Author Topic: Exhaust  (Read 5105 times)

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Offline U12notU2

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Exhaust
« on: Dec 31, 2008, 09:44PM »
Okay I've read similar topics over and over too so bare with me please..

I don't know too much about cars and specific part names so I need some help.

I've got a dented, probably cracked, exhaust pipe right where it bends under the engine, was there when I bought it but has gotten worse (rust/weather etc.) and so it sounds like crap now.
I was going to get a whole new stock exhaust for it but after reading a few topics without a straight out 'right' answer for what I should get I need to know a few things.

1. Should I buy the one from a local wreckers, looks okay but cat might be clogged/crushed

2. Are extractors worth it (more economic on fuel/sounds cleaner)?

3. Should I get a cat from a different kind of car and why?

4. My brother is a fitter machinist, if I was to get him to machine an exhaust what specs should i give him and what material would be best?

Thanks in advance for your time.

Offline cruizer

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Re: Exhaust
« Reply #1 on: Jan 1, 2009, 12:15AM »
1. Might as well go a performance exhaust

2. Most off the shelf extractors aren't worth the money, they don't give much of an improvement.

3. I think there is an article on here somewhere that says a VL cat can be used

4. Exhaust spec wise your looking for a 2.25" or 2.5" (possibly 3") depending on planned modifications. Some people believe 3" is good, others reckon 2.25" is good. I'd recommend stainless steel (madrel bent).

Offline Vithy

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Re: Exhaust
« Reply #2 on: Jan 1, 2009, 03:06PM »
3in on a standard KA24E XD wow lol
wonder wat that sounds like......yay or neigh?
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Offline cruizer

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Re: Exhaust
« Reply #3 on: Jan 1, 2009, 04:54PM »
3in on a standard KA24E XD wow lol
wonder wat that sounds like......yay or neigh?

Chr1s reckons 3" or so I've read. I think thats because his KA24E was pretty worked. I personally think 2.5" is perfect.

Offline SSS

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Re: Exhaust
« Reply #4 on: Jan 1, 2009, 06:28PM »
The OP sounds like he doesn't need something anything like that at all.

I suggest you go to a wrecker and just grab the piping from the cat to the exhaust manifold, problem fixed. Probably set you back $100 if that.

In comparison, a full header back 3" exhaust, in 304 stainless with all mandrel bends, plus a new high flow cat and mufflers, will set you back around the $2k mark from an exhaust shop. They will spot an easy target as soon as you pull in the driveway and know what they can get away with charging.

For a worked NA KA (headwork, cam, high compression, GOOD headers), a full 3" from the headers back will be definetly worth it, but will be fucking loud, and defectable. For on the street, you'd need at least 2 dogleg mufflers to tame the noise.

Offline Vithy

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Re: Exhaust
« Reply #5 on: Jan 2, 2009, 02:53PM »
Chr1s reckons 3" or so I've read. I think thats because his KA24E was pretty worked. I personally think 2.5" is perfect.

ohk
i read in another thread that 3" is fine on a KA and anything bigger you loose power on according to noss i think or sss.
if a 3" system sounds fine and isnt so loud that id get defected then i wouldnt mind spending the extra doosh to put a 3" system on since it will give me a better power gain than 2.5 i presume and would make my car a little more unique. I dont think any of the other TRX boys in SA that arent running boost are running 3" systems. And it would save me buying 2 exhaust systems if in the future i play to work the KA a bit but yea...
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Offline Budgie

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Re: Exhaust
« Reply #6 on: Jan 2, 2009, 03:11PM »
mate, if your looking to simply get rid of the fucked up exhaust leak noise your cars currently making, head to a wrecker and look for a U12 with a newer muffler, chances are it might have had parts replaced exhaust wise.

Otherwise, get yourself  2.5" press bent mild steel system for as cheap as you can, fit a V6 magna cat convertor or a v6 commodore unit... forget the extractors :)

You'll be happy then.  It doesn't sound like your chasing power, but would be happy with a new exhaust thats got a nice note and gives your car a bit more squirt.
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Offline U12notU2

