JWW/EarlySMan (Weber Q's)

[Fishcop]

....or anyone else

I'm trying to improve the performance of my carbs on my 2.2T, I'm currently running 27 venturis, 45 idle, 110 mains. Not sure on emulsion or air correction.

What do you think about converting to 30 venturis, 55 idle, 170 mains? Also what emulsion and air correction should I use bearing in mind that the engine is not cammed or modified?

I don't have noise/emission issues to deal with.

Anyone please feel free to chime in with opinions

Thanks

[TimT]

you could go as large as 32mm for your venturis, and install the tall intermediate venturis.

Just remember that its the heads that really limit how much performance you can get out of a 2.2T, you'd have to open the ports up to the S specs to benefit from carb mods.

[Zendalar]

The venturies are pretty expensive, at least where I am from, and I was wondering if one could drill those bigger? Would they be ruined? After all, the venturies have same diameter from the other end..so why not widen the other end to match what u need. I am just scared that after I drill them to 32mm, they cease to operate.

[T Bird]

Fishcop
Below is the Weber formula for calculating the size of the venturi.
(1) - Divide the volume of one cylinder in cc's by 1000.
(2)- Divide the rpm where peak power is made by 1000.
(3)- multiply the number derived in (1) by the number derived in (2).
(4)-Take the square root of the number derived in (3).
(5)- Multiply the number derived in (4) by 20. That's your officially sanctioned Weber venturi size.

The numbers work out like this for a 2.2T.
(1) 2195cc / 6 = 366; 366 / 1000 = .366
(2) 5500 / 1000 = 5.5
(3) .366 X 5.5 = 2.013
(4) sqrt of 2.013 = 1.4188023
(5) 20 X 1.4188023 = 28.376046
So, a 27 mm venturi is more appropriate for a 2.2T than a 30 mm venturi.

Increasing the venturi to 30 mm on a stock 2.2T will likely give you some significant tuning problems. You will weaken the signal to the idle circuit and make it difficult to tune that circuit. Moreover, going from a 110 main jet to a 170 main jet is guaranteed to create problems. If you are not currently experiencing issues (like a lean idle), then leave the jetting alone. I didn't check, but the numbers you cite sound like the factory sizes.

If you want to make sure that your Webers are operating optimally, then make sure the float levels are set properly; the accelerator pumps are discharging .75 cc per stroke; vacuum is balanced at each carb and side-to-side at idle and at 3000 RPM, and that the mixtures are set properly.

Good luck.

[john walker's workshop]

the .45 idle jets have to go. that's probably most of your problem. i usually go to .55's on just about everything except the larger engines. a 2.2T with it's small port heads, won't benefit much from larger venturis. you could bump the mains up a bit, like 115, but i'd leave the rest alone. get the timing set to 35° total advance, too. if it pings there, turn it back a couple degrees at a time until it doesn't. most don't, with good gas. by the way, don't trust the sizes stamped on the jets. too many have been drilled. use a jet gauge.

[Fishcop]

Thanks very much for the advice. I've just recieved my float guage from PMO and am trying to source a synchrometer. JWW, I've ordered some 55 idlers and will give them a try. I just made up a vial for the pump (I have a laboratory where I work) so hopefully this weekend I'll give them a good tune.

I really appreciate the help