2.5in or 3.0in?

[caverman]

Originally Posted by acuraelin

Thanks suprabad, i saw your video and it soudns nice, that's the system i want!!


Thanks everyone for the inisght, 3in it is!! I knew I can count on y'alls opinion

Here is the Magnaflow #16483 with LTs. This is the setup I have and I love hearing it start up and then settle down into a nice deep rumble.

[usmcjlp]

I just received the kooks 3 inch cat-back exhaust. I currently have kooks headers with a stock cat-back on a force induction setup. I am currently at 660 rwhp. I was told the stock exhaust had become a restriction and that the swap would lower my boost allowing me to run a smaller pulley.

Exhaust will be installed tomorrow and dynoed. I will post results. I will see if the money I spent gets me anything or not.

[SSOOCH]

Here is my video. Keep in mind the really agressive CAM you hear at the beginning of the video is obviously not my Camaro. It's JDP Motorsports Chevelle. But when I start my burnout you get the idea of what the #16483 sounds like launching at around 4500RPM.

[SSE 4 2SS]

Ssooch, I love the sound... Can't wait to decide which way I'm going... Still leaning hard to the TT setup...

Oh, and don't pick any fights with that grocery getter... that thing sounds bad...

[SSOOCH]

Originally Posted by SSE 4 2SS

Ssooch, I love the sound... Can't wait to decide which way I'm going... Still leaning hard to the TT setup...

Oh, and don't pick any fights with that grocery getter... that thing sounds bad...

Thanks.

Oh Don's Chevelle runs like a raped ape! It's got a 383 Stroker and it's blown! I'd love to meet him out at Rocky Mountain Raceway and run a 1/4 mile against him just for ****s and giggles but yeah it's the ultimate sleeper!!

[ackeight]

Guys running headers and the 3" system, do the cats narrow down to the 2.5" and your 3" catback hooks up to that just like to the stock cats? Obviously this is if you are running cats.

[Merc]

3"

[Ivan @ Southwest Speed]

650+ hp.... = 3"

Otherwise, eh.

But it's nice to have options for later down the line.

Either way, Southwest Speed will save you money on your decision!

Call or PM us for a quote!
Ivan

[jdenotter]

3in RDP Motorsports cat-back...great sound and price

Sent from my DROIDX using Tapatalk

[usmcjlp]

Originally Posted by ackeight

Guys running headers and the 3" system, do the cats narrow down to the 2.5" and your 3" catback hooks up to that just like to the stock cats? Obviously this is if you are running cats.

I am running cats. As I understand it, after speaking with Brandon at Maryland speed who sells all of these systems, is that the kooks 3 inch is the only system that has true 3 inch cats as well. The other cat-back systems all neck down to 2.5 to meet the factory system.

[caverman]

Originally Posted by usmcjlp

I am running cats. As I understand it, after speaking with Brandon at Maryland speed who sells all of these systems, is that the kooks 3 inch is the only system that has true 3 inch cats as well. The other cat-back systems all neck down to 2.5 to meet the factory system.

First off KOOKS isn't the ONLY one. LG is 3" all the way and Texas Speed is 3" all the way.

This is only if you buy the complete system (headers, connection pipe, cat-back). Otherwise if you buy just the KOOK headers they are going to come with a connection pipe that has a 3" inlet and 2.5" outlet so that you can connect it up to either your factory cat-back or cat-backs that can hook into your factory mid-pipes.

A lot of 3" cat-backs have a 2.5" inlet and are technically not a true 3". Magnaflow and MBRP are a couple examples of that.

Again...remember that unless you're making big power (like 600+) the 2.5" should be fine. Anything below that the 3" is really going to be more for sound than performance.

[Mindz]

Can anyone give me proof (tangible proof like dyno sheets) that 3" is greater than 2.5" for 550+ wheel hp? I'm trying to figure out what system to get for myself, but I'm a scientific kind of person who likes hard evidence.

[Tallboy]

Originally Posted by Mindz

Can anyone give me proof (tangible proof like dyno sheets) that 3" is greater than 2.5" for 550+ wheel hp? I'm trying to figure out what system to get for myself, but I'm a scientific kind of person who likes hard evidence.

No, they can't. I stayed away from this thread because of the mass amount of mis-information on this subject. I know an exhaust engineer who worked for an OEM, and now on his own. 1/2 inch of diameter per 100 HP is more than adequate.

Now, you're gonna get guys who will say "I gained 10 HP on the dyno from such-and such". Here's the thing: Dyno pulls are rarely reliable on small incrementals in horsepower. Go ahead and dyno your car. Now, let it sit there for a few hours and run it again. The numbers will be different. Every time.

Unless you're going balls-out all the time with well over 600HP, 2.5 is fine. It's not about pipe diameter or volume, it's about flow and balance.

Flame suit on.

[Mindz]

I'm with you on this tallboy. I was wondering if there was something like 30 hp difference running the same setup with a 2.5" vs. a 3.0". If it's like 10hp difference, it behooves me to go with a 2.5" since it's cheaper.