Wastegate Woes

[hottscennessey]

I just wanted to get an opinion on this problem.

I have been running a knockoff HKS 50mm (I think) wastegate for a little over a year now. The wastegate always functioned perfectly on a genuine HKS 10PSI spring (really saw about 13-14 PSI).

I recently installed a genuine HKS 15PSI spring (am actually seeing about 20 PSI). This seems to make sense.. as on the 10 PSI spring I saw ~40% more boost than the spring was rated for, and now I'm seeing ~40% more boost on the 15 PSI spring. Thats all fine. I'm okay with that. I don't really care... the point is it needs to work and it does.

Now heres the thing, my wastegates always worked perfectly with my boost controller (Blitz SBC-ID III). Now, when I up the boost I have to run over 30% duty cycle (and similar gain) to see ANY boost increase. In order to run just over 23PSI I must run a 60% duty cycle (60% gain). Okay, that seems kinda weird, but I'm okay with that too.. as long as it works; and it does.

Now the wastegate makes a strange surging noise (NO, not compressor surge). It opens and closes when my boost is at anything over the spring rate. This is weird to me as I've run the 10 PSI spring up to 30 PSI before and NEVER did it surge. Mind you the boost stays steady.. but whats the deal? It's really annoying to me. I even uninstalled everything and put it all back together.. no difference.

What I've done:
>Re-installed spring. Even used RTV on the diaphram knowing I'd trash it if it didn't fix the problem
>Tested for leaks
>re-set EBC
>Double checked vac. routing
>made sure EBC was set on external


Should I leave it alone, or should I worry?

 

[adampecush]

If you've run the 10 psi spring up to 30 psi without issue, why change to a 15lb?

 

[MK3Brent]

I believe the sound you're hearing is caused by the EBC. You've since adjusted the duty on the stepper/solenoid?

I hear this noise on my tial all the time... mine is just the stepper motor of the EVC trying to regulate boost at the gate.

 

[hottscennessey]

If you've run the 10 psi spring up to 30 psi without issue, why change to a 15lb?

I wanted to run more

I believe the sound you're hearing is caused by the EBC. You've since adjusted the duty on the stepper/solenoid?

I hear this noise on my tial all the time... mine is just the stepper motor of the EVC trying to regulate boost at the gate.

You're probably right, I do recall hearing it once when I had the 'limiter' function turned on by mistake and I was trying to run more boost than the limiter was set for.

Now the limiters off and I can't figure out what would cause it.


I'm starting to think there is an issue between the size WG and the boost level, causing issues controlling boost.. which is making that noise. Unfortunately I'm no scientist and I don't know for sure.

 

[MRSUPRA]

I have a real HKS 40mm wastegate thats as old as dirt and it holds exactly what the spring is rated for. In my case, 15psi.

You need to disconnect your boost controller and only run off of the wastegate. (Just hook a vacuum line from your compressor housing to the side port of your wastegate). This will tell you truly how your wastegate is operating. You should get 10psi on a 10psi spring. If your getting too much boost, your wastegate is malfunctioning or your manifold wastegate port design is bad. Good luck

 

[flubyux2]

hes right. every WG ive seen creates a boost level exactly what the spring is rated for. my friend has a 10lb spring in his ebay tial V40 knockoff and it makes 10psi. i put an hks50mm knockoff with a 10psi spring on my friends T4 manifold w/ CT and it makes.... 10psi. so, something is up w/ your setup.

 

[hottscennessey]

I tried what MRSUPRA said, no difference.

About the boost pressure tho.. there is variance per spring. For instance the same spring will make 10PSI in a HKS Racing gate, vs 14.2 in a HKS Standard gate.

http://www.jazzproparts.com/product_p/1405-ra035.htm
http://www.racerwheel.com/hks-1405-ra035.html

 

[annoyingrob]

All I know is my genuine HKS 50mm, with my Profec B Spec 2 doesn't make any sort of cycling noises.

I run a 15psi spring, and make 15psi. I've turned it up to 18psi, and the same thing, no weird noises, just goes from quiet to ssshhhhRWAAAAAAAAAAA.

 

[suprabad]

How are you measuring your boost? Through an onboard gauge right? Maybe your boost readings are not accurate. (i.e. Gauge f'd?)

Might want to a/b it with another gauge and see if it reads similar or there is a huge discrepancy. Otherwise it's gonna be pretty hard to get readings that make any sense. To my knowledge you shouldn't be boosting any higher than the spring rating on a mechanical wastegate

 

[hottscennessey]

my gauge matches what my Stinger EMS says (both display same #'s peak vs datalog peak).

I think I might just get another WG if it keeps bugging me..

 

[tissimo]

tial ftw

 

[IJ.]

Tial x 2

 

[hottscennessey]

IJ, any theories about the flutter?

 

[IJ.]

Might have to run a 2mm restrictor in the dump line from the valve to settle it down Scott.

 

[hottscennessey]

Thanks Ian! Can't hurt

 

[quake]

wastegate is not the place to save on cash a failure at this part could cost the motor tial 44

 

[p5150]

exactly HOW are your vacuum lines ran? What type of solenoid are you using?

 

[MK3Brent]

Tial x 2

x 3

one of the best wastegate changes I've EVER made.

 

[flubyux2]

tial v44 FTW... even the knock-offs are good. my friend is running 10.50's on one right now. its got a 10psi spring in it. its almost internally identical to a real V44 that my roommate has. the only difference is the diaprhragm and the valve itself. the diaphragm tries to a be a rolling-type, pre-formed unit. it seemed like a single layer of fiber weave impregnated w/ silicone. the real V44 unit is thicker and more accurately formed. as far as the valve, the real v44 has some sort of coating on the stem to make for smoother operation. its also a tighter fit in the body. the knockoff still has cutter marks from lathe cutting and no coating. because of this, it has a looser fit.

long story short, my friend makes 510 rwhp on a dyno dynamics at 23psi on pump/c16 mix thru a 3800 PI stall and a built auto. the profec 2 accurately controls boost anywhere between 23psi on race gas and 18 everyday. no problems in about 15k miles.

 

[MK3Brent]

FYI, Tial recommends a different valve (not the standard valve) if you plan to run leaded race fuel.

I've run a few tanks of 110 leaded through mine with no ill side effects, but it's just a little precaution they say.