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Location:
Sydney
Registered:
June 2003
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20V extractor for sprinter?
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Tue, 31 May 2005 13:09
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what side should the 20v extractor should be made out of?
1.5inch or 1.75inch?
can anyone explan to me what different it make to my car?
plus i'm going for 4-2-1 extrator? it that ok for 20v on a sprinter?why?
what else I need to know about the lenght and stuff
cheers.
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Banned user
Location:
ADELAIDE - The Drift City
Registered:
July 2002
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Re: 20V extractor for sprinter?
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Tue, 31 May 2005 13:17
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the ports on the head are 30mm each, so 1 and a 1/4 inch in the old language. you want to idially run long, equal length runners with a collector merging them into a single 2 inch a fair way from the head.
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Banned user
Location:
ADELAIDE - The Drift City
Registered:
July 2002
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Re: 20V extractor for sprinter?
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Tue, 31 May 2005 13:26
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on that note, if anyone has pics of different extractor set ups... pls post em 
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Location:
Sydney
Registered:
June 2003
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Re: 20V extractor for sprinter?
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Tue, 31 May 2005 20:10
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but that sound small
I was going for a 2.25inch system.
anyone else with more information.
thank you
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Location:
Sydney NSW
Registered:
July 2004
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Re: 20V extractor for sprinter?
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Wed, 01 June 2005 00:09
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When Simon refers to 1,1/4 ", he is referring to the actual individual pipes coming off each cylinder, that then combine (4,2,1) into your "2,1/4" system".
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Location:
Sydney
Registered:
June 2003
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Re: 20V extractor for sprinter?
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Wed, 01 June 2005 02:53
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I knew that
but what I mean was.
if i when for 1.5inch pipe for the extractor. what would that do to my car?
cheers
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Location:
Campbelltown
Registered:
November 2003
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Re: 20V extractor for sprinter?
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Wed, 01 June 2005 02:58
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mate they use 1.75 inch extractors on gen 3 V8's, now these have each cylinder with 712.5cc verus 400cc for you i think it might be a little big.
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Location:
Sydney
Registered:
June 2003
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Re: 20V extractor for sprinter?
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Wed, 01 June 2005 08:58
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so you are saying 1.25inch would be find.
typical me. i alway think biger might be better.
1.75" stock? or 1.75inch custom made?
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Location:
S.E suberbs, Vic
Registered:
December 2003
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Re: 20V extractor for sprinter?
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Thu, 02 June 2005 09:27
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I used 1.5 inch exhaust pipe (outside diameter) for my primaries because its almost exact same inside diameter as the stock head outlet, so it cant be too wrong. I made my own extractors and I havent finished yet, I dont know how long I am meant to make the secondaries anyway heres a few pics:
 
see my worklog for more details
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Location:
Sydney
Registered:
June 2003
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Re: 20V extractor for sprinter?
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Thu, 02 June 2005 09:44
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I'm getting my extractor made for me.
so 1.5inch would be better then 1.25inch?
or 1.25 would be plenty for a 20V sprinter?
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Location:
S.E suberbs, Vic
Registered:
December 2003
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Re: 20V extractor for sprinter?
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Thu, 02 June 2005 09:57
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you might want to state if oyu mean the inside or outside diameter, I assume u mean inside?
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Location:
Hong Kong
Registered:
November 2003
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Re: 20V extractor for sprinter?
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Fri, 03 June 2005 09:19
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Hi
I offer my 20v RWD extractor custom made review for your interest.
http://www.my-acoustic.com/Car/intake_exhaust/cust om_extractor/custom_extractor.htm
edit - forgot to mention, always make let the exhaust port mate to the pipe same size internally, seamless, smooth flow, no turbulences. Although same suggest using slightly bigger pipe to allow a non-returnable-effect, i.e. exhaust comes out of port and into pipe from high pressure to low pressure, hence low pressure side nearly forever cannot go back in.
But my personal opinion is seamless is best. Because different size will cause coughing effect, I forgot the official science name / term, from subwoofer port theory.
The difference size poses different air impedances, power is lost during conversion, not so good....
[Updated on: Fri, 03 June 2005 09:23]
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I Supported Toymods
Location:
Wollongong
Registered:
June 2003
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Re: 20V extractor for sprinter?
