[rotten_sphinx]

I recently picked up a 2003 base model CTS from a friend for $500. He blew the motor up back in 2011. It has been garage kept for the last ten years and he finally decided to get rid of it. I plan on throwing a turbo Vortec motor in but first I need some supporting mods like subframes, brakes, driveshaft and diff. I couldn’t find any threads on this build, so I decided to do one.

I started by pulling the motor and cleaning up the engine bay. All of the chassis parts I got are OEM off of either a Gen1 or Gen2 CTS-V. I started with the Gen1 front subframe(engine cradle). I was pissed off after spending $500 on it, which is the same price as the whole car, to see that it was identical to the base model besides the ABS location. But as I was cleaning it up and was removing the sway bar, which was a bigger diameter, I noticed the engine mounts were double walled and had a reinforced mount. I also noticed the lower control arms were the same casting and only the bushings were different.

Base model ABS location.

CTS-V ABS location, no big deal I will end up deleting this for my build.

This is the base model subframe (view looking up

and this is the CTS-V (same view)

Note the castings on the control arms are exactly the same. Only the bushings are different.

base model lower control arm bushing

CTS-V lower control arm bushing

Got all the surface rust off, applied a couple coats of paint and through it in. I also deleted ABS while everything was out. I used a 2x6 and ratchet strap to hold the steering rack up during the r2. I didn’t disconnect the struts, all I disconnected was the lower control arms and steering rack from the subframe.

 

[Hurricane87]

Why delete the ABS?

 

[rotten_sphinx]

Why delete the ABS?

I’m going to do some light drifting(w/GEN2 Diff) and it was way too tied into the engine harness. It wasn’t worth my time to strip that whole harness down when it’s not a high priority for me.

 

[rotten_sphinx]

I got my GEN2 rear subframe in today, I found it on eBay for $200. It has a lot less surface rust than the front subframe that I bought. I measured the back break mount bolt distance on the knuckle to ensure the GEN1 brakes, I also bought from eBay for $450, fit on the GEN2 knuckles. The measurement was the same and I couldn’t be more excited.

it barely fit in my daily!!

 

[rotten_sphinx]

I also have a diff on order and will be getting an LM7 this month!

 

[dja79]

You might as well paint/powder/anodiz while you have the chance. Naturally, once installed, that'll be way more difficult.

I suggest cobalt:

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[rotten_sphinx]

You might as well paint/powder/anodiz while you have the chance. Naturally, once installed, that'll be way more difficult.

I suggest cobalt:

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I’m not doing anything that crazy! Geez!

 

[rotten_sphinx]

Cleaned up the rear subframe today.

 

[dja79]

Looks good. Nice & clean. Completely as it should be...

But...

You know you wanna

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[rotten_sphinx]

I finally got my rear subframe in.

The different I bought is a LSD from a 2011 base model, it turns out the diff output shafts are a few Mm smaller than the2011 V axles I bought.

I also scored a deal on an LQ4 w/243 heads for $850.

The Gen 2 subframe swap went smoothly besides the LCA contacting the stock 16” wheels I have installed. I found the correct subframe mount bolts/hats on a GM parts website, I attached a picture with part numbers.

Also the stock E-brake did not fit.