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Re: Exhaust
« Reply #7 on: Jan 4, 2009, 02:32PM »
Thanks all for the input, it really helps.
Well cost isn't my greatest concern, I decided against buying a different car for 5 grand and am planning on doing the pintara up a little bit...was going to sell it to my bro for $500 :P
So far its just been general home service stuff, oil/air filters, brakes, fixing rust spots etc. and I bought a new set of rims($1500).
But yeh $2000 might be a bit over what I want to spend on the exhaust alone.  Its probably the only 'known' problem the car has at the moment (touch wood) and I figure if I'm getting a new one that'll cost $200 may as well get one that'll make the car go/sound better for a few hundred more. 
So from what I gather, extractors are nice but not worth it,  2.5" is the safest bet, need a high flow cat or one from a v6 magna(or similar), go to an exhaust place that won't rip me off.  I know the last one is almost impossible but my dad is good mates with a guy that works at a local exhaust joint so I'll get him to take it in. 
People keep saying 'most off the shelf extractors aren't worth it', does that mean there are some that are? and should I just get them anyway, it is my money being 'wasted' after all lol
Thanks again for the replies everyone.

Offline Vithy

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Re: Exhaust
« Reply #8 on: Jan 4, 2009, 02:39PM »
If you do plan to get extractors go custom not off the shelf the are only a few hundred more and work so much better
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Offline cruizer

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Re: Exhaust
« Reply #9 on: Jan 4, 2009, 03:47PM »
What state are you in?

Offline U12notU2

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Re: Exhaust
« Reply #10 on: Jan 4, 2009, 05:54PM »
I'm in NSW, the worst state for car regulations...caused by those dam Sydney hoons.

So will most exhaust places make up custom extractors by request?  If so is there anything specific I should tell them about what size/set up the custom extractors should be?

Cheers

Offline chr1S

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Re: Exhaust
« Reply #11 on: Jan 5, 2009, 01:45PM »
You in Sydney?

I know a few exhaust shops I can take you to that do custom headers and all that jazz, last time I got a quote was around $600.
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Offline U12notU2

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Re: Exhaust
« Reply #12 on: Jan 6, 2009, 03:10AM »
Nah I'm up in Coffs Harbour...not much of a selection up here.

Went to an exhaust place yesterday, he said for a full exhaust would be 1200, extractors, flex pipe, hi flow cat, and that was with a 2 1/4" system.

Does this sound about right? Only other exhaust i have ever bought was a stock one for my old camry for a few hundred.

Offline chr1S

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Re: Exhaust
« Reply #13 on: Jan 6, 2009, 10:35AM »
way too much...

1.2k exhaust on a car worth 2-3k? you nuts?
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Offline noss

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Re: Exhaust
« Reply #14 on: Jan 9, 2009, 10:58AM »
Nah I'm up in Coffs Harbour...not much of a selection up here.

Went to an exhaust place yesterday, he said for a full exhaust would be 1200, extractors, flex pipe, hi flow cat, and that was with a 2 1/4" system.

Does this sound about right? Only other exhaust i have ever bought was a stock one for my old camry for a few hundred.

ok, this would be what you're after

muffler - your choice.. $100-$infinity
high flow cat - $250
2.5" press bent piping - $200
2.5" flex - $150
extractors - $400

so say you went for a 150$ muffler.. $1200 sounds about right i guess.

way too much...

1.2k exhaust on a car worth 2-3k? you nuts?

i know $1200 sounds expensive, but you're replacing everything.. mufflers/resonators, cat, extractors.. most of us do it in pieces. i personally went cat back exhaust which was about $300 including muffler, then replaced the flex and the cat which was about $250 installed, then the extractors which set me back a fortune at $560.. they reckon they had to re-do every stud on the head but it was still a rip off.

i've been generous on the price of the cat too, you would probably get one much cheaper.. you could also get away with a good high flowing lukey muffler for around $50-100. off the shelf extractors are shit, so if you can get away with it you can just not bother replacing them yet.




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Offline 91TR.X

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Re: Exhaust
« Reply #15 on: Mar 7, 2009, 08:39PM »
hey chris, $600 for a mild steel exhaust + custom extractors, pm me!

Offline chr1S

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Re: Exhaust
« Reply #16 on: Mar 8, 2009, 10:10AM »
I got a quote for that at St George Mufflers in mortdale, his quality of work is meh. I wouldn't say he sits there working out lengths and sizes. That's for headers only too.
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Offline 91TR.X

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Re: Exhaust
« Reply #17 on: Mar 8, 2009, 07:51PM »
mate, its only a pintara!

Offline U12notU2

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Re: Exhaust
« Reply #18 on: Apr 23, 2009, 03:42PM »
Okay just a short update.
I ended up getting the Sports muffler, wanted catback but when i rocked up to pick it up the guy told me there was already 2" straight through on it so he left it like that, so it only cost $180 installed with a 3" chrome tip.  Just yesterday got a extractors installed, was $479, he had to redo a couple studs that were broken off in there but didn't charge any extra.

