Centermount turbo setup on a k3500

[3500_6.5]

The explanation is pretty simple. I plan to build a centermount turbo setup for my 2000 k3500. I am in the process of building an engine for it and part of the build includes redesigning the pre turbo exhaust. The centermount setup will require a different intake and moving the ffm, but neither should be an issue. I already replaced the ffm with a spin on filter and the entire fuel system has already been replaced with aftermarket parts, so it should be no problem. I am working on getting the basics for the intake, but I'm having issues with the eBay seller, so we'll see how that turns out...

The system itself is going to be based off of the Hummer NA 6.5 diesel "headers". The passenger side one hopefully will work as is. Worst case, it may need to be shortened slightly so it will clear the firewall. The driver side one curves down and ends up right in the steering shafts path, so it will have to be modified. I plan to cut it and put a straight piece in place of the curved pipe to make it basically the same as the passenger side one. Then I plan to make two 2"-2 1/4" pipes from the headers that will go behind the heads and then come up and mount the turbo where the ffm originally was. I will also be running an intercooler so that plumbing will have to be designed too before it bolts to the heads. I plan to wrap it all to keep the heat in and it will be setup to run my holset hybrid.

The turbo intake is still up in the air at this point. I am considering running a cowl induction hood. If I do that, then I will use the cowl to run a cold air intake. If not, I will route it back to the stock location, or somewhere in that area.

I currently have the headers, but that's the extent of my parts. I already run an intercooler, but it is mounted between the frame rails where the skid plate goes. I am going to change it to a front mounted Cummins intercooler behind the grill. So that will all have to be fabricated and then new piping ran. I have a line on an intercooler that I will probably pick up sometime this week, but my main concern right now is getting the exhaust side figured out.

I was hoping I could duplicate this setup for other 6.5 trucks, but I don't think there is enough room behind the heads. I am running a 3" body lift on mine, so I think I will have the room. But most likely, if someone wants to duplicate it, they'll also need a body lift. I plan to try to design another setup that will work on a stock height body, but that will be after I design this one.

So let the fun begin....


The hummer headers

Current intercooler location

Current intake and ffm setup

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[Will L.]

Those headers are supposed to use the donut gasket on output btw. Do consider chopping of the ends and using a better end like the ball/socket design. Then you can direct the output any angle you need with ease.

Also if you want 2 identicle units for a balanced flow- get another passanger side, cut the junctions into the large pipe and flip the inputs 180 degrees.

Have you placed the turbo back there to see how it fits?

 

[3500_6.5]

Those headers are supposed to use the donut gasket on output btw. Do consider chopping of the ends and using a better end like the ball/socket design. Then you can direct the output any angle you need with ease.

Also if you want 2 identicle units for a balanced flow- get another passanger side, cut the junctions into the large pipe and flip the inputs 180 degrees.

Have you placed the turbo back there to see how it fits?

The original idea was to flip the passenger side one. Seemed easy enough and, like you said, would make them basically identical. But after setting it on a head and looking it over, it will not work. The two short runs can be flipped but the two long runs can't. They would have to be cut off and I would have to start from scratch for those two and make them myself. Redesigning the driver side one the way I am thinking will get them similar enough that they should be close enough in flow. The runners will be slightly longer, but I think it will work well enough for me.

I have contemplated having these sent to a machine shop that would be capable of replicating them if it does work. Then I could have them adjust the lengths on the driver side accordingly to match. But to use on my truck and as a prototype, it should work good. I would only do that if I happened to try and sell them.

I've thought about changing the ends as well for ease of install and better sealing. Once I get the driver side cut up we'll see how it's looking and go from there.

 

[3500_6.5]

With the body lift, the turbo should have no issues sitting back there. Since its currently on my truck right now, I can't test fit it. I will probably wait until the engine is ready to set in before I go that far. The truck can't be down for any longer than it has to be. I do have a hx35 that I forgot about, I may use it to mock things up and see how it fits when I get to that point.


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[Husker6.5]

Have you considered using a Duramax VGT center mount turbo? It would seem a natural fitment.

 

[THEFERMANATOR]

Have you considered using a Duramax VGT center mount turbo? It would seem a natural fitment.

The problem there is a controller for the VGT setup. I know controllers have become available in recent years though. Also of note, the GARRET VGT's do NOT like dirty oil, and have earned a reputation for sooting up and the vanes sticking in them. The LB7 turbo would be a good choice IMHO. Slap a BATMOWHEEL in it, port the covers, and call it a day. They work very well on the DURAMAX up to the 475HP range or so with backpressure not being a HUGE issue(if slightly modified several have gone to 550 on them). They are pretty well limited to 28 PSI of boost if you want them to live, but they can push 32 for a reasoneable amount of time(anything more than 32, and it's a grenade waiting to go BOOM!).

 

[Burning oil]

Watching.

