[jmd-247]

ok, i got some ebay special extractors to get the lil zook breathing a bit better.

i am going to get the rest done next week.,

in peoples opinion from experience and whatever is the best size to run from the extractors back???

wooooop.
thanks
josh

[atari4x4]

got one question, what sort of zook is it?

[mnemonix]

1.3l? 1.75"-2.0" max.
I'd be using the smaller though. The extra size is not worth the potential flow increase for the amount of extra noise.

[jmd-247]

well silly me
please excuse, (just off nightshift and am like zombie)

1.3. ltr.
standard carby.

i was leaning toward 1 3/4 inch..

straight thru? muffler?

[mnemonix]

extractors-cat-resonator-muffler.
With a standard engine, stick to a stockish size freeflowing exhaust. Your extractors don't require anything special to achieve their purpose.
Keep it quiet and mild so it remains pleasant to drive.

[2stroker]

mnemonix wrote:

extractors-cat-resonator-muffler.
With a standard engine, stick to a stockish size freeflowing exhaust. Your extractors don't require anything special to achieve their purpose.
Keep it quiet and mild so it remains pleasant to drive.

Well said

[MacDaddy]

mnemonix wrote:

1.3l? 1.75"-2.0" max.
I'd be using the smaller though. The extra size is not worth the potential flow increase for the amount of extra noise.

Yeah i reckon 1.78in with a high flow muffler... also a High Flow Cat makes a big difference, as the Cat will be the biggest restriction in a better high flow exhaust system, but can be around $300, but if you can afford it, i highly recommend it !

[Moph]

Agree with the above - I have Genie Wildcat extractors into 2" cat, 2" muffler, then reduces to 1.75" exhaust with hotdog resonator. Goes great, has a little bit more of a burble than stock at idle, but is still nice and quiet at speed - no drone.

Nothing worse than a tinny little 1.3L farting away through a huge poorly-muffled exhaust IMO

[jmd-247]

thinking of ditching the cat altogether..

i no its illegal etc etc but as you said highly restrictive and pricey. just might leave it out and put it straight thru with a muffler..

[steak_knife]

jmd-247 wrote:

thinking of ditching the cat altogether..

i no its illegal etc etc but as you said highly restrictive and pricey. just might leave it out and put it straight thru with a muffler..

Your going to kill the dolphin's!!!!!!

[Jasen]

Moph wrote:

Nothing worse than a tinny little 1.3L farting away through a huge poorly-muffled exhaust IMO

Dear god yes! I tore my exhaust system off just behind the cat (not on purpose - a rock decided that I didn't really need the rest of my exhaust) but still drove it for months like that. The G13A(BA) motor does not really have the nicest of notes IMHO. Am doing a G16A conversion atm and originally planned on a 2" straight thru system with just a small sports muffler near the end. But after driving it with practically no exhaust for so long, I now plan on a hotdog res and a decent 2" muffler near the end. Probably not even a straight-thru muffler anymore I reckon. I would think that even a std style muffler (baffled) towards the rear would have plenty enough flow for the 1.6 without affecting performance and be nice and quiet too. (Jeez I feel like I'm gettin old to want a quiet system over an obnoxious one)

[Jasen]

jmd-247 wrote:

thinking of ditching the cat altogether..

i no its illegal etc etc but as you said highly restrictive and pricey. just might leave it out and put it straight thru with a muffler..

Do you REALLY think you'd need to do that? Sure it might make a decent power gain in a hi-po turbo car that's putting out rwkw in the multiple 100's but a std 1.3 with minimal horses (ponies maybe - or maybe it should be measured in large dogs?) it's not gonna make much of a difference (unless ur cat was already blocked) and the legal ramifications are really quite extreme for the gain....

Just my 2.2c (incl GST)

[jmd-247]

steak_knife wrote:

jmd-247 wrote:

thinking of ditching the cat altogether..

i no its illegal etc etc but as you said highly restrictive and pricey. just might leave it out and put it straight thru with a muffler..

Your going to kill the dolphin's!!!!!!

i work in a coal mine so i guess i am even worse right???

[jmd-247]

Jasen wrote:

jmd-247 wrote:

thinking of ditching the cat altogether..

i no its illegal etc etc but as you said highly restrictive and pricey. just might leave it out and put it straight thru with a muffler..

Do you REALLY think you'd need to do that? Sure it might make a decent power gain in a hi-po turbo car that's putting out rwkw in the multiple 100's but a std 1.3 with minimal horses (ponies maybe - or maybe it should be measured in large dogs?) it's not gonna make much of a difference (unless ur cat was already blocked) and the legal ramifications are really quite extreme for the gain....

