Wastegate Questions and Discussion

[STAZ15]

Hi everyone I recently purchased an ATP 2554r turbo from a fellow forum member who told me that they put a 22 psi wastegate on it to help with spool. I don't really know enough about it to know whether it is true or not. I failed trying to search out info. So I guess my question is... how does a higher waste gate help with spool? Are there any other benefits? Is it safe for the FIST ? If not should I just purchase a turbo smart wastegate and work with that?

I love reading about this stuff so answer away so that I may become better educated!

Thanks!


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[letitreign]

I'm no expert either but the basic idea is, the stiffer the spring the more pressure is required for the actuator to open the wastegate. If a wastegate is being held closed for longer, then all the exhaust is being forced through the turbine rather than some of it escaping through the wastegate thus making the turbo spool sooner than if some of the exhaust had escaped through the waste gate. Getting a stiffer spring is a fairly common upgrade for these cars as a number of people have noticed that the stock actuator is fairly soft meaning your wastegate could be opening while you are trying to spool up, therefore delaying the build up of pressure. If you want an example, I believe the stock spring is something like 7 psi? Most guys running hybrid turbos are running either an 11psi or 17psi spring just for the added duration of the waste gate being closed.

 

[STAZ15]

Thanks!!! Great info! I contacted my tuner yesterday to let him know about the install when I told him about the wastegate at 22 pounds he was like "ho-ly.... sh&$" and I was like what?! He didn't respond just wrote me a map for it ha ha


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[mercdank]

Checkout the technical article by Turbosmart that deals with exactly what you want to know. From the looks of it, a 22psi wastegate spring is waaayy too high.

http://www.turbosmartusa.com/technical-articles/internal-wastegate-faq/

Choosing the right spring
The springs that are installed in either an internal or external wastegate should be rated to the lowest boost pressure desired. The lowest boost level achieved cannot be lower than the spring rating as the spring only begins to allow the valve to open at the pressure rating of the spring.

With a boost controller installed, a general rule of thumb is that the maximum boost level that can be achieved safely is double what the spring is rated to. If your target boost pressure is 20 PSI, a minimum spring rating of 10 PSI is recommended. This gives the wastegate more control over the exhaust gas. If the spring rating is too low, as boost levels climb and exhaust flow rates increase, the flow of exhaust can influence the valve more as the only force trying to close it is the spring force.

If the spring is too soft, even with no pressure signal to the actuator, the valve will open if there is enough exhaust back pressure, which will limit the amount of boost produced by the turbocharger.

 

[STAZ15]

Checkout the technical article by Turbosmart that deals with exactly what you want to know. From the looks of it, a 22psi wastegate spring is waaayy too high.

http://www.turbosmartusa.com/technical-articles/internal-wastegate-faq/

Oh man. Well my spring rate is definitely not too soft. So this means that my wastegate is not opening at all? I'm only running 22 pounds at this stage of the tune.


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[mercdank]

If you are running 22 psi of boost you should be at a minimum of 11psi. A popular choice among the hybrid turbo/tuners is the 17psi rating. Depends on what your tuner says. He will be tuning to account for it and if you are getting good results then why bother switching. I am sure someone with more knowledge will come along to answer exactly why but if the car feels good and you aren't throwing codes or getting too many corrections I wouldn't sweat it.

 

[J2FoRS]

The previous could have also misspoke. As above from turbosmart it should be rated for at least half the max desired. Since the 11psi and 17 psi ones are commonly used he may just not really know what he had and be thinking the wastegate was for 22 psi. So 11 could actually be that. Id imagine if your tuner is half decent they are going to be able to figure it out based on logs if its truly a 22psi spring.

 

[STAZ15]

The previous could have also misspoke. As above from turbosmart it should be rated for at least half the max desired. Since the 11psi and 17 psi ones are commonly used he may just not really know what he had and be thinking the wastegate was for 22 psi. So 11 could actually be that. Id imagine if your tuner is half decent they are going to be able to figure it out based on logs if its truly a 22psi spring.

This could be true I will send an email to him and ask. I have the upmost confidence in Ryan!


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[Based]

I am sort of a noob, can someone explain to me what the waste gate does and what the difference between 11psi vs 17psi is


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[BoostBumps]

I am sort of a noob, can someone explain to me what the waste gate does ...

How Turbocharger Wastegates Work - Internal Vs External (Video)

[video=youtube;pn-uCAgB4H8]https://www.youtube.com/watch?v=pn-uCAgB4H8[/video]

 

[Brura22]

I am sort of a noob, can someone explain to me what the waste gate does and what the difference between 11psi vs 17psi is


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A 17 psi WG will stay full closed until 17 psi when it starts to open, so 100% of the exhaust gas is hitting the turbine until 17psi.



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[Based]

A 17 psi WG will stay full closed until 17 psi when it starts to open, so 100% of the exhaust gas is hitting the turbine until 17psi.



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So just that 6 psi will kill the turbo? Damn


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[Brura22]

I am sort of a noob, can someone explain to me what the waste gate does and what the difference between 11psi vs 17psi is


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A 17 psi WG will stay full closed until 17 psi when it starts to open, so 100% of the exhaust gas is hitting the turbine until 17psi.



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[re-rx7]

A 22 psi spring isnt a bad thing. Just means the car will run 22 psi no matter what without a BC.