Ten Pounds of Shit in a Five Pound Bag - Twin Turbo LS3/DCT Daily Driver

[Esser]

This is some solid work! I can't imagine trying to fit something like this in an FD with even narrower frame rails.

I'm assuming the gates will be recirculated right at the housing exit? Will you take exhaust all the way to the rear?

[shainiac]

Thanks. Yes, definitely going to recirc. It's honestly the easiest option with the current setup I think.
I'm not a fan of open wastegate sound on LS's, especially when running really low boost.
The car will definitely have full exhaust. Dual 3" to 4" out the rear. Planning on adding a pressure port on the downpipe so I can see if there's much backpressure after the turbos.
My old dual 3" into single 3.5" was a little restrictive with the cutout closed, but very quiet.
I designed up an "active" rear muffler that I'm still planning on making, but may come later in the summer depending on how antsy I am to drive the car this spring. I also may add a cutout before the muffler like I previously had. It probably makes a little extra power, but it's more for fun than anything.
I'd really like to make the driver's side downpipe out of oval so I can run it in the tunnel vs under the floor like it is currently. The current DS downpipe is considerably longer and has a few spots in the RPM band that sound strange. It also has a not-totally-unpleasant AMG sound that's pretty unique.
If I could choose, I'd want it to sound like a C6 Z06, but with turbo noises Going to measure and try making the exhaust as equal-length as possible this time.

[shainiac]

Turbo kit is DONE! Well, sort of.
I finished the passenger side yesterday. It all fits, but required a little ticking of the frame rail. I test fit everything multiple times when tacking, but I think this side moved a decent bit after final welding.
At first, the wastegate moved too close to the manifold. After cutting and re-fitting, it's literally thousandths of an inch from the frame rail. BFH and good to go 

The other thing I'm kicking myself about - The passenger turbo is a few degrees cocked to the right. I made one last adjustment, cut off tacks, retacked, and used a level to square the turbo to the manifold on the bench. Not sure what happened, but it ain't that straight lol. After the waterpump, radiator and balancer/belt are on, I'm sure it'll be less noticeable, but it bugs the hell out of me. I had the change to get it right and just missed it lol. The height left-to-right is also different, but that's more of a factor of the manifolds not actually being symmetric.

I've ordered oil drain fittings and hose and putting together a shopping list for downpipe materials now. Planning on buying all my stainless from AceRace instead of my usual questionably-magnetic eBay "304". If anyone has recommendations for affordable quality mandrel bends, I'd love to hear em.

Once I'm able to mock up the drain lines, I'll pull the engine back out, weld the bungs to the pan, seal everything back up, and put the engine in for the last time (hopefully).

[Esser]

All the stainless on mine was from either AceRace or Stainless Bros. Both similar, Ace a little cheaper

[shainiac]

The long block is now (was) full assembled. Rockers and pushrods installed. Preload measured out around 0.06" using 7.400 pushrods and new Gen5 LT lifters (PN: 12648846, I was told these are now factory replacement for LS7).

I was turning the engine over by hand, I heard a really weird noise from the front end/front 2 cylinders. From what I could see, nothing was hitting the windage tray.
The noise sounds like a ratchet clicking. There's also no noticeable resistance when turning everything over.

When I pulled the timing cover away from the block, the noise is the same.
Using an OEM LS2 timing chain and gear and a new Mellings 10296 pump that I centered properly with feeler gauges during install.

I also measured peak torque while turning over the engine (rockers on, no plugs) and it was ~18lbft, which seems reasonable.

It got too late last night to keep messing with it, but I just rented a balancer puller, but I'll pull the balancer and cover tonight. I also plan to pull rockers one-by-one to see if I can trace anything down that way also.

Video with sound:
https://i.imgur.com/hVZJdcX.mp4

[shainiac]

Pretty sure the the source of the noise has been found. I believe it's the timing chain becoming unloaded after the cam passes peak lift.
When turning the engine over slowly by hand, I guess there's not enough tension on the cam gear, so after the cam crests peak lift, the spring pressure wants to rotate it forward and creates slack in the chain. I don't think it'd be an issue at any real RPM, but when turning over by hand it's noticeable.

If I remove the rockers, noise goes away. If I put spark plugs in and the engine takes way more force to turn over with compression, the noise is not really noticeable.

MORE VIDEOS:
https://i.imgur.com/S2BnJ1q.mp4

https://i.imgur.com/GSId6kg.mp4

[shainiac]

Still picking away at the turbo kit. The engine is finally all buttoned up. Everything's sealed up and bolted in the car.

