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Oppressa Officially Full-On Dubber

367 posts · joined Oct 2002 ·

#62928


Looking at the above pic, what do each of the numbered screws do. IE air, fuel, etc. and also what does turning clockwise and counter clockwise do on each?
Thanks
1971 VW Beetle
Currently being restored - click here

Baja Wes V6 Baja Pioneer

3,119 posts · joined Aug 2002 ·

#62933
Screws 2 and 3 are idle (low speed) mixture screws. Screws 1 and 4 are air bypass screws.

1 and 4 are used to set the air bypass, they would normally be almost closed. The idea of having one on each throat is so you can open one more than the other if need be to balance the air flow through each at idle. Basically compensate for manufacturing tolerance differences between the butterflys and how tight they seal in each throat.

So to set 1 and 4, screw them all the way in (loosen the lock nut first). Then screw them both out about 1/4 of a turn (having them open too much will make the idle too high even when the throttle is closed on the stops). Then start the engine, if you have a uni-sync or similar your job is supposed to be easy (I bought one and it sucked). The next step is to open or closed one of the screws slightly to balance the air flow at idle through each throat. The easy way is to pull both spark leads off on one side, see how it idles, then do the same and see how it idles. It the difference is uneven then you need to adjust one of the bypass screws until it is even. Once it is set you should never have to touch it again.

2 and 3 are used to set the low speed / idle mixture. The easy way is to set them to about 2 turns from the bottom as a ball park. Start the engine (let it get to temperature). Screw one screw and until the idle drops, then out until the idle drops, somewhere in between will be the highest idle point. That is where you want to set that screw, where the idle is highest. Sometimes slightly in from that point is best. Trial and error. If it still doesn't run right then you need to change the idle jets. Do the same for the other screw.
Wes - www.offroadvw.net - 200HP Quad Cam V6 in a VW Baja - with climate control... 🙂
www.taylorcycles.com.au - My DH MTB racing brothers shop.

Oppressa Officially Full-On Dubber

367 posts · joined Oct 2002 ·

#62936
Awesome. Thanks!
1971 VW Beetle
Currently being restored - click here

NigeType3 Officially Full-On Dubber

371 posts · joined Dec 2002 ·

#62974
Hay Wes is there someting I can read that you would recommend for tuning Webers. Thinking of getting twin 40 IDF's for my 1641 do ya think it would go OK. Want to do all work myself so any help would be great.

Cheers Nige:thumb

NigeType3 Officially Full-On Dubber

371 posts · joined Dec 2002 ·

#62994
Wes you got any other sugestions to get the thing moving a bit quicker. Other than chucking a V6 in it. Youve been doing this longer than me any advice is apreciated.
Cheers Nige:thumb

NigeType3 Officially Full-On Dubber

371 posts · joined Dec 2002 ·

#62995
Thanks Blue74 will check them out to.
:thumb

Bizarre Moderator The artist formerly known as blue74l

12,787 posts · joined Aug 2002 ·

#62997
NigeType3 wrote:got any other sugestions to get the thing moving a bit quicker.
Do a full tune BEFORE you go to duals.
NEW
leads
plugs
cap. points rotor
*COIL!!!*
etc

Set valves and timing

I got caught badly when i put mine on. The coil was a dud but ran with my old set up. With the IDF's it broke down and backfired and popped. Behaving both lean and rich. Went whacko till Greg Ward solved it for me.

Also be jet prepared. With stock heads
130 mains
180 airs
F11 tubes
will see you right.

Idles are what the car wants. Be prepared for anything between 45 - 55. My IDF 36's have 40 idles. Why - no idea but my sweet spot is 1 1/2 turns out so it is right. It may be because they dont have accesible air's but anyway.

Make sure you have access to adjusting the screws before hand.
Have a look at a car already set up and see how you are going to do jet changes and adjust the mixture screws.

Have fun
Futue te ipsum!!!

NigeType3 Officially Full-On Dubber

371 posts · joined Dec 2002 ·

#62999
Yer thatle be fun its had enough getting access to anything on a T3 then alone puting bigger carbs on.
Won't be for a while yet just doing my homework first.
Will have to check out some other cars
Cheers Nige:thumb

Bizarre Moderator The artist formerly known as blue74l

12,787 posts · joined Aug 2002 ·

#63000
Have you bought them yet???

Are you buying new?????

In not and buying

2nd hand - consider IDF36's. Cheaper and use same hardware.

new - consider IDF 44's. Can still work on a 1641 and much more growth potential
Futue te ipsum!!!

NigeType3 Officially Full-On Dubber

371 posts · joined Dec 2002 ·

#63004
Looking at buying new so that ill have les problems with them.
With the 44's do ya just jet them down to suite as I would like to get a large motor in a year or so just need beter accelleration NOW. I get bord easily
Cheers Nige:thumb

Bizarre Moderator The artist formerly known as blue74l

12,787 posts · joined Aug 2002 ·

#63006
You need to vent them and jet them accordingly

I run 32 vents in my 36's

40's come stock with 28's - but can go to 34's or 36's

44's will go to 38's

That means you can put some gig valved heads in there.
I am probabally limited with my 36's at the level i am.

In the US 40's and 44's cost the same.

Check out

http://www.aircooled.net/new-bin/viewproductdetail.php?keyword2=FSK0020&cartid=0702200358226507

John Conolly will jet them to your liking

@ $675 US that is $1k aus. Even with shipping and tax that is well under $2k
Futue te ipsum!!!

Baja Wes V6 Baja Pioneer

3,119 posts · joined Aug 2002 ·

#63013
I agree, if your buying new then 44IDF are the way to go. They will run fine on a 1641 if jetted and driven sensibly (you can't flatten the at 600rpm and expect it to accelerate).

I used to run 44IDF's on my 1915, they were a good carb. Just use a couple of decent fuel filters, and a good quality air filter. The webers are sensitive to crap and the idle jets clog easily.
Wes - www.offroadvw.net - 200HP Quad Cam V6 in a VW Baja - with climate control... 🙂
www.taylorcycles.com.au - My DH MTB racing brothers shop.

NigeType3 Officially Full-On Dubber

371 posts · joined Dec 2002 ·

#63703
Thanks all thats what I wanted to hear. Anyone have any ideas about the head changes I could perform before I get the carbies. Will probabley do all at once.
Right now im running std heads which have been ported & polished by my mechanic who tunes formula 'V' racers.
He dosn't like the idea of me using webers though so Im keen to do it myself.
He built the engine for his son and since I bought the car he dosn't like me changing it from the original idea.
Anyway any head info would be great thanks Nige.

Bizarre Moderator The artist formerly known as blue74l

12,787 posts · joined Aug 2002 ·

#63715
this is for the 1641??

Well big valved heads aint goint to do much with stock cams etc etc.

If anything bump the CR to say 8 to 8.5:1
Get a 3 angle valve job and match port the manifolds to the heads and probabally leave it there.
Save the $$$ for cc's later.
Futue te ipsum!!!

NigeType3 Officially Full-On Dubber

371 posts · joined Dec 2002 ·

#63834
Blue I have an eagle 110 cam ported and polished heads w/-CR at 8.9:1 but with std carbies and air cleaner it dosn't go that hard and I would like to rectify this.
Plus the car itself is noew going on a diet hehehehehehehe
what do ya recon Nige

Bizarre Moderator The artist formerly known as blue74l

12,787 posts · joined Aug 2002 ·

#63849
Diet is good

every 50kgs you pull out is like 5 ponies at the wheels
Futue te ipsum!!!