the top bolt on the flange of the catback is a mother ******... there's 0 angle to get to it... that's what took me so long to do

 

noobs

 

^^ Lol

 

That top bolt is a PETA to get to. Trust me you need two u joints and an extension to get at it.

 

^^ ooh yeah, that thing is a mother bitch

 

I think we all wish there was an easier way.... You only have to do it once though

 

Hopefully only once.

 

:raises eyebrow:

No it isn't

 

Yes it is. Measure it. It is the exact same size as my Hahn DP.

 

stock dp is 3"

i can attest to that

 

What????? 3" stock downpipe????? But it has a cat on it.

Than what's the difference between aftermarket dp's & the stock?

 

a single hi flow cat or catless as compared to having two restrictive cats on your stocker

 

**** me running then.

 

Bingo!

 

What makes you think that the high flow cat is any less restrictive than the stock ones? I know that 1 will be less restrictive than 2, but I'm pretty sure the ones that come stock are still high flow cats...technology has come a long way and cats are not nearly as restrictive as they were when they were first introduced...

 

The stock cat's are NOT high flow, they aren't BAD but they do not flow like a Vibrant or Magnaflow Cat.

For me I would use Vibrant Metal Core Converters myself... less chance of them shitting out on you!

 

Not trying to be a jerk....but how do you know? I don't have any factual info to back up my assumption...just wondering if anyone has some data out there that can support the need to replace the cat...

 

Look inside of it... you will be able to tell.... thats how I know... GM put 2 in there I am sure to pass Emissions testing, they wouldn't sacrifice any "FLOW" or let alone put in 2 cats if they were high flow!

 

The stock cats are considered "high flow" but when compared to an aftermarket cat they will flow less. Why do you think Hahn and CIA angle the 02 sensor even on their catted versions? Not just to keep water out. It will pass emission but the computer will throw a code thinking something is wrong with the rear 02 because it flows so much better than the stock cats.

Typed on my phone sry if its hard to understand lol.

 

I don't think it's HIgh flow... I think it's "better flow" LOL

 

CIA did a flow test, can't fing the post at the moment, but it showed what the stock down pipe flowed and then the high flow. The aftermarket cats are much better then the stocker.

 

This is from the thread,
Flow Bench results:

"Stock down-pipe = 299 cfm (Weighs 17 lbs.)
Clear Image 3" down-pipe with hi-flow cat converter = 400 cfm (Our down-pipe was good for 15 HP to the wheels): (Weighs 10 lbs.)"

 

that doesnt aid much in the argument of how good a stock cat converter will flow. the stock DP is 2.75inches and tapers down to 2.5 at the bungs. Of course a 3" will flow more. Its good to see you're testing your stuff though
a true test would be to take an OEM cat, and an aftermarket cat of the same in/out diameter, and flow test those

 

This is as close as anyone has posted so far for a comparison, and I do not think anyone will go that far.
There's no logical reason why someone would upgrade their DP for the same stock diameter just to have a high flow cat.
3" is going to be the best option for the stock turbo ( dyno proven that it does allow higher Hp & Tq output ) & it's already there for those that upgrade their turbo's down the road.

 

Yeah, that's it right there!