Wastegate Tweak???

[streetsoldier185]

First off, I am in no way planning on doing this, but am curious as to how and what is done.

I have read from some other people on this forum that they have tweaked the wastegate to make it hold more boost to redline.

How is exactly is this done? How bad would it be to make it hold say 15psi to redline as opposed to the 10-12psi it does now? Would an upgraded fuel pump be a really good idea to have done first to make sure it can provide enough fuel?

 

[f_399]

First off, I am in no way planning on doing this, but am curious as to how and what is done.

I have read from some other people on this forum that they have tweaked the wastegate to make it hold more boost to redline.

How is exactly is this done? How bad would it be to make it hold say 15psi to redline as opposed to the 10-12psi it does now? Would an upgraded fuel pump be a really good idea to have done first to make sure it can provide enough fuel?

if you dont plan on changing turbos in the near future i wouldnt tweak the wastegate

from what i have read and heard, our turbos wont hold up

 

[2zzge]

First off, I am in no way planning on doing this, but am curious as to how and what is done.

.....

that's like saying "i have no plans to blow up my turbo but i was just wondering how i could do it...i mean, just in case someone asks me how they could do it.":laugh:

our poor turbos are getting a workout as it is...being chip'ed and all. however, if you search a bit, you'll find a how to i'm sure. :w00t:

 

[angrybaker]

bad idea
________
Depakote Withdraw
________
Spanish girl live

 

[Mike@Forge]

I don't know where you guys heard (read) that "tweaking" the wastegate is going to cause any issues, but that's pretty far fetched.

A wastegate (actuator) exists as a failsafe against compressor surging, to vent exhaust gas pressure away from the impeller wheel to limit how much boost the turbo can build.

The actuator has a spring inside of it that holds the wastegate flapper shut against the exhaust gas pressure that spools the turbo.

Once the application builds up enough boost pressure to overcome the spring pressure of the actuator, or a level that is desired by the ECU and N75 valve (factory boost control solenoid), the pressure will overcome the spring pressure of the actuator thus opening the wastegate flapper bypassing the exhaust gas away from the impeller wheel.

Since the spring pressure of the actuator is a fixed rate, it can only be manipulated by adjusting the level of pre-load on the spring.

This is done by tightening or loosening the tension on the wastegate actuator arm.

Under certain conditions, the possibility exists that the exhaust gas pressure exiting the head of the motor to spool the turbo MAY exceed the spring pressure of the wastegate actuator and it MAY blow the wastegate open prematurely. This can lead to a phenomenon known as boost creep, but it can also affect the boost curve in various other ways as well. The turbo may not spool as quickly as it otherwise would if the wastegate didn't open prematurely.

By increasing the pre-load on the spring, thereby increasing its tension, you can counteract the effect of the exhaust gas pressure prematurely opening the wastegate. This can have a positive affect on the boost curve potentially leading to quicker spool, less tapering, or just an overall raising of the curve.

There is no guaranteed or fixed result that will be achieved from any given level of adjustment, however.

It will vary from car to car and application to application.

By tightening the rod 2-3 turns, you are not guaranteed to see a 1 PSI increase in boost pressure.

You may not see an increase in peak boost at all. You still have to consider that the MAP sensor on the car is monitoring the boost output of the turbo and telling the ECU to control the boost in various ways at various times through the N75 valve, so the ECU will still have control over how much boost the turbo produces.

You may only see quicker spool and less tapering, or just one or the other.

That's why wastegate adjustments are recommended to be done carefully and in SMALL increments. Not because you're going to blow up your turbo, but because you will see different results depending upon how much adjusting is done.

 

[Cybe]

Good info, I added four stars.

 

[julito04]

holy bejeezus! as always mike, you are the sunshine in my turbo life lol

 

[hypnotica003]

I don't know where you guys heard (read) that "tweaking" the wastegate is going to cause any issues, but that's pretty far fetched.

A wastegate (actuator) exists as a failsafe against compressor surging, to vent exhaust gas pressure away from the impeller wheel to limit how much boost the turbo can build.

The actuator has a spring inside of it that holds the wastegate flapper shut against the exhaust gas pressure that spools the turbo.

Once the application builds up enough boost pressure to overcome the spring pressure of the actuator, or a level that is desired by the ECU and N75 valve (factory boost control solenoid), the pressure will overcome the spring pressure of the actuator thus opening the wastegate flapper bypassing the exhaust gas away from the impeller wheel.

