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Ohh, yes you were considering something like this - its not a wastegate - you just used a wastegate . . .

That thing is massive!

What is it set to?
Do you have a valve to keep it off?
 
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Discussion Starter #2,942
It has the 15psi spring so I opens after 15psi of boost :)

The wastegate is normally shut unless there is positive boost pressure so completely leak free :)
 

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I never had a wastegate in the exhaust system I was a running a full 3” quiet exhaust that was causing lots of back pressure at my power levels. So I had the shop weld in a 66mm wastegate onto the downpipe and run it off of boost pressure :)
That is pretty awesome! I like the little heat shield wrap too!
 

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After achieving my power goals I’ve spent the past year trying to “domesticate” the car with a quiet Milltek exhaust, smooth Ohlins suspension, and less harsh engagement with a triple disc. I drive on average 80-120 miles a day to a SD from work and the car has become incredibly tolerable even now with near 1000 crank hp :)



People always ask me what my dream car is and it really is the STI :)
 

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After achieving my power goals I’ve spent the past year trying to “domesticate” the car with a quiet Milltek exhaust, smooth Ohlins suspension, and less harsh engagement with a triple disc. I drive on average 80-120 miles a day to a SD from work and the car has become incredibly tolerable even now with near 1000 crank hp :)

People always ask me what my dream car is and it really is the STI :)
😂Love the new "domesticated" setup. What are your thoughts on the Ohlins? Did you go with the stock 9k/7k springs? I've been debating hard on getting Ohlins suspension, but I'm not sure if the front 9k springs are too much for the daily.
 

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I thought you already had the Milltek and Ohlins? I love the theme of crazy power but still somehow keeping things civilized.

@388whp STI I don't think they're too much for a daily at all. I'm a pretty big curmudgeon in terms of mods and I find them pretty pleasant. I would say really sudden jarring impacts like potholes are worse on the coilovers, but nearly everything else actually feels more comfortable. I do feel a bit distracted at times watching out for pot holes, and there is one "hump" near my freeway exit that feels like I'm getting airborne and then nearly bottoming out, whereas it's not noticeable in my wife's car. However, on the whole I am extremely happy with them and I'm really not a mod guy (I have the Milltek as well as a reference point haha)
 

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Will be my second VA mod . . .? :)
 
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Good to see you looked into the back pressure issue! Are you controlling the gate via an emap/back pressure sensor or just a boost pressure? Big gains!
Controlling it based on boost pressure which is less susceptible to outside temperature and generally more consistent than Emap :)
 

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You must be close to 1:1 pressure ration now given the substantial difference of the graphs! Absolute monster now :) The difference in the graphs for my XR7164 looked similar (200whp less) when going to 1.03 rear and 3.5" dump from .86 rear and 3". They really sing when there is no flow restrictions!
 

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Hell the way I justified putting the exhaust bypass on was that it was safer for the motor LOL I don't know if me maxing out my prior 3" exhaust at 750whp could have contributed to the valve spring failure due to backpressure indirectly affecting the valve spring seat pressures
 

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I don't know if me maxing out my prior 3" exhaust at 750whp could have contributed to the valve spring failure due to backpressure indirectly affecting the valve spring seat pressures
Pretty sure all the "extra" forces are metal to metal, not on the spring, and that spring wear is almost all cause by their "normal" travel/motion. Surely your cams were harder on the springs than a stock cam would have been. But, the mfg knew what travel they would likely be used with.
 
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Enjoyed a nice Saturday autumn drive early in the morning today. Coming upon 12 years of ownership, I have to say I love driving the STI over the GT4. The symphony of sounds with a big turbo from the spool, cracking the wastegate slightly open, then letting off to hear the BOV still makes me giddy :) Sure the GT4 sounds epic but you have to be at 8k to really get the whole experience whereas the STI turbo sounds I can enjoy at low to mid rpm range just casually driving

You can take me out of the rice fields but you can't take the rice fields out of me
 

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Pretty sure all the "extra" forces are metal to metal, not on the spring, and that spring wear is almost all cause by their "normal" travel/motion. Surely your cams were harder on the springs than a stock cam would have been. But, the mfg knew what travel they would likely be used with.
I've been considering on my next motor to go down to a smaller Kelford 264 cam which puts less stress on drivetrain and gives me more midrange. I'm willing to sacrifice some horsepower because 800whp is too much of a handful :)
 
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