ive found 2 carbs atm, a holley 350 2 barrel and a holley 500 2 barrel.
is there a better type of carby, or is there any problems about putting either of those carbys on my car? i have a GL scorion with a astron 2 motor.

well, ud prob get a better reponse from sigma-galant, but meh
imo, the 500 is abit overkill, i know a guy with a 600, but he has some pretty decent mods,
the 350 is quite a decent size.
u could put the 500 on, but either A get some mods or B rejet it.

what type of mods should i get if i get the 500?

shaved head, cam, zorst, pistons perhaps, better fuel pump.
etc.
just mods that would utilise the extra fuel.
but as i said, u can just replace the jets.
the 500 is ok if your looking at modding the engine a fair bit later on.
the 350 i more a sensible carb to apply now and not have to spend extra just to make it feel at home.

i think the 500 would be way overkill for the size engine unless u run very high compression and a wild cam
my mate has a 570 holley with smaller jets running on his very heavily modified VH commodore and even with the mods it runs like **** cause it gets way too much fuel.

better off with a 350 holley or what i recommend is get a weber 34 ADM(XF falcon carb) i bought mine completly rebuilt off of ebay for about $160 that does the job nicely and will be more than adequate for future mods.

I think running a Holley on a Magna is pointless, get a Weber off of an XF and convert it as TM-SE-RED did (change the jets etc), they are an easier and cheaper carb to fix when they break and they aren't overkill for the engine.

You could also dare to be daring and convert to EFI, it is not that hard.

I have a Holley600 on my Mitsubishi Sigma 2.6 II. It is overkill, what you need to do is work out your maximum CFM, @ 7,000 rpm a mitsubishi's maximum is only 308CFM. I know those ford carbies work, but I am not sure about fitting a 4 barrel on a magna with the different manifold positioning.

I am currently in the process of downgrading to a 450, even though I wanted a Holley390, it was a 500 buck difference and I got a bigger carby for less, so explain that!

Anyhow, if you want a big carby, basic starting point is your Cam, and work your way from there. Its taken me almost 8 months now and the car isnt properly tuned, but its just about done.

Hope this helps,

Ben
-------------------------

1984 Mitsubishi Sigma '4G54' = I kill commodores

cheers for the help! im pretty sure im gonna go with the 350, its had the jets changed to suit a 4 or a 6 cyl engine and has been cleaned, rebuilt and recoloured.
got a reground cam coming in atm. hopefully can work out some more mods to do to it soon.
thanks for the help!

cool,m post some piccies up when ya do, despite not being a magna. but i love the scorps.

only bought the cam atm, got it second hand for $61 off ebay(not too many people looking for them i spose?), thinking of buying the holley 350 performance carb for about $350-380(dont know if they are overcharging but has been suited to a large 4 or a small 6 for best air intake).
still need to get some extractors etc... but not too sure on the price, also want to get a few other things done, but will figure them out as i go along.
what other sorts of mods can i make to it that are worth while(being n/a) and maybe some aroundabout prices?
cheers!

so u have the larger carb and have a cam coming.

i would suggest getting extractors and exhaust system next if u dont already. think about it... u are getting a larger fuel/air ratio into ur engine through the larger carb, and the mild cam is letting the mixture in for longer and exhaust gases escape out for longer and so creating more power that way. though there are more exhaust gases being pushed out, there is no improvements in the manifold and/or exhaust to help the exhaust gases escape quicker. so thats the reason for the extractors (on a 2.6L a 4-2-1 design is best) and exhaust (with big mods happening like carb, cam etc i would suggest AT LEAST a 2.25" mandrel bent exhaust. press bent is a waste of money and for ppl who want noise over improvements)

after those 2, i would consider a good Cold Air Induction kit, the carbys love the cold air. i have a smallish scoop sitting right above my carb, and the difference between night time to day time is phenominal. then youll want to look at things like compression ratios, port matching and flowing the manifolds... fueling. get urself a better fuel pump and fuel pressure regulator. thats getting pretty hardcore though, wen u start to pull ur engine apart to flow things to get an extra 10kw from it or something. thats all ive got atm

brendan

mandrel bent is a waste of money unless your goin turbo as the gains over press bent are very minimal when NA, and 2 1/4 is the BIGGEST i would suggest for the astron when it is N/A

mandrel bent is a waste of money unless your goin turbo as the gains over press bent are very minimal when NA, and 2 1/4 is the BIGGEST i would suggest for the astron when it is N/A

i agree, i have 2 1/4 and its plenty for this size engine
loud enough to sound nice/borderline too loud. ive heard my dad driving the car from 300-500m away and he wasnt even driving it hard. it was ***g loud at the dyno day :badgrin:
any higher and it would be too "ricey" and have no back pressure

mandrel bent is a waste of money unless your goin turbo as the gains over press bent are very minimal when NA, and 2 1/4 is the BIGGEST i would suggest for the astron when it is N/A
yeah 2.25" is what what i have, but mandrel bent, got it close to same price, so just looked nicer :nuts:
but yeah, with the carb and cam, exhaust, the list goes on, depends which direction u wanna go also.

mandrel bent is a waste of money unless your goin turbo as the gains over press bent are very minimal when NA, and 2 1/4 is the BIGGEST i would suggest for the astron when it is N/A

y not go mandrel bent? it dosent cost that much more and if u decide in the future that u do want to really mod the car, then u already have the exhaust for it. dont think for now, think for the future. otherwise you wouldve spent twice as much money wen u couldve got it done right the first time.

and 2.25" is definately the biggest u would want on a stock magna, even 2" is heaps for stock. wen u start doing mods like a larger carby (or twin carby especially), wild cams, headwork etc etc, u could get away with 2.5" because of the amount of exhaust gas being created over stock. my car has 2.5" and is too big but i dont have any hardcore headwork or a wild cam in. so dont just think large diameter exhaust for forced induction... big N/A mods also need a larger diameter exhaust to help with the flow and extraction of exhaust gases.

TM-Terror - can i take a guess and say u have a press bent system if its that loud? if not, u dont have a mid muffler or the like in. and there is no such thing as that back pressure.

yeah both press bent exhaust and im running without a resonator. what do u mean there is no such thing as back pressure ? you need a little bit back pressure in the exhaust to help to keep noise levels down and it improves low rpm torque. so if you go too overboard with a large diameter zorst u loose bottom end drivability

yeah both press bent exhaust and im running without a resonator. what do u mean there is no such thing as back pressure ? you need a little bit back pressure in the exhaust to help to keep noise levels down and it improves low rpm torque. so if you go too overboard with a large diameter zorst u loose bottom end drivability

press bent is louder then a mandrel bent system. and can sound much ricier, because of the poor quality bends in the piping. forget the reasoning behind it but its a fact.

and backpressure shouldnt b used... exhaust velocity is a much better word for it. im sure we mean the same things but our wording is different.

read this post if u havent already... myth of back pressure (http://www.aussiemagna.com/forums/showpost.php?p=235060&postcount=20)

it refers to hondas, but thats only cause it was taken from a honda site. it refers to all cars, and im sure youll find out after reading it

hmm intresting read
we both meant the same thing i just thought it worked a bit differently to that