ignition performance mods?

[Gixx1300R]

The Busa's coils sit directly above the spark plugs.There are 4 of them.I dont know of anyone that has changed coils yet.Contact TurboRick or Frank on this one.

 

[Guest]

Can you replace coils with hotter ones or anything? Like a hi-po cap?

Kurt

 

[Guest]

I called JohnnyCheese and he got one off the shelf and read me the numbers, I've been looking all damn morning for nippondenso sites that would give up the specs on the MOSFET, no luck yet.

If anyone out there is in the semiconductor industry, please comment.

Suzuki part # 33410-24F00,
mosfet id # is J0396

thanks

 

[Guest]

I am in the semiconductor industry. I design ASIC validation PWB's, among other things. If you have a manufacturer and a part number AND the device is not proprietary I may be able to help.

 

[DaveO]

Kurt,

If I understand you correctly there is a mosfet in the plug cap?? Where did you get this idea????!!!

You peaked my curiousity so I pulled a plug cap off my Busa. I see NO signs of anything other than a normal Xformer. Markings on the cap are:

129700-3960 (probably OEM part #)
J0396 (possibly date code,3rd week 1996)

I also checked my service manual for the schematic, they show just a Xformer, no active devices. A resistance check of the device supports this. I think more than two input connections would be required to switch the gate on/off, and energize the primary. And why bother, this is done in the ECM anyway.

Not trying to knock your idea of improving the stock ignition...but this is the 2nd time I have heard someone claim there is a solid state device in the plug cap. I work in this field, and find no evidence to support this. If you can explain this to me, I will stand corrected......

Dave

[This message has been edited by DaveO (edited 19 June 2000).]

 

[Guest]

Thanks for responding, Tom. It's a Dennso device, I think I'm going to have to get ahold of one(the whole spark plug cap) and slit it open to get to the actual mosfet device. I searched hi/lo on nippondennso and dennso pages for the numbers on the top of the plug, nothing.


Anyone, the part number for the 750 cap is different from the 1300, it's a -35F00 vs. 1300's -24F00---what's the diff? More current, less? Has anyone ever tried them on a busa?

Thanks,

Kurt

[This message has been edited by 'lantabusa (edited 19 June 2000).]

 

[OB_Animal]

Partnumbers with 24F in the second string indicate it's Busa specific and thus (at the time the Busa came out) not used on any other Suzook, that's all the partnumbers can tell you I'm afraid.

Guess that if you had both OEM workshop manuals you could compare ALL specs related to this, especially the digital multimeter checks described there on these parts like resistance for the primary and secondary side etc. etc..

[This message has been edited by Animal (edited 19 June 2000).]

 

[Guest]

This is getting dang frustrating.

Where I'm going with this is,

a) it would be simple to build a little opamp circuit for each of the source voltage ECU outputs to the caps, but am afraid to do it until I KNOW the cap's mosfet can handle the additional load.

b) if I could find the characteristics on the device perhaps it could be replaced with a semi that turns on harder(more current capability).

c) I GUESS the only way to see if the 750 cap is hotter or colder would be to buy them and see if the bike goes rich or lean...

Wish I still had access to an Oscope, my fluke is way too slow to sample the gate trigger. Maybe that could even be amp'ed to turn on the mosfet harder...??? Tom, comments?

Kurt

 

[Guest]

Dave, I'm going by what I was told by someone else, I don't even have my manual yet thanks to my shop who 'forgot' to order it 3 weeks ago when I handed them my Visa. After I started this post I went out on the web and freshened up on mosfets and started wondering what in the world kinda mosfet can work on only 2 i/p's, so my bet is you're probably right.

Well, what do you think? Is there anything we can do? What do you think about an opamp cranking up the o/p of the ecu?



[This message has been edited by 'lantabusa (edited 20 June 2000).]

 

[OB_THE MOTORHEAD]

yea ive seen it at mosfet why not ask them.http://www.irf.com/product-info/auto/app-info.html

 

[OB_THE MOTORHEAD]

service manual?i have a brand new spare at home!!!!fires every 720 degrees.why not carp f-1 coils/they use them too!!i know price .hey just a thought

 

[Guest]

well duh. Posting too early in the AM---3rd connection would be the plug itself, so;

high side is source(from ecu) trigger from ecu is gate, plug is drain...???

Been a long time since I actually worked on mosfets and such, been 'puter geeking too long!

 

[Guest]

thanks themotorhead!!!

