Setting up 48 IDA'S

[coinop101]

Hi Guys
I Have a 1985 street cobra with a 1966 427 side oiler , w/ 48 IDA's . I read the book tuning webers , great book even through they did'nt have a schmatic on 48 IDA's which I felt would be helpfull in understanding and working on them . Anyway , I would like to cheat by starting with the best values that you guys invested the time and money on . I know you share them on the site , but they seem to be updated and changing .
Give a guy a break . What do you have ?

Peace and Love
Peter

[*13*]

I posted this a couple weeks ago, based on the Weber Jetting Survey thread. Keep in mind, the Column that says "overlap" should read "Lobe Seperation" I was in a hurry & someone wanted to see the comparison so I posted what I had... Anyhow, if you look at the chart you can see few similarities that stick out. Most notably, to me was the Lobe Separation to Emulsion tube. Good Luck & read that thread under the Weber Tuning section under this site. Some good info in there. Let me know what you come up with & I'll add it to the list. url=http://www.clubcobra.com/photopost/showphoto.php/photo/76592][/url]

[jhirasak]

ERA FIA 2088,

I recently installed a set of 48 IDAs on my 1966 GT 350 Replica and would like to share my information with those listed in your chart. Here are my specs:

Engine - Ford 302
Displacement - 331
IN dur @50 - 232
EX dur @50 - 240
IN lift - .565
EX lift - .574
Lobe Separation - 112
Venturi Size - 37
Main Jet - 135
Emulsion Tube - F11
Air Correction - 110
Pump Jet - 50
Idle Jet - 65
Idle Jet Holder - 120
Carb - 48IDA

Before I installed the Webers, my car showed 365 HP on a chassis dyno at the rear wheels with a Holly 715 cfm Shelby carb mounted on an Air Gap manifold. I also have AFR heads and estimate my compression ratio to be approximately 10 to 1. With the new Webers, it feels like that performance has been improved over the range from 3500 rpms to redline at 6500. After I complete the jetting sequence using a wide-band O2 sensor, I will try to put it back on the same dyno to compare results. Since I have the dyno graph from the previous configuration, the comparison should be interesting.

John

[*13*]

The improvements can be in the range of 20% increase. I know they woke my motor up, right out of the box.

[jhirasak]

What is the best way to balance the flow between two barrels of a 48 IDA? I have read the Weber Tuning Manual as well as several other publications and there is a discussion on adjusting the air bleed screw (which the 48 IDA does not have), but there is no information on this topic for the 48 IDA.

John

[Rick Parker]

The 48IDA 2 BBl (unlike the 3BBL Porsche variant) does not have provision for balancing the flow between the bores on a single carb. However using small ("ignition wrenches") on the flats of the throttle shaft they can be twisted very very gently in opposite directions to achieve very minor flow differences. This adjustment assumes the throttle plates were properly seated in the bores when being assembled. Keeping the leather bearing seals moist or better yet, using sealed bearings will assist in achieving equal flow.

[carmine]

The old twisting of shaft trick that Rick mentions above works pretty good.
Ive done it and found them easier to twist after the carbs are heat soaked after good running.

[jhirasak]

Thanks Rick,

The Club Cobra Weber Tuning forum has been a great help to me in setting up my 48IDA carbs. One thing that I learned from the process was to never assume that even new carburators have been properly set up when dealing with multiple carburators. I guess that I just had to pass through the initiation ritural for those who choose to run Webers on their engine.

Regards,

John

[DMXF]

Does anyone have or heard about a tool to remove the shaft bearings while the carb is assembled, ie; with throttle plates and shafts still installed? I have the old original unsealed bearings in my carbs and would like to install sealed ones, but don't want to mess with the throttle plates if I can help it because they are all set up.