ssbowtie1

iTrader: (16)

How much difference, if any, would there be on a bolt on lt1 with long tubes going into a 2.75" catback with a magnaflow muffler vs. a 3" catback with a magnaflow muffler?

I have a 2.75" catback now and I'm just trying to decide if its worth going for the 3" catback or not.

SoxXpupPeT

iTrader: (34)

what would the price difference be for you ? the stock exhaust on these cars severely limit the power from the engine. if you had the choice of a 3.5" catback thatd be even better. or true duels for the best. but a 3" catback will give you more gains then a 2.75" one. id say do it.

RamAir95TA

iTrader: (2)

The stock catback is 2.75". There's a reason most aftermarket cat-backs go to 3" and up.

hitmanws6

iTrader: (20)

it will help a little bit but it wont be a huge night and day difference

MasterTomos

iTrader: (15)

well if you plan on just having a bolt on only car, 2.75 is prolly enough, but with 3 inch you'd have more power, plus with a 3 inch you'd be good to go with many more modifications later if you want.

TheDon619

iTrader: (4)

actually a full 3 in exhaust is a little over kill on bolt on motors, my buddy is running close to 900 hp on full 3 in exhaust and its still not limiting him, id say keep the 2.75 with the bolt ons to save the money sense you already got it installed. If you do head/cam.intake swaps then consider 3 in.

happysem

iTrader: (5)

Don, I'm not sure where you got your info, but that sounds extreme.

I thought 3" was good for under 500hp, not sure of that number...but I'm pretty sure 900 is being choked.

RamAir95TA

iTrader: (2)

I have no idea where some of you are getting your ideas from...

STOCK exhaust is 2.75". Most every cat-back available is 3" or larger for a reason. And why is exhaust usually the first recommended modification? Because it offers the most HP right out of the box than any other bolt-on modification by itself.

Yikes!

Vicious95Z28

iTrader: (1)

Boy, my dual 3" setup must really be killing me. That must be why my car feels like such a terd, sheesh1

ssbowtie1

iTrader: (16)

Has anyone actually put a stock car on a dyno then installed a 3" catback and compared results? Mine would be a bit different as I already have the magnaflow muffler but I'm looking for more convincing proof.

StealthFormula

iTrader: (35)

"A 2.75” (stock) single system is good for a 310hp engine with zero loss…
A 3” Single system is good for a 370hp engine with zero loss…
A 3.5” Single system is good for a 503hp engine with zero loss…
A 4” Single system is good for a 657hp engine with zero loss…
A 2.25” dual system is good for a 457hp engine with zero loss…
A 2.5” dual system is good for a 513hp engine with zero loss…
A 3” dual system is good for a 812hp engine with zero loss…"

taken from LT1engine.com

A bolt-on LT1 will make more than 310hp at the motor therefore a single 3" catback would be beneficial over a 2.75" system. If you ever plan to rip into the internals of the motor, the 2.75" system is going to be a big hinderance. Are you running the stock catback with a magnaflow muffler welded in? If so, simply jumping to an aftermarket 3" catback would net gains by being mandrel bent on top of being a larger diameter.

SoxXpupPeT

iTrader: (34)

yup what he said

Rob

iTrader: (6)

I still had the stock 2.75" exhaust on my 89 TTA when it was running 12.1. I had it dynoed the same weekend and it was 318/455 on a dynojet. Granted that was a turbo V6, it shows you can still make power with the stock exhaust.

RamAir95TA

iTrader: (2)

Make power? Yes. Maximum power? No.

MasterTomos

iTrader: (15)

of course you can still make power, the 2.75 won't keep you from makin power completely, it'll just hold it back some.

RamAir95TA

iTrader: (2)

Think about this statement....

RED94Z28

iTrader: (1)

lmfao hahahaha

MasterTomos

iTrader: (15)

what's wrong with the statement? I know it's an obvious statement but that's what I was getting at...

pillarpod

nothing, great point

amstech

If catback, 3" Stainless or bust.