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Fri, 03 June 2005 12:08
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Location:
S.E suberbs, Vic
Registered:
December 2003
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Re: 20V extractor for sprinter?
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Fri, 03 June 2005 14:28
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hey acoustic, your pipes look very interesting, maybe you can help me with something:
I cant understand your charts, I have some 4-2-1 pipes and I have a 500mm primary length with has a 1.5 inch O.D, this goes to a 2 inch set of secondaries. What RPM tuning does 500mm corespond to? and how long should I make my secondaries? Lastly isnt it a big issue that you dont have a flex pipe?
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Location:
Brisbane
Registered:
February 2003
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Re: 20V extractor for sprinter?
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Fri, 03 June 2005 14:59
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| Sam_Q wrote on Sat, 04 June 2005 00:28 |
Lastly isnt it a big issue that you dont have a flex pipe?
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I made a thread about this recently because I was concerned about not having one in my system. Aparently it's a thing that spawned from fwd layout exhausts, and not too important.
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Location:
S.E suberbs, Vic
Registered:
December 2003
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Re: 20V extractor for sprinter?
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Fri, 03 June 2005 15:10
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I would argue that severly, I used to miss one in my system and it trasmitted strong vibrations from the engine through to the cabin, I only want my extractors to move not my entire system.
Got a link for that old thread?
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Location:
Hong Kong
Registered:
November 2003
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Re: 20V extractor for sprinter?
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Fri, 03 June 2005 17:28
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Hi Sam
Thanks for your interest, and sorry that my chart is confusing.
1st the easy bits, I've got a single flexible when it goes into the final now. However due to the length or distance the flexible knocks my chassis some times  - if you've got more $$$ perhaps you can make a twin flexible at the secondaries itself ??? but I suppose most people would not agree, so do I 
I didn't have any vibrations before the installation of flexible. Lucky me I guess. Except my muffler always fall off from the bracket, because too much stress I suppose. The rubber also always fall off
After using the flexible and ADD one more bracket at the neck above the axle and tighter rubbers it's all fine now.
Now to answer the more complicated question.
500 mm primaries should mate with 250 mm secondaries, which both must be 1.5" diameter. They are optimised for 10,200 rpm. The starting power comes one octave below which is 5,100 rpm. And an even lighter feeling of power output comes another octave below at 2,550 rpm.
Has these been what you've got ??? power starts to come at 5k rpm ???
You have not made your secondaries right? and you plan to use 2" instead of 1.5". This will complicate matters. With 2" you'll need longer length to "be equal" of "the half of the primary"
However if you follow 250 mm, then it's frequency = rpm will be lower hence you gain some low-end.
There is a concern of flywheel weight / total crank rotational weight.
When I had a 5.8kg flywheel with a 0.85kg crank pulley - power starts to come 1,700 rpm and it kicks at 2,500 and becomes stagering at 4,000 to 6,000 because my sweet spot is 5,200 rpm. It still goes smooth and powerfull all the way to 8k.
After I change the flywheel to 5.2kg and change of a slightly larger muffler 2" in 2" out slightly larger volume box, my low end suffered a little. Power starts 2,500 instead of 1,700 and power it kicks at 3,500 and stagering at the usual 4,000 and onwards.
I've also got a race muffler stand-by for swap (straight flow) 3" in 3" out and sucks completely at low end below 4,000 on light and partial throttle.
This muffler is meant for race and must be used with lots of full throttle. So, when full throttle is applied, power comes stagering from around 2,500 rpm - may be lower.
The rev goes up very very fast...
My silvertop RWD considering more drive train loss can maintain position against ford 1.8 dohc ff.
Hope this helps.
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Location:
S.E suberbs, Vic
Registered:
December 2003
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Re: 20V extractor for sprinter?
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Fri, 03 June 2005 22:32
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yeah thanks heaps, I had no idea that I needed primaries so long, kinda disapointing really. I can't afford to do such a thing though as I still want to run my flex pipe and also my long resonator in the middle. I am not running my 20V yet so I dont know what it will do.
Anyhow I do have a 2 inch O.D set of secondaries, I will measure what I.D that works out to, why is this so bad? With a large degree of dificulty I can change this and even make my extractors longer but how would it help? Would it help at all to convert my system to a 4 into 1 with extra long primoraries? because then I could afford the extra length. Also it's heaps harder for me because unlike yourself I have an australian bellhousing which means I have a clutch fork and slave to deal with, so thats an issue too.
