How well would this perform compared to stock/shorties/LT

Stock Y pipe
Cats removed
Stock restrictive Y replaced with a true double 2.5" in 3" out.



Wondering if this setup would perform a little better than stock. Don't wanna make the jump to LT's yet, scared of broken manifold bolts!

 

Bump always wondered if doing this would be worth it on a stock y pipe

 

I don't know... You can get headers so cheap now I bet it's the same cost. What year is your truck and how many miles? Start hitting them with PB blaster a few days before the job and I usually get lucky. If they break off often times after the manifold comes off there is enough sticking out to grab with some pliers and back them out. If you can use an air gun to whack them repeatedly as opposed to steady torque there is less of a chance they break while doing the job.

 

If the bolts do break of flush, hold a nut over the stud that's left and weld directly to stud and fill the nut with weld. Then back the nut off and the rest of the bolt will come with it.

I even did this on the fill plug on my rear end to get the plug out after someone broke a ratchet in it. I tried to drill and remove it with an extractor but it broke and this was my last ditch effort and it worked.

Wish I would have done this from the start. Works every time. I have never had to drill or extract what's left when using this method.

 

Go to a dealership and get the updated exhaust manifold bolts. The stock ones are 10 or 12mm (don't remember), the new ones are 13mm. Considerably stronger and I haven't had one break yet.

Torque specs:
First Pass 15 Nm (11 lb-ft)
Final Pass 25 Nm (18 lb-ft)

 

Compared to LT, it will perform like ****.

Unless you are putting headers, don't waste your time. JMO.

 

how restrictive are our cats? I know when I redid my exhaust last year I had it cut wide open about 5 inches after both cats, and I started the truck, it was quiet as a stock truck, I was quite surprised, making me believe they must be somewhat restrictive. Thats what gave me the idea behind this post.

 

Not very restrictive at all.

Your cats may be plugged up because way back when I took just the catback off and had an open stock Y pipe it was quite loud.

 

It's important to note the head size was 10MM and they changed it to a 13MM but the thread size remained the same.

I think it was an M8 X1.25 thread approx. 25-30mm in length measured under the head.

 

I actually pressure tested my cats once, thinking they were plugged up. I only had a .5psi difference in exhaust pressure before/after the cat. So they are not restrictive at all. I wouldn't waste the time modding the stock y-pipe. It's actually pretty good. Just spend the $350 for some headers and ORY.