Apparently I didn't learn my lesson the first time or second time, and I'm back for more. I figured this time I could track my journey both to share with you guys as well as look back and laugh at myself in a few years.

My truck has had both a Procharger and a single Borg Warner S369 on the 4.8 that it came with, both making 500ish hp. The 4.8 was getting tired, so I ended up getting a Thompson Motorsports iron 5.7 with forged internals. I should have just used the single turbo kit with the new 5.7, but we found out we were having our first kiddo right after I bought the engine, so I ended up selling the turbo kit to cover the cost of the engine. Fast forward a year, and the 5.7 is running in my truck naturally aspirated. I always wanted to build a twin kit, and was able to source some parts though my job, so now I'm going for it.

My goals for this build are power in the 750-800whp range and the best response possible from a turbo setup. For that, I'm going to use two Borg Warner EFR7163s. They seem to be one of the most responsive (if not the most responsive) turbos for their size, and with all the data that Borg Warner provides, I was able make sure they would work for my project. According to matchbot, they are damn near perfect for what I'm trying to do. It looks like 15-16psi on E85 should get me very close to my goal.




I initially was leaning towards a top mounted turbo setup, but after seeing that I'd have some serious wiring to move as well as brake lines, I think I'm going to go with a low mount setup. My goal is to use factory truck manifolds and build some adapter tubes (Similar to AGP's gen 5 Camaro kit) and mount the turbos more or less where the factory cats are.

So far I've got 2 EFR turbos along with 2 44mm Tial wastegates. I've scanned the underside of the truck with the manifolds in place to find the mounting location for the adapter turbos as, well as my work envelope. I also scanned the turbos (with the compressor covers clocked differently that I needed unfortunately.) I'm working on getting the placement just right where I have maximum clearance in all the necessary areas, as well as keeping all the hot side piping far enough away from anything that may potentially burn. Here's a pic of my current scan:

I'm planning on merging the single 2" compressor outlets into single 2.5" outlet and running that up front to a front mount intercooler. I'm probably going to have to notch the cross member underneath the engine to make room for the turbo inlet piping. I'd like to build some type of air box up front under the intercooler do draw in fresh air.

One thing I've still not 100% figured out is the turbo oil return system. I think I may just run a similar setup as AGP uses on their Camaro kits; from what I can tell they are very reliable and work great.

I'm going to try my best to track my progress and take pics as I go. I'm sure it will be a while before it hits the road, but I have a good feeling that its going to be a hell of a lot of fun once its done. Thanks for checking it out, hope you guys enjoy!

 

I was wanting to do low mount twins but Rick told me it would be extremely difficult because of my 4wd transfer case. So I'm doing hi mount but it will be after Summer before I can get started. Sub'd to your build!

 

Thanks, ya this wouldn't work for a 4wd unfortunately. I'm excited to see how your twin build goes as well!

 

I figured you couldn't just stay N/A after having a turbo. Excited to see how it turns out

 

I'm finally getting some time to work on my truck again and making a little progress. I ditched the low mount idea after talking to a few folks at work about scavenge return pumps. I know it has been done before, but I decided to stick with the traditional top mount gravity drain setup.

The part that made me the most nervous was the manifolds since I've never made one before. I was probably a little overly nervous about welding them myself and them cracking, so I got the help of an extremely talented fabricator and friend at work to help me out. I modeled the fixture and manifolds up, got the parts cut, fixture printed, and let him weld the majority of the manifolds. I think they turned out great, and after seeing the finished product, I really doubt they will break. Still have to add the ports for the wastegates, but I'm 90% there.



With the scary part done, I was able to make an intercooler and start working on all the plumbing. After putting a turbo on the drivers side, I definitely see the benefit of running a large single on the passenger side. There is WAAAY more room. The charge piping was surprisingly compact which I really like.




I still have a ways to go, but its looking promising and I'm motivated to work on it again. I realized that if there was ever a time to do a hydro-boost conversion, I should do it now. The vacuum booster is huge, and the hydro-boost seems to be the way to go with forced induction on these. I also am going to have to re-route some brake lines and wiring on the driver side, and make a new AC line for the passenger side.

My rack and pinion has been slowly dying, and its at the point were I need to replace it before it fails completely. I've already replaced the OEM one about 5000 miles ago with a reman, and this one is sloppy as hell and leaking from both boots. With that said, who makes a good rack and pinion for our trucks? I wish I could find a new OEM one, but the only thing I've been able to find from GM was reman. Have ya'll tried a new rack from NAPA or O'reilly? Has anyone had any experience with Flaming River, or had them build a custom rack?

Hopefully I can work on this thing more often and make some progress here soon.

 

I was hoping see an update on the low mount twins. What you are doing is pretty cool though and looks great. I do understand the concern with the oil scavenge system on low/rear mounts.

Interesting you say that about the reman rack. I replaced my leaking OEM rack several years ago with a new (not reman) Cardone unit along with spindles and coilovers and experienced a slow turn in response I attributed to the new geometry. Changing to a different aftermarket spindle and various alignment settings made no difference with the slow response. I would love to go to a quicker ratio but from what I understand, that is not as easily done with R&P. I would love to hear your findings if you pursue this with the aftermarket companies.

 

Nice job on the setup and will follow this as there will be another TT build here over the summer is my guess (hoping sooner). But yes Rick said the D/S is a bit tricky and built me 2.5” into 3” downpipes to get around the steering shaft and said a couple new lines are required. I’ll also be doing the Hydroboost conversion so hopefully that buys some real estate as I’m already looking ahead lol.

 

I really was set on low mounts too, and I'm sure its something that someone could make happen if they wanted too. When I first started the low mount project I was going to use some TD05-20G turbos that we use for Subaru applications. I then decided to switch to the EFRs which are slightly bulkier (still pretty dang small though) and I started running out of room for the low mounts. If I were going to do it again, Id probably use something as compact as possible like a Garrett GT30 sized turbo. That coupled with the scavenge pump concerns put my over the edge and made me switch to top mounts.

After looking and reading some more, I think I'm just going to go with the Napa Premium New rack and pinion for now. My replacement rack never felt right, and I think if I had a properly functioning OEM style rack it would make me happy for now. Also, this turbo kit has already taken longer than I thought, If I can just get an OEM rack in it now and actually drive it, then I can come back later and see about possibly putting a quicker rack in it. With that said, Flaming River would almost certainly have a quicker ratio. They advertise 2.7 turns lock to lock with 3" of travel to each side. I haven't measured our OEM racks travel, but it sounds slightly quicker than what we have.

 

That's awesome, you going to use the Trick manifolds? I use his manifold on my single turbo setup before, it work well. Looking forward to seeing your build progress too! I haven't done it yet, but the hydro boost unit looks much smaller, that should help out a ton with space. I'm also going to relocate the battery to the rear on the frame somewhere. Between those two, there should be plenty of room to make something happen on the drivers side.

 

Yeah, sadly I’ve had this kit boxed up almost 2yrs lol. It was originally for my 2010 All Terrian that I sold but I just decided to buy a dedicated toy that just so happen to be 99 which works out. The kit was built almost exactly for the same goal you are but using BW 257sxe’s. Yep already have the battery out back and once I get this body off to get the frame PC’d I’ll swap the Hydroboost in there. You going to run 2.5” or 3” DP’s?