Carburetor spacers

[chevy350]

Ciao a tutti,

visto che sono un po' ignorantello in merito ai V8 cerco di imparare qualcosa ogni giorno step by step.

In questi giorni finalmente sto cercando di godermi quanto piu' la mia piccola e sonno sempre in cerca di migliorie eperfezionamenti(secondo i miei limiti).

Direte voi embhe'!

Vorrei installare uno spacers tra intake e carburetor e ho trovato una spiegazione che magari a chi come me ne vuole sapere di piu' !



Ne avevamo gia' parlato,pero' magari qualche spunto in piu' non guasta mai !



Questo articolo penso sia abbastanza esplicativo:



Carburetor Spacers



written by: Doug Schriefer of Braswell Carburetion



Carburetors spacers can be a very useful tuning aid when working on your streetcar, or racecar. A spacer can be used to move the torque and power-band where it is more usable in your application, or they can be used to help work out inefficiencies in your combination.



4-Hole Spacers. As a rule of thumb a 4-hole designed spacer (4 individual holes one under each barrel of your carburetor) will increase your throttle response, and acceleration. They can also move the torque and power-band down in the RPM range. This is accomplished by keeping the air and fuel flowing in more of a column, which increases the air velocity. This can be a perfect addition if your vehicles throttle response is not as good as you’d like, or you’re getting passed when you pick up the throttle coming off of the corning. A 4-hole spacer can also help make up for something in the intake tract being larger than optimal (too large of a carburetor, cam, intake, etc.)



Open Spacers. As a rule of thumb an open designed spacer (1 big hole underneath your carburetor) will decrease your throttle response, and acceleration. They can also move the torque and power-band up in the RPM range. This is accomplished by increasing the plenum area, which will help in the higher RPM’s. This can be a perfect addition if your vehicle has traction problems when accelerating, or coming off of the corner. A 4-hole spacer can also help make up for something in the intake tract being smaller than optimal (too small of a carburetor, cam, intake, etc.)



Combination Spacers. A combination spacer (half 4-hole, and half open) can give you the best of both worlds. Increasing your throttle response, and acceleration over not using a spacer, and increasing or broadening the torque and power-band.



Plenum Dividers. A Plenum divider does as the name implies divides the plenum in an open plenum intake manifold from side to side. These are generally used to help prevent fuel slosh from side to side in high G load Oval-Track, or Road-Race applications. It is common on certain engines to have lean cylinders do to fuel slosh. A SBC oval track engine running on methanol can run lean on cylinders 3 & 5 while cylinders 4 & 6 will run rich. A plenum divider can help eliminate this.



Spacer thickness. Varying the thickness of your spacer will affect how it affects your engine. Normally the thicker the spacer the more of an affect if will have on your combination. Meaning if a ?” thick spacer helps you a little a 2” thick spacer can give you more of the same affect.



Spacer Material. There are many different types of materials used for manufacturing spacers. They all have pro’s and con’s. Wood for example is a great material as far as thermo efficiency, but can wick fuel, which is not safe. Plastic, or composite spacers are also very good at not transferring heat, but are not as strong, and can be harder to modify. Generally Phenolic fiber, or Aluminum is preferred. Phenolic is very good at not transferring heat, but can be hard to modify. Aluminum is not as good at heat dissipation, but can be ported or modified easily to work on specific applications.



Spacer Tuning. Since each spacer will react differently on each combination there is not a right or wrong type. Spacers are a great tool to have to help dial in a new combination, or tune your racecar for varying track conditions. Swapping out a spacer is a very simple change that can have great impact on the drivability of your streetcar, or racecar. Having a couple types, and thickness of spacers around is always a good investment.





ANY OPINION AND ADVICE ARE WELCOME !!!

[Guest]

[quote name='chevy350' post='298288' date='29/6/2010, 13:15']Ciao a tutti,

visto che sono un po' ignorantello in merito ai V8 cerco di imparare qualcosa ogni giorno step by step.

In questi giorni finalmente sto cercando di godermi quanto piu' la mia piccola e sonno sempre in cerca di migliorie eperfezionamenti(secondo i miei limiti).

Direte voi embhe'!

Vorrei installare uno spacers tra intake e manifold e ho trovato una spiegazione che magari a chi come me ne vuole sapere di piu' !



Ne avevamo gia' parlato,pero' magari qualche spunto in piu' non guasta mai !



Questo articolo penso sia abbastanza esplicativo:



Carburetor Spacers



written by: Doug Schriefer of Braswell Carburetion



Carburetors spacers can be a very useful tuning aid when working on your streetcar, or racecar. A spacer can be used to move the torque and power-band where it is more usable in your application, or they can be used to help work out inefficiencies in your combination.



4-Hole Spacers. As a rule of thumb a 4-hole designed spacer (4 individual holes one under each barrel of your carburetor) will increase your throttle response, and acceleration. They can also move the torque and power-band down in the RPM range. This is accomplished by keeping the air and fuel flowing in more of a column, which increases the air velocity. This can be a perfect addition if your vehicles throttle response is not as good as you?d like, or you?re getting passed when you pick up the throttle coming off of the corning. A 4-hole spacer can also help make up for something in the intake tract being larger than optimal (too large of a carburetor, cam, intake, etc.)



Open Spacers. As a rule of thumb an open designed spacer (1 big hole underneath your carburetor) will decrease your throttle response, and acceleration. They can also move the torque and power-band up in the RPM range. This is accomplished by increasing the plenum area, which will help in the higher RPM?s. This can be a perfect addition if your vehicle has traction problems when accelerating, or coming off of the corner. A 4-hole spacer can also help make up for something in the intake tract being smaller than optimal (too small of a carburetor, cam, intake, etc.)