 

[3500_6.5]

Here's what I have so far. Cut the driver side up and it's all welded back together. Still needs cleaned up, but it's not done yet. But it's ready to be bolted on and mocked up to see what piping I need. I threw some paint on it to keep it from rusting since it was already bead blasted and nice and pretty. The passenger side one I just cut the flange off. I'm putting v band flanges and clamps at all the connections. This will allow for easy clocking if I happen to be off a little (that never happens....) and for all around ease of install and disassembly. Hoping to get all the parts I need ordered and start on the hard stuff next week.

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[3500_6.5]

Driver side one is getting cut up again. The back pipe and probably number 5 both need moved. I didn't even think about the fact that they (number 7 especially) are going the wrong direction. That is where the original one curved down so it worked then. I'll have to cut them off and try to adjust them to flow the right direction. The joys of "playing"


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[3500_6.5]

New angles cut and tacked into place. I'm going to cut the entire main pipe off and redo it too. I ordered all the flanges and angles I think I'll need last night. I was hoping they would be here today (from summit), but they must be slacking bc they haven't even shipped them yet.

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[n8in8or]

New angles cut and tacked into place. I'm going to cut the entire main pipe off and redo it too. I ordered all the flanges and angles I think I'll need last night. I was hoping they would be here today (from summit), but they must be slacking bc they haven't even shipped them yet.

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Dang. You're having terrible luck with Summit lately!!

I like what you're doing. I kind of wish I had a body lift because it would be nice to be able to run those pipes around the back of the heads like you are. I don't have that luxury so I was going to run mine over the valve covers, but the steering shaft really makes that tight. If I ever go through with it I'll have to get creative on the driver side. I can't wait to see the finished product....though just as I get caught up to you, you go and take a it a step further like a jerk

 

[3500_6.5]

They must have known they were slacking, everything usually gets shipped to me via ups from them. Ups never delivers on Saturdays (at least not the shipping Summit uses). This time they shipped it fedex, and they deliver on Saturday. So it's showing everything will be here today.


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[3500_6.5]

I had a little bit of time to start cutting and welding. I have both pipes welded on now, but I didn't get a picture of that. I know, my welds are ugly. But I'm not a welder and I am currently using an ancient stick welder that isn't very forgiving. I'm counting on my grinding skills to smooth out the ugly welds lol.

I also got the last of my exhaust pieces today. The pipes came from summit, all the flanges came from eBay. The turbo flange is a t3/t4 flange that should work for the two turbo options I may be running.

The band clamp and flanges are different than the normal ones I have seen (the band clamp is the same, the flanges are not). They are machines with a lip on the back side so the exhaust pipe has a lip to sit on and weld to. And where they mount together, they have a male and female end so that they have to align perfectly for them to mate together. They were basically the same price as any other normal flanges ($20 shipped), so I figured I'd give them a try. Just looking at them and feeling them "lock" together, I really like them. We'll see how well they work in real life though soon enough....hopefully.

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[n8in8or]

I had a little bit of time to start cutting and welding. I have both pipes welded on now, but I didn't get a picture of that. I know, my welds are ugly. But I'm not a welder and I am currently using an ancient stick welder that isn't very forgiving. I'm counting on my grinding skills to smooth out the ugly welds lol.

I also got the last of my exhaust pieces today. The pipes came from summit, all the flanges came from eBay. The turbo flange is a t3/t4 flange that should work for the two turbo options I may be running.

The band clamp and flanges are different than the normal ones I have seen (the band clamp is the same, the flanges are not). They are machines with a lip on the back side so the exhaust pipe has a lip to sit on and weld to. And where they mount together, they have a male and female end so that they have to align perfectly for them to mate together. They were basically the same price as any other normal flanges ($20 shipped), so I figured I'd give them a try. Just looking at them and feeling them "lock" together, I really like them. We'll see how well they work in real life though soon enough....hopefully.

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I dig those V-band flanges.

 

[Burning oil]

Nice, I started on my center mount officially tonight to.

I didn't know you were stick welding this stuff, you gotta get a mig.

 

[3500_6.5]

Nice, I started on my center mount officially tonight to.

I didn't know you were stick welding this stuff, you gotta get a mig.

I have a mig welder. It is also old. They are both hand me downs from my dad (he replaced them with newer and better ones of each). I was planning on using the mig welder, but I needed a new tip. And then the trigger stopped working. It has a bad connection somewhere in the line bc I can jiggle it and it will kind of work sometimes.


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[Burning oil]

I do 99% of my welding with a cheap Hobart 135. Around $500 brand new.

 

[n8in8or]

I use a Hobart 175. Our welding rep at work says that Hobart is made by Miller, it's just the lower priced line. Many parts are interchangable with the Miller welders. I've had mine for 10 years and I love using it. I've had to replace the power switch but otherwise no problems.

 

[Will L.]

Yup, basic welder with good wire speed control. Quality wire and argon/ co2 mix is big for welding things like exhaust.
One of the most important thing is practice, so all those guys asking you to weld something up for them and the tendency is to shy away- nope do it all, that's how you get better. Just have them cover material costs so your not paying to learn.

I like the flanges with the little lip inside. Link?

 

[n8in8or]

Yes, Argon/CO2 makes a huge difference in weld quality...I forgot to mention that's what I run.