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Old 05-04-2020, 04:25 PM   #1001
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Originally Posted by Alex Buchka View Post
I usually purge a tube for 3-5 minutes at 15cfh or so, then turn the purge flow down to 5cfh, this saves quite a bit of gas. Those purge plugs you can buy are nice but I've built many headers with just aluminum foil to cap the ends. A large gas lens helps immensely as well, I use a 1" diameter cup and lens from an automation torch that I hacked together but the SPW or furick stuff is also very good.
Once you have your sweet spot for welding current just weld short sections and jump around to different joints on the tube. This will keep the interpass temps reasonable so you don't have to wait too long. You'll notice pretty quickly if things are getting too toasty. If I'm in a hurry I will purge several runners simultaneously so I can keep skipping around to different tubes while others cool down.



Agreed, those spiral wound tube things both look and are ****ty.



Unsupported bellows are finicky. They really shouldn't be flexed at all on installation to maximize life and should only be strained in one direction if possible. It looks like vibrant sells lined bellows and it's very important to make sure the liner is oriented correctly with regard to the gas flow direction. Overbraided bellows are usually more resilient to cracking since the braid effectively works as a travel limiter and a friction damper against the convolutions which makes the bellows less likely to fatigue crack.
I went from a normal 7 cup to a Furick 12 with a lens and that helped immensely with stainless. I actually filled a whole extra canister to use for the manifold purge, but it's at Noah's house. Maybe for the wastegate tubing, I'll see if I can pick it up and rig a purge setup.

I've been looking at the wastegate situation and to do it right, it's going to be really tricky. BY FAR the easiest/simplest thing would be to run the front wastegate over the collector, pick up the rear wastegate, then turn down right into the 4" section of the down pipe. That would only be about 8-10" post-turbine, so not ideal. But maybe the 4" down pipe will help offset the flow issues? I'll try the right way first, but I'm doubting my abilities.
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Old 05-04-2020, 07:38 PM   #1002
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Originally Posted by Alex Buchka View Post
Overbraided bellows are usually more resilient to cracking since the braid effectively works as a travel limiter and a friction damper against the convolutions which makes the bellows less likely to fatigue crack.
This is essentially what I was trying to convey earlier; thanks for typing it out in a much more thorough and cogent manner.



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I've been looking at the wastegate situation and to do it right, it's going to be really tricky. BY FAR the easiest/simplest thing would be to run the front wastegate over the collector, pick up the rear wastegate, then turn down right into the 4" section of the down pipe. That would only be about 8-10" post-turbine, so not ideal. But maybe the 4" down pipe will help offset the flow issues? I'll try the right way first, but I'm doubting my abilities.
If you end up joining the front wastegate outlet into the rear one upstream of the main join into the downpipe, make sure you've got a bellows or flex section in each section of outlet tubing. If the front pipe is longer and routed over the top of the collector then it will experience a greater change in length as it expands and contracts, so some compliance there becomes crucial. If your main downpipe is 4" in diameter and you're joining 8-10" downstream of the turbine housing, I wouldn't get too bent out of shape. I don't think the turbine outlet flow will be disrupted much in that case except for instances when wastegated flow might be greater than turbine flow. In general, try to blend the wastegate outlet into the downpipe at a shallow angle, matching the flow direction of the main downpipe as much as possible. All of this stuff is highly dependent on packaging constraints but if you can follow the spirit of most of these guidelines you'll be OK. The big idea is to maintain turbine performance and minimize wastegate flow restrictions.
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Old 05-25-2020, 05:58 PM   #1003
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Welp, I got it done. It was touch and go for a bit, and at times I was about ready to throw the whole thing in the river. Each wastegate has as few bends as I could get away with, and two ~1.5” holes in the down pipe will definitely flow enough to keep the boost wherever I want it.







The next thing on the turbo side will be making a brace. Current thinking is to put two rod ends on the ends of a 3/4” tube and go from the turbo flange down to the motor mount area. I’m thinking that I could put a slight bend in the tube to help it accommodate the heat expansion on the manifold. Anyone know if that’s a good or bad idea?

