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Discussion Starter #1
I have an on3 kit for my fox with a 7675 precision turbo and a 45mm Turbosmart wastegate. The wastegate has a 7 lb spring in it and at 5100 rpm the boost is at 12.4 according to my tuner. Car is currently there. We are trying to figure out what to do. He thinks it’s where the wastegate is located that it’s not able to let off the pressure it needs to. Has anyone had an issue like this with the on3 kit and did you fix it?
 

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Are you sure it's a 7psi WG spring?

Is the 12psi of boost being achieved on just the WG spring pressure and all the WG lines disconnected to atmosphere?

ks
 

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Discussion Starter #3
Yes that’s just spring pressure, it’s supposed to be a 7 lb spring
 

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Did On3 put the gate placement on the pipes or was that you? If On3 welded it on then I doubt it's the placement which leads to the WG itself. I would take the WG apart to make sure the valve isn't sticking and verify that the spring is correct and if all looks good then you can look at the placement of the gate. Springs are cheap and it may be worth the effort to simply get another spring and pop it in.

ks
 

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That should be fine. I would look at the gate and spring. Just do some verifying that everything is what it's supposed to be. I would start with the idea that the spring is actually stiffer than what it's supposed to be.
Usually springs are color coded by the MFR so this could help right away.

ks
 

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Discussion Starter #7
He said the first thing he’s going to do this morning is pull the waste gate and verify everything. But he seems to think it’s the gate location
 

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Hopefully when the Corral world wakes up someone with the On3 kit will chime in about the WG placement. I've seen gates in a LOT worse position than that work perfectly fine. Your system isn't even moving that much air so I have a hard time thinking that the gate position is the issue.

ks
 

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No issues with that wastegate placement. Just picked up a car with an On3 system with a 76mm ball bearing turbo and it makes 5.0-5.4 PSI throughout the RPM range with a 5# spring. It even has the On3 supplied wastegate. Worked on another and had no issues with a 7# spring.
 

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My wastegate is in the same spot also. No problems on my rig. How much boost are you running? If your car is really having boost creep issues I wonder if you should cut off the wastegate and weld on a bigger unit that can flow more. That’s what the creeping is, the gate isn’t flowing enough. So either it’s not opening up all the way or it cannot flow what your trying to ouch through it. I would think it should flow a 76mm turbo with 10+ PSI without any problems. I think your gate is getting hung up. Bench test it like Previously mentioned


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Discussion Starter #12
He was able to get it to flatten out by adding a little more boost. Car made very good numbers I feel almost too good. 687-675
347
Afr 185
F cam
Precision 7675
9:1 compression
93 pump gas
 

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??? Mine doesn't creep. I've used a 4psi spring, 8psi, 10psi, and 14psi and none of them crept. Now I use a 4psi spring with electronic boost control and still don't have issues. Definitely not the placement.
 
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