Hello forum peeps this is my third post but i am a long time reader, i am by no means a car newb, i am part of the golf mk1 forums and i take pride in my car.

I've been doing alot of reading regarding weber 32/34 carbs, I want to convert my golf GF block to twin barrel carb, which is not a problem, i already blocked the exhaust ways and removed the piping that leads back to the exhaust manifold, i got my self a manifold off a 1.3 mk2 polo and all the neccessary adapters/plates for weber, i got a weber 32/34 DMTL for a vauxhall astra/cavalier 1.3, but i want to rejet it for mine, now I've been doing alot of searching on this and clubgti forums regarding jets but everyones mixed and matched theirs, so I'm confused and dont know what jets to run i was hoping someone may have the OEM jets list for a 1272cc vw engine,

These are the current jets on the carb now

Primary.

Main - 117

Air - 200

Emulsion - f22

idle - 55

pump jet - 45

Secondary

Main - 125

Air - 165

Emulsion - f25

idle - 50

What do you guys think i will need to change for my car to run nice and sweet?

Cheers.

Edited 12 November, 200718 yr by BiG_J

right at the top of this forum theres a pinned topic for webers..it should eventualy be a faq for those fitting a weber

Judging by the jet sizes you have 24/25mm venturis so I'd go for something like this:

1st stage

Main - Keep original or maybe go up to a 120

Emulsion - F30

Air - 165

Idle - 45

Pump - Keep original

2nd Stage

Main - Keep original

Emulsion - F30

Air - 165 or above

Idle 70

These settings worked well on my HH (basically the same as GF)

Cheers Gaz,

Did you randomly choose these jets? Or was you experimenting with different jets or did someone recommend you these jets?

Did it ever overfuel, bog down at certain revs and throttle etc with those jets? How was fuel economy?

Sorry if I'm asking too much questions but i rebuilt my driver 2 months ago, it was running sweet until that shoddy solex carb decided to 'fail', it will rev eractically (revs will go up and down on its own, was overfueling etc) I haven't even driven it or wore it in yet, i planned on doing the weber conversion anyway so it was my perfect excuse but i want it to run right, i dont want no overfueling or underfueling business otherwise its gonna destroy my block, wash down the bores and seize etc.

Has anyone else done a weber conversion on a HH or even GF, if so i will like to know how it runs and what jets your running.

Cheers.

Cheers Gaz,

Did you randomly choose these jets? Or was you experimenting with different jets or did someone recommend you these jets?

Did it ever overfuel, bog down at certain revs and throttle etc with those jets? How was fuel economy?

Sorry if I'm asking too much questions but i rebuilt my driver 2 months ago, it was running sweet until that shoddy solex carb decided to 'fail', it will rev eractically (revs will go up and down on its own, was overfueling etc) I haven't even driven it or wore it in yet, i planned on doing the weber conversion anyway so it was my perfect excuse but i want it to run right, i dont want no overfueling or underfueling business otherwise its gonna destroy my block, wash down the bores and seize etc.

Has anyone else done a weber conversion on a HH or even GF, if so i will like to know how it runs and what jets your running.

Cheers.

It was through my own experimentation with the help of an air fuel ratio meter and a lambda probe. (so I know the mixture is about right) I had the first stage pretty much nailed (picked up quickly and smoothly with no bogging down, Started up nice and easily both cold and warm etc) but the second stage was a bit more troublesome. I ran a 130 in for a while and changed various air correctors but eventually settled on the 125. The second stage can be very hit and miss as it can vary between engines depending on what manifolds are fitted and so forth. For example I have the bigger continental GT manifold (GK engine code) so it can flow better at higher rpm than the HK/MH/2G one, which means the 2nd stage jets I ended up with may not be quite right for your car and you may need to weaken the mixture a bit with a bigger air corrector (hence 165 and up) :)

MPG was very good, over 45mpg average when I went to belgium in it. And it regularly got 40+mpg. But I tend to use the derby for shows so it only goes on long runs. MPG may be less day to day, but certainly alot better than it was on the old solex!

are there any sites anywhere that give any advice on jetting etc? i kinda get the jets bit but how do you know what emulsion tube to use with what etc

Wow impressive mpg hope i can get the same,

you say it depends on engine setup, my engine as follows,

My block is complete standard apart from polished/smooth piston tops, my head has had quite a bit of work, inlet and exhaust valve ports been opend/ported and polished, valvle throats been reworked, i enlarged and rounded the chamber on the combustion for a better 'squish' and also cut v grooves on the chamber, and a standard polo mk2 1300cc manifold (small port) apart from the that everything else is standard cams, exhaust etc...

I will try the jets u suggested, i got to get them ordered first and i will let you know how it goes.

