Still only 9lbs of boost what next?

[3 bar]

Ok guys I'm still stumped. Rebuilt my motor a year ago. Installed a new FTG ko4-15xl turbo running a new techtonics high flow car to a 3 inch exhaust. Have a front mount, new n75 and a forge DV. For software I'm running a GIAC p-16 file chip. For some reason I'm only spiking at 9 psi where previously before I blew up the motor it was spiking at 21 psi. I pulled the wastegate hose off of the n75 and it did spike to 21. One forum mentioned to clean the MAF which I did today. Also put in a new filter. Was gettin P0244 codes so installed an O2 spacer today as well no more codes. Car runs better however I'm still not getting much boost. Any other suggestions? About at my wits end with this car. Thanks!

[SynapticA4TQM]

In for info... Struggling with only getting 10psi...

Have you tested for vacuum leaks? Get a can or two of carb cleaner, brake cleaner... Something flammable... Must it over your engine, specifically over areas where you have vacuum lines... If the rpms increase, you may have located a vacuum leak.

Also, you may have a boost leak, dry or cracked tubing, hoses and/or clamps not attached securely enough. You'll want to do a boost leak test too.


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[Wrath And Tears]

Are you 100% sure you have the N75 vacuum lines plugged in correctly? This has been known to cause issues.

Are you 100% sure you have the forge DV installed correctly with the correct springs and what not? It's common to put DV's in "upside down".

The P-16 file is for the k04 correct? I think I remember it is but I want to double check with you.

Perform a boost leak test as mentioned by Synaptic.

Are you AEB or ATW? Sorry I don't know the year split for the change. Either way you need to log requested boost or load if AEB and actual boost or load as well as wastegate operation (N75 duty cycles). Then open the log in a spreadsheet and post it here.

Those should be your first steps.

[SynapticA4TQM]

Neither the ATW or AEB are able to log requested boost or actual boost for that matter... Block 120 is simply blank... You can log wastegate duty cycle... I just don't remember the block number.

The map sensor didn't show until dbw was introduced after the 99.5 facelift.

You're right the PC-16 file is from GIAC and is for the k04.


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[xdewaynex]

I would highly suggest doing a boost leak test first and find any leaks you may possibly have. Leaks always seemed to be my biggest problem after having a boost pipe off and not getting it sealed the first go around.

[Avant Nate]

Are you in limp? Because either your ecu is telling your n75 to run wastegate pressure(ftg have a stronger than stock spring?), or your n75 is bad. Do you have the original one? Or as Wrath stated earlier, n75 hooked up properly?

[rockbeau25]

I'm looking at doing this same FTG setup, interested to find out what it ends up being and what kind of gains you get out of this setup.


Sent from my iPhone using Tapatalk

[M-Hood]

Neither the ATW or AEB are able to log requested boost or actual boost for that matter... Block 120 is simply blank... You can log wastegate duty cycle... I just don't remember the block number.

The map sensor didn't show until dbw was introduced after the 99.5 facelift.

You're right the PC-16 file is from GIAC and is for the k04.



Oozed from a pustule of thought somewhere within the recesses of my mind...

ATW does have a MAP sensor and can log requested/actual boost on block 115.

115,0,Charge Pressure Control
115,1,Engine Speed
115,2,Engine Load
115,3,Boost Pressure,(specified)
115,4,Boost Pressure,(actual)


Block 120
120,0,Traction Control (TC/ASR)
120,1,Engine Speed
120,2,Engine Load,(specified)
120,3,Engine Load,(actual)
120,4,Status,,Display Range: TC active/TC n.active


118,0,Charge Pressure Control
118,1,Engine Speed
118,2,Intake Air,Temperature
118,3,Wastegate (N75),Duty Cycle
118,4,Boost Pressure,(actual)
;
119,0,Charge Pressure Control
119,1,Engine Speed
119,2,Charge Limit
119,3,Wastegate (N75),Duty Cycle

[M-Hood]

Ok guys I'm still stumped. Rebuilt my motor a year ago. Installed a new FTG ko4-15xl turbo running a new techtonics high flow car to a 3 inch exhaust. Have a front mount, new n75 and a forge DV. For software I'm running a GIAC p-16 file chip. For some reason I'm only spiking at 9 psi where previously before I blew up the motor it was spiking at 21 psi. I pulled the wastegate hose off of the n75 and it did spike to 21. One forum mentioned to clean the MAF which I did today. Also put in a new filter. Was gettin P0244 codes so installed an O2 spacer today as well no more codes. Car runs better however I'm still not getting much boost. Any other suggestions? About at my wits end with this car. Thanks!