Just my 2.2c (incl GST)

well i am cutting it out and starting again so yes i want it gone. I have taken it out on several cars before.. i am getting everything i can outa this lil puppy..

[Gwagensteve]

jmd-247 wrote:

... but as you said highly restrictive and pricey. just might leave it out and put it straight thru with a muffler..

[/quote]

It's your car and all, but you are wrong. If you are determined to build an illegal and annoyingly loud car go for your life, but off the shelf cats aren't that expensive, they won't restrict a 47Kw 1.3 enough to make any difference, and the noise a sierra makes with a loud exhaust is embarrassing.

I have no problem with well tuned cars with a nice note, but I hate listening to stock motors that make too much noise. It's ghey.

as has been stated - 1.75" with a cat, a resonator (like a 12" hot dog) and a triple flow muffler will make a nice noise under full throttle but will be nice and quiet when you're not on it.

Steve.

[jmd-247]

yeah i understand what u are saying about noise.. nothing worse than a droning annoying car on a trip longer than 3 minutes.

In my past experience, (i may be wrong) but when removing or gutting the cat on previous occasions has made very little change to the noise the car makes.. i have no problems with muffler as i couldnt stand the sound of it without one.

[MacDaddy]

Jasen wrote:

Moph wrote:

Nothing worse than a tinny little 1.3L farting away through a huge poorly-muffled exhaust IMO

Dear god yes! I tore my exhaust system off just behind the cat (not on purpose - a rock decided that I didn't really need the rest of my exhaust) but still drove it for months like that. The G13A(BA) motor does not really have the nicest of notes IMHO. Am doing a G16A conversion atm and originally planned on a 2" straight thru system with just a small sports muffler near the end. But after driving it with practically no exhaust for so long, I now plan on a hotdog res and a decent 2" muffler near the end. Probably not even a straight-thru muffler anymore I reckon. I would think that even a std style muffler (baffled) towards the rear would have plenty enough flow for the 1.6 without affecting performance and be nice and quiet too. (Jeez I feel like I'm gettin old to want a quiet system over an obnoxious one)

If you are gonna do to the trouble of putting extractors on the 1.6, with a 2in system, and then put a stock baffled muffler on, you are just adding restriction, which is defeating the purpose... i had G16A in my old Vit, and i definitely notice the difference when i got a 2in straight thru system put on, so yes, removing any kind of restriction, does make a difference...

jmd-247 wrote:

thinking of ditching the cat altogether..

i no its illegal etc etc but as you said highly restrictive and pricey. just might leave it out and put it straight thru with a muffler..

I like to thumb my nose up to stupid laws as much as anyone.. but removing the cat, is not a good move...
We as 4WD owners, are copping enough crap from others and their restrictive offroad laws... but removing the cat just reflects badly on all of us, as responsible 4WD owners, and just gives fuel to those that think all 4WDers are assholes... and attracts unwanted attention from the Police...

[Proxy]

my sierra came with extractors no cat and a highflow muffler,

SOUNDED TERRIBLE!!!!!!

$200 put a cat in cause i had been yellow stickered (add on $130 of fines and fees)

Sounds WAY better and actually Goes better, simple!

only other mod i did was a nice tip welded on, and in the future i will replace the muffler cause it's old and looks outdated so i assume it's not performing well, i want something with a deeper noise not the tinny crap

[MacDaddy]

Proxy wrote:

my sierra came with extractors no cat and a highflow muffler,

SOUNDED TERRIBLE!!!!!!

and in the future i will replace the muffler cause it's old and looks outdated so i assume it's not performing well, i want something with a deeper noise not the tinny crap

Not sure what kind of setup 96Coily has on his sierra, but it sounds deep and really, really Good !

I had a Mercury brand HiFlow Muffler put on mine, its Aussie made, gives it a nice growl, and sounds a bit like a rally car at high RPM !

[matt91112011]

I read a comparison in one of those hi performance street car magazines that a good high flow cat vs no cat, actually makes around 1rwkw difference and remember we are talking car with over 200rwkw. If ur doing it to save money then go for it, but if u get a fine then I don't think it's worth it in the end.

