CDI - Kada bi trebalo tj. mora ?

[Gumetina]

Pozdrav svima

Imam jedno interesantno pitanje ...

Kada je potrebno da ne kazem neophodno ugraditi CDI tj pri kojim snagama po cilindru ili pritiscima punjenja ili hladnoci svecica ?

Poceo sam da imam problema na 2 motora sa cca 100ks po cilindru pa se pitam da li je moguce da fabricka bobina "ne ume" ?


Kad smo vec tu, koji cdi kupiti, koji je bolji, jeftiniji, ima da se kupi itd ?


pozzz

RAle

[cvrle]

Re: CDI - Kada bi trebalo tj. mora ?

Mislim da nema deklarisano za koje snage je potrebno konretno vec do samog projektovanja motora i njegovih mogucnosti. Neke fabrike to stavljaju u serijske automobile jer su po koncepciji namenjeni za sportsku voznju i veliku potrosnju struje iz bobine pri visokim obrtajima.

Evo neki uopsteni tekst sta, kako i zasto :

A conventional induction ignition creates a spark by applying electric potential (12 volts) to the primary side of the coil. The coil steps the primary potential up to as much as 10,000 volts and delivers this high voltage to the spark plugs. However, this "step up" process is relatively slow, and as crank speed (rpm) increases, the secondary voltage declines dramatically.

This limitation was partially solved by the development of capacitive-discharge ignition (CDI) systems. Instead of applying 12 volts to the coil, a CD ignition increases the primary current by storing it in a kind of miniature battery called a capacitor. When this higher primary current is applied to the coil, the secondary voltage is dramatically increased.

The principal advantage of a CDI system is the ability to present a superior spark to the air/fuel mixture inside the combustion chamber, thus maximizing burn efficiency. The easiest way to get a bigger spark is to increase the spark plug gap size. However, increasing the gap distance also increases the voltage necessary to ionize the air/fuel mixture. And the resistance of the air/fuel mixture increases as the mixture is pressurized in the cylinder, requiring even higher voltage to spark across a plug. A CDI system provides the higher voltage required by the increased spark plug gap size, thus providing very intense spark.

A CDI ignition system can create spark potential as high as 37,000 volts. Most engines only need about 20,000 volts for reliable ignition. The stock system begins to 'droop' as the rpm goes up. At highway speeds, the spark voltage becomes more and more marginal, averaging about 18,000 volts. With a CDI system, the step up process is very fast compared to a conventional 12-volt induction. This assures a more consistent spark delivery across the plug gap, even at very high crank speeds (rpm).

Vrlo je moguce da fabricka bobina nema dovoljno snage da podrzi i da prilikom visokih obrtaja slabi i pocinje da luduje jer je predvidjena verovatno za dosta slabiju potrosnju.

Jedna od najpopularnijih firmi koje znam je MSD Ignition, cak sam imao u planu da kupim nesto slicno ali sam trenutno odustao zbog drugog jeftinijeg resenja, a opet pouzdanog. Mozda bi ti zavrsio posao model MSD 6AL plus neka ozbiljnija njihova bobina, ima ih dosta na ebay-u. Prosvrljaj malo na njihovom sajtu, pa pogledaj karakteristike modela i sta nude.

www.msdignition.com/

[Type_R]

Re: CDI - Kada bi trebalo tj. mora ?

ford 37kV komad

[Gumetina]

Re: CDI - Kada bi trebalo tj. mora ?

Znam ja vrlo dobro kako funkcionise sistem paljenja, i sta je dwell

Mene zanima da li je neko imao iskustva sa ovim problemom, ili iskustva sa cdi modulima (skuter , motocikli tj AC CDI me ne zanima) uopste....

Isto tako, msd 6a je model koji tera jednu bobinu, a ja ih imam 6 tj 4

Neko ?

[fire]

Re: CDI - Kada bi trebalo tj. mora ?

Obicno problemi pocinju pri 200-250 konja po litri s manjom turbinom.
Na jednome autu bili problemi na cca 150konja, ali je ispalo da je katalizator bio zagusen pa se stvaro jako veliki backpreseure.