Circuit to Get High Voltage from an Ignition Coil
------- HV out
)
)
-------------------- )
| | )
| ----------------------- )
| | 8 7 6 5 | +----- +12 volts
| | | )
| ) 555 timer IC | )
| | | |
| | 1 2 3 4 | +-----
| ----------------------- D| |
| | | G | --| |
-------------+-VVV-+---------------| V 130 or 150 VAC MOV
| Timing | --| |
| Resistor IRF730 S| |
| or IRF740 +-----
| power |
----- Timing MOSFET |
----- Capacitor |
| Gnd
Gnd

 

[DaveO]

Kurt,

I looked up the link MOTOR provided. Yes there are MOSFET devices to control the new "coil caps". If I am NOT mistaken, these are the devices in the ECM which are energizing the primary side of the coil. These are substitutes for the normal bipolar transistors normally used. I assume higher peak current/voltage is their advantage.

I see NO reason to locate these devices in the plug caps, since space is at a premium. Also these devices need to "sink" heat, therefore they are probably heat sinked in the ECM case. The plug cap would be an undesirable environment of choice.

As for the plug being the "gate" connection, do you understand the coil layout in the cap?? I don't think so....The switched +12V from the ignition is common to both coils. The other side of the primary goes to the ECM to control/collapse the field causing the discharge.

The other side of the secondary goes where?? You guessed it, the plug center, where it archs across to the gnd electrode during discharge, completing the circuit. I suggest you get your hands on a service manual and look over the ignition circuit.

As for increasing the primary's input voltage...YES that would increase the secondary's output voltage, reulting in a stronger spark. The question is what is the max peak voltage that can be applied to the primary....only Denso knows that.

Dave

 

[Guest]

Thanks, Dave. Like I said, it's been about 4 years since I was a component level tech working on 2 way radios(Motorola, etc).

I'm guessing we're probably not seeing more than 20KV, and could potentially goto 40KV if we can figure it out.
Called idiot shop again today, still no manual...WTF? Are they back ordered?

 

[DaveO]

Kurt,

Here goes:

What I "think" is that the OEM ignition on our beloved Busas is damn good "out of the box". I have NO data to support my opinion that it will be tough to get more than small gains by boosting secondary coil voltage.

By adjusting ignition curve, and full advance, there should be modest gains. I doubt that increasing the output V of the coils will gain much. Like I stated earlier, a turbo/N2O/blown application will be different. A piped/airbox modded engine is NOT a big change in my book, therefore my belief that the stock coils work well enough.

To really approach this correctly, one would need to characterize the existing ignition ckt. I would start by measuring the 2ndary output voltage. If it was NOT >20KV, then I would agree with you. But I would bet it is much greater than 20KV, I was getting those values on the old POS KZ1000 coils back when I worked on them. BUT I have NEVER measured a "stick coils" output. I would have to set it up on the bench, and trigger it with a generator. Keep in mind the GM HEI ignition's of the 80's could generate 35+KV's, do you think current technology has gone backwards in that area?

My mindset comes from working in engineering for the last decade+. Back in the early 80's it was EASY to improve on existing designs on cars/bikes. That has changed dramatically nowadays. We CAN improve, but usually at a compromise somewhere. Most engineers strive to produce the highest quality products possible, cost considerations aside. I believe the Denso engineers to have the same mindset. Then you ask, why can we gain easily from pipe/airbox mods? This is due to sound restrictions of course. There are restrictions on electronic emissions from ignitions also(FCC regulated). You worked on Motorola's, so you know this.

The last bike I had was an FZR1000. I built several motors for this. The strongest was just under 170rwhp(NO bull). Torque was about 88ft/lbs @8500 rpm. While tuning on the dyno, I swapped the OEM coils for 2.2ohm Dyna's. I gained NO HP anywhere, even after trying to rejet the FCR's just to check. The torque/HP curves were identical. This engine had gained 30% in power, and the OEM coils were still up to the task. The only benefit I found, was it started easier when the bike was hot. I assume from a hotter spark at low voltage.

To be fair, I am assuming the stick coils to be equal to/or better than their predecessor's. If this is NOT the case, then a switch to aftermarket coils will show a gain. I still maintain that YOUR time would be probably better spent looking for HP in other areas. But I DO respect your ideas/thoughts.

Now what about unshrouding those intake valves.......

Dave

[This message has been edited by DaveO (edited 21 June 2000).]

 

[Guest]

So, Dave, you're saying that Denso went full boat on the ignition and increasing the voltage won't help any? I disagree. If one was to double the voltage(say 20KV) to 40KV you wouldn't be able to richen it up and add power? Remember I'm not talking about stock, I'm talking about full airbox mod, pipe, PC2(my setup).

Thanks

Kurt

 

[Guest]

Dave, thanks for helping, you have me convinced. Reason I started this thread was cuz I'd never seen ANYONE discuss ignition.

You're definitely qualified IMHO, to speak with impunity on the subject!

themotorhead, how are those cleaned up throttlebodies doing???

Thanks all

Kurt

 

[OB_gsxr1300]

Here's a tip that might be worth looking into...
The coils off the new Corvettes, maybe a nice replacement for the Busa. I'm looking into them for my TurboGPZ