Extractors worth it?

Smikey · 01-09-2003, 01:34 AM

Going a bit post crazy here, but these are times of change mechanically.

I currently have a CAT back exhaust as the only 'performance' boost to the car at the moment. Was reading about ignition leads etc. but was advised that extractors would probably be the next best move for the biggest increase in performance to the car. Just wondering about peoples thoughts on this if any of you have done it this way around and found it to be miraculous/ disappointing for the money paid.

K&N panel filter comes up next, anybody in sydney know where to get a good price for one of these :?:

JynX · 01-09-2003, 08:49 AM

autospeed.com

Cosmo Dude · 01-09-2003, 09:51 PM

About three months ago I was quotes $380 (fitted) from my local Midas. Add a length of pipe and new cat. That and a CAI should improve things all round.
For mid range 4-2-1 extractors would be best, for top end 4-1 best, I'd go midrange performance as high and low will not be compromised.

Rod

Smikey · 02-09-2003, 01:02 AM

Ouch, it seems i'm gettin charged quite a bit more over here

When u say 4-2-1 / 4-1 what exactly is that referring to? no idea what the numbers mean

ops:

KittyKatSmack · 02-09-2003, 10:23 AM

oooooh oooooooh pick me, I know this one......

*concentrates real hard*

4 2 1 means that when the extractors come out of the engine, 4 individual pipes merge into 2 individual pipes and then merge into one pipe that goes down into the cat and the pipe blah blah muffler blah ta da exhaust...

ok my version is a lot shorter than the mechanical geniuses out there....

but when you look at the head of your motor, you see the ports for the exhaust, there are four of them. 4 2 1 just explains how the piping merges until it turns into the "cat back" part you already have.

4 to 1 is just a faster and less piped way of doing it, it misses the 2 step.

Its all about how the exhaust emissions get drawn from the engine and how fast it does it, you want the motor to breathe at its best, like a runner... that's why Cold Air Intake and Exhaust are the first things to do to a motor to improve it's performance. I took out the resonator box part of doing Cold Air Intake and I will agree that it has done a LOT to improve the way the motor runs. Another cheap mod I can personally recommend for handling is a rear sway bar. At $150 and you can fit it yourself, it improves your cornering ability and puts a big grin on your face

That's my bit......

Did that make sense?
Did I do gooderest?

Please say yes otherwise the boys will never let me explain anything again.... :cry:

Now, I will step aside and the mechanical whips out there can give you the longer, more involved answer to your exhaust explaination......

Good luck

*runs away*

JynX · 02-09-2003, 10:43 AM

not bad kitty, thats pretty much the nuts and bolts of it.

sik astina · 02-09-2003, 10:49 AM

Dayym Kitty! You got it going on! Great response, Couldnt have put
it better myself!

-Mick

Cosmo Dude · 02-09-2003, 04:18 PM

Well done KittyK.
It also has something to do with the timing of the exhaust to the junctions in the pipes(you don't want two cylinders getting to the junction at the same time collision) . Some rotary people just go two all the way through.
Equal lenght is more jargon you may come across, this just means the pipe from the head to the junction is the same for all cylinders. Better but not totaly essential. On the BP number 4 may be slightly shorter than number 3,2 then 1 due to where the exhaust has to go.

Rod

P.S. HPC coating can both improve the performance of extractors (Also makes 'em look pretty) :wink:

Smikey · 02-09-2003, 11:42 PM

Wow, thanks for the explanation, easy at 1, 2, 3.... 4 or however u want to count it. :roll:

Btw, if u get a rear sway bar, i think i read on a previous post that u gotta adjust ur camber as well to compensate for the stiffer body?

KittyKatSmack · 03-09-2003, 12:05 AM

We didn't adjust my camber with my rear sway bar....

It is just fine, but I did get a 4 wheel alignment on my next tyre change, that also helped.

Don't know if that assisted in the sway bar doing its job, doubt it......

