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 Post subject: Weber tuning (Bris)
PostPosted: Thu Dec 29, 2011 6:22 pm 
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Weekend Cruiser

Joined: Sun Apr 12, 2009 7:30 pm
Posts: 54
Hey guys,
Just seeing if any Brisbane locals could help me out with tuning my 48 weber on my 13b ep?
I have been at it for a while now, some days its good, others its not so good, just want to see if other people tune them different to me?


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 Post subject: Re: Weber tuning (Bris)
PostPosted: Sat Jan 14, 2012 4:54 pm 
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Weekend Cruiser

Joined: Sun Apr 12, 2009 7:30 pm
Posts: 54
Nobody?


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 Post subject: Re: Weber tuning (Bris)
PostPosted: Sat Jan 14, 2012 7:15 pm 
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Boost Me Up

Joined: Tue Nov 10, 2009 11:21 pm
Posts: 712
Location: Brisbane
Hi, can you give some specs on what jets, chokes, needle valve and seat it has. Also what fuel pump, size lines, fuel pressure you are running etc.

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 Post subject: Re: Weber tuning (Bris)
PostPosted: Sat Jan 14, 2012 7:21 pm 
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Joined: Wed Oct 30, 2002 11:52 pm
Posts: 5871
Location: N.S.W.
What are you running?

My preferred setup for an EP is as follows.

3mm needle and seat is a must, I prefer a return line and prefer Carter pumps over the Holley and reg setup. Make sure your float level is set right and your fuel pressure is also correct, otherwise your tuning troubles will not only be jetting related.

39-40mm chokes
F2 Emulsion Tubes (often gives better drivability at part throttle than the F11 emulsion tube combo)
200 airs (might need to be down to 180, that's part of fine tuning)
180-190 fuels
F10-65 idle jets (could also be F10-60 or f10-70 depending on what your motor likes)

Alternative setup

39-40mm chokes
F11 Emulsion Tubes
120 airs
190-200 fuels
F10-65 idle jets (could also be F10-60 or f10-70)

Mixture screws, I always find screw them gently all the way in, then back them out three complete turns, and adjust from there.

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 Post subject: Re: Weber tuning (Bris)
PostPosted: Sun Jan 15, 2012 10:18 am 
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Weekend Cruiser

Joined: Sun Apr 12, 2009 7:30 pm
Posts: 54
I have absolutely no idea what jets/needle and seat etc I have!
I am running a carter fuel pump with standard RX2 fuel lines, no return line as per my tuner and no pressure reg, needle and seat does not leak.
Car was dyno tuned, the carb was jetted to suit my motor, that's all I know. My trouble isn't in full throttle application, it's at idle, on takeoff and cruising, I have a flat spot and I have been trying to tune it out as best as possible through timing, idle speed and idle mixture, some days it works better than others. I will check my mixture screws today, and see if they are around the 3 turn mark.
Cheers for your help guys


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 Post subject: Re: Weber tuning (Bris)
PostPosted: Sun Jan 15, 2012 10:39 am 
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Boost Me Up

Joined: Tue Nov 10, 2009 11:21 pm
Posts: 712
Location: Brisbane
GTI4ME wrote:
I have absolutely no idea what jets/needle and seat etc I have!
I am running a carter fuel pump with standard RX2 fuel lines, no return line as per my tuner and no pressure reg, needle and seat does not leak.
Car was dyno tuned, the carb was jetted to suit my motor, that's all I know. My trouble isn't in full throttle application, it's at idle, on takeoff and cruising, I have a flat spot and I have been trying to tune it out as best as possible through timing, idle speed and idle mixture, some days it works better than others. I will check my mixture screws today, and see if they are around the 3 turn mark.
Cheers for your help guys


First question is who tuned this for you?

Also your flatspot won't be resolved with the idle mixture screws being adjusted. It should have a return line and a pressure regulator for starters with out even getting into what the jets and chokes it has etc.

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 Post subject: Re: Weber tuning (Bris)
PostPosted: Sun Jan 15, 2012 2:23 pm 
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Joined: Wed Oct 30, 2002 11:52 pm
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Location: N.S.W.
Carter fuel pump may be ok with no reg, that was the best thing about running them years ago as opposed to a noisy Holley.

Return line is always a good idea if it's still fitted. With the correct fitting it will not reduce the amount of fuel going into the carby, and is a better system in a road car as it tends to reduce vapour lock and similar heat related fuel problems in hot weather.

Stumbling when getting on the throttle could be the accelerator pump jets, either being blocked, too big, or plain not working. Rotaries typically need the smaller pump jets as they give a longer squirt rather than a big short squirt.

General light throttle stumbling will be a combination of idle jets and mixture screw positions in general. Too small an idle jet can give a stumble when you are very slightly on and off throttle, so if it's an F10-60 try an F10-65 or F10-70.

If the chokes are too big for the application (bigger than 40 is just not needed) this can also give poor low end response. Don;t be fooled into thinking the chokes need to be huge in a road car.

Webers are very responsive to small changes, but once you dial it in they drive exceptionally well.

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 Post subject: Re: Weber tuning (Bris)
PostPosted: Sat Jun 23, 2012 5:41 pm 
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The Bug Has Bitten

Joined: Thu Jun 22, 2006 11:04 am
Posts: 265
Location: hunter valley.
looking at Dazz,s extend port jetting options.


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