extractors questions
how do extractors work? are they simply batter flowing exhaust manifold? how much power do they really give you? lol and whats with the pipe goin from the exhaust to my efi intake? lol seens a little backwards like cold air intake gives you better power because the particals are closer together when cold therefore putting more fuel and oxygen into the same area. so the exhaust going to the intake would be woking opposite to that lol
captain halfajob
the pipe is the 'heat riser' and helps you on startup on cold mornings by feeding exhaust temp (just temp, there isnt any gasses flowing its attached to the outside of your exhaust manifold) dunno much about EFI but on carbs the TVS (thermal vacuum switch) should shut it off when it gets to operating temp.
extractors are a debated topic on here. i mean, they WILL make a performance increase, thats not in question, but there are varying opinions on how they work. this could get really complicated...
MY UNDERSTANDING, im not saying im right, this is just what i been told:
your cylinders are a certain volume, lets say for example you had a 1 litre per cylinder X 6 cylinders, so a 6 litre engine. the volume of gas that fits into that is a certain mathematical equations that i cbf learning. once it is compressed, then burnt, that gas reduces size. the rule of thumb i been told is it reduces by a third, so now you have 666cc's of burnt air/fuel as a gas. the primary pipe leading from your engine needs to be 666cc'c to fit the first charge of burnt fuel/air.
k, now that the charge is in the primary pipe, it will be heading towards the collector (where the two pipes meet) the collector should be the exact opposite cylinder to the first, so lets say for example 1 was your first charge, then maybe 3 would be next (depending on your firing order, it needs 2.4.5 and 6 to all go b4 3 if that makes sense) the first charge passes the collector and ALSO reduces size due to heat dissapating and creates a small vacuum behind it which actually SUCKS the next charge out of number 3 (as per our example), thus the name EXTRACTORS cos' they exctract the next charge.
further down the exhaust requires all sorts of other physics equations relating to the size of reduced temp gases etc and i dont know what they are, each collector will need to be cut to a different length due to the amount of heat lost along the way.
but i do know that exctracots make your car "fully hektic"
edit* i made a little drawing. the primary pipe needs to be 666cc, so the secondary should be 1332cc cos there are 2 pipes leading to it, but it isnt cos' the gas has reduced size, so it'd be more like 1000cc's or so, then the exhaust should be 1000cc time 3, but again it isnt cos heat has reduced further, making the gas smaller again.
understand?
Donating Member
Extractors are generaly only cut to make fit the easiest, yes they will be better than cast headers.
To get best performance you would ask for tuned length extractors.
As stated above they can help by " Extracting Gas "
Tuned length work as the pipes are cut to special lengths and when i high pressure wave goes down the exhaust and into the collerctor it passes the other pipe in the collector that should have a low pressure wave in the collector therefore scavenging the exhaust gas and drawing it out the pipe with the low pressure wave and each pipe does this in turn to the pipe next to it.
To gain maximum effect generaly it is advised to have a modifed camshaft to help in this proccess.
A camshaft with valve overlap mean both valves are open at the same time which allows the extractors to draw any excess exhaust out of the combustion cylinder and also draw a bit of new fuel and air as well therefore flushing out the cylinder and accepting a fresh charge without it being contaminated with unburnt exhaust gas's still in the combustion chamber.
Well i hope that sorta makes sense because there is alot to it if you want to gain maximum performance out of your engine.
In saying that a stadard set of extractors will still be alot better than a cast iron manifold.
wow thats way more complex then i was thinkin! very smart thinkin there! so the standard extractors on my vk any good? are there any better after market ones? recomend a cam that would give me this overlap? im lookin to make this engine setup very quick off the line and very torquey. im happy if it only gets to like 140 as a top speed. any suggestions?
captain halfajob
if you want torque then i dont think a high overlap cam will suit you cos' generally they are geared around top end HP, rather than hitting good torque figures down low. you would be more looking to wards a 'tow-cam'
of course, if you decided to get a tall diff, really high stall and make your engine a revvy monster then you will be fast off the line.
na not lookin at high reving just lots of hp just quick and light and responsive gonna be like a sort of sleeper. nothin lookin too fancy but give it a poke and catch ya later lol not lookin to take on v8s but be good to have the off the line speed to give em a scare then il back off lol they will be like what just happened. the exhaust set up on it sounds like a v8. nice and deep and lumpy! not hell loud but.
Cammed & Eventualy Blown!
lol i dont think a 202 would give the 5.7 & 6L's a scareOriginally Posted by vktorana
hey dont diss the 202! just standard i could hold with a worked 253! till about 80k's then it would pull away! i know 253s aint nothin to a ls1 or hehe i have a thing for the ls7! but i gonna be puttin it in my torana and strippin everything out of it! so very light. i recon if i work it right il at least make v8 drivers go "what the **** is wrong with this picture!"
Cammed & Eventualy Blown!
lol kk mate (i wasnt dissin the 202s btw lol) i didnt realise it was going into a stripped out torana, have u got a thread up for the build? if not ya should
lol i know ya wasnt dissin i was just puffin my cheast out lol i tell eveyone my 202 would beat a lambo if i wanted it to! just protective! :P got 3 of em now! lots of mats went and swapped bigger engines in thier cars and pretty much gave me thier old 202s! yea i dont know what builds i have up and what i dont! got 3 motors and only 2 cars! got my vk which i still cant even get back form adelaide and my first car which was a uc torana! could never get rid of my first car! served me well! lol god i better stop bablin on now!
captain halfajob
i would rather a 4 cylinder to a 253...
there is no cheap way to get power, power usually comes with revs. building your motor/driveline to rev is the only way to get power sadly, cos' its missing a couple of cylinders and about 2 liters.
fair enough ari. i dont really want it to rev too high because that means getting stronger pistons valves rods everythin lol. would it be possible to mayb get a supercharger and tune it for low revs up to say 5,000 rpm?
lol this is makin me wanna just say **** it and do the ecotec conversion!
"Fully hektic"
ROFL!!!! Thanks, needed that...
captain halfajob
*sigh* whats wrong with a 308? what is the deal with everyone on here wanting to do that conversion WHATS WRONG WITH YOU PEOPLE!!!!
lol.
Exhaust Guru
The little pipe going to the intake manifold is actually the EGR pipe. It recirculates exhaust gas. It is all to do with the emissions laws from the era of the engine.
so it is pumping shitty air into my fuel? can ya like leave it off or somethin?
Exhaust Guru
It is recirculating some of the exhaust gas to be reburnt to try and cut down on emissions. Yes, you can leave it off and block it up.
haha ok so weld it up? cos would look out of place just hangin off!
Exhaust Guru
What I have done in the past is weld the inside of the pipe blocking off the hole in the flange, then bolt it back up so it looks like it is still connected, but nothing can flow through it.
i was thinkin get a piece of sheet metal and cut it shape of the end where it conects to the intake so it just covers it over! then bold it on nice and tight. is toing this gonna effect the was the extractors work? because there will be more gasses goind out the pipes, will this screw up the whole gasses volume ect?
Exhaust Guru
No it won't affect it.
sweet il block it off then lol
Mine is blocked off with a blanking plate. It only recirculates exhaust gas on off throttle (high vacuum and engine up to temp - check out the hoses to the valve) I believe, so I don't really think having it disconnected makes any diff to performance. Correct me if I've got this wrong. Mine came blanked and I haven't bothered connecting it...
ok mayb il leave it! man talk about decisions! lol
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