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Old 05-25-2020, 09:35 PM   #1004
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Holy sht thats sexy as hell
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Old 05-26-2020, 02:12 AM   #1005
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A brace with heim joints is a great idea. Ideally keep it fully vertical to take the weight while allowing for free growth of the manifold. If you can go up to a solid structure above it braced to the head that will work well because the rod will be in tension as a hanger, and the support structure and manifold will both move with the head. Going downward should work as a support, it will be in compression but with a 1/2” tube I don’t think it would buckle. Try to mount it to the engine though - I would be cautious about relative movement between the engine and body. You don’t want to end up breaking something expensive...

I can show you an Audi Le Mans turbo hanger brace as an example if that would help!
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Old 05-26-2020, 03:15 AM   #1006
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Daaaaaamn!
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Old 05-26-2020, 04:45 AM   #1007
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That looks gorgeous, nicely done!
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Old 05-26-2020, 09:15 AM   #1008
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Thanks guys, I'm pretty happy with how it came out.

Chris, I think I've seen that Audi brace, or something similar. I also found a Renault F1 brace that had a triangulated brace coming off the valve cover bolts, with a heim jointed rod hanging down holding the turbo. I don't love the look of the brace on top, and my turbo is only about an inch from the hood, so I doubt I'd have room for one anyway. You have a good point about the brace being as close to vertical as possible. I hadn't thought about a vertical brace's ability to pivot to allow for movement, versus a more horizontal one being in tension, side to side. Maybe I can build a bracket from the block to put the lower heim joint closer underneath the upper one. It's all pretty tight under there, especially once I route the oil cooler lines. I really wish someone would tell me oil coolers aren't necessary with high tech synthetic oils...
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Old 05-26-2020, 10:46 AM   #1009
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The quote the D.O.C. "this is serious bidness".
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Old 05-26-2020, 12:17 PM   #1010
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That looks killer. Nice work!
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Old 05-27-2020, 02:22 PM   #1011
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So, I'm hoping to make some progress on the intake manifold in the next couple weeks. The flange and runners are at Noah's getting tacked, then I'll see how short I have to make the runners in order to fit the plenum, which is made of a 4" tube with a plate welded to one side. My first question is about injector angle.

Common sense tells me to keep the angle less than 45° to the direction of air flow down the runner. Any harm in keeping it right at 45° (the steeper the injector is, the more room I have for the plenum), or should I be trying to get more towards 30° or so?
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Old 05-27-2020, 06:21 PM   #1012
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Injector placement really depends on the spray pattern. A good rule of thumb is to make the fuel cone intersect with the back of the intake valve. I would probably focus on not shooting the spray pattern directly at the port floor.
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Old 05-27-2020, 06:48 PM   #1013
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Injector placement really depends on the spray pattern. A good rule of thumb is to make the fuel cone intersect with the back of the intake valve. I would probably focus on not shooting the spray pattern directly at the port floor.
Cool, thanks. I'll see what I can do spray toward the back of the valves. The stock 16v intake seems to position the injectors at a fairly shallow angle, so I wonder if that's what it takes to spray at the back of the valve. That would make it so my fuel rail would likely hit the top edge of the plenum. I can notch the plenum, but it's already smallish and I'm hoping for as much volume as possible.
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Old 06-27-2020, 04:41 PM   #1014
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Still working on this thing. Today I finished the turbo brace. Originally I wanted it to be hidden under the manifold, but that wasn't going to work. So I went the F1 route and made a pretty ridiculous contraption to dangle the turbo from above.

Very simple 1/8" steel plate with a nut welded to it:




The brace uses two m6 studs on the valve cover, and one m8 stud down on the head. It's really stout. The reason I made the lower heim joint mounting point so low, is that it seems like a longer lever there will allow for a straighter path for expansion of the manifold. Really, that's just a theory, as I don't actually know which direction it'll expand in. Either way, longer seems better.




