2.5 in to 3"

ebfalcon13.5 · 18-02-2007, 08:00 PM

will i lose much power going to a 3" maybe a 2.75" cat back system? i know it will be a dog in the low end but if i change my diff ratio u think it should be allright to mayb a 3.9 or 4.11. i used to have a 2."5 in my n14 SSS and it sounded sweet. i just want my exaust to sound better. also in a 2.5" system on a falcon sound-wise, what sort of a difference will bigger headers make and a high flow cat? some answers from ppl who have upgraded their system plz also my exhuast was from a muffler shop i domnt think it is mandrel bent how can i tell? thanx guys im pretty new to the modified falcon scene

ebfalcon13.5 · 18-02-2007, 08:02 PM

its a stock eb i6 btw cfi

dansedgli · 18-02-2007, 08:04 PM

Mandrel bends stay the same size through the bend. Press bent systems get smaller through the bend.

Its easy to see when you look at one.

ebfalcon13.5 · 18-02-2007, 08:19 PM

Quote:

Originally Posted by dansedgli

Mandrel bends stay the same size through the bend. Press bent systems get smaller through the bend.

Its easy to see when you look at one.

oh ok then, i knew what a mandrel bend was, but wasnt sure if it was THAT noticeable, mine must be mandrel then?

Rollin · 18-02-2007, 08:33 PM

Leave the 2.5 for a while yet, after you have done the MPFI conversion, cam, chip and diff gears maybe think about getting a bigger exhaust.

Im assuming you already have extractors and bigger cat?

ebfalcon13.5 · 18-02-2007, 08:39 PM

Quote:

Originally Posted by Rollin

Leave the 2.5 for a while yet, after you have done the MPFI conversion, cam, chip and diff gears maybe think about getting a bigger exhaust.

Im assuming you already have extractors and bigger cat?

nope i have only a 2.5" catback being the only mod to my car

ebfalcon13.5 · 18-02-2007, 08:41 PM

nice car rollin, got any pics?

nos_james · 18-02-2007, 08:41 PM

i would leave the 2.5 for now has it got one muffler or two also a set of extractors and hiflow cat will make it a bit louder

ebfalcon13.5 · 18-02-2007, 08:47 PM

my car has only one muffler, what would a second one make it sound like?
i will definately have to save for some extractors and a high flow cat (after i get my new mpi manifold) but money is the set back at the moment.. i heard you can mod your stock cat to make it flow better..true? will it make my exhaust sound bodgy? ive heard what a screwed cat converter sounds like before

BPXR6T · 18-02-2007, 09:07 PM

I've just had a 3inch system fitted to my bog stock EF in preperation for the turbo to be hooked up.(free spooling turbo at the moment) I took it for a run and its pretty gutless. It would be worse for you as a turbo would be providing some back pressure.

It is loud too, and a turbo adds a muffling effect. So without turbo and just straight plain headers it would be way too loud. My system is mandrel bent 3inch, with 3inch high flow cat, and 3inch straight thru muffler.

But negatives aside I've got to admit it does sound pretty good with a deep throb throb throb at idle.

ebfalcon13.5 · 18-02-2007, 09:52 PM

k haha will stick with the 2.5 for now untill im runnin boost etc if i do lol... can you mod your cat to increase the air flow?

ebfalcon13.5 · 18-02-2007, 09:54 PM

without it sounding shitty

kyro_02 · 18-02-2007, 10:00 PM

Quote:

Originally Posted by ebfalcon13.5

k haha will stick with the 2.5 for now untill im runnin boost etc if i do lol... can you mod your cat to increase the air flow?

Yeah but it wouldn't be legal having a hollow cat :P -- and big fines $$ apparently !

.. just buy a HI-Flow cat

RG · 18-02-2007, 10:09 PM

Cut the 2.25" flanges off the cat and replace them with 2.5" ones.

ebfalcon13.5 · 18-02-2007, 10:09 PM

yeah.. good thinking i dont have a licence at the moment ... got a couple fines to pay as well. getting it bak midnight 4th of april and counting.. lol.. should give me some time to make my eb pretty sweet by then

ebfalcon13.5 · 18-02-2007, 10:11 PM

Quote:

Originally Posted by RedXR347

Cut the 2.25" flanges off the cat and replace them with 2.5" ones.

yeah might get my mate to do this if it is legal as he likes to weld things

RG · 18-02-2007, 10:12 PM

Quote:

Originally Posted by ebfalcon13.5

yeah might get my mate to do this if it is legal as he likes to weld things

Legal and easy. Cheap too if your mate can do it.

ebfalcon13.5 · 18-02-2007, 10:29 PM

Quote:

Originally Posted by RedXR347

Legal and easy. Cheap too if your mate can do it.

have you done this mod before ? did you notice and sound / power difference?

ebfalcon13.5 · 18-02-2007, 10:31 PM

just out of curiousity while were on the subject how big is the stock exhaust?

