How much boost should be stock 99 AEB 1.8tqm have?

[PsorianoPre99A4]

I just installed the VDO boost gauge, and I only hit about 5 PSI in 2nd and 3rd gear, but I hit 6.5 in 4th and 5th gear, from what i've heard I'm suppose to have about 7-8?
If I have a leak, where can I check? I already replaced the breathing system with the 034 breathing kit with new check valves, I did install a silicone TIP, but I made sure all the hoses were secure. I haven't cleaned my intercooler yet I doubt the previous owner did. I just got this car and its about 128 k now. But I have all the maintenance and the previous mechanic said there is oil in the intercooler, would that be the cause of loss of boost?
Thank you!

[thedownwardsprl]

I just installed the VDO boost gauge, and I only hit about 5 PSI in 2nd and 3rd gear, but I hit 6.5 in 4th and 5th gear, from what i've heard I'm suppose to have about 7-8?
If I have a leak, where can I check? I already replaced the breathing system with the 034 breathing kit with new check valves, I did install a silicone TIP, but I made sure all the hoses were secure. I haven't cleaned my intercooler yet I doubt the previous owner did. I just got this car and its about 128 k now. But I have all the maintenance and the previous mechanic said there is oil in the intercooler, would that be the cause of loss of boost?
Thank you!

Stock that's about normal. I run a forge boost controller on tip with forge diverter valve and f21 turbo. Stock tune. I run 10 lbs and the controller is in parallel with the n75 valve. Boost comes on very fast. Been running it for a year no issues. Max boost on aeb is around 7-8 lbs.

[SynapticA4TQM]

Approx 8psi is stock... I believe the actual spec is in Bar though. 12psi is the absolute ceiling on a stock ecu before it records an overboost situation and before the ecu begins imposing any "limp mode"...

And thedownwardsprl, if you're running a stock tune on an F21 you're missing out on a world of benefit/performance. The f21 is a larger-than-k04 hybrid and flows a fair amount more than a k04-015.


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

[Turbo_B5]

Stock that's about normal. I run a forge boost controller on tip with forge diverter valve and f21 turbo. Stock tune. I run 10 lbs and the controller is in parallel with the n75 valve. Boost comes on very fast. Been running it for a year no issues. Max boost on aeb is around 7-8 lbs.

Approx 8psi is stock... I believe the actual spec is in Bar though. 12psi is the absolute ceiling on a stock ecu before it records an overboost situation and before the ecu begins imposing any "limp mode"...

And thedownwardsprl, if you're running a stock tune on an F21 you're missing out on a world of benefit/performance. The f21 is a larger-than-k04 hybrid and flows a fair amount more than a k04-015.


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

Yea why the fuck you blow money on a bigger turbo and not be boosting it?

[thedownwardsprl]

I'm selling it and it still smokes the balls off of stock. Took back the injectors and such. 10 lbs of f21 is alot of air ya douche. Duty cycle maxed for stock fueling. May vary car to car. But aeb doesn't boost but 7-8 lbs stock on that pos k03. More air either way. It's a cheap 30 hp. And i like what I like. And are you going to tell the op to get 440 cc injectors turbo and tune for better boost. Boost isn't exactly more air. ... cfm is counted on by the turbo mapping, the tip, And of course manifold pressure and much other variables. Don't get hostile with me.

[PsorianoPre99A4]

Yeah I plan on upgrading to the F21 with a stage tune with United Motorsport, with 440cc injectors.

But I agree with King_, the point to have an upgraded turbo is to tune it to your car... Especially a F21..

So anyone else agree that 5-6 on a stock AEB is normal? what factors would let me reach 7-8? I know getting a tune will increase boost, but anything else?

[PsorianoPre99A4]

Approx 8psi is stock... I believe the actual spec is in Bar though. 12psi is the absolute ceiling on a stock ecu before it records an overboost situation and before the ecu begins imposing any "limp mode"...

And thedownwardsprl, if you're running a stock tune on an F21 you're missing out on a world of benefit/performance. The f21 is a larger-than-k04 hybrid and flows a fair amount more than a k04-015.




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

I don't think AEB has a "limp mode"

[MarcRogers]

I'm selling it and it still smokes the balls off of stock. Took back the injectors and such. 10 lbs of f21 is alot of air ya douche. Duty cycle maxed for stock fueling. May vary car to car. But aeb doesn't boost but 7-8 lbs stock on that pos k03. More air either way. It's a cheap 30 hp. And i like what I like. And are you going to tell the op to get 440 cc injectors turbo and tune for better boost. Boost isn't exactly more air. ... cfm is counted on by the turbo mapping, the tip, And of course manifold pressure and much other variables. Don't get hostile with me.

So how much you want for the setup?