Have you checked to make sure the wg arm is tight and set to open at the same pressure as your old FTG turbo?

[SynapticA4TQM]

Thanks for that clarification Mike!


Oozed from a pustule of thought somewhere within the recesses of my mind...

[Wrath And Tears]

Neither the ATW or AEB are able to log requested boost or actual boost for that matter... Block 120 is simply blank... You can log wastegate duty cycle... I just don't remember the block number.

AEB can log boost. Its called Requested load vs Actual load (LIKE I SAID IN MY FIRST POST). It is more difficult to understand sure, but can still be used to diagnose boost issues.

I guess Mike already explained ATW.

Block numbers for AEB are 112 or 114 or 115, cant remember.

[SynapticA4TQM]

Uhm... Terrific... Help me understand it then please?


Oozed from a pustule of thought somewhere within the recesses of my mind...

[Wrath And Tears]

Once you make a log then we can help, but if you just want to look at the numbers yourself I'll give you a guideline. Requested Load is the amount of boost the ECU is request. This boost is generated by the N75 valve duty cycle increasing once boot pressure has built enough to crack the wastegate. The higher the duty cycle of the N75, the harder it is trying to clamp the wastegate shut.

So in Requested Load you will see a value from 5 to... I think I saw up to 12. In Actual Load you will see another number that should be close to the Requested Load value while under heavy boost. If you have a tune, under normal driving and low boost the requested number might be higher then the actual by a bit. For example with my k0mpressed tune the ECU is constantly asking for a requested load value of 5 (I assume this is close to the stock boost requested load) and once the actual load gets close the the requested load, the value starts increasing the more I step on the gas.

[SynapticA4TQM]

I'll not nitpick with just what it is that builds boost... But since the n75 is essentially a bleed type controller what it is actually doing is oscillating between open/close and is allowing air to reach the wastegate that has a preset "crack pressure" which is the lowest pressure that will begin to open the wastegate. The more the n75 stays open the most air is vented to the wastegate thereby controlling the amount of boost created by the turbo.

The thing is, I am 100% certain that the AEB does not have any mechanism to measure the amount of boost that is being created by the turbo. It has some base maps that engineers may have nested in the ecu of what compression could be... How every if you've upgraded anything that improves flow through the engine, that number will be off. So there may be a requested number, but all that will tell you is the amount of boost the tune is designed for.

The duty cycle of the wastegate is actually a comparison of how much it is staying open to the maximum amount of time it can be open. The more it is open, the more it vents to the wastegate. So in actuality it isn't clamping the wastegate, it is actually increasing pressure against the internal crack pressure in an attempt to open the wastegate so that less pressure is created by the turbo.

So I'll stand by at least half of my statement... The AEB doesn't not have a requested vs actual boost measuring block as it does not have a sensor to measure manifold pressure.


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[Wrath And Tears]

Alright so I gave a very brief and simple explanation of how to interpret the data you are looking at, not an explanation of how the parts actually work. I did this because I figured since you couldn't figure it out on your own simple would be better. Now after being a nice guy you go and call me wrong again (incorrectly again), while yourself being wrong again.

I had originally typed out a nice response pointing out how wrong you are, but you aren't even worth it. I'm sure someone who can't diagnose their own car knows more about how to diagnose the problem they are having then some one who's actually fixed it.

Edit: Really frustrated here because everything you are saying I can't do and I'm wrong about, I have done and it has worked so what the hell man.

Edit2: Paging Walky as you and him could probably have a long talk in which you would learn a lot about how all that works. He made a few really informative posts about the subject that I can't find.

[SynapticA4TQM]

Okay... You can search for yourself about the AEB. I was wrong about the ATW. However, I did say that cars that came with DBW had map sensors and would be able to log their own boost values... I just didn't realize the ATW was apart of that group.

It's no skin off my back.


Oozed from a pustule of thought somewhere within the recesses of my mind...

[Wrath And Tears]

I own an AEB, check my sig. I have diagnosed lack of boost using the way to check boost on the AEB engine using Actual and Requested load. My lack of boost was a low rolling misfire due to an aged coil. The misfire would only happen under high boost only after a boost spike, or at least bad enough to cause the CEL. However while logging I noticed that even a slow roll to full boost I would start misfiring and it was causing me to not see the full boost of the tune.

How can you not understand this by now?