What is the actual formular for working out the lengths?
Also I am going to get my vernia and do some proper measurements for people on the I.D and O.D of both 1.5 and 2.0 inch pipes.
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Location:
Brisbane
Registered:
June 2002
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Location:
Brisbane
Registered:
February 2003
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Location:
S.E suberbs, Vic
Registered:
December 2003
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Re: 20V extractor for sprinter?
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Sat, 04 June 2005 01:34
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ok thanks, not many arguments were really said there though so I will add my bit here. I am using hard rubber straps on my exhaust instead of O style rubber rings, theres are more rigid and are much easier to use. I think a flex pipe should be there because firstly it goes to what I said before about trasmiting vibrations into the cabin and also theres a bigger factor. When an engine rocks due to its movement the whole system will have to move obviously enough, I think this places undue stress on all the mounts and makes the system prone to hit the body. I have a very low car and I like it that way. So because of that I am designing my system to hug the body very closely and the only way I can do that is by not allowing for movement in the sytem. If I had no flex pipe then I would have to allow a decent amount of room for the system to move. Looking at it from a different point of view a decent flex pipe is only about 150mm and has a mesh on both the inside and out, that means its short and is no restriction.
Acoustic: I noticed that there seems to be a large amount of room for one of these after your secondaries come together and bend off on an angle. Theres a straight section there where you should be able to fit one. You exhaust definetly can't unhook itself if you put this in, that is unless u like to hit it occasionly.
lastly I remeber all exhausts are normally 1.6mm wall thickness so heres a quick chart:
2.0 inch O.D = 51mm O.D = 47.5 I.D
1.5 inch O.D = 38mm O.D = 35.5 I.D
so from now on could people quote inside or outisde diameter when the talk about pipe sizes (I.D or O.D).
So having a 2 inch O.D secondaries is way too big?
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Location:
Hong Kong
Registered:
November 2003
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Re: 20V extractor for sprinter?
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Sat, 04 June 2005 02:26
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Hi Sam
The formula is contained in a excel worksheet on my site in another link called xxx calculater. Did you find it?
The various rpm optimization is simulated hence various lengths are recommended.
Both 4-1 and 4-2-1 results are there.
2" is too big for secondaries.
My quoted sizes are out diameter, sorry forgot to explain.
The basic theory of octave lengths goes like this. If you have area "1" and length "A" to get higher one octave you'll need to shorted "A/2", to get one octave below you'll need "2xA"
If your area increased to from "1" to "2" then the original length of "A" will need to be "4xA" in order to maintain the same frequency / rpm
So, when you increased from 1.5" to 2" have an area of 989.789 versus 1772.055 respectively, which 2" is larger by 1.79 i.e. 79% larger - which is nearly 2 times.
In this case when you make a shorter secondaries it will optimize for higher rpm - what frequency I do not know because lazy to work it out, I recon - very high too.
Regardless, no matter how - a extractor is still a extractor it will still work. Just that weather you like the feel or not. I think.
I'm going to invite another friend over to share his experience using larger OD all round as he told me the fabricator was so amazed with the power delivery everywhere that he kept making them for sale. Dam, just lost all my royalty there
Hahahaha, oh well, it wasn't my formula to start of with
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Registered:
November 2004
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Re: 20V extractor for sprinter?
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Sat, 04 June 2005 08:45
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hi all,
i'm the one tht Acoustic was inviting.
my current extractor
was custom-made following the formula found in acoustic's site, but, mine is a little bit different from his.
and yes, the fabricator was shocked whn i showed him the simple sketching of the extractor i wanted to make. and after mine, he made more, which were exactly the same as mine.
length
primary: 34"
2ndary: 17"
O.D
primary: 1.7"
2ndary: 1.9"
final pipe: 2.5" all the way till muffler
mine was optimised for 6kRPM. but from Acoustic, as the pipe diametres vary, the power range will be changed. maybe it's no more 6kRPM but 7kRPM? not sure where it is now..
why did i choose to make one with 1.7" primary, 1.9" 2ndary, 2.5" pipe? it was beacause of this:
this was the photo i printed out, and i sketched another one which was exactly the same to be passed to the extractor fabricator. (TODA RACING's EXTRACTOR)
convert all the diameters into in" and u will find them to be 1.77", 1.96", 2.36". very close to mine...arent they?