Cheers.

are there any sites anywhere that give any advice on jetting etc? i kinda get the jets bit but how do you know what emulsion tube to use with what etc

The weber DATR is an auto choke version of the DMTR and is quite popular with fiat x1/9 owners so if you have a look around on the web there should be some info about jetting those (they also have a 1300cc engine so the jet sizes will be comparable) I think this is where I got the idea for using an F30 EM tube from in the first stage, the F22 and F25 em tubes were miles too rich.

Also my fuel economy was probably helped quite a bit by fitting of a 5-speed economy box. :)

Just having a look through my bookmarks, I have quite a few relating to carbs, so here they are:

http://www.aircooled.net/gnrlsite/resource...les/jetting.htm

http://www.norrismotorsport.co.uk/nacvhcarburetors.html

http://smg.photobucket.com/albums/v328/Joh...arb%20pictures/

http://archive.mirafiori.com/show.php?fid=6&msg=5700

http://members.aol.com/dvandrews/webers.htm - about twin 40s but still useful

Right!

It's been a while but i finally got the carb on the engine, its been jetted with the jets u suggested which are,

1st Stage

Main - 120

Air - 165

Emulsion - F30

Idle - 45

2nd Stage

Main - 125

Air - 175

Emulsion - F30

Idle - 70

The engine fires up fine and idles ok when warm, when cold the choke has to fully up for it to warm(needs adjusting) and takes a while for it to warm until i can leave it idling without stalling, biggest thing that bugs me is that while idling if i rapidly open the throttle it bogs right down (on the verge of switchin off but actually has stalled 2 or 3 times) then picks up again and revs, the exhaust also pops on heavy acceleration in high rpms and on deceleration.

Somethings definatly not right, so what do you guys think that needs adjusting? The CO idle crew? Jets? Other? Possibly timing even (I'm 98% sure its correct) but il check anyway.

And i woudln't say that my manifold is completely standard would that play a part, heres some pics so you understand what i mean,

Cheers.

Edited 9 January, 200818 yr by BiG_J

Anyone? Gaz?

I'd stick to the original jets they looked about right to me for the capacity. e.g. .55 idle jet. There should be a base setting for the mixture, 1.5 turns out? You should be able to adjust when the second choke opens too which is often a cause of flat spots. I would check the igntion timing with a strobe light, it's impossible to tune the carb if this isn't right and check for air leaks from vacuum hoses etc. Also, are the jets in good condition, people can't help sticking pins in 'em! This is stuff I discovered on Sciroccos.

Anyone? Gaz?

First check your ignition advance, if it's too far either way it can cause running problems, although if it's run perfectly fine before and you haven't touched it since, it's probably not that.

Double and triple check your inlet manifold gaskets (those after the carb) incase they are not sealing and causing a misfire agitated by high-vacuum conditions?

Also adjust your CO needle which, if you don't know where it is, is right at the bottom backmost side of the carb (approach it from the passenger side, lean right over and there'll be a screwhole at the baseplate of the carb which you can put a thin screwdriver into and adjust the idle needle).

With the engine at operating temperature, adjust this needle clockwise (tighter) until the engine begins to slow down a bit due to a lean mixture. When this happens, stop, then turn the needle anti-clockwise about half a turn, and you've got the optimal setting, provided your idle RPM control screw (much more noticeable, backside of the carb again.) is set reasonably OK. Fiddle with the two, alternating between them.

Yea thats what i thought too regarding the idle jet, as the carb was already jetted for a 1.3 vauxhall engine, i haven't played about with the mixture yet as i dont have a CO reader, ignition timing may need adjusting even tho its neither on advanced or retarded its in the center, theres no air leaks as i blocked the vaccuum pipe on the manifold temporarily, its using new gasket, the carb flange/plate is sealed up with gasket, its 100% air tight and yes the jets are in good condition as they are brand new from fast road cars, il have a proper tinker around during the weekend, but for the meanwhile any tips and help is welcome please.

Cheers.

P.S do you think i should change both primary and secondary idle jets with 55 and 60? or 55 and 70? or 60 and 70?

These are the jets for a 1.3 nova (SR maybe not sure?)

1st Stage

Main - 117

Air - 165

Emulsion - F30

Idle - 55

2nd Stage

Main - 125

Air - 165

Emulsion - F25

Idle - 60

Ok, i changed the idle jets to

55

60

I also played about with the CO screw as the way danny lee suggested, once warmed up it idles very nicely now,

but still when i rapidly open the throttle it bogs down not as bad as it used to tho, otherwise its ok, it doesnt happen all the time only when sat on idle for a while, but i still think it running rich as i can smell it from the exhaust, its not coughing black smoke but it does smoke when revving at higher rpms, do you think i should go down on the main jet to 117 or 115? Or go up on the air jet 175, 185, 200 on 1st stage?

Edited 11 January, 200818 yr by BiG_J

Dunno about the F25 .. what's the wall thickness compared to F24 or F22?

I removed a stumble on a 22/22 DMTR by fitting a larger pump jet size 50.

(but I also use F30 in both stages and very lean 2nd air corrector 210).