I finally received the OEM LS3 intake manifold. It took 3 different vendors before I found one that was actually in-stock.
The Radium rails had to be reconfigured for the LS3 intake and I had to remove the injector spacers so that they fit. I also upgraded from ID1000s to Snake Eater Performance "Pro" 1500cc injectors. They're apparently manufactured by Bosch EU with all stainless internals.

There are a few more things that have been checked off the list, but it's still a very long list. I de-powered the steering rack since there's no room for a PS pump. Disassembling the rack and removing the piston seal was easy, but welding the torsion spring in the pinion sucked. No matter how much I cleaned the pinion, as soon as I started welding, it'd weep a bunch of ATF into the weld and catch fire as soon as the argon stopped flowing. The pinion also isn't dead-straight. With the OEM torsion spring, I think the pinion is able to self-center on the rack bearings. Once it's rigid, it's not as easy to install and has a bit more stiction. Hopefully with the E-power steering column, it's not noticeable and the rack self centers properly.

The downpipes have been a giant pain in the ass. Because the turbos sit tighter to the block, I had to modify the Ronin motor mounts to get the downpipes off the turbines.
The driver's side downpipe also had to clear the steering shaft, while also being placed where I could still recirc the wastegates. Below is what I came up with. Not ideal wastegate recirc, but I think it'll work. The pipe stub from the WG to the downpipe is 3/4" long LOL

I've been traveling for work every week for the last month and will be for most of the next month, so progress has been slow. Here's most of what's left:

• Turbo oil feeds and coolant lines
• Downpipes and full exhaust
• Compressor hot and cold side piping
• Various heat shields for the manifold/wastegates
• Final assembly with gaskets and torque

[digitalsolo]

That recirc layout is crazy compact.   Wow!

[shainiac]

Compact is a nice way to put it lol.
It would have been a decent bit easier to just run open dumps, but this thing will probably spend most of its time on pretty low boost. I still have flashbacks of my GT40R 13B opening the external gate going up long inclines while maintaining interstate speeds. The headaches...
I really don't like the sound of open wastegates unless the engine is really screaming on high boost and you're fully committed to being a menace lol.

[kinger]

I love that WG set up!  Almost looks like its part of the turbski!  Nicely done.  I hate WGs such a pain to plumb.  I have dual 38mm on my compound boost snowmobile project and they are loud when I am cruising as well.  I have been playing with the tuning to keep them shut in certain conditions, it makes a lot of boost and thus uses a lot of fuel and meth so I have to balance sound against that.  I love your set up. 

[stubbyfoil]

This is awesome! Are you using VSRacing wastegates? Im curious how well these work. Ive used their diaphragm style wastegates with great success, but the piston/o-ring style seem more robust. Staying tuned! This build is sick! I miss my turbo LS FD. 

[shainiac]

They are the VS 50mm piston-style wastegates. They kind of look like a hybrid between JGS actuators and Turbosmarts valve/body.
The build quality is nice and it comes with what looks like a Viton o-ring.

My only concern is with the downpipe so close to the piston, it may fry the o-ring or seize something. I also put 3psi springs in it and I hope it's able to seal okay. The piston/o-ring has a good bit more stiction than a diaphragm gate.

[driftnfb]

so the "scavengers" you are using are referring to are the cutouts essentially relieving pressure in the case @ said RPM? I'm having some crank case pressure issues myself on 10PSI it appears to be coming from the passenger side.

[shainiac]

I'm not exactly sure what you're asking.
I haven't added the scavengers to these downpipe yet, although I intend to.
The scavengers on my last turbo setup worked well, but with quiet 3.5" muffler out the back, there was a slight increase in crankcase pressure at high RPMs under boost. I think it'd creep up to 1.5-2psi by 7000rpm.
If I opened the rear exhaust cutout, the scavengers were more effective and crankcase pressure was ~0.5-1psi. That engine had pretty loose ring gap to keep the stock pistons alive under boost, so it had some blowby.

The exhaust cutout made the scavengers more effective because it reduced backpressure and increased exhaust flow past the scavengers. I could do back-to-back pulls with the cutouts closed vs open and crankcase pressure would drop.

[driftnfb]

Okay I think I can see it now! I was looking for your definition of scavenging— looks like they’re welded onto the exhaust and pulls into there as opposed to using a mechanical pump or something. That’s a great idea. I need this