and if u get a string to measure the O.D of the pipes on your computer screen now, then compare the length u measured using the string with the real O.D stated by TODA, u will get the scale for the drawing.
now, use the string to measure the length of the pipes, then multiply the measured length with the scale figure, u'll get the real length of the TODA pipes....
again, u'll find tht the measurements for my pipes are close to TODA's.
haha...tht's how a stupid + simple minded + poor person thinks. using an extractor made for heavily modded engines on a slow+stock engine. sigh...
btw, how does my car feel?
whn i start from 1kRPM, i can feel the engine goes freely till 2kRPM.
between 2kRPM - 3kRPM, it feels very heavy. so, at 2kRPM, u feel the car jerking. from powerful to weak....
then after 3k, it goes all the way till 5k in a very very short time. even if u r in 2nd gear, it's like revving the engine in free gear. wow~
but after 5k RPM, again, i face the same feeling like wat i had in 2kRPM. the engine suddenly feels heavy till the redline.
for the sudden power drop between 2k-3k RPM....i really have no idea. this, i must consult Acoustic. he may be able to explain.
for the power drop after 5kRPM, i think tht it's because of my stock exhaust. still using my stock Corolla KE70 exhaust while waiting for the performance muffler i bought from somewhere outside my town.
so, it maybe caused by the restrictive exhaust...<---i Hope!!
conclusion:
IF the formula is correct, which i strongly think it is...hehe
we know that TODA's extractor is optimised for 7kRPM.
hehehe~
here is the photo of my extractor: (for viewing pleassure)
so sad, poor guy doesnt have $ to make one using galvanised/stainless steel...sigh~
[Updated on: Sat, 04 June 2005 12:49]
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Location:
Hong Kong
Registered:
November 2003
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Re: 20V extractor for sprinter?
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Sat, 04 June 2005 10:48
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The power variations ???? not sure..... the few variables under suspects are
1) pipe a little bit too big.
2) I think it's not 7k. Lets calculate from 1.5" to 1.7" would be around 14.6% increase. To obtain the correct length it is approximately 14.6% times 4. This is wrong of course because it's not suppose to be a linear increase but logarithmic.
Anyway, I put my best guess figure that extractor is designed for around 8k rpm. With very useful range from around 6.5k to 9.5k
3) clutch slips - very prone on 20v using stock pressure plate.
4) flywheel heavy
5) muffler not match
I think......
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Location:
Hong Kong
Registered:
November 2003
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Re: 20V extractor for sprinter?
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Sat, 04 June 2005 10:50
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forgot to mention, the toda racing secondaries are way too short in reference to it's primaries. Basic theory from acoustics.
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Registered:
November 2004
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Re: 20V extractor for sprinter?
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Sat, 04 June 2005 12:44
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it's abt half of the primary's....is tht still too short?
cluth slip? hmmm..probably
but 1 thing for sure, between 3k-5kRPM, u can really feel the power. the car just zoom out suddenly...i like it.
i hope the power lost at 5krpm is caused by the restrictive exhaust.
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Location:
Borneo
Registered:
October 2004
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Re: 20V extractor for sprinter?
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Sat, 04 June 2005 23:55
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i was just wondering, since your extractor is designed like toda and obviosly its design for racing at high rpm, and you are getting power from 3k-5k. is it possible that you get the power at that range because of your stock muffler (if that is what you mean), being restrictive abit and produced lots of back presure so you get power at the lower end/mid range, and probably will lost that power when you get a performance muffler and cause the power to come at 5k-8/9k?
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Registered:
November 2004
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Re: 20V extractor for sprinter?
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Sun, 05 June 2005 13:33
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yeah...after changing the muffler, i will have no more power at 3krpm..
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Location:
S.E suberbs, Vic
Registered:
December 2003
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Re: 20V extractor for sprinter?
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Wed, 08 June 2005 09:18
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what rpm would my engine be tuned for if the primaries are 75cm? also should the secondaries always be half of the primaries?
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Registered:
November 2004
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I supported Toymods
Location:
Ademelaide, SA
Registered:
July 2003
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Re: 20V extractor for sprinter?
