Jetting advise

Saturday, 25-Mar-2000 19:53:02

Message: writes:

I just got my first 2-liter together (formerly a 1776,testing it out in my pop's '58) and in the car yesterday,and attempted a spin around the


Before getting it out of the yard,it was apparent that the jetting, which ran great when the car was in its stock stroke form, is now way


I was wondering if I could call on you guys vast experience to give me a *ballpark* estimate on jetting (Or what range I should buy,),I

just want to get it close enough to make it *drivable*,then I can play with It some more once Ive driven it around some.

The carbs are 44IDF Webers,the current jetting is 55 idles,160 mains,210 air correctors

The old engine combo: 69X90.5,Engle 120,8.0:1 compression,Pauter "a" style non welded 40X35.5 heads,1 5/8 merged w/ dual qps.

The engine is basically the same now with the exception of a 78.4 DMS crank and 8.5:1 compression

Id appriciate any replys,with Weber jets being $5 a pop Id just like to get close!



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you didn't give us the venturi size on the carbs.... (John Connolly) (25-Mar-2000 21:44:14)

Re: Doh! I knew I forgot something! They're 36MM..... (Ian) (26-Mar-2000 00:44:58)

Re: if you have not drove it yet what makes you think its lean (n/t) (D L H) (26-Mar-2000 00:49:39)

Start here... (John Connolly) (26-Mar-2000 01:30:27)


Start here...

Sunday, 26-Mar-2000 01:30:27 writes:

Buy 50 and 52.5 idles (you have 55s)

135, 140 and 145 mains.

180 Airs, and F11 emulsion tubes (you should already have these).

this is close.

One more thing: remember that unless your jets are NEW, you don't know what size they are! Drilled jets are very common, and even

undrilled jets "grow" as they are used (they wear). Jets are not based on size, but on FLOW when weber makes em', so using a drill or a

gauge only gets you close. The same "size" jet can flow different amounts based on how deep the hole is, the radius, etc... this is why

new jets are the way to go if you aren't sure!


John Connolly




44 IDF venturi size ??? Saturday, 23-Sep-00 10:55:12 writes: I need help with vents on my 2165 (78x94).Running SE heads 44x37.5, FK8,1 5/8 merged single muffler,44IDF's with 36 vents,145 main,175 air,50 idles (these may be a little small).Stock fuel pump,MSD 6A,blaster 2 coil,009 w/points. Trans is stock ratio. Car pulls good down low,but flattens out above 4500. I think the vents should be opened a little,maybe to 38 but then the jetting becomes a problem. Thanks in advance for any help. Denny

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You have almost the same motor as me..76X94 (2109). My mains are 135's. Mine pulls hard to 6,000 then flattens out. You might be running rich up top??? I do feel though, that 36's are a little small for this size engine to reach full potential at hi rpm's. Are your heads ported? (n/t) (Ohio Tom) (23-Sep-00 11:17:24)

Re: 44 IDF venturi size ??? (Jeff N.) (23-Sep-00 12:09:47)

try a 200 or 220 air. That's your problem! (n/t) (John Connolly) (23-Sep-00 12:32:17)

The stock pump can be used on HP applications, but is it providing enough volume for your engine? (Jim Ratto) (23-Sep-00 12:48:52)

Re: 44 IDF venturi size ??? (Denny) (23-Sep-00 12:52:35)

blend the seats into the ports'll find some more power!! I did on the same heads a few years ago! (n/t) (Jim Ratto) (24-Sep-00


Re: 44 IDF venturi size ??? Saturday, 23-Sep-00 12:09:47 writes: I had same basic problems with my car. 2110 same profile cam as K-8 with 44's and 9 - 1. I was using a cb electric pump though. How I found out I had fuel pressure problems was the car would pull to 7000 no prob in 2nd a little less in 3rd and still less in 4th. Next thing I did was vent the tank and put a big electric pump and bigger line in. I also put a bigger elbow on tank bottom. Then my problems went away. BTW my 44's have 36mm vents also. You could try letting the gas get low and drive it with the cap off to try the vent idea. Good luck. Jeff N.


The stock pump can be used on HP applications, but is it providing enough volume for your engine?

Saturday, 23-Sep-00 12:48:52 writes:

John is on to something with your jets too. Sounds like your air jets are too small.

To make peak HP with your engine at 6800 rpm you need a 38-39mm venturi, and probably a 60 idle, 150-155 main and 200-205 air.

Have fun.

Jetting depends on your altitude.

Jim Ratto


Re: 44 IDF venturi size ???

Saturday, 23-Sep-00 12:52:35 writes:

Heads are as cast bugpack SE's





Jetting Wednesday, 10-Jan-01 01:17:35 writes: How do you guys jet your carbs properly the first time? It seems to me to get a set of carbs set up perfectly someone might have to buy a few different size sets of jets. This could get rather expensive. If I brought my bug to a vw shop, would they have all the different sizes there so they could get it right and then at the end tell me if and which ones I would need to buy or should I just buy a jet reamer? Matt

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We need to know engine specs. Type of carbs. and Venturi sizes...... (n/t) (Ohio Tom) (10-Jan-01 02:32:39) Re: Jetting (Matt) (10-Jan-01 02:51:32)

50/130or135/200/F11 I've seen the SAME engine combo require different jetting. Every engine is different. This is a good start. (n/t) (John Connolly) (10-Jan-01 12:10:20)

I've never none anyone that could get it right the first time unless they had previous experience with the same or VERY similar engine build. Forget the reamers unless you have a LOT of experience using them. Talk to someone like Art Thraen, or post your complete engine build here for some differing opinions... (n/t) (george brown) (10-Jan-01 11:00:26)

Took a lot of trial and error, lots of reading, and a few dollars in jets, e-tubes etc., but>>more (Jim Brown) (10-Jan-01 18:30:38)


78x92, with 40x35.5 valves, 1.4 ratio rockers, FK8 cam, 40 IDF webers with 32mm vents.



