Wehrli Custom Fabrication 2001-2016 Duramax Billet Exhaust Manifolds - WCF100363

Hey guys, welcome back to the channel.

I'm Jason Wehrli with WC Fab, and today, we have our LML Duramax high-flow stainless steel up pipe kit.

WHAT ARE UP PIPES?
So we've got our high flow two-inch up pipe kit for the 11 to 16 LML Duramax. So what is a turbo up pipe, and why must I upgrade it? So, every model of your Duramax has turbo-up pipes. They connect the exhaust manifold on the left and right bank of each cylinder head at the outlet of the manifold, and then they sweep up to the valley of the engine and connect to the turbocharger.

WHY DO I NEED TO REPLACE THE FACTORY UP PIPES?
The factory up pipes leave a lot of room for improvement and it's a pretty common failure point on the Duramax, not only on high performance and tuned applications, but we've even seen failures on higher mileage OEM applications as well. The factory up pipes are made from a mild steel 16 gauge .065 wall material and have a very lightweight bellow. Anytime these up pipes see extended heat. If your truck is again high mileage and just had a lot of heat cycles, or if you use your truck for a lot of towing hot shotting or a lot of heavy hauling.

WHAT HAPPENS WHEN UP PIPES FAIL?
And what happens with that very thin wall OEM up pipe is they will start to get hot, red hot in some cases and the metal itself will kink or fold. And when that happens, the pressure inside of the up pipe will take that up pipe bellow and expand it like an accordion, which leads to a crack or even sometimes a separation. And those up pipe failures leave a massive exhaust leak right on the back of the engine. And it's not uncommon to lose nearly all drivability because you're losing, if it's only one side that cracked, you're losing essentially half of your engine drive pressure feeding that turbocharger. So turbocharger drive pressure goes down, your boost is going to come down, your engine power is going to be major reduced. You're going to have excessive soot output, which is going to clog the DPF and cause a lot of issues to the emission system.

BEST TIME TO REPLACE UP PIPES?
So if you're doing a turbo install, you're already removing the factory up pipes, perfect time to upgrade. If you're doing a transmission, a built transmission install, you're obviously running higher horsepower, likely have a turbo upgrade, likely have tuning upgrade, and you're going to reach levels where those factory up pipes are going to fail sooner. So those are the two most common times to do an up pipe upgrade and save yourself some labor as far as ease of installation.


WCFAB UP PIPE CONSTRUCTION
Let’s get to the construction of our up pipe versus the OEM. The biggest improvement on our up pipes is that we go to a full two-inch outside diameter 11 gauge stainless steel construction. So we’re doubling the wall thickness and increasing the diameter of that pipe tremendously.

BENEFITS
What this does is increase exhaust flow from the manifold to the turbocharger, which in turn gives you quicker turbo spool up and makes your turbo more efficient.

WCFAB UP PIPES ARE INDESTRUCTIBLE
You will not blow up these bellows, you will not bend these up pipes. We've run these up pipes on major 1500 plus horsepower applications, even as much as 2000 horsepower using the same bellows and stainless steel material. And these are not something that you're going to fail on a street or a race truck in any of these applications. So they are a hands down reliability upgrade and you get that added increase to boot. That extra size from the factory inch and five eights to our two inch gives you a 45% increase in flow in exhaust flow a 68 CFM gain compared to the OEM component. So it's a pretty tremendous increase over the factory part. We start with half inch laser cut flanges. We go a little thicker. There's a lot of other up pipes out there made from thinner flanges, but what you'll see with thinner flanges is with the extended heat cycles and sometimes even during their manufacturing process, if they don't check that surface for flatness afterwards, you'll experience a warp in that flange.
And the factory bolt pattern on the factory manifold has a pretty long stretch between the bolt holes, which leaves an area here and the center between those mounting bolts where it's common for gasket failure if you don't have a perfectly flat flange or a thick enough flange to disperse that bolt load pressure when you're tightening those down. Another feature on the laser cut flanges in particular on the passenger side is we actually put these flanges in the CNC machine before assembly at the fab bench. We do a little bit of CNC work on the backside of that flange to give you a really nice smooth transition from the stainless steel pipe into that flange, especially in this case where the flange has to get mounted very close to that bend radius and is not as quite of a sweeping bend as it is on the driver's side where that pipe can have a nice direct perfect match to that opening.
So on the passenger side, because of the offset of the cylinder head and clearance for that OEM downpipe, we've got a dent in there to clearance that downpipe, whether you're running factory or our high flow three inch.

ARP UP PIPE BOLT KIT
Now as these LML Durmax are getting a little bit older now, some of them 10 plus years, it's a good idea to upgrade the installation hardware as well. A lot of times when you're removing that factory hardware, when you're removing that OEM uppi, the factory bolts can break. Sometimes you can tear up the threads on 'em because they've been through so many heat cycles inside the exhaust housing and the manifold. So it's a good idea when you're purchasing up pipes to opt for the a RP hardware package, we offer those as a separate purchase item. Even if you're not installing our up pipes and you're just doing a factory replacement or anyone else's up pipe, it's a very nice upgrade. The ARP bolt kit comes with the washers and the ARP assembly lube.

EMISSIONS COMPLIANT - NO TUNING REQUIRED
Another thing you'll notice on the LML here we have on the table, which is a new release for us, is the LML specific model, which makes this up pipe kit emissions compliant. This is an uppipe kit you can put on your bone stock truck, whether you're running factory tuning or aftermarket performance tuning. These work with the emission system. So no tuning required, no service engine lights, Bolton application 49 state legal. You see a lot of other guys out there just taking the factory leg, the lightweight mild steel tubing and the lightweight bellow and just removing that from the factory up pipe and welding it to their new stainless up pipe. Well, they're only fixing half the problem because this bellow here and this leg here is another failure point in the OEM assembly.

WCFAB UP PIPE BUILDS INCLUDE NEW EGR COOLER LEG
So we opted to not use any of the OEM component like some other brands do, and we manufacture that whole leg assembly from new product. We use the same 11 gauge wall material. It's a little bit smaller diameter as we're feeding a smaller bellow, but still the same wall thickness. Same manufacturing specs as our two inch bellow over here, just smaller in diameter and a little bit shorter in length. Casted our own new elbow to connect to that bellow to the EGR system. That cast elbow of course still includes the provision for the OEM temperature sensor there for reading EGT pre EGR cooler.

WCFAB UP PIPES BOLT TO OEM OR ANY AFTERMARKET MANIFOLD
One more thing I will touch on before we wrap up is the addition of our high flow billet exhaust manifolds. Now these up pipes are meant to work with an OEM style manifold. They bolt right to OEM or any aftermarket manifold that replaces exact OEM specs, which means our WC fab billet manifolds are a applicable item as well.

UP GRADE OPTIONS
So if you're not ready to purchase the whole kit manifolds and up pipes at once, you can do this upgrade, run it with your stock manifolds and upgrade to our billet ones later on if you choose, or vice versa. If you want to do manifolds first, they're compatible with the OEM up pipes and then you can upgrade to the stainless units later on. We do offer this kit also available as just a single passenger side upgrade and just a single driver's side upgrade. If you happen to fail just one side or if you already have one of our passenger sides and just want to upgrade the driver's side, they're available separately to purchase and then they're also available as a kit, both items together, which saves you a little bit money versus buying 'em individually. And then again, they're available in a complete kit with the billet manifolds as well.

CONCLUSION
So that wraps up our two inch high flow stainless steel up pipes. If you've got any questions about this product or anything else that we offer for the LML, feel free to leave a comment below or reach out to our sales team. Thanks a lot for watching.