Sent from my iPhone using Tapatalk

[SynapticA4TQM]

No... 5-6 is low... A clean MAF, a properly adjusted throttle body, no boost or vacuum leaks, a heathy catalytic converter, no knocking/pinging/detonation, good quality gas, unclogged fuel filter/injectors/air filter are all things that need to be right for you to be running optimally. If you've never done anything with your turbo (or if nothing has been done with it by any previous owners) the turbocharger itself may be tired ... Ie bearings worn, oil passages may be coked, seals leaking, cracked exhaust housing or wastegate, deteriorated wastegate actuator spring are all things that could also be getting in the way of you making the boost you're supposed to.


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

[PsorianoPre99A4]

I'm selling it and it still smokes the balls off of stock. Took back the injectors and such. 10 lbs of f21 is alot of air ya douche. Duty cycle maxed for stock fueling. May vary car to car. But aeb doesn't boost but 7-8 lbs stock on that pos k03. More air either way. It's a cheap 30 hp. And i like what I like. And are you going to tell the op to get 440 cc injectors turbo and tune for better boost. Boost isn't exactly more air. ... cfm is counted on by the turbo mapping, the tip, And of course manifold pressure and much other variables. Don't get hostile with me.

Sell to me first if you don't want it :)

[redline380]

10 lbs of f21 is alot of air

No, it isn't. More than stock, yes. But a lot? No.

[SynapticA4TQM]

I don't think AEB has a "limp mode"

Yes it does... It does not have the soft limp mode that the ATW or AWM have, but it does have limp mode, it just doesn't come on as easily as the others. For example... If you disconnect the plug to your n75, it will default to always open which will limit your boost to the wastegate spring pressure, which oe is approx 5 psi if it adjusted/set correctly.

The stock ecu takes the MAF flow value and calculated a load value that in stock form relates nearly perfectly with the amount of boost created... It ISNT necessarily the amount of boost being created, but it does correlate very closely with it. It uses this value in reference to various maps in the ecu coding to determine the duty cycle for the n75. The n75 essentially works like a bleeder boost controller. A needle toggles opened/closed (which is the direct relation of its duty cycle). The higher the duty cycle the more often it is open and the more pressurized air it is allowing to reach the wastegate actuator. When that pressure reaches the actuators "cracking pressure" (which is the amount of pressure that is required to begin opening the wastegate) this is when air is being vented through to the exhaust portion of the turbine and out into the exhaust.

In the event of certain DTC events, the ecu will set a duty cycle of 99% for the n75, resulting in all pressure being vented to the wastegate actuator, which then will result in no more than 5psi being created.


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

[SynapticA4TQM]

No, it isn't. More than stock, yes. But a lot? No.

Agreed entirely... An f21 is still smaller than a gtrs, gt28, or a t3-48... For 10psi to be substantially more airflow, you'd need to running a full frame t4 compressor housing, or something like a gt30, gt35 or larger.

I do see and appreciate the perspective that 10psi is more from the larger turbo, but since the AEB ecu is using maps based on airflow for fueling delivery and timing, whether you run 10psi on an f21 or 5psi on a t70, it doesn't matter...

Lastly, the OE MAF had a maximum of approx 190g/s of airflow that it is able to register. Additionally, based on how clean the element is, how healthy the element is that limit may be decreased, and quite simply how old it is, that maximum may be less than intended.


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

[SynapticA4TQM]

I'm selling it and it still smokes the balls off of stock. Took back the injectors and such. 10 lbs of f21 is alot of air ya douche. Duty cycle maxed for stock fueling. May vary car to car. But aeb doesn't boost but 7-8 lbs stock on that pos k03. More air either way. It's a cheap 30 hp. And i like what I like. And are you going to tell the op to get 440 cc injectors turbo and tune for better boost. Boost isn't exactly more air. ... cfm is counted on by the turbo mapping, the tip, And of course manifold pressure and much other variables. Don't get hostile with me.

You are right... I hope you didn't think j was being hostile... It wasn't my intention.

One thing to consider is that your duty cycle may be maxed, but unless you've have your injectors cleaned, or have installed new injector, they very easily may not be flowing as much fuel as they could/should be... As a result you may be hitting an artificial, premature limit... The stock injectors flow 240cc@4 bar.... If they have lost just 10% of their flow duty to being dirty, you're down to 216cc, and across all 4 that's nearly 100cc of fuel that your engine isn't getting.

