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I have a 331 dart with a 76mm turbo laying down 644 with 15lb of boost. My problem is when I turn up the boost I get a loud flapping/clapping noise coming from around the wastegate. (evolution w/9psi spring) I will see as much as 20psi on my gauge. and power has increased to 711 rw. The car still pulls hard but the noise is a concern. I am running a manual boost controller.
My online research leads me to believe that the wastegate valve is being pushed open prematurely by exhaust back pressure. Running 112 octane and air fuel is good. I have tried two different controllers same result noise at 18 psi and above. Another forum suggested that I increase the wastegate spring rate. What do you guys think?
 

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also that wastgate is most likely too small. I had one on my 306 and it was too small. I'd run a 44mm ,or try like stated above with a stiffer spring
 

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The Evolution wastegate (By Turbonetics, I am assuming) is undersized for the application.

I would recommend the Turbonetics RG-45 (up to 800HP) or the Turbonetics Newgen for your application. If you are planning on running "high boost" consistantly and want room to grow, I would recommend the Newgen HP.

FYI, RG-45 is 45mm. Newgen is 50mm. "HP" in Newgen stands for "high pressure". Both are V-band connection.

There are several Corral-supporting vendors you can go through. Hope this helps.
 

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I'm worried you might be having compressor surge.
Which is VERY bad.

I ran the numbers for a 331 with 20psi and 6,000 and 3,000rpm
and plotted them out on a T-76 compressor map.

The blue lines are CFM and boost level.
The red line is the level the turbo follows as it comes up from
0 boost at idle to full boost at 3,000 rpm (the first vert. line)

as you can see it bumps past the surge line. Thats bad.

I'd turn down the boost till you get a bigger turbo and wastegate.
Current set-up is maxed out at 15psi, which is about right actually.

http://videos.streetfire.net/video/True-Turbo-Compressor_163406.htm

 

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Is the noise coming from the solenoids? I would think they are constantly adding and releasing air on top of the gate to maintain pressure higher than the spring alone.
Turbonetics, Do you work for Turbonetics? If so is a 76 too small in your opinion?

Edit: OOPS! I re-read MBC
 

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Yes, my name is Steve and I am an actual Turbonetics employee responding to assist.

From the information provided, T-76 seems fine for your application. Along with many valid points made by forum members, under-sized wastegate could be the culprit.

Good luck.
 

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Discussion Starter #11
Steve, I suggest you call Hellion and educate them on the limits of the evolution wastegate. They have repeatedly assured me that this wastegate is utilized on their beast kits that support even more power than I have. Are you suggesting that I upgrade turbo, wastegate or both?
 

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also that wastgate is most likely too small. I had one on my 306 and it was too small. I'd run a 44mm ,or try like stated above with a stiffer spring
I agree its TOO SMALL. I run that exact wastegate/spring combo on my STOCK motor and its too small. I cant run under 9psi and get boost creep in the higher gears/rpm. When I swaped to bigger tires in the rear it got worse.

you could try a stiffer spring which will prolly help but I would concider a EBC. it will use boost pressure to hold the gate closed so exhaust pressure dont push it open.but that wastegate is still rated for WAY less HP then your running.
 

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Toutlaw, it is true that Hellion has several (and I do mean SEVERAL) street cars with higher power and higher boost running the Evolution wastegate. Call it their design ingenuity or extensive R&D on their kits... it works. However, there are many variables come into play

It appears that your Evolution WG is working very hard to control your boost level. You say that you "will see as much as 20psi on my gauge"... are you wanting to run 20psi or is it happening "on its own"?

As far as the noise (assuming it's not surging or coming from the BOV), it seems to be coming from the valve (rapid movement) diligently trying to control the boost level. On your setup, for more precise boost control (sans noise), I would recommend the RG-45 or the NewGen/HP. There are no options for Evolution WG spring higher than the one installed in the unit.

Good luck.
 
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