[SynapticA4TQM]

Guess I'm an idiot... But the AEB cannot measure its own boost... Period.


Oozed from a pustule of thought somewhere within the recesses of my mind...

[Wrath And Tears]

Stop being hung up on the word BOOST it has no meaning for the AEB. Actual Load is the BOOST for an AEB.

So yes... fucking yes the AEB can't measure its own boost.

Everytime any AEB goes into boost it blows up the turbo or engine because it has no idea how much its boosting

[SynapticA4TQM]

Here's some info for you...

This came from this thread... Determining Boost pressure with a vagcom thread in the 1.8t technical sub-forum

The AEB engine has no map sensor, and therefore cannot measure how much boost is being created. It isn't a hard fact to prove.


Oozed from a pustule of thought somewhere within the recesses of my mind...

[Wrath And Tears]

It's not 115 for the AEB, its 112 or 114. Like I've said a million times you are not seeing just boost, you are seeing the overall engine load, this includes boost and is the only way to check boost in an AEB. Please for the love of god actually read and try to understand what I have been saying.

http://www.ross-tech.com/vag-com/m_blocks/110-119.html

Group 114 Boost control, well I'll be they even call it boost control and well look at that, you can read it on an AEB.

Edit: spelling

[SynapticA4TQM]

Fwiw, the signal the n75 uses is calculated from the MAF signal, this is how the n75 manages to not blow up anytime the AEB goes into boost... If there's a boost leak after the MAF that value will be incorrect, the n75 will be venting more compressed air to the wastegate than it should, and the oe 5lb spring in the actuator will begin to open at a much lower psi than what the ecu is expecting... However, the turbo will still be pulling in the air, past the MAF, and pushing it into the system past the n75...

With that said, I will admit that there is a lot to be learned about how things operate and managed. I don't know everything, but I've thought that I had studied up on how my engine works. It appears there is always more to learn, in spite of how sure I thought I was.

I'll do a search for Walky, if there's a way to mechanically figure how much boost the AEB is operating with, I'd be thrilled to learn it.


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[Wrath And Tears]

Yes I was making a joke.

The signal that you are talking about to the n75 is the calculated load from block 114 (this is not necessarily 100% true, but its all you need to understand about it). This calculated load is not actual boost but rather calculated boost using the Data from the MAF and one or two other PIDs.

Understanding every little detail is all good and fine and go you for doing it. But you are losing the overall view of how systems work and function as a whole.

[SynapticA4TQM]

I'm trying to understanding the overview by understanding the minutia... (Shrug)

So Walky isn't the guy to search for? I wasn't joking... I'd love to learn about it.


Oozed from a pustule of thought somewhere within the recesses of my mind...

[Wrath And Tears]

No I was joking about AEB's blowing up, thus the rolleyes.

Walky_Talky20 is most certainly the man to talk to really nice and super knowledgeable

[SynapticA4TQM]

Ahh the joke was in back up there... Yeah I caught that.

Cool, I'll be searching his posts out in the next few days...


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[SynapticA4TQM]

Okay ... I've tested and I've seen. Here's a log from driving today.

The behavior I've been chasing is lower than expected boost from the turbo. I unplugged the tube to the wastegate and the turbo very easily would run up to "scary" ... and by that I mean the first I lay into it a little I watched it quickly swing up towards 25psi... So the turbo will do it. Getting everything plugged up, it'll sometimes peak around 15-16psi, other times would only get up to 9-11psi. I need to do some logging with video so I can compare the boost gauge with what the log says.

Here is a link to the log with some highlighting... I'm curious of your impressions...

https://www.dropbox.com/s/ef9l5f01l5...3-002.csv?dl=0


Oozed from a pustule of thought somewhere within the recesses of my mind...

[Wrath And Tears]

Everything looked perfectly normal on the logs, when the tune called for boost you were boosting at or slightly over the requested amount.

Did the issue present itself during that drive?

To get the full boost out of your tune you have to stomp the gas pedal to the floor. The more air and gas entering the engine, the more powerful the explosion, the larger the volume of exhaust gasses, the faster the turbine spins, the more boost is created. My tune is for 18PSI, but during regular driving and even spirited driving I normally don't see more than 15PSI. I really have to stomp on the pedal in third or fourth to ever see over 15. From my experience just because your tune is written for a certain PSI, doesn't necessarily mean you will see that. It all depends on your set-up. The max PSI is how high the tune allows boost to get before dumping it, more or less.

