2.5 or 3inch???

[kniever]

im getting a new exhaust put on this week and wondering what u guys think would be better? 2.5 or 3inch? at the moment its got the original exhaust on it from 17 yrs ago and its too quiet. im also planning on doing a few mods later on down the track like cam etc.

was thinking the 3inch but i dont want it to have that cheap sound like some 5ltrs have from having too bigger exhaust. what ya's reckon bout 2.5inch with 1 muffler in the middle and straight thru at back with dump pipe?

[Mr Booyah]

twin 2.5 ?

[kniever]

nah im only gonna go single

[RVN 355]

single 3" with some pacemakers,maganaflow muffler,high flow magnaflow cat and resinator to reduce drone,

If you are going to cam it man go 3". If ya gonna keep it stock with a cai and headers 2.5" is good for 150rwkw around about there. Id go 3" do have a magnaflow stainless usa made corvette muffler for sale if you are interested.

[stocky]

twin 2.5 ?

agreed. go with whats been proven to work well

[RVN 355]

yeah true maybe performs good but isn't a 3" fine for a non cammed 5L?

[kniever]

you think 3inch will drone at all? i mainly want a nice v8 sound and i still want it to run nice till i get it cammed and all that.

im on a bit of a tight budget cos im saving for a house so it will be a while between mods

[minux]

single 3" with some pacemakers,maganaflow muffler,high flow magnaflow cat and resinator to reduce drone,

If you are going to cam it man go 3". If ya gonna keep it stock with a cai and headers 2.5" is good for 150rwkw around about there. Id go 3" do have a magnaflow stainless usa made corvette muffler for sale if you are interested.

I'd just go stock cats or opened up LS1 cats, they are fine on 230rwkw LS1's so i am sure price wise and performance wise they would suit much less power from a 5.0 litre.
I'd go 2.5" even with cam, 3" is probably getting a lil big, besides, 2.5's have proven their worth time and time again. End of the day it's not my money, just my opinion

[Cobez]

But, if vl 5speed doesn't like your view, shouldn't we not like it either hahaha

[kniever]

I'd just go stock cats or opened up LS1 cats,

what ya mean by opened up cats? do you mean the guts ripped out cos i wanna keep is legal

[minux]

But, if vl 5speed doesn't like your view, shouldn't we not like it either hahaha

Nice call

what ya mean by opened up cats? do you mean the guts ripped out cos i wanna keep is legal

They cut the flanges off them which are 2". Open up the openings by cutting back entrance and exit of cat then they re-weld new 2.5" flanges or 2.5" pipe directly to the cat, allows better flow with stock internals. Most guys have picked up a tenth and 1 mph just doing this. Only cost's $60.

[Jack87]

what ya's reckon bout 2.5inch with 1 muffler in the middle and straight thru at back with dump pipe?

Thats exactly what ive got. Single aswell, it puts a smile on my face everytime i put the peddle down even just a bit, or lately as its driving off

That open cat idea sounds alright, anybody have some diagrams or something so everybody knows what ur talking about lol?

[kniever]

yeh i just got single redback 2.5inch with no rear resonator and twin dump pipes and she sounds nice as and the car feels alot smoother now too, they charged $290 for exhuast and $90 for the twin dump pipes.

when i looked at the factory exhuast they pulled off the car it just looked poorly made compared to the redback system

[nathans1987]

i had pacmakers then into single 3" with a luky turbo mufler. was pretty loud all the time you couldnt drive it quiet but it sounded beautiful from out of the car. just droned all the time in it haha. no cats either. it would have been ok with a rear resinator tho. extractors make a big difference to sound tho i think they give a much nicer sound.

[Emackulation]

2.5" is a v6 exhaust modification, you have a v8, go the 3" or duel 2.5".

[kniever]

didnt want to spend $1000+ on a duel system and was too worried that a 3inch system would drone like alot of v8's ive heard with a 3inch system, i'm really happy with the 2.5inch as it sounds just right and if you heard it you would agree too and aslo i got a 2yr old daughter thats gotto get into my car from time to time so didnt want it too loud.

[immortality]

2.5" is a v6 exhaust modification, you have a v8, go the 3" or duel 2.5".

fairly sure greenfoam was running a single 2.5" system until recently and his VP was plenty quick

as always it's a trade off. 3" may give you more peak power but the 2.5" should be better for low to mid range torque. seeing as that is where the majority of street cars are driven it's the better option for a stock to mild V8.

[greenfoam]

Yeah I made the 9.10 on the 2.5 inch and single stock (working cat), was pretty much a full second quicker over the half track than most 5 litres so it wasn'tholding it back much. Wont know till April 20 something how much better it is with a full on exhaust, still I expect to pick up over at least 15rwkw on the top end over the 2.5 single and more likely 20 but that's with lengthened pacemakers and all the goods

[RVN 355]

3" wont drone with a big resinator,good cats,and the right muffler for the job. ls1 cats are good but not easy to fit.

[Blown V6 Hatch]

LS1 cats not easy to fit?? No harder than fitting aftermarket cats.......just a matter of cutting them back and welding a couple of flanges on. Same as they do with aftermarket cats

[Ryan Mckd]

Say i was gonna get a 2.5in cat back exhaust on a stock v6 vt commo would it drone or would it have a nice sound to it?can any1 record the sound and post on utube if uve got it done :0

[KRUPTD]

Hi,i have the VN HSV style extractor headers,single 3inch exhaust with 3 inch high flow cat,no mufflers,and just a 3 inch resonator at the rear of the car (very small).It doesnt drone in the car/its loud but not as loud as some other cars i have had,but it has the note like a ferel V8 ute with no mufflers.But on the other hand its also has a lumpy exhaust note which is very noticeable In the next few weeks will be upgrading the exhaust and fitting a offset highflow 3 inch muffler and some 4 into 1 paccies.

[PaRaDoX]

Yeah I made the 9.10 on the 2.5 inch and single stock (working cat), was pretty much a full second quicker over the half track than most 5 litres so it wasn'tholding it back much. Wont know till April 20 something how much better it is with a full on exhaust, still I expect to pick up over at least 15rwkw on the top end over the 2.5 single and more likely 20 but that's with lengthened pacemakers and all the goods

i still dropped 0.3 in the 1/4 mile from running open headers on a stock motor, 2.5" dosnt flow enough for a v8

either does a stock cat..

twin stock cat + twin 2.5" + x pipe ftw!!

you can get a custom 2.5" system made up for $600-700

im making my own atm

[89 vn]

From an article I seen :
v6 2.5 inch catback (no bigger as it isnt needed and you can lose power?)
v8 dual 2.5 also this is apparently as big as u need for a mild v8
turbo : 3-4" or as big as you can get

also if your after exhaust notes look on youtube they probably have them there

btw I have 2.5 inch with no resonator its real loud, drones sounds 'ok'

my gfs vs sounds the best ive seen but its a bit quiet, she has 2.25 with a resonator

my sisters bf 'had' a vr calais 5L which had a 3" wide exhaust, resonator and to be honest sounded like ****.

[STEALTHY™]

Twin 2.5in ftw

YouTube - VP Calais International Burnout