized air is then modified (by the solenoid valve housed within the chamber) according to the selected control settings.

3. CONTROL VALVE PRESSURE OUTLET PORT #3
From the contol valve pressure outlet port, constantly modified pressurized air received by the control valve pressure inlet port is routed to the wastegate actuator. This precisely regulated pressure maintains accurate wastegate action resulting in stable maximum boost levels in any gear and almost any atmospheric condition.

4. BLEED OFF PORT #4
Through this port excess signal pressure is discharged.

And this is what the part looks like. (at least the solenoid).

 

[laserspeeddemon]

This is the diagram they show for setup. (FYI) This is the actual diagram from the HKS Manual, despite the child like artwork.

 

[dsm-onster]

Thanx oldman for that post on the pvc system. . .

One off-subject question:

PCV side : IM -> heavy duty check valve -> inline/sealed catch can -> PCV valve -> VC

Doesn't the pvc valve already qualify as a heavy duty check valve? wouldn't this eliminate the need of another check valve before getting to the valve cover?

So instead: IM -> PCV valve -> inline/sealed catch can -> VC ?

 

[oldman]

1. MANIFOLD PRESSURE SENSOR PORT#1
This port when connected to an uniterrupted intake manifold source (compressor by pass signal line for example) will allow the EVC microprocessor to sample plenum conditions every 2.4 ns. Using this data the EVC can constantly feed the wastegate corrections.

As long as this signal is only used for checking and is not a part of the actual pressure bleeding process, you should be OK with using the BOV line. With that said, I would still leave the BOV line alone and use one of your two top 90' TB fittings to minimize possible leakage on the BOV line, assuming your TB vacuum lines have been remove and you're still using stock intake manifold.

Doesn't the pvc valve already qualify as a heavy duty check valve? wouldn't this eliminate the need of another check valve before getting to the valve cover?

So instead: IM -> PCV valve -> inline/sealed catch can -> VC ?

The heavy duty check valve is there mainly for two reasons.

1. To prevent pressurizing the inlined catch can, one can only imagine what a catch can looks like under 20+ psi of boost.

2. There is absolutely nothing heavy duty about the OEM PCV valve, having the extra check valve will solve the infamous PCV leak, especially during high boost applications.

You might then ask, why not get rid of the PCV valve altogether and use just the heavy duty check valve? PCV valve in this case still serves two purpose due to it's design.

1. A PCV valve is a variable valve, it regulates flow base on different vacuum conditions.

2. It minimizes the amount of oil being pulled out.

http://www.dsmtuners.com/forums/showthread.php?t=229338

 

[dsm-onster]

thank you for the thread Bruce.

 

[oldman]

No problem Matt.

 

[laserspeeddemon]

As long as this signal is only used for checking and is not a part of the actual pressure bleeding process, you should be OK with using the BOV line. With that said, I would still leave the BOV line alone and use one of your two top 90' TB fittings to minimize possible leakage on the BOV line, assuming your TB vacuum lines have been remove and you're still using stock intake manifold.

Well my concern was that the 4th Port, which discharges excess signal pressure, may be "bleeding" the pressure off, and would allow the BOV to leak boost. However, changing to a SSQV type BOV may allivate this problem sine the pressure in the charge pipes may aid in sealing rather then leaking.