Build Thread Want To Blow 5 Years And $50k On A Foxbody? Step By Step Instructions Inside!

Good points. I can easily test the intercooler drop by swapping my plx gauge to a T off the boost controller while leaving the Holley MAP sensor on the manifold line. The two read within a half psi of each other, so it will be a relatively accurate test.

The Tial gate came with the turbo kit when I bought it used. My luck with used parts has been less than stellar, so it would be my luck that something is wrong with the gate.

For the spring, I've learned that having too small of a spring can prevent the turbo from spooling adequately to higher boost levels depending on backpressure. I'll up it to a 15 psi spring and see how that helps also.
 
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Im sure you will figure it out, you also have the right attitude about dyno numbers, like you said, it is a tool, the numbers really dont mean too much at the end of the day, if the combination is happy it will show on the dyno and it is a great tool to test what works and what does not.
 
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Screw it. Just drive the damned thing until something pops and you have to replace it. hehe

So long as you're making in the neighborhood of 400 HP before 2800 rpm? Win! ...and a ton of fun on the street. lol
 
Good points. I can easily test the intercooler drop by swapping my plx gauge to a T off the boost controller while leaving the Holley MAP sensor on the manifold line. The two read within a half psi of each other, so it will be a relatively accurate test.

The Tial gate came with the turbo kit when I bought it used. My luck with used parts has been less than stellar, so it would be my luck that something is wrong with the gate.

For the spring, I've learned that having too small of a spring can prevent the turbo from spooling adequately to higher boost levels depending on backpressure. I'll up it to a 15 psi spring and see how that helps also.

Huh,...two uses of the word "stellar" w/i a couple of days.......go figure.:shrug:
 
Awesome pal I am glad to see this is all finally paying off


Sent from my iPhone using my fingers while my auto correct makes me seem illiterate
 
Thanks man. I'm excited to finally be able to enjoy it.

So, I opened up the wastegate today and I believe I found the problem.

e6bd65a12ecb34d5d0cc258bd78fd82d.jpg


I knew I had a yellow spring, which according to Tial is an 8.7psi spring. The issue is that spring pictured is not a large spring, it's a small one. The small yellow is rated for 2.9psi. When I originally checked the spring with my untrained eye, I didn't even consider the fact that there are large and small springs the same color. Duh! That completely explains not being able to hit the higher boost numbers.
 
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Pardon my dumb questions, but the logic doesn't add up to me. I understand how a WG works in theory - Once you hit a certain pressure, the WG diaphragm is pushed open and any excess pressure bleeds off over the set pressure. I also understand that running on a spring isn't going to net you the exact rating of the spring. But how did you make 15 lb on a 3 lb spring?
 
To answer both your questions, that's what the electronic boost controller does. The bottom of the wastegate sees manifold pressure (from compressor outlet) and the top of the gate sees an input from the boost controller. The manifold pressure forces the diaphragm open diverting exhaust gas to limit boost. The pressure from the boost controller acts against the manifold pressure and tries to keep the diaphragm shut (basically making the spring stronger), which makes the turbo produce more boost than that gate spring would allow by itself. The problem with a tiny spring is that the exhaust backpressure has enough force to push on the wastegate valve and inadvertently compress the spring, which reduces boost. The boost controller then has to fight the pressure from the exhaust to try to keep the gate shut so boost can build. It can only do that to a certain extent, especially without CO2 control. From what I understand, the wastegate spring should rated for about half of what you want your max boost to be. I went with what I thought was a 10psi spring because I wanted around 20psi of max pressure. It's actually surprising that I was able to even make 15psi on a 3psi spring.

I bought a large red (10.1psi) spring, so that will give me 13psi when I use both springs.
 
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Screw it. Just drive the damned thing until something pops and you have to replace it. hehe

So long as you're making in the neighborhood of 400 HP before 2800 rpm? Win! ...and a ton of fun on the street. lol

That's generally the plan! I do want to see how the car spools up with the correct size spring in it now. I would have to guess that it should spool up much faster.
 
My other concern is that there is no gasket or seal between the top and bottom part of the spring housing. This area sees pressure from the boost controller, so I'm guessing this should be sealed so it can hold the pressure. Is there usually a gasket there? @90lxcoupe @GroverDill, what do you guys think?

Looks like the diaphragm assembly could act as a seal. Check out this exploded view from Tials website
http://www.tialsport.com/documents/explodedmvr.pdf

I know it's not the exact same model as yours but should be similar. You have the V44, right?
 
How does the boost controller produce the pressure to offset the boost? Is it an air pump of sorts, that can have CO2 assistance?
The electronic boost controller uses 2 solenoids to control the pressure at the top of the wastegate. It uses manifold pressure. Nothing but vacuum lines. It adds pressure to effectively increase the resistance of the spring. If you have a 10psi spring, but you want to make 14 psi you would set the boost controller to 4psi. It adds that pressure on the top of the spring until the controller sees 14psi and then it backs off. The solenoids (one increase, one decrease) keep constantly working to maintain that pressure on the top of the gate.

The benefit of CO2 is that it provides a constant pressure to the solenoids at all times, which will create more stable boost levels. Important for drag racing, but not as necessary on the street. You can also run a smaller spring with CO2 and still get larger boost numbers because the solenoids will always have something like 40 psi on them all the time.
 
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