Cheers

Matty

[MrRocky]

2"

[Proxy]

MacBear wrote:

Proxy wrote:

my sierra came with extractors no cat and a highflow muffler,

SOUNDED TERRIBLE!!!!!!

and in the future i will replace the muffler cause it's old and looks outdated so i assume it's not performing well, i want something with a deeper noise not the tinny crap

Not sure what kind of setup 96Coily has on his sierra, but it sounds deep and really, really Good !

I had a Mercury brand HiFlow Muffler put on mine, its Aussie made, gives it a nice growl, and sounds like a bit like rally car at high RPM !

i like the sound of this rally idea

[Fatzook]

MacBear wrote:

If you are gonna do to the trouble of putting extractors on the 1.6, with a 2in system, and then put a stock baffled muffler on, you are just adding restriction, which is defeating the purpose...

In my experience, an exhaust is only as good as its most resrictive part.

MacBear, was your " 2" straight through system" press bent or mandrel bent? If mandrel, the cross-sectional flow area through the bends would be less than that of a straight 1.5" pipe.

My point is that system DESIGN is more relevant that pipe size. And adding a tripple flow, chambered muffler at the rear of the system will have little to know effect on power over a straight through muffler when you consider that the exhaust gas has significantly slowed by that point due to turbulence and internal inertia of the pipe walls.

A properly routed 1.75" system with ( for shits and giggles ) a 2" CAT and a 1.75" tripple flow muffler will be more than capable of handling the gas flow of a pizzling little 1.6L.

I ran this setup on my ute and it was outstanding.

[MacDaddy]

Proxy wrote:

MacBear wrote:

Proxy wrote:

my sierra came with extractors no cat and a highflow muffler,

SOUNDED TERRIBLE!!!!!!

and in the future i will replace the muffler cause it's old and looks outdated so i assume it's not performing well, i want something with a deeper noise not the tinny crap

Not sure what kind of setup 96Coily has on his sierra, but it sounds deep and really, really Good !

I had a Mercury brand HiFlow Muffler put on mine, its Aussie made, gives it a nice growl, and sounds like a bit like rally car at high RPM !

i like the sound of this rally idea

Here is a link to what mine sounds like doin a Dune climb, taken on a phone, so not the best, but you can hear it -
http://s1216.photobucket.com/albums/dd3 ... deo016.mp4

[TASSIETOYUKI]

IIRC, the factory cat on most vehicles only privides about 3% of the total back pressure in the standard exhaust system.
The older style press bend stock systems quite often have more restriction in the pipes than the main muffler itself.
Any good exhaust shop should be able so supply you a universal cat in the correct size for a reasonable price and will help to keep you legal as well.
Walker exhausts have listed in there catalogue a basic recomendation on exhaust sizing chart for custom built systems.

[hooki]

whats the ideal exhaust size for a 1L (f10a) with extractors?

[MacDaddy]

hooki wrote:

whats the ideal exhaust size for a 1L (f10a) with extractors?

I would say... 1.75in !

[hooki]

MacBear wrote:

hooki wrote:

whats the ideal exhaust size for a 1L (f10a) with extractors?

I would say... 1.75in !

Yeah? i geuss as long as it provides enough backpressure for the 1L so it doesn't loose all it's low down

[MacDaddy]

hooki wrote:

MacBear wrote:

hooki wrote:

whats the ideal exhaust size for a 1L (f10a) with extractors?

I would say... 1.75in !

Yeah? i geuss as long as it provides enough backpressure for the 1L so it doesn't loose all it's low down

Ha ha, forget about back pressure, its a myth...
Its about maintaining enough restriction... right pipe Diameter, and right length, while still having a higher flow exhaust, i think 1.75in, and the length of the pipe from engine/extractors, to outlet at back of zook, would still give you enough restriction to not loose much power at low RPM... depending on the muffler you get put on, straight thru, or baffled, it will help if you are concerned about loosing low down...

[Gwagensteve]

MacBear wrote:

Its about maintaining enough restriction... right pipe Diameter, and right length, while still having a higher flow exhaust

After a few inches downstream of the extractors collector, there's no such thing as "maintaining enough restriction"

Extractors are designed to match the exhaust pulses from each cylinder so that each pulse arrives at the collector separately. After that point, any scavenge effect from pulse timing ceases to exist, and the point is about getting the gas out as fast as possible.

The "required restriction" or "backpressure" exists between the head and the collector. after that point, backpressure is lost power.

This is not necessarily the case with log manifolds that aren't equal length, where removing backpressure might reduce scavenging.

I'll just reiterate - downstream of a turbo or the extractors collector, backpressure or restriction is not "required"

Steve.