Just wondering...

JeffAU1 · 15-10-2006, 07:33 PM

How much performance difference is there between an I6 with the following:

2 1/2 Inch Exhasut
2 3/4 Inch Exhuast (do they even make these)
3 Inch Exhaust

GK · 15-10-2006, 07:55 PM

Quote:

Originally Posted by JeffAU1

How much performance difference is there between an I6 with the following:

2 1/2 Inch Exhasut
2 3/4 Inch Exhuast (do they even make these)
3 Inch Exhaust

I think The Dok has a 2 3/4 inch but not sure exactly.

He was talking about it on the "exhaust tip on wagon" thread.

GK

HLC · 15-10-2006, 07:56 PM

performance, i dunno...

noise, LOTS.

jonbays · 15-10-2006, 08:44 PM

A good cat back 2.5" exhaust is all you need for a small gain 5rwkw proabably.

GK · 15-10-2006, 08:45 PM

Quote:

Originally Posted by jonbays

A good cat back 2.5" exhaust is all you need for a small gain 5rwkw proabably.

Do you mean with no other mods, jonbays?

I just got one on Friday, so would I expect that 5?

GK

bodes-sh · 15-10-2006, 09:16 PM

they do make 2 3/4 inch ones, apparently wrx's come from the factory with them, i can't tell you about a 3 inch because the exhaust shop here wouldn't even give me a price for one unless the car was turbo or supercharged, but i find a pretty good gain with a 2.5 inch one...i'd imagine that noise would be the most difference, but unless you plan on doing major engine mods a 2.5 should be ok

mattsAU1 · 15-10-2006, 09:51 PM

as far as i know if you go any bigger on a stock 6cyl motor than 2 1/2 inch there isn't enough back pressure in the exhaust and you actually lose power, dunno how true it is, just what i heard, i have a 2 1/2 inch sports system, one box, no resonator behind the diff like some and have a set of race series pacemaker extractors and noticed an enormous difference straight away.
Cheers Mat

mik · 15-10-2006, 10:49 PM

Quote:

Originally Posted by mattsAU1

as far as i know if you go any bigger on a stock 6cyl motor than 2 1/2 inch there isn't enough back pressure in the exhaust and you actually lose power, dunno how true it is, just what i heard, i have a 2 1/2 inch sports system, one box, no resonator behind the diff like some and have a set of race series pacemaker extractors and noticed an enormous difference straight away.
Cheers Mat

recently i fitted lukey headers to my xr6 i had already a 3" from the cat (ford one) i cut the the extractors and made them 3" outlet all the way through +hi flow cat and actually did`nt notice any difference that day i told my brother i was dissapointed, a few days later it did seem to pick up noticeably by the bumometer, my brother confirmed definatley pulling harder ,and one good side effect, prior to the headers it was NOISEY, but to my surprise its quiter and sounds like sex, deeper and the drone is gone completley :Reverend:, definatley has`nt lost go down low in this instance.

stiddy · 15-10-2006, 11:03 PM

LOL not again..

2.5in is fine for an N/A 6... even a modded n/a 6..
3inch imo is better, although alot dont agree.

As for the loudness hlc its just cause I only have 1 small muffler, it would be like any other exhaust if I put in normal size mufflers.

Take your choice.. all the talk about loosing power cause of backpressure.. laugh at them and walk away, they dont know what they are talking about.

stiddy · 15-10-2006, 11:06 PM

Quote:

Originally Posted by mik

recently i fitted lukey headers to my xr6 i had already a 3" from the cat (ford one) i cut the the extractors and made them 3" outlet all the way through +hi flow cat and actually did`nt notice any difference that day i told my brother i was dissapointed, a few days later it did seem to pick up noticeably by the bumometer, my brother confirmed definatley pulling harder ,and one good side effect, prior to the headers it was NOISEY, but to my surprise its quiter and sounds like sex, deeper and the drone is gone completley :Reverend:, definatley has`nt lost go down low in this instance.

NICE! exactly what im doing.. ive got the 3inch cat and cat back, waiting for headers and im gonna run a drop saw through the collector at 3inch so theres no 2.5in bottle neck.
I definately think it improves the cars power with a 3inch system over 2.5inch.

nat_daly · 15-10-2006, 11:08 PM

yeah, well trust me on this, stiddy's car is definately not sluggish, its farken quick!
i know ill be going to 3 inch eventually..

mik · 15-10-2006, 11:37 PM

worth it just for the sound difference i reckon now it has sort of a pulse effect that sets off car alarms at idle, sort of basey

if i can get my bro to put a sound file on during the week i will (i`m technichly challenged)
cheers mik.

stiddy · 15-10-2006, 11:50 PM

haha I know what you mean.. but mines got a crazy crackle at 3000rpm.. not many people on the street believe that its a 6, they think its an XR8 with XR6 badges on it.
Even stopped and popped my bonnet a couple of times so I can prove to the non believers that its only a 6.

fomoco3628 · 16-10-2006, 05:03 PM

stiddy do have any pics of your exhuast? does it get annoying or do u get any droning at highway speeds or anything?

nat_daly · 16-10-2006, 05:34 PM

i've been in stidd's car plenty, his exhaust sounds orgasmic..you could never get sick of that noise

troppo · 16-10-2006, 05:47 PM

Quote:

Originally Posted by stiddy

LOL not again..

