ShopTalk Forums | Aircooled VW Tech & Restoration Help

hello,

i have 2 36 IDF italian webers and i want to put them on my 1600cc stock engine.
can u suggest me what size of jets should i use and what performance should i expect from the engine performance with the 2 carbs?

the carbs have now the idle jet 52,main 135,air 220,venturie 30 and emulsion tube F50

thanks,

silviu

Mark Harney wrote a great article on converting the 36 IDF to ACVW use. Not finding it, anyone mirror that?

i'm looking for his article for about 2 months but i can't open teh web page...

We were looking for the same thing

There are "some" bits off info here from harney on the Samba
http://www.thesamba.com/vw/forum/viewto ... df+jetting

I have no idea how he got them to work with large idles

Mine were set up as
F11
32 vents
135 mains
45 idles
cant remember airs

Was ok but idles blockes at least once a month
At least the idles are on the top

I'm not familiar with F50 tubes, usually F11s are used for dual-carb ACVW applications...but it sounds like you're close enough to run, and base any changes upon plug readings. You can't expect a huge performance increase (I'm assuming you're already running a less-restrictive exhaust) but with a stock cam and compression ratio there's not a lot to be gained. Once you get the jetting dialed in the mileage may actually be better than with a stock 1-bbl (when you keep your foot out of it, anyway ) Guesstimation of power increase is only ~5HP, but there should be a noticeable improvement in midrange response so it may feel like more. Adding 1.4 ratio rocker arms would maybe double that.

some guys suggest me to start with idle 60, main 125, emulsion .3,air 170 venturie 30...

what do you think about this combo?actually i'm a little bit afraid to put the carbs like "as it is".or what jets should i keep in the carbs ?

thanks

p.s. the exhaust is S&S header 1 3/8 single quite pack

I had some luck using the wayback machine, no pictures;
http://web.archive.org/web/200801171021 ... 36_idf.htm

Myself I wouldn't be afraid to try what you have, tuning is much art.

thanks a lot for the link...a lot of goodies there

and about tryng what i have ...i'm a little bit afraid ...but till i will find the proper jets for them i'll try with what i have now...

thanks once

ssk wrote:some guys suggest me to start with idle 60, main 125, emulsion .3,air 170 venturie 30...

A 60 idle jet is a cruel joke for them to play on you.
What is the elevation where you are?

What is a .3 emulsion?

.3 is probably the F3 emulsion tube

i never tried to "play" with dual carbs so...i'm newbie in this context

harney says in his tech articles " I've noted a formula in the books (basically 1.6 * vent size) for idle jet sizes, and I have to say that vent size has little to do with idle jets, on the vw engine at least. More efficient engines can benefit from leaner idle jets, and less efficient engines probably need a little more. 50-60 is the range, and there is a trend toward larger jets for larger carb bodies. The throttle plate size is a key factor."...so for me the idle jet is 48 by calculating the venturie size 1.6 x...so probably will be 50 or 55..what is your opinion ?
Considering that it is a stock engine for the moment,all i want is just some more power by installing these two carbs.

I have to disagree with Mark on that one. The size of the idle jet has absolutely NOTHING to do with the size of the venturi. There is no rule, no mathematical relationship whatsoever. They are two completely independant circuits.
I recall many years ago when I was using 48 IDAs. I had the engine perfectly tuned with 37mm venturis, then switched to 42mm vents. Not only did I not change the idle jet, I didn't adjust the idle mixture screws. Driving on the idle cct was unaffected.

A 36 IDF will NEVER, NEVER, NEVER, need a 60 idle jet.

What is your elevation?

what do you mean by "elevation"? ..I don't understand your question

How many m are you above sea level?

ssk,

he's asking where you live,and therefore how high is your location above sea level.

If you live in New Orleans your elevation is 8 ft below sea level.

If you live on the coast of San Diego your elevation is between 0 and 50 ft above sea level.

If you live in Denver you live about 5200 ft above sea level.

It makes a big difference in which jets you choose, because the lower your elevation, closer to sea level at your location, the denser the air is, and therefore the bigger jet you'll need.

You'll use a bigger jet in San Diego than you would in Denver, much different.

Thanks why he's asking.

So, where do you live? Which city in which state/county/province?

so

in the wintertime i'm living in bucharest-romania where is somethin' like 10-20 m high from the sea level and in the summertime i live in berlin-germany...i don't know the altitude there...but i don't think that is higher than bucharest...
i didn't know that these have an influence for choosing the proper jets ...









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