Pod Filters, Catback questions

[Zackk]

My DA9 has a 4" Catback (I think, from what I've read up on Catbacks, I think I'm right, lol) and I was just wondering if it gives me a performance boost over a regular 2" exhaust?

Also, would I benefit from putting a Pod filter in my car as far as performance goes? The battery sits between the filter and the engine, so is there need for a shield/box if I wanted some more power? And, what parts would I need to switch to a Pod filter, is it just bolt on?

[fabezzz]

Lol if its 4" whoever did it is a dumbass.

[Zackk]

Lol if its 4" whoever did it is a dumbass.


Bought the car with it :P Don't look at me aha.

Curiousity - I'm not really smart when it comes to car stuff, so what's so wrong with a 4"? And DOES it give me a performance upgrade?

[Joe kickarse]

You'd actually lose performance with a 4".

As for Pod filter, there is not much gain at all if any. Plus even if you shield or box it, you can still get defected for it.

Go with 2.5" catback.

[Crapdaz]

agreed as above...

bigger exhausts = only better if you had boost setup...as you would prefer the fumes to be shot out rather than backpressured....

whereas N/A would be better with slight backpressure, hence 2.5" is ideal for it even 3" might be a tad too big.

[Zackk]

Oh okay, I think it was put on moreso for the sound, which I'm in love with as well. I've got the original exhaust as well, I think it's only 2" but obviously won't sound as tough.

So I can get defected for having an aftermarket box even in QLD?

I've still got the factory box at least, so I could just cover it?

[Joe kickarse]

If you could modify your factory box to cover your pod filter then go for it. You could always just look for aftermarket filter for the factory box.

[Zackk]

True, thanks.

Curiosity, would the filter actually do anything? Haha. Sound wise? seeing as performance wise I'll get little to none :p

[CB7_OWNER]

Your 4"inch exhaust would drone out any sound that the pod filter would normally make on induction anyways.....the pod filter does sound nice on honda engines... but with exhaust like yours,, i doubt you would hear it much =)

[Zackk]

Ah thanks very much for the info! :D

[n473]

Yep, pods sound nice - especially when they're sucking in air =D

[gach2]

im suprised no one else hasnt mentioned this
are you really sure its a 4 inch catback
if it was you would have so much backpressure your car would drive like shit
im pretty sure your exhaust is 2-2.5 inch but has a 4 inch tip on the muffler
take it to an exhaust shop and ask them
but even easier just go under your car and measure the circumference somewhere near the cat converter and from that get the diametre

[55EXX]

doubt it is 4 inch! am i the only non noob to read this!

bigger exhaust diameter the less back pressure not higher.

exhaust is not about back pressure its about exhaust gas velocity. as you would imagine as each cyclinder exhuast valve opens it fire the burnt fuel gas out of the motor and into the exhuast. as each one comes out it creates a pulse. as the pulse is a higher gas pressure section and in between these pulses is less pressure section. the high pressure wants to travel to the low pressure and creates a flow of these pulses that pull each other along.

this travels back out from the engine etc but when tuned correctly will create the less pressure point after the exhaust valve to be a vacum increasing the motors efficency and therefore torque at that particular range in the rpm. the larger the piping the higher in the rpm range the exhaust gas pulse tuning has an increased efficency. smaller the lower. 4" would place it efficency point so high you car would never rev to to utilise. 2 inch is ideal for most street 4 cyls. vtec being able to rev high may want 2.25" or 2.5" for hypo reving engines. my twin cam d which i daily rev to 7000 has a 2.25 inch and i found that it moved peak in my power band to 5500rpm to 6500. previous 2" was more 4500 to 5500 so guessing 2.5 would be 6500-7500+?

its not about backpressure it exhaust gas velocity. the better the flow the better the exhuast gas flows out of the engine and out your tailpipe. it is resistance in the flow you want to stop. too much the pulse cram together and to lose the effect you wanted and too big too high in the rpm range it goes. anyways i've said this a million times in other threads so search. get the exhaust diameter to suit your driving. i wring the neck of my twin cam the sacrifice to power below 3000 didn't phase me as i'm never in the rpm range other than when i'm maintaining speed. drop back 2 gears and she's off instead of the usual one otherwise.

[Zackk]

Ahh true!

I got totally confused then! It's only standard size until the tip!

-facepalm- I was thinking that the cannon I've got doesn't really drain power, because it's pretty zippy as is (from experience, which is minimul :p) BUT, the tip and leading up to the tip is 4" etc. Goes from fatter to a bit smaller by about an inch at the tip, then back down to the stock size on the piping.

That was completely my bad! :eek:

I do understand though, so you've 100% completely answered my question now, thanks 55EX! :D