Since the spring pressure of the actuator is a fixed rate, it can only be manipulated by adjusting the level of pre-load on the spring.

This is done by tightening or loosening the tension on the wastegate actuator arm.

Under certain conditions, the possibility exists that the exhaust gas pressure exiting the head of the motor to spool the turbo MAY exceed the spring pressure of the wastegate actuator and it MAY blow the wastegate open prematurely. This can lead to a phenomenon known as boost creep, but it can also affect the boost curve in various other ways as well. The turbo may not spool as quickly as it otherwise would if the wastegate didn't open prematurely.

By increasing the pre-load on the spring, thereby increasing its tension, you can counteract the effect of the exhaust gas pressure prematurely opening the wastegate. This can have a positive affect on the boost curve potentially leading to quicker spool, less tapering, or just an overall raising of the curve.

There is no guaranteed or fixed result that will be achieved from any given level of adjustment, however.

It will vary from car to car and application to application.

By tightening the rod 2-3 turns, you are not guaranteed to see a 1 PSI increase in boost pressure.

You may not see an increase in peak boost at all. You still have to consider that the MAP sensor on the car is monitoring the boost output of the turbo and telling the ECU to control the boost in various ways at various times through the N75 valve, so the ECU will still have control over how much boost the turbo produces.

You may only see quicker spool and less tapering, or just one or the other.

That's why wastegate adjustments are recommended to be done carefully and in SMALL increments. Not because you're going to blow up your turbo, but because you will see different results depending upon how much adjusting is done.

good info...so you say there is a safe way to tweak the WG and still see gains? what kind of gains do you think are possible/realistic while doing this in a safe way?

 

[Mike@Forge]

Like I said, it's really impossible to gauge a finite level of improvment for a given level of adjustment of an actuator.

I would suggest to never adjust an actuator any more than 2 full 360 degree turns at a time.

It's POSSIBLE, but NOT guaranteed, that 2 full turns MAY net somewhere in the neighborhood of a 100 RPM sooner spool up of the turbo or 100 RPM later onset of the taper of boost towards redline, but again, there are no guarantees.

Like I said, overall peak boost may not be affected too greatly when still using the OEM N75 valve to control boost. On another application using a manual boost controller or running off of wastegate pressure alone, where the ECU doesn't have full control over boost, adjustments can, indeed, net gains to the peak boost output of the turbo.

It is possible to tighten a wastegate actuator too much as well.

It is doubtful that the OEM actuator spring pressure and the units adjustment range is such that you could ever add enough pre-load to prevent the unit from opening altogther, which would result in a severe overboost condition, but tightening the unit too far may affect the boost curve in such a way that the onset of boost pressure or the overall shape of the curve is different from that which the ECU is looking for.

If spool is reached too quickly or boost doesn't taper enough towards redline, as the ECU is using the MAP sensor to measure boost pressure continuously and it is looking for a specific level at specific points, the ECU may find a "fault" with the new curve and may throw a soft fault code or even a check engine light.

Consider that power potential will be dependent upon fuel delivery as well, so you can't expect power to increase solely by changing the boost curve if the ECU isn't capable of making the corresponding adjustments to the fuel trims as well.

Like I said, you're not going to blow up your turbo, but you need to make adjustments cautiously and in small increments being very careful to note changes along the way. If you reach a point at which the ECU begins to intervene (soft fault code, check engine light, fuel cut, limp mode, etc.) you've gone too far beyond what perameters the ECU (in it's current state of tune) will allow.

 

[JhnR]

there was somebody here who did this, and they saw an increase in boost.

EDIT: http://golfmk5.com/forums/showthread.php?t=23337&highlight=wastegate

 

[t.c. gtimkv]

spoken like a champ!

 

[Raven6t9]

Subscribed!

Is this something safe to do if Im already peaking at 25 and holding 23psi on APR stageII+ programming?

 

[Lou_Y2mK5]

Subscribed!

Is this something safe to do if Im already peaking at 25 and holding 23psi on APR stageII+ programming?

Nagatory and thanks for raising the dead. :thumbsup:

 

[wannagofast]

Subscribed!

Is this something safe to do if Im already peaking at 25 and holding 23psi on APR stageII+ programming?

Are you looking for more boost? Are you using a boost gauge or vag com?

 

[g60_corrado_91]

Wow, I'm holding about 15-16 on APR Stg 2 now. Can't imagine 23. I think my PCV is bad. I really need the BSH solution.