EBIIXR6 · 18-02-2007, 10:36 PM

run about 700 mm of 3.5 inch pipe after the diff with a 2.5 incher sounds real nice

ebfalcon13.5 · 18-02-2007, 11:22 PM

Quote:

Originally Posted by EBIIXR6

run about 700 mm of 3.5 inch pipe after the diff with a 2.5 incher sounds real nice

ok cool gettin some pretty good ideas here thanks

EBIIXR6, got any pics of your car? i may have seen it around, i goto cruisin at terrigal sometimes on a thursday night

Hybrid34 · 18-02-2007, 11:34 PM

I've just just a straight 2.5" to the cat as well, which is teh cheapest way to make it sound a bit more grunt....high cat?? what prices are you looking at?

RG · 18-02-2007, 11:37 PM

Quote:

Originally Posted by ebfalcon13.5

have you done this mod before ? did you notice and sound / power difference?

No, I just replaced mine (when I had my EL I6) with a high flow one as the stocker was screwed. Sound was majorly different, but that was more to do with the fact that the old one was gutted, and the bum-o-meter didn't notice much of a difference.

Quote:

Originally Posted by ebfalcon13.5

just out of curiousity while were on the subject how big is the stock exhaust?

Stock is 2.25"

ebfalcon13.5 · 19-02-2007, 12:29 AM

Quote:

Originally Posted by Hybrid34

I've just just a straight 2.5" to the cat as well, which is teh cheapest way to make it sound a bit more grunt....high cat?? what prices are you looking at?

well i payed $300 for my 2.5" cat - back exhaust from topline automotive in wyong and fitted with new muffler and tip, dont really want to go over $150 for the cat if i can help it

Skooter · 19-02-2007, 01:06 AM

Dont skimp on the cat if your getting a new one. The no name "high flow" cats can actually be worse than the stock ones. In saying this I have no idea how much a good cat costs lol.

Rollin · 19-02-2007, 09:38 PM

Quote:

nice car rollin, got any pics?

Click the "RIP L44124" part of my signature, I have a cardomain website.

Leave the cat back alone, just get bigger flanges welded to the cat and get a set of extractors, your car will sound much better and actually go faster to boot.

ebfalcon13.5 · 20-02-2007, 12:53 AM

Quote:

Originally Posted by Rollin

Click the "RIP L44124" part of my signature, I have a cardomain website.

Leave the cat back alone, just get bigger flanges welded to the cat and get a set of extractors, your car will sound much better and actually go faster to boot.

yeah, i think ill save up for some extractors.

sweet ride that front end is awesome
in your boot, is that a plasma ball from jaycar?

Rollin · 20-02-2007, 01:52 AM

I went to a sound-off ages ago at some random car autdion place (like 4+ years) and they had one sitting there with a broken cord, so i bought it off them cheap

It's a massive hit with drunk people, it really messes with their heads!

Oh yeah, I think you should have said "That front end was awesome" because I stoved the car into a tyre barrier at QLD Raceway late last year...it's still sitting in the garage waiting for me to either fix it or swap all the stuff into another body :(

Hybrid34 · 20-02-2007, 09:28 PM

He has the same wheels as me

, how much you pay for them?

ebfalcon13.5 · 21-02-2007, 02:20 AM

Quote:

Originally Posted by Rollin

I went to a sound-off ages ago at some random car autdion place (like 4+ years) and they had one sitting there with a broken cord, so i bought it off them cheap

It's a massive hit with drunk people, it really messes with their heads!

Oh yeah, I think you should have said "That front end was awesome" because I stoved the car into a tyre barrier at QLD Raceway late last year...it's still sitting in the garage waiting for me to either fix it or swap all the stuff into another body :(

it sets off your boot layout real good, you did a great job on the whole car, its a shame you crashed it it will never be the same i would of cried. im guessing you didn't have insurance? are you planning to do another eb?