It is an easy/cheap mod that will work.... the guys here know that I have been raving about it since I had it done.

And it looks like I will be spending a little bit of money on the beast again soon, thanks to grandma!

Gotta love grandma's and their cheque books fella's :wink:

Wait and see though, not going to count my cheques before they're cashed........

BigMal · 03-09-2003, 02:42 PM

Just to add my 20c on extractors. I believed that the 4-2-1 against 4-1
was the scavenging affect. A 4-2-1 each cylinder has a 1 partner in
sucking the gasses ie cylinder 3 would be say paired with cylinder 1 so
that a vacuum would be created against 3 from the gasses exiting from
cyl 1. Same would happen with 1 to 3. The scavenging effect is good
for low end when things are going slowly but as the revs increase the
effect deminishes as its only the effect from one other cylinder. With a
4-1 you have the vacuum created from 3 other cylinders which is better
for high revs but has an adverse effect at low revs as it sucks out good
air/fuel from the chamber. Thats why almost all street applications are
4-2-1.

Regards

Mal

Aaron · 03-09-2003, 09:28 PM

4-1 headers work best on long stroke motors... Are about 50/50 on 'square' engines and less than optimal on short stroke motors.

Why I hear you ask? Well for a start I better make it clear I'm talking about road car, daily driven here not an outright power chase. (other wise it's the other way around!!!!)

With headers you're going to be trying to maximise the 'scavenge' effect of gasses out of the cylinder from teh moment the exhaust valve starts to open... This works best when you can creative negative pressure in the header tube. That is always the case! (even for turbo configs)

So anyway typically for all the reasons mentioned above a 4-1 will improve higher RPM breathing, although you can play 'harmonics' and find thata 4-1 will work very well from a much lower point than what some people suggest. But back tot eh point, long stronke motors typically are toruey compared to short stroke, 4-1s on a long stroke will open up the top end with very little loss of bottom end...

4-2-1s try to compromise across several tuned lengths to create humps of performance gain as harmonic points are crossed. In theory this can flatten a torque curve which can actually kill top end in some motors...

Like most car things there's ****e load of full on maths to be played with to make an 'optimum' set.... But be assured that you will almost always find off the shelf units geared aroudn packaging issues and cost moreso than total outright performance, and also geared towards seat-of-pants performance gains.. Afterall the company has to sell you something that makes you happy....

Cosmo Dude · 03-09-2003, 10:04 PM

And you thought you asked an easy question

If you get out your slide-rule and design a set of tuned headers (for your favourite rev range) you will then need to adjust the porting and valves in the head, cams, intake manifold, turbo if you've got one, inlet manifold, fuel mapping and ignition. Many other factors come into play.

The off the shelf extractors are fine for your application :wink:

Rod

Smikey · 04-09-2003, 11:02 AM

It seems i'll soon be able to answer my own topic question. Put the car in for some 4-2-1 extractors *drool* mandrel bent...shiny. also replacing the flex joining thingy (enjoy my technical vocabulary) since the stock one was smaller. Gettin the guys there to rip out the resonator too to get more air into my panel filter too.

Hopefully wheel balance soon, the previous owner must have loved driving diagonal with left wheel first over bumps for what... the last 6 years ;p

BigMal · 09-09-2003, 11:31 AM

Hey Cosmo,
Do you know how to calculate header length for rev range. Is the
biggest missing piece in my understanding of exhausts.

Ta

Mal

Aaron · 09-09-2003, 12:15 PM

Mal dig up a copy of Graham Bells book "Performance tuning in theory and practice"

It's a surprising good read and does procide some nice easy to use graphs to grab data out of

http://tom.marshall.tripod.com/exhaust.html

Shows an example of what kind of stuff you can generate from the formulae in the book .... Overall I wish I hadn't lost my copy a few years back it was an exceptionally handy thing for this kind of stuff

A.

bwhinnen · 19-09-2003, 11:31 AM

Hi guys and gals first post here.

