What's the differnce between Hot Shot Series CDI Box or advancing your timing
- Thread starter lasxgames
- Start date
good memory paulie !!!!
i have never had an advanced timing plate, still to this day ...stock timing.
i did have a hotshot cdi, installed it with the monster coil at the same time, which was on a fresh rebuild, i was still in the break-in period just puttin around in 3rd gear 1/2 throttle when the piston fried a hole right thru it
this was before the easy available leak down testers on here, seems a yamaha dealership had gouged my cases with a screwdriver while installing a crank for me, causing a massive airleak = boom
so i never got to really test out any gains the cdi/coil provided, and was quick to blame them for the melt down, so they got sold on craigslist while my motor went to ken oconnors for repair, then he found the case gouges/airleak was to blame
i've always considered giving both items another try someday ???
as i understand it, the hotshot cdi adjusts the ignition curve as the rpms rise, versus the advanced +4* at "all rpms" the timing plate or keyway provide
adjusting the timing per rpm's makes more sense to me over always advanced ???
i would not run a hot shot cdi with an advanced plate or keyway.
there are far more reliable ways to gain power than flirting with dangerous timing advances, IMO
I've been doing a bunch of research on the CDI system that yamaha uses. The blaster seems to be a bit of a "black hole" as far as the EXACT timing specs go BUT I can give generalizations.
No CDI unit on a jap quad has a "flat" timing curve. Flat timing curve means that it has no retard or advance, just wherever the pickup is set, it fires. They all have some form of timing control based on engine RPM. Common advance (on most mild 2 strokes) is ~25 deg BTDC at maximum RPM's which tapers down as it nears idle to nearly perfectly TDC to reduce kickback during starting and to ease the idle.
Moving the timing plate ADDS to that base timing all the way across the board (so ~ 4 deg advanced at idle and ~29 degrees advanced at maximum RPM).
The aftermarket CDI boxes have a completely different timing map HOWEVER, in my research, I have not found a single instance where an aftermarket CDI can increase the total advance beyond that which the stock CDI can. That's because the maximum advance is set by the manufacturer with flywheel position in relation to pickup position. The recalibrated ignition map on the aftermarket CDI's are mainly written "in the middle" to get more power at mid rpm instead of top end.
No CDI unit on a jap quad has a "flat" timing curve. Flat timing curve means that it has no retard or advance, just wherever the pickup is set, it fires. They all have some form of timing control based on engine RPM. Common advance (on most mild 2 strokes) is ~25 deg BTDC at maximum RPM's which tapers down as it nears idle to nearly perfectly TDC to reduce kickback during starting and to ease the idle.
Moving the timing plate ADDS to that base timing all the way across the board (so ~ 4 deg advanced at idle and ~29 degrees advanced at maximum RPM).
The aftermarket CDI boxes have a completely different timing map HOWEVER, in my research, I have not found a single instance where an aftermarket CDI can increase the total advance beyond that which the stock CDI can. That's because the maximum advance is set by the manufacturer with flywheel position in relation to pickup position. The recalibrated ignition map on the aftermarket CDI's are mainly written "in the middle" to get more power at mid rpm instead of top end.
i would guess thats what the hotshot cdi does, advanced on the bottom and retard the timing as the rpms increase
as it does advertise higher rpm's
hence why i've never done the +4 timing plate, and not sure i've ever found the top rpm limits, it just keeps pulling and pulling till i get worried and leave off
No need, I'm looking at making my own programmable CDI box. If you set the trigger coil REALLLLLY far advanced (more than you'd ever need) and then delay the event a given time, you could have a completely adjustable (more than good sense says you need) ignition system using only the electronics of a PIC chip board.
Blaner
Your Friendly South African Ambassador
I share your doctrine boet. its a scaly way of producing power....kinda like NOS
I should add that the CDI box I'm planning on building and tuning is for my dragger, running EXTREMELY slow burning fuel. The tune I'm talking about running is not the same as what might work with a stock blaster. In fact, a stock blaster timing system won't hardly work for a setup like I'm going to be running anyway.
i'm not really seeing why the +4 is even a popular mod, it gives you mainly bottom end, slight mid gains, then losses of top end/rev out if i'm understanding this correctly ??
where above it was stated the aftermarket cdi's are mapped for mid gains, and retard timing for further rev out, where prolly 99% of us would benefit from it
where above it was stated the aftermarket cdi's are mapped for mid gains, and retard timing for further rev out, where prolly 99% of us would benefit from it
Actually, the +4 timing mod increases the stock timing across the board (including the maximum advance available) but the real gains you can "feel" are in the middle.
The aftermarket CDI box changes the timing map but cannot advance the upper end timing past that of the stock CDI box (limiting the upper end power to some extent)
I'm not sure were sicivicdude was with his PIC, but he is correct, AC-CDIs can only retard timing, not advance. Max timing is set at the stator/flywheel, the CDI can only retards timing from there.
The CDI cannot increase spark voltage. That is done at 2 places. The source coil on the stator, and the ignition coil before the plug. The stator will put out about 200 volts. The ignition coil steps this up considerably.
I plan on tearing down one of these hot shot CDI's if i can get my hands on one. But from what i can see, they are physically the same size and more than likely are exact replacements for stock with no changes.
The stock CDI doesn't have room for any components to adjust the ignition curve. It's as flat as they could make it. In turn, I've been slowly working on an adjustable CDI with ignition curves that can be adjusted. Due to the original statement, the CDI will probably require a 4-8 degree advance to really reap the gains. It's going to be tuned for the entire RPM range of these machines. It'll also retard at idle so it can be kicked without breaking your foot! I've got a thread of this somewhere... lol
The CDI cannot increase spark voltage. That is done at 2 places. The source coil on the stator, and the ignition coil before the plug. The stator will put out about 200 volts. The ignition coil steps this up considerably.
I plan on tearing down one of these hot shot CDI's if i can get my hands on one. But from what i can see, they are physically the same size and more than likely are exact replacements for stock with no changes.
The stock CDI doesn't have room for any components to adjust the ignition curve. It's as flat as they could make it. In turn, I've been slowly working on an adjustable CDI with ignition curves that can be adjusted. Due to the original statement, the CDI will probably require a 4-8 degree advance to really reap the gains. It's going to be tuned for the entire RPM range of these machines. It'll also retard at idle so it can be kicked without breaking your foot! I've got a thread of this somewhere... lol
