I need an engineer!! lol

[Phlebmaster]

I have a Weber/jetting calculation question. Datzenmike?? :D

 

Is there a known calculation for figuring out Weber jet sizes by engine or by cylinder CC?? In other words...how would you know if your Weber 32/36 was jetted for an L-16 or an L20?? There must be a calculation to get it right, right? :confused:

 

Please help me out so I can figure out what size jets I need for a little supprise project on my truck. :D

 

Thanks Much!!

[datzenmike]

Geez I bought $10 6-7 used Holly/ford/chrysler/vega weber knock offs couple of years ago just to take a look inside. Threw them away..:lol::lol::lol:

 

http://www.racetep.com/webjettune.html

[72240z]

I know I'm no expert but I always thought you had to tune to each particular engine that that threw a set chart or calc out the window. I was taught to use the mixture screw to tell and for the 32/36 I think its if you have to open more then 2 turns you need to go up (too small)and if close more then 1/2 turn you need to go down(too big). If no equipment is had to fine tune I use the plugs on top of power and driveability to tell. How you know which it was jetted for originally Idk, I'm sure mike does. There has got to be a stock jet list.

 

Idk if my way is right or wrong but that's how I was taught to jet.

[72240z]

I was right, I'll be damned....I think? lol

Edited February 13, 2009 by 72240z

[hang_510]

plugs = plug color.

be sure your butt dyno is tuned as well :P

 

Please help me out so I can figure out what size jets I need for a little supprise project on my truck.

 

open up and see whats in there.

if was on an L16(L20 now) get 2-3 of ea a size bigger and play :w00t:

not likely to need smaller jets at this point

[Phlebmaster]

plugs = plug color.

be sure your butt dyno is tuned as well :P

 

open up and see whats in there.

if was on an L16(L20 now) get 2-3 of ea a size bigger and play :w00t:

not likely to need smaller jets at this point

 

:lol:

 

Maybe....maybe not. We will see soon enough. :D Everyone will get a video soon..........

 

That's all I am going to say at this point..heheheh ;)

[datzenmike]

Charts will get you close just like L20Bs timing is 12 BTDC. It's a starting point and will work..... in theory. In the real world there is always room for tweaking it closer, up, or down.

[Phlebmaster]

I guess it depends on a lot of variables like: cam, bore, stroke, elevation, fuel, atmospheric pressure, temperature, intake size, exhaust flow and size, star alignment, and the mood I am in.:D

 

Looks like we will have to play with it to get it right.Thanks for your help I do appreciate it. I just was not sure if there was a sure fire way to get it right without having to try a ton of different things. Hahahahaha Who was I kidding. :rolleyes:

[72240z]

That's the thing about carbs i dislike. I really enjoy how every aspect of the tuning is mechanical, just the level of consistency ruins it for me.

 

Maybe I'm just never satisfied lol.

[datto510]

My wife is a marine engineer, has the degree to prove it............... strangly she can't even change her own oil.

[hang_510]

^ oil & water dont mix

 

unless your HG fails :lol:

[HRH]

For a 32/36 Weber, there are a few things you should consider:

 

1. Your main jet determines how much fuel economy or power you're going to get. Most 32/36s come with 1.35 or 1.40 main jets, which is plenty for most stock L16-20 engines. There are two, one for each barrel.

 

2. Air correctors determine how much the main jet is leaned out. Most 32/36s come with a .60 in the primary side and a .70 in the secondary. Good enough to run, but often times they start out richer, helps to increase the air corrector jet size. Do so in one size increments, don't want to run it too lean now!

 

3. Idle jets. The idle circuit operates below about 2500ish rpm. A .45 or .50 idle jet is usually sufficient for most types of stock L16-20 motors.

 

These are all baseline values. Then you have to spend time tweaking each to achieve maximum fuel economy/power desired. Which can be annoying, but such is the way with carbs. :D I have two 32/36s and one pair of SUs. Soon the 510 will be fuel injected, which will be ever so much nicer, but also more expensive.

[ppeters914]

My wife is a marine engineer, has the degree to prove it............... strangly she can't even change her own oil.

 

Not so strange. Most programmers can't do squat on a computer other than email and programming.