I'd agree with Aaron on the book, the other one to grab is his forced induction performance tuning.

ISBN for the first = 1 85960 435 8 and the second = 1 85960 691 1

I've found them invaluable in tuning my own car, if only the wife would let me work on her's.

Cheers
Brett

01-09-2003, 01:34 AM	#1
Smikey AstinaGT Regular Join Date: Aug 2003 Location: Sydney Car: BA '97 Astina Posts: 452	Extractors worth it? Going a bit post crazy here, but these are times of change mechanically. I currently have a CAT back exhaust as the only 'performance' boost to the car at the moment. Was reading about ignition leads etc. but was advised that extractors would probably be the next best move for the biggest increase in performance to the car. Just wondering about peoples thoughts on this if any of you have done it this way around and found it to be miraculous/ disappointing for the money paid. K&N panel filter comes up next, anybody in sydney know where to get a good price for one of these :?: __________________ Just Do It - Smikey

01-09-2003, 08:49 AM	#2
JynX Senior Member Join Date: Dec 2002 Location: Sydney Posts: 1,767	autospeed.com __________________ JynX 1994 Turbo BA Astina 200whp @ 12psi "If you cant drive fast with 90hp..... 900hp wont help you"

01-09-2003, 09:51 PM	#3
Cosmo Dude コスモ Join Date: Dec 2002 Location: Location: Vic Car: Mazda '95 Astina I4, '86 B2K and '10 3 MZR-CD Posts: 7,888 View Photos By: Cosmo Dude	About three months ago I was quotes $380 (fitted) from my local Midas. Add a length of pipe and new cat. That and a CAI should improve things all round. For mid range 4-2-1 extractors would be best, for top end 4-1 best, I'd go midrange performance as high and low will not be compromised. Rod __________________ My 'stina Hatch

02-09-2003, 01:02 AM	#4
Smikey AstinaGT Regular Join Date: Aug 2003 Location: Sydney Car: BA '97 Astina Posts: 452	Ouch, it seems i'm gettin charged quite a bit more over here When u say 4-2-1 / 4-1 what exactly is that referring to? no idea what the numbers mean ops: __________________ Just Do It - Smikey

02-09-2003, 10:43 AM	#6
JynX Senior Member Join Date: Dec 2002 Location: Sydney Posts: 1,767	not bad kitty, thats pretty much the nuts and bolts of it. __________________ JynX 1994 Turbo BA Astina 200whp @ 12psi "If you cant drive fast with 90hp..... 900hp wont help you"

02-09-2003, 10:23 AM	#5
KittyKatSmack Banned Join Date: Mar 2003 Location: Australia Car: Mazda Posts: 3,961	oooooh oooooooh pick me, I know this one...... concentrates real hard 4 2 1 means that when the extractors come out of the engine, 4 individual pipes merge into 2 individual pipes and then merge into one pipe that goes down into the cat and the pipe blah blah muffler blah ta da exhaust... ok my version is a lot shorter than the mechanical geniuses out there.... but when you look at the head of your motor, you see the ports for the exhaust, there are four of them. 4 2 1 just explains how the piping merges until it turns into the "cat back" part you already have. 4 to 1 is just a faster and less piped way of doing it, it misses the 2 step. Its all about how the exhaust emissions get drawn from the engine and how fast it does it, you want the motor to breathe at its best, like a runner... that's why Cold Air Intake and Exhaust are the first things to do to a motor to improve it's performance. I took out the resonator box part of doing Cold Air Intake and I will agree that it has done a LOT to improve the way the motor runs. Another cheap mod I can personally recommend for handling is a rear sway bar. At $150 and you can fit it yourself, it improves your cornering ability and puts a big grin on your face That's my bit...... Did that make sense? Did I do gooderest? Please say yes otherwise the boys will never let me explain anything again.... :cry: Now, I will step aside and the mechanical whips out there can give you the longer, more involved answer to your exhaust explaination...... Good luck runs away

