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Carb tuning class
http://motorsportsvillage.com/forum/viewtopic.php?f=6&t=9830
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Author:  Beretta [ Fri Dec 28, 2012 1:26 pm ]
Post subject:  Carb tuning class

Thinking of attending =; ....Anyone else??
http://nickersonperformance.com/automotive/a_news.html

Author:  Ken0069 [ Fri Dec 28, 2012 1:35 pm ]
Post subject:  Re: Carb tuning class

That link is not working?? :-k Googled it then went to their main site and it's not working either?? You must have crashed their server!

Author:  Milan.. [ Fri Dec 28, 2012 1:49 pm ]
Post subject:  Re: Carb tuning class

Link works for me , I have to say Ive learned a bunch here and it all worked without a glitch.
Plus tons of info to read. Thanks Milan

Author:  Ken0069 [ Fri Dec 28, 2012 3:06 pm ]
Post subject:  Re: Carb tuning class

Hummm, rebooted my router, which changed the IP address and then it connected OK?? :-k

Author:  jmarkaudio [ Fri Dec 28, 2012 4:23 pm ]
Post subject:  Re: Carb tuning class

Never know what secrets you might learn... :-k

Author:  Ken0069 [ Fri Dec 28, 2012 4:53 pm ]
Post subject:  Re: Carb tuning class

jmarkaudio wrote:
Never know what secrets you might learn... :-k


This is very true as if you only learn a couple of things you didn't already know, and you go to several of these things then sooner or later you'll know it all. O:)

The price seems a little hight though, hey?

Maybe I should start charging a fee for access to our fuel systems section?? :-k

Author:  Beretta [ Fri Dec 28, 2012 6:07 pm ]
Post subject:  Re: Carb tuning class

He is one that just don't "by" into the 2 circuit theory at all...He say's that a properly tuned 3 circuit
will always be faster..
I would like to know what he is doing with that 3rd circuit to make it run...I know several guys at the track that use his carbs and 2 of them told me that they can put a real big jet in them and they don't go any faster O:) ..... I have looked at there carbs and they all have the Holley metering blocks also..

Author:  Ken0069 [ Fri Dec 28, 2012 7:17 pm ]
Post subject:  Re: Carb tuning class

Beretta wrote:
He is one that just don't "by" into the 2 circuit theory at all...

I know several guys at the track that use his carbs and 2 of them told me that they can put a real big jet in them and they don't go any faster O:)


And if they can't get it phat enough to slow it down, then it's not likely running as fast as it can. ;-)

Author:  Beretta [ Fri Dec 28, 2012 9:06 pm ]
Post subject:  Re: Carb tuning class

Ken0069 wrote:
Beretta wrote:
He is one that just don't "by" into the 2 circuit theory at all...

I know several guys at the track that use his carbs and 2 of them told me that they can put a real big jet in them and they don't go any faster O:)


And if they can't get it phat enough to slow it down, then it's not likely running as fast as it can. ;-)




Bingo =; =;

Author:  jmarkaudio [ Fri Dec 28, 2012 9:24 pm ]
Post subject:  Re: Carb tuning class

Nothing special, although the main emulsion was better than most. As we know, mainwell size dictates how much fuel will pass with idle feed tubes.
Image

Author:  Ken0069 [ Fri Dec 28, 2012 11:02 pm ]
Post subject:  Re: Carb tuning class

3x.023 bypass air? Is that a screw in bleed or holes in the blades? :-k And if bleeds, where are they located?

Author:  jmarkaudio [ Fri Dec 28, 2012 11:06 pm ]
Post subject:  Re: Carb tuning class

If I remember they were in the top, screw in.

Author:  shrinker [ Sun Dec 30, 2012 1:07 am ]
Post subject:  Re: Carb tuning class

That carby has the exact size main jet to get 12.8 AFR on a 2 circuit so what is the 3rd circuit for? Answer, Its used to extend the t-slot circuit, note the idle/t-slot is a very small jet with a small Idle air bleed. Also the MAB is small so its not going to start the booster flow early, this can be done because its a 3 circuit. The 3rd circuit is filling the gap between the idle and the booster. technically this is a good way to go but practically why bother when a 2 circuit can get the job done and its easier to tune because its simpler to understand.

Author:  Ken0069 [ Sun Dec 30, 2012 1:27 am ]
Post subject:  Re: Carb tuning class

Yeah, I had wondered about that IAB and IJ being so small and figured that the 3rd circuit had something to do with that. We "normally" run like .040 IJ and .065+/- IAB.

Having one less circuit to deal with definitely makes it easier. That and not having the idle tubes in the mainwells is a plus also. I noticed that there wasn't anything listed on the size of those? :-k

Author:  shrinker [ Sun Dec 30, 2012 5:01 am ]
Post subject:  Re: Carb tuning class

The basic technique employed in this 3 circuit is to have the IFR way too small to feed the demand from the t-slot that you would normally experience with a 2 circuit, then use the 3rd circuit to replace that fuel. So what is the advantage? NONE. If you know how to tune a t-slot there is no point but if you don't then this is the easiest way. There is no advantage in using a 3 circuit this way. Because the main well is restricted you have to have modified metering blocks which is what is listed. But its not clear how the metering blocks are modified, so i would assume it has larger diameter where the idle tubes are.
It seems a sensible spec to get enough fuel for a higher HP limit than stock metering blocks. At least it would use the booster to do the main amount of fuel supply. But the tuning issue would be if you needed more fuel (like suggested by the people who take the main jets really Big with no change) you have to get it from the intermediate and that means that the bottom end where the crossover from t-slot to booster is happening becomes too fat. Simply put the tune can quickly become a mess. A 2 circuit is far better, if you want more booster fuel just up the main jet and it will have a small effect on the IFR size but thats easy to deal with.

When you run the 2 circuit setup the amount of air traveling through the drilling is far more than this 3 circuit tune, the air exits via the t-slot and atomizes the fuel, that doesn't happen when its coming from the piss and dribble third circuit tube. There is some atomization from the tube fuel but there is virtually none from the actual t-slot. The technique of this 3 circuit carb does not take advantage of the high air speed at the t-slot, instead it replaces it with fuel dribbling out above the blades when it could be fuel atomized but the high air speed at the top of the slot.

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