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Sun, 12 June 2005 08:28
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just one thing to notice on these, apart from primary/secondary lengths being out of whack, the collector after the secondary is of smaller diameter than the next section...notice how it tapers up after the collector.
an exhaust will only flow as much as it's narrowist point, yeh? so why did they put that tapered section in there? why go bigger past the collector?
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: 20V extractor for sprinter?
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Sun, 12 June 2005 08:36
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the thinking is that the narrow section creates a low pressure area due to the venturi effect, which will suck the other pulses out or something.
as for the lengths being out of whack, i think it is summed up in racing "look"
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I supported Toymods
Location:
Perth, WA
Registered:
May 2003
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I supported Toymods
Location:
Perth, WA
Registered:
May 2003
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I supported Toymods
Location:
Ademelaide, SA
Registered:
July 2003
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Re: 20V extractor for sprinter?
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Sun, 12 June 2005 10:26
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Ian, JASMA stands for Japanese Automobile Sports Muffler Association.
it's not a brand name.
it's like our Australian Standards thingo here...like a stamp of approval.
soz...pet hate
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I supported Toymods
Location:
Perth, WA
Registered:
May 2003
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Re: 20V extractor for sprinter?
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Sun, 12 June 2005 10:31
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oh ok,
i think theyre fujitsubo
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Location:
S.E suberbs, Vic
Registered:
December 2003
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Re: 20V extractor for sprinter?
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Mon, 13 June 2005 03:28
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TauhuTauhu: thanks for that
thanks for the pics guys, very interesting. Now the question now is that if it's so good to have such long pipes then why not make them into a 4-1 design? most of the jap companaies seem to have that idea, I think the RSR design looks good. Do people have dyno sheet or experience of 4-1 Vs 4-2-1 with the same length primaries?
Something else that really bothers me with extractor design is that when they take pipes off the flange at a steep angle, so many people are guilty of doing this. I know that there should be no more than 7 degrees of change of direction at any one time, so when a pipe is welded in on an angle to the flange it creates some pretty bad vorticies on the inside edge as a low pressure zone is devoloped. I made sure this wasnt the case with my design.
I am going to order some 1 3/4 stainless pipe and a 180 mandrel soon to do some more work. I will have to do most of the work though once the engine is in the car which will be a while yet.
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: 20V extractor for sprinter?
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Mon, 13 June 2005 03:39
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on a 16 valve, primary number 1 will pretty much always come out at a downward angle to avoid melting dizzy caps, but on a 20 valve you are free to have each pipe coming straight out of the head and gentler bends.
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Location:
S.E suberbs, Vic
Registered:
December 2003
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Location:
Ireland
Registered:
May 2002
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Re: 20V extractor for sprinter?
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Tue, 21 June 2005 10:58
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You guys probably know about this already but on a 4-2-1 make sure cylinders 1&4 merge together to form one secondary. 2&3 should merge to form the other secondary.
I believe bilzillas site details this common fabricating mistake.
I wonder though if theres an optimum pattern for 4-1 merges.
OO 14
OO 32
Something like the above??
Im a tad Bored today, just throwing ideas out there. Dont mean to hijack the thread. Excellent info, bookmaked AND downloaded.
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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kk
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Tue, 21 June 2005 11:27
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there is indeed an optimum entry order for 4-1, everything i have seen points to it being entering in a circle in order of firing order, like this
correct me if im wrong, but lets say the 4AGE firing order is 1,3,4,2 (i had a datsun 1200 once that was different)
EDIT: even if the firing order is 1,2,4,3 this configuration will still work, just the pulses will rotate in the opposite direction.
then the pipes will merge like this, following from your superb word art
00 13
00 24
in this case they are ordered in clockwise rotation, but im sure anti clockwise would work too, as rotation it is perpendicular to the ground and the correalis force will have no effect 
they merge like this so there are no uneven pulses, otherwise you would have diagonally opposed pulses coming out and side-by-side pulses too.
im interested in making a set of 4-1 extractors using small diameter pipe joining the primaries to each other, like you see on some motorbikes, but i need to look into the science behind this first.
[Updated on: Tue, 21 June 2005 11:30]
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Location:
S.E suberbs, Vic
Registered:
December 2003
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Re: 20V extractor for sprinter?
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Wed, 13 July 2005 02:36
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hey guys is there any chance you can explain to me how to use this forular to work out the length of my primaries? maybe with an example of 80cm? or 6000rpm?
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)
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