Conclusion - Muffler made it sound a lot better, old muffler was rattled inside as well.  Sounds more like a v6.  While I still had the old manifold which obviously wasn't on properly (2 broken studs) it was way too loud and vibrated the car too much.  After getting the extractors on it though sounds soo good, and drives so much better.  The way I judged it was that normally I'll sit on 2k rpm and stay at about 80km/h (It's an automatic) now sitting on 2k it sits at about 95 with ease.  Having loose headers before probably didn't help at all but I'm happy with the extractors anyway.

Thanks for everyone's input as well.

p.s. Kevin Rudd paid for my extractors :P

Offline chr1S

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Re: Exhaust
« Reply #19 on: Apr 23, 2009, 08:02PM »
rofl, I didn't know extractors changed gear ratios.

I love seeing the effects of placebo.
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Offline sxtacy

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Re: Exhaust
« Reply #20 on: Apr 23, 2009, 11:31PM »
rofl, I didn't know extractors changed gear ratios.

I love seeing the effects of placebo.

 :D

It was probably a little true tho.

I bet his manifold was letting half the exhaust out with the broken studs making it run like shit. Once he bolted the new one in there were no more leaks so his engine doesn't have to work as hard anymore.
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Offline Kranzy

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Re: Exhaust
« Reply #21 on: Apr 23, 2009, 11:46PM »
The engine will still be at the same rpm. The only way to change rpm/speed would be different gears. No amount of leaking exhaust gasses will change that.
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Offline DeathPlaza

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Re: Exhaust
« Reply #22 on: Apr 25, 2009, 09:06AM »
slipping clutches, or a torque converter during vortex flow or at idle, and a slipping tcc are all ways vehicle speed and and engine rpm can vary from the set ratio...  seeing as he has an automatic.  Obd2 computers often utilise input and output shaft speed sensors to monitor whether the slip is coming from the internals of the transmission or the torque converter clutch

i doubt a leaking exhaust system would cause this though. 

a clogged exhaust system would have a greater effect on engine vacuum that might cause adverse shifting. in that case the vacuum would increase (because the engine would be drawing in air on intake but there would be no where for the majority of it to go), which would simulate low load causing the transmission to want to shift up.

on a slight grade the tranny shifts up (or stays in od) when it is actually under a load and runs up the rpm higher to go the same speed, causing the torque converter fluid to heat up eventually possibly leading to transmission or torque converter failure.  this is all speculation as i am assuming a u12 ka24e tranny uses a vacuum modulator.  i know that 240sx automatics have an electronic kickdown, so it is possible that they use the tps for load sensing as well which would throw this out the window. 

interesting to think about tho, in either case theres no problem anymore so cheers! 

back to exhaust

hopefully your non-custom headers dont leak, i have some type-r replica headers on my gsr motor and they leak a tiny bit where the collector is welded to the flange (its been about 1 1/2 yrs), and you can see a small amount of carbon escaping.

the ka24 has a crappy manifold, My u12's manifold is completely in two pieces the middle part of the manifold where the primarys meet into the secondaries the crappy mig weld broke loose to reveal almost no penetration the weld is all attached to one side, so i gotta get it welded back together (makes me wish i was still in welding class) or find another manifold at pick a part or something. 

btw long time no talk antrx glad to see u guys still are active, its great to see people who actually take care of their cars rather than use it til it breaks and buy another one. 
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Offline chr1S

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Re: Exhaust
« Reply #23 on: Apr 26, 2009, 12:49PM »
^ your the gearbox man, thats where I remember you from, off topic here

A friend of mine's torque convertor is on its way out, well its pretty much gone, the car won't accelerate very fast, feels like its in 3rd gear trying to accelerate off the lights and gives harsh shifts. Gearbox fluid has been changed, still doing it. Is there a band aid additive? The car only has to last another 5months or so.
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Offline DeathPlaza

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Re: Exhaust
« Reply #24 on: Apr 28, 2009, 06:27AM »
unfortunately theres not much u can do to bandaid a torque converter... actuallly, replacing it is as close of a band aid fix as u can get because if the torque converter starts shedding metal it goes straight to the trans as its pump is located on the back of the converter. so if u replace a torque converter without rebuilding the whole box ur gonna have metal crap all in ur valve body and its not gonna shift right, and grenade itself pretty fast.  the problem with auto tranny diagnostics is its a lot easier if u can drive the car urself to see if it does certain things.  there are friction modifiers (additives) but those are used when there is a slipping problem, slipping problems are ussually attributed to hydraulic integrity problems (or using the wrong fluid to begin with). 

