Cat Back Exhaust - Does Nothin' Except Noise?? Your opinion wanted.

[holden#1]

i have a mate who put a cat back straight through 2&1/2'' exhaust. he owns a crapped out VN with 250,000k's on it.
got quarter mile time b4 exhaust & service - 16.73. after service and exhaust got a best time of 16.75!!
i said 'mate thats what i've been tellin' ya all along. cat back exhaust will do nothin except make noise'.
just wanted some opinions, as me mate disagreed. can't quite explain the slown down however!
I have a sports exhaust on my Calais (cat back) it doesn't seem to make any diff performance wise.
my dream exhaust for my V6 would be stainless twin setup. with good extractors naturally. but these setups are around $1500 i believe.

[gumbs]

The exhaust my have lost him a bit of back pressure which would affect power but tisd alot more likley to have to do with air temperature. The Colder the air the more dense it is and as cush more oxygen goes into the engine and you get more power.

[holden#1]

the conditions in which we did quarter mile were exactly the same. must be a finely tuned balance between loss of backpressure and a free flowing exhaust. thats you you should stick to the good gear i spose

[Mark]

nah back pressure shouldnt have been a problem... but it does only make noise... a catback by itself wont give u power gains... extractors will.. but and i say but if u put extractors on with a stock catback u will have flow issues.. so u have to do it.. but by itsself = no real gains!

[Wonderboy]

yeah i know what vpbeast is on about, i got a 2.5inch catback single muffler, sounds alright but i really only notice it sounds better whilst mid donut. i can actually hear the car. but seriously i was about to get a set of pacemakers $480 BUT the guy was telling me how they are only made of mild steel which is steering me towards this other set for $490 which is stainless steel the brand name is hi-tech. ill get em after i pay rego and tell yas how it goes.

[RVN 355]

i have a mate who put a cat back straight through 2&1/2'' exhaust. he owns a crapped out VN with 250,000k's on it.
got quarter mile time b4 exhaust & service - 16.73. after service and exhaust got a best time of 16.75!!
i said 'mate thats what i've been tellin' ya all along. cat back exhaust will do nothin except make noise'.
just wanted some opinions, as me mate disagreed. can't quite explain the slown down however!
I have a sports exhaust on my Calais (cat back) it doesn't seem to make any diff performance wise.
my dream exhaust for my V6 would be stainless twin setup. with good extractors naturally. but these setups are around $1500 i believe.

wouldnt waist my time with a cat back . Full system or nothing. 2 1/4 way big enough for the buick v6 in my view its not always the size of the system but backpressure,type of material c.s.a all major views.

[aokman]

wouldnt waist my time with a cat back . Full system or nothing. 2 1/4 way big enough for the buick v6 in my view its not always the size of the system but backpressure,type of material c.s.a all major views.

I find that completely wrong, i gained plenty with a 2.5" redback system. Then when i dropped the rear muffler, the car gained MUCH more in the midrange. Along with extractors and CAI its a nice setup

[ucwepn]

yeah there can be some gains with only a catback 2&1/2 but only in the mid to high rev range and a V6 makes its power relatively low in the rev range, a high flow airfilter would help it breathe a little harder. but ultimately extractors hi flow cat and 2&1/4 would be the most useful for the price and give the best bang per buck. but make sure the induction side has something as well.
my 2c

[chrome calais]

Quote:
a catback by itself wont give u power gains... extractors will.. but and i say but if u put extractors on with a stock catback u will have flow issues.. so u have to do it.. but by itsself = no real gains!
(quote button don't work for me)

I have VS Calais with cracked left hand exhaust manifold. Looking at extractors as all 2nd hand manifolds are showing small cracks, and a new manifold is $417 NZ. What problems will I have if I just put on extractors without doing anything else to exhaust?

They are gonna cost $850 total, as Calais has progressive steering and standard extractors don't fit... so I gotta find out if it's gonna work first!

[greenfoam]

Hey hey, you can't judge what an exhaust does on that car, because if a VN is running 16.7 in the first place it has other serious performance issues like running on 5 cylinders , a good cat back with good a good muffler should/will make you more top end and mid range power. To gain the bottom end and midrage you need to have extractors though and better still two cats.

Backpressure is a hoax btw, it can only help you if the rest of the exhaust is wrong

[NOGEN 3]

Got a cat back single 3" mandrel lukey system on mine. I only got gains (I did notice it)coz of that crappy restriction at the back of the system near the transaxle I reckon, bottle necking the exhaust gasses at the junction after the twin mufflers, As 4 back pressures, the only thing that seems 2 affect, really is engine braking.
Def make alot bigger difference with Extractors 'n twin cats tho', but when u pay $250 4 the exhaust system who would complain?...