02-09-2003, 10:49 AM	#7
sik astina Senior Member Join Date: Mar 2002 Location: Wollongong , N.S.W , Australia Car: Ba 1.8L Turbo astina Posts: 1,739 View Photos By: sik astina	Dayym Kitty! You got it going on! Great response, Couldnt have put it better myself! -Mick __________________ [UNL35H] CANDY BA 1.8L Turbo - with the Twotone spread with the loco paint 2sus custom resprays

02-09-2003, 04:18 PM	#8
Cosmo Dude コスモ Join Date: Dec 2002 Location: Location: Vic Car: Mazda '95 Astina I4, '86 B2K and '10 3 MZR-CD Posts: 7,888 View Photos By: Cosmo Dude	Well done KittyK. It also has something to do with the timing of the exhaust to the junctions in the pipes(you don't want two cylinders getting to the junction at the same time collision) . Some rotary people just go two all the way through. Equal lenght is more jargon you may come across, this just means the pipe from the head to the junction is the same for all cylinders. Better but not totaly essential. On the BP number 4 may be slightly shorter than number 3,2 then 1 due to where the exhaust has to go. Rod P.S. HPC coating can both improve the performance of extractors (Also makes 'em look pretty) :wink: __________________ My 'stina Hatch

02-09-2003, 11:42 PM	#9
Smikey AstinaGT Regular Join Date: Aug 2003 Location: Sydney Car: BA '97 Astina Posts: 452	Wow, thanks for the explanation, easy at 1, 2, 3.... 4 or however u want to count it. :roll: Btw, if u get a rear sway bar, i think i read on a previous post that u gotta adjust ur camber as well to compensate for the stiffer body? __________________ Just Do It - Smikey

03-09-2003, 12:05 AM	#10
KittyKatSmack Banned Join Date: Mar 2003 Location: Australia Car: Mazda Posts: 3,961	We didn't adjust my camber with my rear sway bar.... It is just fine, but I did get a 4 wheel alignment on my next tyre change, that also helped. Don't know if that assisted in the sway bar doing its job, doubt it...... It is an easy/cheap mod that will work.... the guys here know that I have been raving about it since I had it done. And it looks like I will be spending a little bit of money on the beast again soon, thanks to grandma! Gotta love grandma's and their cheque books fella's :wink: Wait and see though, not going to count my cheques before they're cashed........

03-09-2003, 02:42 PM	#11
BigMal 1ST BA TURBO MEMBER Join Date: Mar 2002 Location: Sydney Car: BA Astina Turbo Posts: 4,195 View Photos By: BigMal	Just to add my 20c on extractors. I believed that the 4-2-1 against 4-1 was the scavenging affect. A 4-2-1 each cylinder has a 1 partner in sucking the gasses ie cylinder 3 would be say paired with cylinder 1 so that a vacuum would be created against 3 from the gasses exiting from cyl 1. Same would happen with 1 to 3. The scavenging effect is good for low end when things are going slowly but as the revs increase the effect deminishes as its only the effect from one other cylinder. With a 4-1 you have the vacuum created from 3 other cylinders which is better for high revs but has an adverse effect at low revs as it sucks out good air/fuel from the chamber. Thats why almost all street applications are 4-2-1. Regards Mal __________________ If you want wind in your hair add a Hairdryer !!!