Combination Spacers. A combination spacer (half 4-hole, and half open) can give you the best of both worlds. Increasing your throttle response, and acceleration over not using a spacer, and increasing or broadening the torque and power-band.



Plenum Dividers. A Plenum divider does as the name implies divides the plenum in an open plenum intake manifold from side to side. These are generally used to help prevent fuel slosh from side to side in high G load Oval-Track, or Road-Race applications. It is common on certain engines to have lean cylinders do to fuel slosh. A SBC oval track engine running on methanol can run lean on cylinders 3 & 5 while cylinders 4 & 6 will run rich. A plenum divider can help eliminate this.



Spacer thickness. Varying the thickness of your spacer will affect how it affects your engine. Normally the thicker the spacer the more of an affect if will have on your combination. Meaning if a ?? thick spacer helps you a little a 2? thick spacer can give you more of the same affect.



Spacer Material. There are many different types of materials used for manufacturing spacers. They all have pro?s and con?s. Wood for example is a great material as far as thermo efficiency, but can wick fuel, which is not safe. Plastic, or composite spacers are also very good at not transferring heat, but are not as strong, and can be harder to modify. Generally Phenolic fiber, or Aluminum is preferred. Phenolic is very good at not transferring heat, but can be hard to modify. Aluminum is not as good at heat dissipation, but can be ported or modified easily to work on specific applications.



Spacer Tuning. Since each spacer will react differently on each combination there is not a right or wrong type. Spacers are a great tool to have to help dial in a new combination, or tune your racecar for varying track conditions. Swapping out a spacer is a very simple change that can have great impact on the drivability of your streetcar, or racecar. Having a couple types, and thickness of spacers around is always a good investment.





ANY OPINION AND ADVICE ARE WELCOME !!!



[/quote]

beato te che capisci l'inglese, per me ? Gaelico !

io so che serve soprattutto a migliorare la velocit? di caduta della miscela e ha anche lo scopo in certi casi di isolare, per quanto possibile, il carburatore dal resto del motore ad esempio negli Edelbrock ci sono problemi con la messa in moto a caldo e qualcuno li monta per tamponare il problema (addirittura ci sono alcuni modelli in legno !), chiedo perdono in anticipo per le eventuali cappellate ed aspetto con trepidazione l'intervento dei "Guru"...

[Guest]

forse ho capito male ,hai detto che vuoi mettere uno spacer tra intake e manifold ? o volevi dire tra intake e carburator ?

perdonatemi ,ma sono gi? alla frutta della giornata..

[chevy350]

Beh praticamente l'art(in breve) spiega le varie tipologie di "spacers" e caratteristiche,e materiali di cui sono costituiti.



Il maggior beneficio in termini di isolamento lo hai con quelli in "phenolic".



Poi hai due tipologie grossomodo quelli aperti "Open Spacers" e 4-Hole Spacers che ricalcano i 4 barrel(corpi) del tuo carburatore e per finire spreader bore (due meta').



Oltre ad avere il beneficio dell'immettere miscela aria benzina nelle camere combustione in questo modo aumenti la lunghezza dei condotti di aspirazione edi conseguenza la velocita' d'immissione della stessa.



Gli Open Spacers sacrificano i bassi e hanno un maggiore rendimento agli alti regimi.



4-Hole Spacers spostano il tiro/coppia in basso.

Questo ? un misero riassunto ovviamente.



Ovviamente le migliorie devono essere ad un buon set up di motore altrimenti l'unico beneficio che si puo' avere ? quello di raffredare la miscela aria benza.

Io lo voglio installare appunto per avere un po' di benza piu' fresca,ho un edelbrock e in effetti a caldo stenta leggermente a partire.



Per i commenti piu' tecnici lasciamo spazioa piu' illuminati!

[chevy350]

[quote name='Micael Wittman' post='298339' date='29/6/2010, 16:37']forse ho capito male ,hai detto che vuoi mettere uno spacer tra intake e manifold ? o volevi dire tra intake e carburator ?

perdonatemi ,ma sono gi? alla frutta della giornata..[/quote]





Hai ragione oscritto na' vaccata,ho corretto !



Grazie

[Ricky426]

Aggiungerei che servono sopra a un single plane tipo Edelbrock Victor. In quel caso i condotti sono studiati per essere uniformi e pi? dritti possibile.

Sopra ad un dual plane non ? che facciano granch? perch? generalmente le curve sono molto accentuate e di diversa lunghezza.



In sostanza la fluidodinamica di un collettore disegnato pensando poco alle prestazioni non si migliora con uno spacer ma cambiandolo con uno serio.

[mopar]

Utili quelli in cartone/resina fenolica per isolare il carburatore dal caldo dell'intake. Qualcosa fa.

[Guest]

Tempo fa leggevo di una modifica fatta fra spacer e manifold sul 390 cadillac del 1959. In pratica una piccola guarnizione in metallo che impediva le sfiammate, molto frequenti su questo modello. Sopra la guarnizione in cartone morbido, in mezzo lo spacer, poi altra guarnizione. Un sistema semplice ma che impedisce le grandi sfiammate e regola meglio il lavoro del carburatore.

[Guest]

io lo farei in bachelite.....cosi a naso...

tiene altissime temperature me ? uno scarso conduttore, con il risultato di maantenere piu freco il caburatore perche fisicamente isoli metallo su metallo, nel caso specifico alluminio, ottimo conduttore termico...

ma nn credo che serva poi a molto a motore e ventole ferme da un p?, sotto il cofano questi motori han dei tempi di rafreddamento eterni...quindi il carbu finisce per scaldarsi lo stesso, certo non come se fosse connesso metallo su metallo...