if u think it actually is starting in 3rd that could mean the tranny has no voltage (auto trannys are designed to work in one forward gear even if they have no electronics ussually 3rd), or the manual select lever is not hooked up right, also debris in the valvebody could cause this, as well as a lack of a load sensing device (vacuum modulator?). 

lol im not the tranny guy (i remember him), i used to be a dumb teenager but now im almost done with my auto associates degree moving on to engineering soon. 
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Offline Jono

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Re: Exhaust
« Reply #25 on: Apr 28, 2009, 09:57AM »
a clogged exhaust system would have a greater effect on engine vacuum that might cause adverse shifting. in that case the vacuum would increase (because the engine would be drawing in air on intake but there would be no where for the majority of it to go), which would simulate low load causing the transmission to want to shift up.

A clogged exhaust would cause lower vacuum, a clogged intake would cause higher.

it is possible that they use the tps for load sensing as well which would throw this out the window.   

They do, but that doesn't throw your statement out the window. A less efficient engine means greater throttle openings for the same power, so it would change the feel and timing of  the shifts.
« Last Edit: Apr 28, 2009, 10:02AM by Jono »
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Offline chr1S

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Re: Exhaust
« Reply #26 on: Apr 28, 2009, 10:36AM »
auto associates degree, what's that?

your equivalent of a mechanic?
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Offline DeathPlaza

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Re: Exhaust
« Reply #27 on: Apr 28, 2009, 10:59AM »
yup thats me.  i prefer technician tho lol, it sounds fancier.  associates = 2 yr degree right now im finishing up general ed, english and history. 

Jono- yah i spent a lot of time thinking what a clogged exhaust would cause and i wasn't 100% sure that it would increase vaccuum but i gave it my best shot without any reference materials.  thanks for correcting me. 

4 the record, in the case of a clogged exhaust vacuum would go down because the engine would be intaking an abundance of air that gets stuck in the manifold which increases its pressure. 
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Offline Jono

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Re: Exhaust
« Reply #28 on: Apr 28, 2009, 11:18AM »
The engine would not push as much out the exhaust so there would be a higher residual pressure in the cylinder, therefore less vacuum in the cylinder to suck air out of the intake manifold  ;)

Engines don't suck air into the intake manifold, they suck air out of it. The air rushing into the manifold is to replace the air that the engine has removed from it.
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Offline DeathPlaza

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Re: Exhaust
« Reply #29 on: Apr 29, 2009, 05:45AM »
i think we're on the same page but i believe the engine really is pulling air into the intake manifold (it wouldn't flow in if it weren't for the expansion of the cylinder).  what ur saying is kindof like saying that a pump isn't sucking on its inlet hose, its only sucking on the inlet port.  technically the motor is really only acting on the cylinder directly not the manifold, but regardless by taking air out of the manifold it is effectively pulling air into it.  the vacuum that causes air to go through the air filter in the first place is vacuum the engine created, i think its just complicated to word things like this.  instead of saying the engine is sucking we could say the atmosphere is blowing if u like that better , but the atmosphere has to blow through everything (filter, intake tube, maf, throttle body, intake plenum, port, valve) to get to the engine so its the engine that causes the atmosphere to blow. 

so essentially everything that sucks blows hahaha
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Offline chr1S

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Re: Exhaust
« Reply #30 on: Apr 29, 2009, 09:08AM »
hmm.. i'm gonna get abit technical here but engines don't actually "suck" air in  :P
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Offline Smiley Of Terror

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Re: Exhaust
« Reply #31 on: Apr 29, 2009, 09:33AM »
hmm.. i'm gonna get abit technical here but engines don't actually "suck" air in  :P

isn't that just what deathplaza said only using way less words?
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Offline chr1S

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Re: Exhaust
« Reply #32 on: Apr 29, 2009, 11:27AM »
I skipped his post lols. But yes his correct.

The piston on the downward motion doesn't "suck" air in, it's simply the pressure differential in the cylinder and exhaust.
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to be fair, it wouldn't be ANTRX if we stayed on topic.

and if someone wasn't cranky at Chr1s for something he said...