03-09-2003, 09:28 PM	#12
Aaron Stiff Member Join Date: Apr 2003 Location: Canberra, ACT Car: 1994 Lynx BP-T Posts: 1,198 View Photos By: Aaron	4-1 headers work best on long stroke motors... Are about 50/50 on 'square' engines and less than optimal on short stroke motors. Why I hear you ask? Well for a start I better make it clear I'm talking about road car, daily driven here not an outright power chase. (other wise it's the other way around!!!!) With headers you're going to be trying to maximise the 'scavenge' effect of gasses out of the cylinder from teh moment the exhaust valve starts to open... This works best when you can creative negative pressure in the header tube. That is always the case! (even for turbo configs) So anyway typically for all the reasons mentioned above a 4-1 will improve higher RPM breathing, although you can play 'harmonics' and find thata 4-1 will work very well from a much lower point than what some people suggest. But back tot eh point, long stronke motors typically are toruey compared to short stroke, 4-1s on a long stroke will open up the top end with very little loss of bottom end... 4-2-1s try to compromise across several tuned lengths to create humps of performance gain as harmonic points are crossed. In theory this can flatten a torque curve which can actually kill top end in some motors... Like most car things there's **e load of full on maths to be played with to make an 'optimum' set.... But be assured that you will almost always find off the shelf units geared aroudn packaging issues and cost moreso than total outright performance, and also geared towards seat-of-pants performance gains.. Afterall the company has to sell you something that makes you happy.... __________________ Current: Stinky the imfamous Lynx**

03-09-2003, 10:04 PM	#13
Cosmo Dude コスモ Join Date: Dec 2002 Location: Location: Vic Car: Mazda '95 Astina I4, '86 B2K and '10 3 MZR-CD Posts: 7,888 View Photos By: Cosmo Dude	And you thought you asked an easy question If you get out your slide-rule and design a set of tuned headers (for your favourite rev range) you will then need to adjust the porting and valves in the head, cams, intake manifold, turbo if you've got one, inlet manifold, fuel mapping and ignition. Many other factors come into play. The off the shelf extractors are fine for your application :wink: Rod __________________ My 'stina Hatch

04-09-2003, 11:02 AM	#14
Smikey AstinaGT Regular Join Date: Aug 2003 Location: Sydney Car: BA '97 Astina Posts: 452	It seems i'll soon be able to answer my own topic question. Put the car in for some 4-2-1 extractors drool mandrel bent...shiny. also replacing the flex joining thingy (enjoy my technical vocabulary) since the stock one was smaller. Gettin the guys there to rip out the resonator too to get more air into my panel filter too. Hopefully wheel balance soon, the previous owner must have loved driving diagonal with left wheel first over bumps for what... the last 6 years ;p __________________ Just Do It - Smikey

09-09-2003, 11:31 AM	#15
BigMal 1ST BA TURBO MEMBER Join Date: Mar 2002 Location: Sydney Car: BA Astina Turbo Posts: 4,195 View Photos By: BigMal	Hey Cosmo, Do you know how to calculate header length for rev range. Is the biggest missing piece in my understanding of exhausts. Ta Mal __________________ If you want wind in your hair add a Hairdryer !!!

09-09-2003, 12:15 PM	#16
Aaron Stiff Member Join Date: Apr 2003 Location: Canberra, ACT Car: 1994 Lynx BP-T Posts: 1,198 View Photos By: Aaron	Mal dig up a copy of Graham Bells book "Performance tuning in theory and practice" It's a surprising good read and does procide some nice easy to use graphs to grab data out of http://tom.marshall.tripod.com/exhaust.html Shows an example of what kind of stuff you can generate from the formulae in the book .... Overall I wish I hadn't lost my copy a few years back it was an exceptionally handy thing for this kind of stuff A. __________________ Current: Stinky the imfamous Lynx

19-09-2003, 11:31 AM	#17
bwhinnen Junior Member Join Date: Sep 2003 Location: Hills, hills and more hills = Brisbane Posts: 7	Hi guys and gals first post here. I'd agree with Aaron on the book, the other one to grab is his forced induction performance tuning. ISBN for the first = 1 85960 435 8 and the second = 1 85960 691 1 I've found them invaluable in tuning my own car, if only the wife would let me work on her's. Cheers Brett __________________ MY00 WRX - 13B BP - Caspian 9x23 - Remington 1100 (for sale) <- my toys. '03 Astina SP20 <- wife's toys.

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