Tucked in behind the turbo:




Here's the state of the whole swap. Noah and I are working on the intake manifold when our schedules line up, but it'll be a bit before that's done.



I'm also almost ready to have the block machined and the head checked out. I drilled and tapped for the turbo oil return, and I just got some freeze plug retainers in the mail yesterday. Not looking forward to drilling/tapping 24 tiny holes, but whatever. Once that's done I can bring it to a machine shop.
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Old 06-27-2020, 10:20 PM   #1015
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Bad ass.
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Old 06-27-2020, 11:51 PM   #1016
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Hot damn
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Old 06-28-2020, 02:48 AM   #1017
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Very nice, very nice indeed
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Old 06-28-2020, 11:12 AM   #1018
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Damn, Tyler
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Old 06-29-2020, 11:32 AM   #1019
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Bad ass.
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Hot damn
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Very nice, very nice indeed
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Damn, Tyler
Thanks, guys. All this turbo stuff represents a lot of firsts for me, so it's cool to read the kind words.
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Old 06-29-2020, 12:21 PM   #1020
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I mostly want it running to get the verdict on that turbo and backhousing combo
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Old 06-29-2020, 01:24 PM   #1021
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Looks nice Tyler!

Makes my dinky fuel rail project seem like childs play. lol
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Old 06-29-2020, 01:38 PM   #1022
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I mostly want it running to get the verdict on that turbo and backhousing combo
Same. I confirmed that the .85 twin scroll housing is the exact same form factor, so it will be easy to swap if the 1.00 is too laggy. I really doubt it'll be terrible, aside from potential problems with my manifold design.
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Old 06-29-2020, 01:40 PM   #1023
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Looks nice Tyler!

Makes my dinky fuel rail project seem like childs play. lol
Well I bet yours will run before mine does at this point. I'm almost done with the fuel rail for this, I just need to bring it to Noah's to face the ends. I got -8 ORB fittings, but I don't know how to cut an accurate chamfer in the hole for the o ring to seal, so I'll probably just use copper or aluminum washers. Is that what you did?
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Old 06-29-2020, 05:53 PM   #1024
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Yeah, we'll see about that. I can't find the stupid heater hoses, gotta just bypass them at this point since the firewall plate is different than a 240 and NLA, and mine's rusted. At least that heater pipe we fabbed up fit nice though! lol

Might fire it up this weekend if things go well, then I can start tuning on the new setup, assuming all the cards align perfectly...
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Old 06-30-2020, 12:09 AM   #1025
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Well I bet yours will run before mine does at this point. I'm almost done with the fuel rail for this, I just need to bring it to Noah's to face the ends. I got -8 ORB fittings, but I don't know how to cut an accurate chamfer in the hole for the o ring to seal, so I'll probably just use copper or aluminum washers. Is that what you did?
There's a whole spec (pdf) for the ORB/J1926-1 fitting and when properly applied with a port tool (pdf) I've seen these take a 10,000m of water column (from the outside!) when assembled by highschool kids. On the flip side it's a pretty resilient seal if the chamfer is concentric to the hole, smooth, and provides a good corner crush into the fitting. The forces between the ramp and the inside edge of the fitting are tremendous given the force exerted by the threads.

I modified my NiW fuel rail to take ORB and an external regulator and, carefully, hit it with a 60* cutter down to a little less than the right port ID. I did that by hand but I hedged my bets and cut the threads deep enough that I could face off another 0.050 or so and try again if I needed. After populating it with injectors and mounting it on the head I set the regulator with compressed air. The fittings were happily leak free. I've since recut the oil filter/thermostat housing and a coolant port at that angle but those fit in the mill. The oil thermostat ORB "ports" had nothing more than a thread lead-in to seat the o-ring. I imagine most users just tighten the crap out of that and it's leak-free-ish enough. At these pressures its a fairly robust sealing method.

So impressed with the build. I keep telling myself: "no, I'm not going to rip mine up. First it needs to run before it comes apart again!" You're so many iterations ahead of mine.
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