make my brumby go harder!

birdy · Post by **birdy** » Sun Jan 29, 2006 10:26 am

hey guys, now that i have a working motor, what are a few simple and cheap things i can do to make the ea81 go a bit harder, and how much fuel efficiency do i have to sacrifice?

xaymaca · Post by **xaymaca** » Sun Jan 29, 2006 10:38 am

Best place to start would be here!

http://www.ausubaru.com/main/modules.ph ... opic&t=414

GTlegs · Post by **GTlegs** » Sun Jan 29, 2006 4:24 pm

In addition to the above, if you get a dual carb manifold, and put twin DGV 32/36 webers on it, your car should go much faster!

tim_81coupe · Post by **tim_81coupe** » Sun Jan 29, 2006 7:18 pm

I seriously doubt that, GTLegs. I hardly think two Weber's would make any increase in power, the Weber is that much bigger a carb than the Hitachi. You'd have flow problems in the manifold & heads well before needing to upgrade from a 32/36.

AndrewT · Post by **AndrewT** » Sun Jan 29, 2006 9:57 pm

Of course there is the REALLY cheap mod you can do to the standard EA81 carby......"The Wire Mod".

I beleive you get a piece of thin handywire and stick it in a certain place which effectively changes the secondary jets from vacuum operated to mechanically operated.

Not too sure on the particulars, somebody who's actually done it could go into more detail

simmo · Post by **simmo** » Sun Jan 29, 2006 10:24 pm

speakin of the wire carby mod... my carb is different?? i thought it was original hitachi but i must of been wrong. there is no mechanical part to the secondary pipe.. i guess it only opens when there is enough pressure in the intake manifold....

subanator · Post by **subanator** » Mon Jan 30, 2006 12:31 am

That is how the standard Hitachi works - vacuum operated secondary butterfly! You need to over ride that by using a piece of wire to the primary linkages so they operate in unison. (not sure if thats correct as I havent done it myself, only seen the mod on posted on this board. The mod may mimic as described below)

The Weber secondary is staged to open proportionally at a percentage of the primary movement. The 32/36 DVG Weber is around 300CFM, a max flow that would not be achieveable as Tim said for those reasons.

birdy · Post by **birdy** » Mon Jan 30, 2006 8:42 pm

tahnks fellas, what would one of these carbs cost? Bearing in mind that i am a chippie and i am severly mechanically challenged, would i be able to install one of these myself?
thanks again for all the advice.

tim_81coupe · Post by **tim_81coupe** » Mon Jan 30, 2006 10:41 pm

Very roughly I'd say about $200. ~$50 for the carb from a wrecker, ~$50 for an adapter plate, ~$50 for a rebuild kit and ~$50 for the unknown. Cost starts going up if you can't rebuild it yourself, I'm lucky enough that I've never had to rebuild a carby (always kill the motor first

) so I can't really suggest what it would cost.

birdy · Post by **birdy** » Tue Jan 31, 2006 2:57 pm

good place to start, thanks mate, im off to the wreckers!

steptoe · Post by **steptoe** » Fri Feb 03, 2006 2:54 pm

Birdy, just think of the carby as a house with bits n pieces inside.

Take photos of before and during dismantle, take note of the jets sizes numbers and where they came from and where they go back

You can use (your own) chisel to scrape off old gaskets, prepsol or thinners like in laminex work is good to clean the metal parts in only (not the rubber bits, diafragms etc). Soak em and use your compressor to blow clean and dry

Straight and philips screwdrivers - you'd have them on your tool belt ! is usually all you need to undo things

Better still just find a mechanic that needs a pergola built or sumptin'

Just kidding, have a go, get a kit and if you get stuck jump in here and some one sure to help

birdy · Post by **birdy** » Sat Feb 04, 2006 8:17 am

its all so much clearer now! lol

steptoe · Post by **steptoe** » Mon Feb 06, 2006 10:10 pm

saw a guy the other day in an Aussie flag blue Brumby UTE89B tear arseing around, sounded good, went well. I suspected a nice mod providing his motorvation. Nuh, stock EA81 with head work and exhaust mods.

I was impressed.

There you go, find a set of heads, get em opened up a bit and serviced and see how you go. EA82 Y pipe / header pipe is said to be the go and a 2 inch zaust !