2.5in is fine for an N/A 6... even a modded n/a 6..
3inch imo is better, although alot dont agree.

As for the loudness hlc its just cause I only have 1 small muffler, it would be like any other exhaust if I put in normal size mufflers.

Take your choice.. all the talk about loosing power cause of backpressure.. laugh at them and walk away, they dont know what they are talking about.

Couldn't agree more. What gets me is people that pass on this advice without ever bothering to find out.

stiddy · 16-10-2006, 06:47 PM

fomoco, its just a 3inch pipe with no press bends and 1 muffler in it, sorry no pics.

I have my days when I start to get sick of the noise, but once it spins up to 6000rpm you cant help but smile and it drones, drones big time, like as a joke with my mates I can 'drone out' other people in there cars.. its funny to watch them put their windows up.. and hold their dash to stop it from rattling

But if you drive it normally its not that loud at all and is quite comfortable to drive at highway speeds.. ie under 2500rpm.. another over that you'd be cruising at 120ish and it is killer.

JeffAU1 · 16-10-2006, 07:24 PM

ok Cheers all

Ima take a ride in HLC's and decide from there....

stiddy · 16-10-2006, 09:15 PM

Jeff I can take you for a spin in my car if you like, not tonight though, but i'll be in erskine park tomorrow arvo.

JeffAU1 · 16-10-2006, 09:20 PM

Quote:

Originally Posted by stiddy

Jeff I can take you for a spin in my car if you like, not tonight though, but i'll be in erskine park tomorrow arvo.

rofl ive heard your car... it was a head turner to say the least....

a little loud for me... especially with the plan of kids on the way.

But on that ride, i will take u up on that offer soon.

stiddy · 16-10-2006, 10:02 PM

lol you've heard my car? so you obviously live within a 12km radius of me LOL

JeffAU1 · 16-10-2006, 10:13 PM

Quote:

Originally Posted by stiddy

lol you've heard my car? so you obviously live within a 12km radius of me LOL

ya ya....Maybe im only on Bennett Road....

i heard u rock up at St Clair shops...

fomoco3628 · 16-10-2006, 11:16 PM

so would every one agree that there is no difference in power gain in a 2.5 then in 3" cos i want the sound of stiddys but i don't want to lose power.

JeffAU1 · 16-10-2006, 11:19 PM

have you heard stiddy's in person ?

fomoco3628 · 16-10-2006, 11:22 PM

Quote:

Originally Posted by JeffAU1

have you heard stiddy's in person ?

no but i've only heard good things. why is that?

JeffAU1 · 16-10-2006, 11:29 PM

Quote:

Originally Posted by fomoco3628

no but i've only heard good things. why is that?

It sounds like a beast, definately a head turner

as long as ur after a LOUD exhaust

fomoco3628 · 16-10-2006, 11:34 PM

yeah i'm after a loud exhaust but i don't want a headache after a 3 hour drive to brisbane. aslong as it dosn't drone on the highway i'd be able to live with it.

JeffAU1 · 16-10-2006, 11:36 PM

Quote:

Originally Posted by fomoco3628

yeah i'm after a loud exhaust but i don't want a headache after a 3 hour drive to brisbane. aslong as it dosn't drone on the highway i'd be able to live with it.

When are you going to get urs fitted ?

im gonna gor for a ride in a car with a 3" and a 2.5" exhaust, and the highway droning is what im listening for too.

BUt i wont be doing this for another 3'ish weeks. i will post the results...

stiddy · 17-10-2006, 09:10 PM

I think 3inch gains power over 2.5inch especially over 3000rpm.
the only reason mine is loud is because its only got 1 small sports muffler. It will quieten down heaps with another muffler.. but why? lol
Ive never gotten a headache from my car that includes a trip to qld (10hrs). Its not that bad provided you keep it under 2500rpm on the highway, no drone and its about asloud as any other sports exhaust, but plant it, it will shake shop windows.
Sounds the best going through tunnels

everyone moves out of ya way LOL.

fomoco3628 · 17-10-2006, 10:50 PM

don't know when i'll get mine done. prob go 3" just for the sound... performace will be an extra

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