Carb Tuning Education

There are some great books on Webers - one by Pat Braden and Pierce Manifolds also has one. To me, the best are some Weber carb tuning threads on FChat. Would also specifically look at some Boxer tuning threads on the 'other' board which by content could be often referred to as 'Boxer-talk'. Especially David Feinberg among others are extremely experienced.
Looking forward to coveting your spectacularly beautiful car in person and getting one of my own!
rt

 

You guys are heretics. I never go to the other site. This one already takes up too much of my time. I'm afraid to even LOOK at the other one!

I wrote a tutorial on doing the 308 carbs a while back. Search the archives for carb synch tutorial and you will find it quickly. It's not the same as a Boxer, but probably similar.

Hey DC isn't too far, maybe I should come down and help you out with it. Always wanted to get a ride in a Boxer!

Birdman

 

Would heartily endorse Bird's Weber thread - very very well done.
Porsche 911s use similar carbs, so a lot of IDA/IDF tech stuff around.

rt
looking for carb'ed boxer

 

Hi Birdman ... found your thread on the subject (http://www.ferrarichat.com/forum/showthread.php?t=20179) but there's no pics ?

 

I have a copy of Birdman's excellent article in Word format, which includes the pictures lost in "The Great Fire".

PM me if you would like a copy.

 

Oh crap, I can't believe those pics got lost. They WERE there after the great crash last year, so I don't know why they are gone now. Rob has been promising a technical procedures area for a while now. Maybe I'll just put this whole thing up on my own site. Stand by....

Birdman

 

OK here it is in one place:

http://home.comcast.net/~jonathan.bird/sync/carb_synch_tutorial.htm

Birdman

 

Another good book that covers the basic tuning of a range of Ferrari carbs is: Ferrari A guide to performance by Allen S. Bishop. I can't remeber the publisher, but found if easily enough on Amazon

 

we need to get our voices together :::::: HEY ROB !!!!!!!!!!!





OH ROB !!!!!!!!!!!







we need a tech procedures area !!!!!!!!

 

Thanks for the info Bird. I will be starting my carb rebuilds at Thanksgiving. Hopefully I can get them back on the car at X-mas break.

 

Quite frankly unless you are a carb tuning expert i would not touch them on a Boxer, a V8 Ferrari yes but the 12s must be tuned perfectly to run right.

Each linkage adjustment, idleset screws, idle bleed screws, mixture or various float levels not spec'd in the workshop manuals will have a profound effect on how the car is running and you'll be chasing your tail in circles for weeks trying to figure out whats not correct, especially if you don't have such things as a gas analyzer or years of experience with Italian carb cars, and even the best carb mechanics have a hard time adjusting the 4 Weber 3 barrels on a Boxer just right, someone that has little or no experience will have a very difficult time and make things run worse more than likely.

If the car is running well change the plugs and wires maybe and check the cap and rotor then make sure the dist is advancing correctly is about the extent for a amateur minor tune-up.

 

I also respectfully disagree that we should keep our car's mechanicals at arm's length as a mystery. To me, the beauty of these cars begins at the engine - and to fully appreciate the beauty, one needs to dive in. Sure there may be challenges, but in DC there are always Maestri available.
And after all, it is ultimately an internal combustion engine car.

Now, there is nothing beautiful or elegant about the Ferrari electrical system...

 

By the way, don't ask me for details, because I don't remember them, but I do recall one of the techs at FoW telling me that he will often put the front carbs on a 308 *just slightly* off synch from the rear carbs. Says this helps w/ shutdown (no run-on? no backfiring?) or something like that. FWIW.

 

I agree with Russ. There is nothing mystical here, these are just carburetors. The Boxer has 4 triples, right? (Not 6 doubles?). Hey man, it's just 4 carbs with a linkage. You follow the same procedure:

1. Synch the linkage at 1500 or so RPM (i.e. higher than idle)
2. Synch the idle with throttle stops
3. Adjust the throats to each other within each carb with air bypass
4. Tweak the idle mixture.

Only step 4 is "tricky". Everything else is pretty straightforward, and frankly even step 4 is not that critical. You need it rich enough to idle smoothly and not too rich or it fouls plugs. There is really no harm to be done if it's a little rich. Remember that the idle mixture is only marginally adjustable anyway. Most of the real mixtures are set by jets that have to be swapped out to change. Not rocket science.

Believe me, if I can teach myself how to do it, you can too. I was a complete newbie with no clue and now I can synch a 308 in half an hour (once the airbox is off ).

DMAX, we have many friends in DC. My wife is heading down there for a conference in December, but alas I have to stay home and take care of our daughter. HOWEVER I can certainly come up with another excuse to go down there at some point and help you out, or just go for a ride!

Birdman

 

Not trying to say don't do it but just know what you are getting into. I think its a great idea to read up on the Weber carbs because if you do have a problem down the road you can help diagnose if its carb or ignition. You will also need to clean out the idle jets periodically as part of regular maintenance if they get plugged for various reasons it's something easily done.

Tuning the Boxer carbs is not as simple as other carb V8 Ferraris, the linkages have a profound effect as its a bit of a crude design to link all the carbs together and get them in sync, slight movements cause the butterflys to open and you could be idleing through a progression hole vs the idle mixture screw, thats were it gets tricky, their are also little tricks with the air bleeds in relation to the idle mixtures, an air leak in somewhere can drive you crazy as well such as in the lead plugs in the carb bodies or base gaskets, a good running car I'd leave alone, check the plugs and see if the look good and if the car performs well, if you have a carb problem thats where the skill comes in.