[Tilothe40th]

Hey all, hoping this reaches out to anyone. I've noticed that there are absolutely no aftermarket parts for any 03 - 07 CTS with a 3.6L and I'm looking to get creative with my own and hopefully share with you all the knowledge I learn as a part of this project, seeing as how no one runs into any particular problem or has any of my specific answers I need.

First things first, adding a turbo.

I understand that sacrificing one of my exhaust pipes will allow me to add a turbo to my CTS. Along with routing pipes, which I see will not be an issue, and I know I can tune out my downstream sensors, has anybody come to terms with sacrificing a dual exhaust system with one aftermarket exhaust system with bigger pipes to compensate for the amount of exit flow I'll need to keep from restricting my engine?

My turbo will, proposedly, sit where the airbox will be (similar to the Overkill Supercharger Kit on the 08 and above CTS's) and I will heat wrap and shield the hell out of the engine bay for it to work.

I'm just asking for any tips or any issues that I haven't quite thought about yet. I love this car and as much as I love the V, running up that kind of cash isn't as easy nowadays seeing as how a first generation V runs a premium of $10K, even in high mileage.

Thanks all and I will keep you updated with any photos and any issues that arise within my build. This is for my first gen CTS drivers that love their cars.

Situated problems - Single Turbo = Single exhaust outlet FROM turbo, but requires Y-pipe to turbo inlet. Aftermarket high flow catalytic converter will be installed, as well as a possible glasspack and bullet muffler straight out the back. Will keep box muffler in mind. (Droning may be an issue but I believe the bullet muffler or the glasspack will resolve that for me.)

Exhaust Manifold on driver side will have to be remanufactured/piped into Y-pipe into inlet for turbo. (My worry is if this will cause any backflow connecting the two pipes together.) Waste pipe will go into single exhaust pipe. Pipe will be either upsized to 2.5"or 3" from stock 2.25"

Intercooler will be mounted on from and intake manifold will be fed from opposite side (much like the Overkill Supercharger Kit.

Inline fuel pump will be in discussion if rebuilding another fuel pump with a stronger capacity is not achievable.

New fuel injectors may be needed depending on how powerful the stocks are (will be accounted for in budget)

Aftermarket throttle body is thoughtfully kept in mind.

TUNING will be a big part in the build, thankfully I live down the street from a dyno shop.

I am just a back yard mechanic but I understand more than enough to fabricate my own systems that could most likely help with the build.

Call me crazy if you'd like, though.

 

[RyanY]

I have not tried to tweak anything on my CTS but I built several cars in my younger years including retrofitting a 396/Muncie into a Camaro. In every case, the final cost/effort was about three times what I had planned for. I therefore suspect the cost of a project like yours will exceed the cost of a used V. Nevertheless, your build sounds like fun, and I hope it turns out well! (If I were doing it, I would probably just simplify the project with heavier springs/trans/differential, and put a modified small block under the hood)

If you don't mind, please take lots of pics of the mods. These are very helpful to others who are interested in trying to copy, especially since this info is not available any where.

 

[Tilothe40th]

I have not tried to tweak anything on my CTS but I built several cars in my younger years including retrofitting a 396/Muncie into a Camaro. In every case, the final cost/effort was about three times what I had planned for. I therefore suspect the cost of a project like yours will exceed the cost of a used V. Nevertheless, your build sounds like fun, and I hope it turns out well! (If I were doing it, I would probably just simplify the project with heavier springs/trans/differential, and put a modified small block under the hood)

If you don't mind, please take lots of pics of the mods. These are very helpful to others who are interested in trying to copy, especially since this info is not available any where.

Oh I absolutely will provide pictures once the project takes place. Currently parts are all on order and being shipped to me, so I will give every bit of information I get.

Also I've adjusted the project a little, as per an idea I've gotten from another. Rear mounted twin-turbo. Will show the updates very soon.

 

[Tilothe40th]

I have rearranged my ideas, and my mechanic (whom I ask for advice and when I need welded items) thought the idea of a rear mounted twin turbo was the best choice on account of the lack of space for a big, singular turbo in the engine bay where the airbox would be (regardless, the airbox has to go) it seems the spaces for the muffler on the rear of the car may be more than enough room to set the turbos symmetrically.

The only detail that needs to be talked about is the oil supply and return.

Our idea is that we tap an oil supply from the oil pressure sensor, and tap the return straight into the pan with a valve so when comes time for an oil change or to service in the oil pan, the valve can be shut before and opened thereafter. Will provide pictures as soon as parts start arriving and craziness happens.

On account of cost, most of the money I was expecting to spend was gonna go toward a mechanic to pay (mainly because the extent of my knowledge is tweaking and tinkering) but it seems the most ill spend would be in the tuning section and parts section because my mechanic has been in the business since he began in the military and has done countless turbo installs, replacements, and more services on vehicles than I can even comprehend.

So I'm hoping the cost won't be up to buying a new V, but I'm hoping to get a car I can drive for lots of fun.

 

[Tilothe40th]

Turbos have arrived yall! I'll get some photos up as soon as the install gets going and show all the custom fab work I'm planning out before I get going. Should take about a week to install if everything is planned right and we work through all the snags and whatnot.

Also putting twin cherrybombs to replace the stock resonator so I can still roll with the twin turbo idea.

Most likely charge pipes to a Y to the front, maybe even the addition of an intercooler, but we'll see!

 

[RyanY]

Looking forward to the pics/results! You have a lot more ambition than I have!

 

[AAIIIC]

Google for "STS turbo CTS-V" - STS used to build rear-mount turbo setups for the CTS-V. You should be able to find some pics and details that might help you with your setup.

 

[TA Coupe]

How is this project coming along? Any updates?

Roy

 

[Tilothe40th]

Hey all quick update. Ordered some parts in from MACE for the LY7. Will need to take the block to be machined for a .5mm wider bore and hopefully relieve some compression in the cylinders. Also did my own custom exhaust build and I can feel a huge difference in low-end torque and hp delivery to the ground. I'll link you guys a cold start I took this morning. Since Corona hit, been taking a real toll on my bank account but I'm getting her back on track soon.

Link will be up soon.

 

[Tilothe40th]

Here's the sound of the exhaust on cold start after I modded it.

 

[Submariner409]

Huge difference? - what did the before and after dyno runs or dragstrip timeslips show ? Sound and butt dynos reveal nothing.

 

[Tilothe40th]

Huge difference? - what did the before and after dyno runs or dragstrip timeslips show ? Sound and butt dynos reveal nothing.

I can get you some dyno pulls when I throw in the CAI over the weekend. Maybe +10hp hopefully lol

 

[AAIIIC]

Hey all quick update. Ordered some parts in from MACE for the LY7. Will need to take the block to be machined for a .5mm wider bore and hopefully relieve some compression in the cylinders.

Boring the cylinders itself will not change the compression ratio. That will depend on the crown design of the new pistons vs the crown design of the stock pistons. (Assuming you're not doing any work to the heads to change the combustion chambers and won't be using head gaskets with different compressed thickness.)

 

[Tilothe40th]

Boring the cylinders itself will not change the compression ratio. That will depend on the crown design of the new pistons vs the crown design of the stock pistons. (Assuming you're not doing any work to the heads to change the combustion chambers and won't be using head gaskets with different compressed thickness.)

I appreciate the info, I hadnt thought about that! Ill definitely look more into it.

Thanks!