To the OP: For quite some time I've been running a unitronic 1+ tune on my 98 AEB. Logs have shown that I max out at 175g/s from approx 5k rpm to 7k rpm (+/- .5g/s) using a rough value of .8 x MAF flow, it's estimated that I'm running approx 218 crank hp. That's a 60hp increase above stock... Now the tune is written for a k03... I've ordered 550cc injectors, and a ko4 tune so that I can take full advantage of my equipment. Right now the car has near 230k miles, the engine I swapped last summer for one with 35k miles. I've also had to replace a number of vac lines and I've had to fix boost leaks... While frustrating I've ultimately been fine with having to do these repairs because it means refreshing things from their old tired shape and back to the way the engineers meant for the engine to run (boost and vacuum wise)... I bought the car 3.5 years ago with 196k miles and haven't looked back since. As long as you have taken care of (or know that the previous owners took care of the scheduled maintenance, you should be totally good to go with increasing boost.


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

[thedownwardsprl]

Yeah I plan on upgrading to the F21 with a stage tune with United Motorsport, with 440cc injectors.

But I agree with King_, the point to have an upgraded turbo is to tune it to your car... Especially a F21..

So anyone else agree that 5-6 on a stock AEB is normal? what factors would let me reach 7-8? I know getting a tune will increase boost, but anything else?

That is the tune i was on my way for but decided to go with a different car. I spent a lot of my time preparing the car for a stage 3 tune. Everything is new but money is getting tight. That's why im selling it.

[SynapticA4TQM]

I can totally appreciate that!


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

[thedownwardsprl]

So how much you want for the setup?


Sent from my iPhone using Tapatalk

selling the car for 3500. This comes with the brand new coil overs

[MarcRogers]

selling the car for 3500. This comes with the brand new coil overs

Ahh I though you where just selling the turbo set up. I wish I had know of this before I bought mine would have paid 3500 in a heartbeat!


Sent from my iPhone using Tapatalk

[thedownwardsprl]

Sell to me first if you don't want it :)

yours for 3500

[thedownwardsprl]

Ahh I though you where just selling the turbo set up. I wish I had know of this before I bought mine would have paid 3500 in a heartbeat!


Sent from my iPhone using Tapatalk

Alot of money in maintenance and built to this car. Just don't have money or will to keep going

[MarcRogers]

Yea I'm in the process of building mine shit is not cheap


Sent from my iPhone using Tapatalk

[thedownwardsprl]

Build*

[PsorianoPre99A4]

No... 5-6 is low... A clean MAF, a properly adjusted throttle body, no boost or vacuum leaks, a heathy catalytic converter, no knocking/pinging/detonation, good quality gas, unclogged fuel filter/injectors/air filter are all things that need to be right for you to be running optimally. If you've never done anything with your turbo (or if nothing has been done with it by any previous owners) the turbocharger itself may be tired ... Ie bearings worn, oil passages may be coked, seals leaking, cracked exhaust housing or wastegate, deteriorated wastegate actuator spring are all things that could also be getting in the way of you making the boost you're supposed to.



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

Thanks for your advice, I am changing my fuel filter tomorrow, and I know my waste gate flapper does rattle a little on the deceleration, I have a K&N Filter with a eBay Silicone TIP, I put my hand on the compressor turbine and felt ZERO shaft play. I have a 710N TT DV with all new silicone vacuum hoses. I just passed emissions with my current stock cat and exhaust system, though I do have a eBay cat delete test pipe I plan on putting on. I buy Chevron 92 Octane only, brand new maf

I haven't used an air compressor and tried it on my turbo actuator yet*

[PsorianoPre99A4]

yours for 3500

PM me the details, Is your F21 kit in there right now?

[SynapticA4TQM]

Sounds like you've got things well sorted and ready for some addition power


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

[PsorianoPre99A4]

Yes it does... It does not have the soft limp mode that the ATW or AWM have, but it does have limp mode, it just doesn't come on as easily as the others. For example... If you disconnect the plug to your n75, it will default to always open which will limit your boost to the wastegate spring pressure, which oe is approx 5 psi if it adjusted/set correctly.

The stock ecu takes the MAF flow value and calculated a load value that in stock form relates nearly perfectly with the amount of boost created... It ISNT necessarily the amount of boost being created, but it does correlate very closely with it. It uses this value in reference to various maps in the ecu coding to determine the duty cycle for the n75. The n75 essentially works like a bleeder boost controller. A needle toggles opened/closed (which is the direct relation of its duty cycle). The higher the duty cycle the more often it is open and the more pressurized air it is allowing to reach the wastegate actuator. When that pressure reaches the actuators "cracking pressure" (which is the amount of pressure that is required to begin opening the wastegate) this is when air is being vented through to the exhaust portion of the turbine and out into the exhaust.

In the event of certain DTC events, the ecu will set a duty cycle of 99% for the n75, resulting in all pressure being vented to the wastegate actuator, which then will result in no more than 5psi being created.


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

Would you Suggest that I replace my N75? I know the MAF was replaced with a bosch one. just 30k ago.