I have finally arrived at a smooth Air/Fuel curve for a similar setup:78x90.5, 120 cam, 1.1 or 1.25 rockers, 40x37.5, 44IDF's. Here's what I ended up with: 55 idles, 140 mains, 175 air corrector, F15 e-tube. Out of the box, these carbs came set with either 50 or 52 idles (can't remember which), 135 mains, 175 air corrector, and an F11 e-tube. Although it was lean in both fuel jets, the biggest gain in smooth operation was correctly selecting the F15 e-tube. This was by no means easy, and was a long frustrating battle; well worth the results though. Stock F11 e-tube had the mains coming on too soon, overlapping the progression circuitry too much. This caused an over rich condition around the 2500 RPM range, hence a huge, stumbling flat spot. F15 raised the 8 main braking holes approximately 2mm, slowing the mains just slightly. Air/Fuel gauge was a must to figure this out (along with many hours reading Weber/Carb manuals, changing jets way too many times, and a few choice words). I'm glad it has finally come to an end. Except now I want to add to the torture, by turbo charging this engine. Guess it's part of the hobby (addiction?). It's never finished (but I'm glad for that). E-mail me if you would like further carb tuning tips.

Jim Brown




Carb jetting

Tuesday, 06-Mar-01 00:47:05 writes:

im helping a friend jet his 44idf can you guys give some idea where to start. motor is 1776 40x35 valves k-8 cam 9.0:1 c/r stock vents

ray mejia

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Message thread:

Carb jetting (ray mejia) (06-Mar-01 00:47:05)



Re: Probably 36mm vents in 'em? Maybe start with 55 idle, 135-140 main and F11 emulsion, 190 air corrector if indeed 36mm vent (n/t) (Jim Ratto) (06-Mar-01 00:55:44)

36 vent, 50 idles, F11 tubes, 50 pump, 145 main, 210 air? (n/t) (george brown) (06-Mar-01 10:07:54)

since we are on the subject....PLEASE>>>>> (dean n.) (06-Mar-01 01:44:56)

I have a similar engine........ (Ed) (06-Mar-01 07:08:03)

For best results with IDF's, close air bleeds all the way and Lok-Tite them, then jet. (n/t) (george brown) (06-Mar-01 10:02:34)

???? What about fine-tuning? you will not be able to do that on jets alone. (n/t) (Ed) (06-Mar-01 10:23:18)

Run both air bleads in on the common carb. Balace those two cylinders by screwing out the one not flowing as much. Then lock down. (n/t) (Steve Arndt) (06-Mar-01 10:30:23)

DON'T EVER LOCTITE AIR BLEEDS!!!!!!!!!!!!!!! (Bruce Tweddle) (06-Mar-01 13:15:48)

C'mon, Bruce, a tiny dab of blue Lok-Tite on the outside suface of nut/screw isn't gonna hurt anything or make it impossible to get out. (n/t) (george brown) (06-Mar-01 14:01:35)

go ahead and screw up your own carbs then (Bruce Tweddle) (06-Mar-01 15:52:35)

Dean, my 2,110 is 8.5 to 1, using a merged heater box 1 5/8" exhaust, has dual 44's with 36 vents, F11's, 55 idles, 155 mains, 200 airs, and 60 pump. Cam is Web Cam 121/125, 270in/262ex @ .050" with lift at valves .490in/478ex. (n/t) (george brown) (06-Mar-01 10:00:50)

My experience with two-throat Weber carburetors (Italian, with and without idle air correction screws) is that each throat flows the same, or so close to the same that you couldn't measure the difference with a Uni-Syn or like gauge. If someone has rebuilt them and screwed something up, or twisted a throttle shaft such that the plates aren't in sync, then they might be used to equalize flow at idle, but would still be out of sync at different throttle openings. Just my opinion/experience... (n/t) (george brown) (06-Mar-01 16:30:33)


how about jetting recomendations for motor please.

2110. 8.5:1 comp. a massivly huge 110 cam 44idf's

36 vents.

have 32 vents but dont really want to put them in.

heads are p&p'd a little like mini d's

thank you in advance.

dean n.

dean n.


Yes I'm yelling. It took me over an hour to set-up two carbs in the mill to mill out such an air bleed screw that some moron either torqued the hell out of or loctited in. If you want it all the way in, turn it in and gently snug it up. The O-ring will prevent it from turning in Dells, and the locknut on Webers.

Bruce Tweddle


I have a 2110 with a Scat C35 (very similar to a 110), 44's with 36 vents, 42x37 heads, 7.55 compression, and a 1 5/8" merge. I am running the jetting the carbs came with, and about three turns out on the air bleeds. My plugs are perfect, and it runs very nicely. If you think the jets that came in your carbs might be different, I can pull mine out tonight and see what they are. Except the idles, I'm not going to take them out!!!


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