Rotary Car Club - Any Weber guys here?

Rotary Car Club (https://rotarycarclub.com/index.php)

- Carburetors and Carb Tuning.. (https://rotarycarclub.com/forumdisplay.php?f=95)

- - Any Weber guys here? (https://rotarycarclub.com/showthread.php?t=2402)

Quote:

Originally Posted by craig3x (Post 111028)

can't seem to find what you are talking about. can you refer to this schematic and let me know what you're talking about? Also, how important are the air horns? (number 58 on the schematic)
http://webernorthamerica.com/pdffiles/48IDA.pdf

"Pump exhaust valve", number 11 in the diagram. Its purpose is to bleed off some of the accelerator pump shot. A "zero" bypass jet indicates that it has no bypass hole in the side.

The air horns smooth the airflow into the carb, increasing power. They come in different sizes so you can fine-tune the length of your intake system.

Also, are you sure you have 47mm main venturis in a 48 IDA? That doesn't even seem possible, and certainly not recommended.

Quote:

Originally Posted by PercentSevenC (Post 111229)

you're right. I did not measure the venturi correctly. I measured at the bottom. When I measured that narrowest part, it measured 42mm, which I understand is still big. But venturi size should not affect a rich or lean condition.

also, I have been told to increase my pump jets from 50 to 90, which is only possible by drilling. I'm not gonna do that. But it's funny how so many opinions and advice can contradict others. Either way, I have learned a lot from everyone.
By the way, F#@k RX7club.com and their rules. This forum is 100x better

42mm venturis sound fine.

What exactly does your wideband do when it bogs? Does it go rich briefly and then go lean, or the opposite, or just lean, or what?

Quote:

Originally Posted by 730RWHP12A (Post 111027)

what is the acc. bypass jet in the bottom of the float? it has to be a zero

Quote:

Originally Posted by craig3x (Post 111000)

I am having a similar problem. Choppy at cruising speeds. But on a long deceleration, it seems to "build up" or something, cuz when I get back on the throttle, it bogs and then farts a huge backfire out the exhaust and sometimes dies. Most of the time I have to pull over and wait a few minutes then fire back up. I do have a wideband, but it is digital and not sure how accurate. (question, i had to install a switch on my wideband guage to go back and forth from each rotor because I am using 2 0xy sensors. has anyone solved that problem?)
here are my jetting settings:
Weber 48 IDA on a 13b street port. (4 port)
250 MAIN ( I know this is big, but my problem is at lower RPMs. Ordered a 190 and 220)
70 Idle
50 Pump Jet
F-11 emulsion tubes
160 Air Corrector Jet

Please help if you can! Thanks

Ok, so I got some new jets. I just swapped in a 60 idle and 220 mains. And now my problem seems worse. And my wideband is reading richer than before at idle. The choppyness is worse too. How can it be richer with smaller jets? AARRGGHHH!!

I actually think my condition is lean. There is a huge "cutout" when gassing it from low rpm to midrange and higher. Plus my wideband is saying lean as well. But I don't know how that's possible with 70 idle jets and 250 mains. wtf???
I have heard about drilling out a 3rd progression hole. But I don't have the ballz to do that...and am unsure if that would solve anything anyway