[PsorianoPre99A4]

You are right... I hope you didn't think j was being hostile... It wasn't my intention.

One thing to consider is that your duty cycle may be maxed, but unless you've have your injectors cleaned, or have installed new injector, they very easily may not be flowing as much fuel as they could/should be... As a result you may be hitting an artificial, premature limit... The stock injectors flow 240cc@4 bar.... If they have lost just 10% of their flow duty to being dirty, you're down to 216cc, and across all 4 that's nearly 100cc of fuel that your engine isn't getting.

To the OP: For quite some time I've been running a unitronic 1+ tune on my 98 AEB. Logs have shown that I max out at 175g/s from approx 5k rpm to 7k rpm (+/- .5g/s) using a rough value of .8 x MAF flow, it's estimated that I'm running approx 218 crank hp. That's a 60hp increase above stock... Now the tune is written for a k03... I've ordered 550cc injectors, and a ko4 tune so that I can take full advantage of my equipment. Right now the car has near 230k miles, the engine I swapped last summer for one with 35k miles. I've also had to replace a number of vac lines and I've had to fix boost leaks... While frustrating I've ultimately been fine with having to do these repairs because it means refreshing things from their old tired shape and back to the way the engineers meant for the engine to run (boost and vacuum wise)... I bought the car 3.5 years ago with 196k miles and haven't looked back since. As long as you have taken care of (or know that the previous owners took care of the scheduled maintenance, you should be totally good to go with increasing boost.


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

Thanks for the information, How are you liking your Unitronic Tune so far? how much torque you have?

[SynapticA4TQM]

It's a good tune... Just not made for the equipment I jave


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

[richardodn]

Wow. What a thread jack.

[redline380]

Wow. What a thread jack.

What is this supposed to mean?

[richardodn]

Exactly what was said. Thread began with a member asking about how his stock car is supposed to behave and ended up being completely off topic about a different member's non-stock car. That's pretty much the definition of a thread jack.

[pbcrazy]

Exactly what was said. Thread began with a member asking about how his stock car is supposed to behave and ended up being completely off topic about a different member's non-stock car. That's pretty much the definition of a thread jack.

Eh, it would be a thread jack if downward was just trying to sell his car randomly, but OP and him have exchanged posts:

PM me the details, Is your F21 kit in there right now?

Definitely off-topic though, but that doesn't really matter as long as OP doesn't care

[adam044]

Buys bigger turbo... does nothing with it... oh okay..

[PsorianoPre99A4]

Anyone still have any factors of why my boost would be around 5-6psi at stock intervals? I realize my injectors could be dirty, so I just put some seafoam in the fuel tank. I also just changed the fuel filter yesterday, hoping that will work. Any other suggestions? I also forgot to mention, it does stay solid at 5-6 as i floor it, until I let go.

[SynapticA4TQM]

Seafood will destroy your filter and injectors ... But the omega-3 might helps their ability to stay focused... #ihearttypos!


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

[PsorianoPre99A4]

Lol I thought I edited it, my bad

[Turbo_B5]

Have you even done a boost leak test? just throw in a tune and do a test. and get boosting. I wouldn't worry about 1-2 psi unless your tuned.

[PsorianoPre99A4]

Have you even done a boost leak test? just throw in a tune and do a test. and get boosting. I wouldn't worry about 1-2 psi unless your tuned.

Only test was installing my boost gauge. And I figured, I just didn't want to throw my stage 2 tune if I had a boost leak that I should take care of first, before putting more pressure on the engine.

[Turbo_B5]

I would just throw the tune in, run it for awhile then do a boost leak test. More boost=more leaks. your not going to get the more leaks untill you add the more boost. no sence in testing twice.

boostleak test diy: http://www.a4mods.com/index.php?page...boostleak.html

[SynapticA4TQM]

As far as worrying about boost leaks... It won't hurt to go ahead and replace any tubing that's not been replaced ... Ever?

Like the boost hose going from the manifold to the top of the DV... The hoses between the compressor housing, the n75, and the wastegate... Of course inspect your boost pipes between the compressor outlet to the hard crossover pipe (crosses the front of the car taking charge air from the turbo to the smic) and the pipe from the crossover pipe to the smic for any brittleness, cracks, holes, etc.

Just as problematic are vacuum leaks, these can be in any of the emissions hosing as well as some of the hoses that go from the manifold through the firewall, namely there is a little green cap that has broken on mine and created a vacuum leak...

One test you can do is to spray carb cleaner or brake cleaner over vacuum lines, if you get an increase in rpm then you've found a vacuum leak...

A way to find boost leaks is to take soapy water over boost lines, then you have two options... 1: use a tool to pressurize your system and look for bubbles, another option is to rev the engine good using the throttle body so that you get some boost built, and look for bubbles...


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