[SynapticA4TQM]

Makes sense... Interestingly enough, it seemed as though I only saw 15psi (on the gauge) when I floored it in first, it'd hit 15 in 2nd and then 3rd... Ran out of "test track" after that. However, not sure that run was apart of the log I posted though... But none of my logs showed 15psi. The highest they showed was 12.??. Which would you think is more reliable? An analogue boost gauge or the ecu calculations?

I've been considering putting my MBC back in. I had put it in before the n75 so that n75 would see anything until the boost opened the MBC.

Everything looks to be pretty good and healthy to me... Except that the highest I saw was 15ish psi. Question: if I have a stock exhaust system, that wouldn't limit over all boost would it? I thought I've always heard that a restrictive exhaust (2" though it is) restricted your spool...


Oozed from a pustule of thought somewhere within the recesses of my mind...

[Wrath And Tears]

The number in the logs isn't showing PSI. Its showing total engine load, and I don't think there is a conversion. What it is showing you is that you are boosting to the values the tune is calling for. Using the MBC in your old set up would have increased the boost you would see on your gauge, but you can't make more power by throwing more boost at it. It has to be tuned for a correct amount boost. Most people use a MBC in replace of the N75 to change how boost is generated because a MBC is either open or closed. The N75 is allowed to open and close as the tune calls for so that you get a nice "smooth" boost.

Edit: A stock exhaust will most certainly affect boost and the car's ability to maintain it. The Cat is the worst offender. That being said I am not sure at what boost levels this becomes the limiting factor or rather more limiting than it is normally. Even with a stock 1.8t putting on an exhaust will help free up the turbo from backpressure and that helps the flow. You might not see large horsepower gains but there would be some.

[SynapticA4TQM]

Yeah... Had the mixture not seemed like it was good and healthy I was ready to put the MBC in parallel with the n75 to limit boost... That way I wouldn't be running lean (which is what I thought might be going on...

Any explanation of what the corrected value is for load?


Oozed from a pustule of thought somewhere within the recesses of my mind...

[SynapticA4TQM]

Also, I'm aware that simply increasing boost doesn't necessarily add hp or torque... But unless things are going lean, the definitely more power to be had from cramming more air in there... Hmm just realized I need to do a lot of iat's to see how much things are heating up...


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[Wrath And Tears]

No idea what corrected load is. The more I try and figure it out the more confused I get so I'm sure it's palmface simple once it gets explained. Gonna try googling now in fact.

[SynapticA4TQM]

:thumb up: the struggle is real lol


Oozed from a pustule of thought somewhere within the recesses of my mind...

[SynapticA4TQM]

Found this snippet ...

If actual load meets or exceeds corrected specified load, then you know the car is delivering all of the boost requested. if actual load is less than spec. load, AND the WG duty cycle is very high (like 90-99%) then you have a mechanical problem.

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[Wrath And Tears]

Yeah I saw that but still wasn't able to track down an actual answer. Maybe this is the true unicorn of the AEB.

[3 bar]

Thanks guys. I did the "Mexican blueprint" method and looked at the n75 and DV routing on my Audi compared to my Passat and determined that it was correct. I will have to take it over to my friends who has vagcom and determine what the hell is going on. I did the 2.0t coil pack conversion using an ATW harness so I know it's not a coil problem. Was getting low boost with the k04-15x as well as the K04-15xl. I do know that I do get 21 lbs of boost with the wastgate line removed so I don't think it's a turbo issue.

[SynapticA4TQM]

Help me out here... Mexican blueprint method? Maybe too much eggnog....


Oozed from a pustule of thought somewhere within the recesses of my mind...

[Tanzimur]

what kind of dv are you running? have you checked that?

[OverSpun]

Ok guys I'm still stumped. Rebuilt my motor a year ago. Installed a new FTG ko4-15xl turbo running a new techtonics high flow car to a 3 inch exhaust. Have a front mount, new n75 and a forge DV. For software I'm running a GIAC p-16 file chip. For some reason I'm only spiking at 9 psi where previously before I blew up the motor it was spiking at 21 psi. I pulled the wastegate hose off of the n75 and it did spike to 21. One forum mentioned to clean the MAF which I did today. Also put in a new filter. Was gettin P0244 codes so installed an O2 spacer today as well no more codes. Car runs better however I'm still not getting much boost. Any other suggestions? About at my wits end with this car. Thanks!

My thoughts...

Which spring are you using in your Forge DV? I use the Yellow in my 007PA.

Next, check all of your check valves. Those can cause your issues. Especially if you're using your original ones.