Jump to content

Who wants to know more about their CDI?

By mrriggs,
in DRZ400/E/S/SM

 Share

Recommended Posts

Enthusiast

mrriggs

Posted
Posted

Playing with the TPS has got my mind going. It seems no one has really mapped the CDI box to see what the advance curve is and how the TPS effects it. I've done a bit of ignition work in the past. When I was drag racing I designed and built my own crank triggered programmable ignition for my car so I could make changes from the drivers seat. One night I gained 4 mph through the trap without ever shutting off the car or taking off my seat belt. Wish jet changes were as easy. There is a lot of power to be had from the right "curve". There was as much gain from ignition changes as there was from jetting. I'm surprised with all the jet talk around here there aren't more guys tweaking the ignition. I'd like to bench test the CDI and map out the advance. I can build a box that feeds it crank sensor and TPS readings and measures the output. May even tackle building my own adjustable CDI box.

Few things I need to know first. I don't have my manual in front of me but I seem to remember there are two crank sensors. Where are the two crank sensors in relation to TDC? I assume one is 40-50 degrees before and the other at TDC, that's how most cars do it anyway. Does the CDI read the rising or falling edge of the signal? I can figure out the crank sensor if I have to but if someone already knows then it would save me some work. Also, where can I get the OE wire pigtails to plug into the CDI?

Link to comment
Share on other sites
  • Replies 41
  • Created
  • Last Reply

Top Posters In This Topic

  • 3

  • 9

  • 4

  • 7

Popular Days

Top Posters In This Topic

Popular Days

Grand Master

10guy

Posted
Posted

Don't really care what their maps look like, so far have avoided even being told that they are different. Trying to keep an open mind. I do know that I can not only tell the difference between the different ones, but not between the same ones, but that I can do it fairly quickly. Just a short ride is all it takes. My bike seems to be fairly tolerant as far as running these, starting them is different but it will do it with a fresh battery. Not after starting and stopping 20 times in a 1/2 hour though. Replace with stock cdi and fires right off.

Link to comment
Share on other sites
Community Regular

duckjyb

Posted
Posted

10guy, it's really hot here, and I cannot for the life of me follow that last post!

Riggs, if you've got the equipment and know how, I'd like to hear what you find. I think you're right, that there could be some gains with tuning the ignition curve. It would be difficult, I think, to recreate the box however, and still have the same physical realibility.

Link to comment
Share on other sites
Grand Master

10guy

Posted
Posted

I was concurring that there is definatly some gains to be had with more aggressive mapping. I also think that that is exactly what procom is working on right now, can't say for sure though because I have intentionally left myself in the dark on it. I don't think they are working on just the rev limit which had been one of the issues before.

I was also humored by the idea of more testing after the last weekend. My bike was either fun to ride, really fun to ride, or get me off this damn thing to ride.

Link to comment
Share on other sites
Grand Master

Noble

Posted
Posted

Few things I need to know first. I don't have my manual in front of me but I seem to remember there are two crank sensors. Where are the two crank sensors in relation to TDC? ----- There is one inside the flywheel and one outside. I do not know how these work together.

I assume one is 40-50 degrees before----Sounds right.

and the other at TDC,--- don't know.

Does the CDI read the rising or falling edge of the signal?----Don't know.

I can figure out the crank sensor if I have to but if someone already knows then it would save me some work. ----I think you are on your own.

Also, where can I get the OE wire pigtails to plug into the CDI---ebay a used harness. The E & S harnesses are different as are the CDI boxes but you can improvise. The difference is in the kill wire or the side-stand interlock. S, the interlock wire must be grounded. E, the kill wire must be open.

Link to comment
Share on other sites
Mentor

Redrodent

Posted
Posted

If it's that easy, please proceed. One of the great advantages of a better map is throttle control. I just had my first dirt ride with the Mitsubisi Yosh CDI. In the tight stuff it's an amazing difference. Instead of lurching, chugga chugga, fall over, just smooth control. If this could be reproduced, even with no increase in rev limit, it would sell like hot cakes. You need to look no further than this map. Starting reliably is the problem at this point.

Link to comment
Share on other sites
Enthusiast

mrriggs

Posted
  • Author
Posted

10guy, I've seen the posts about your experiments, I think the blind test is really cool. A great way to test available units. But for guys who are powertuning for every horse being able to adjust the map to fit their setup would be ideal. When you put on a pipe and cut a hole in your airbox you rejet the carb to fit. You don't just buy a box of carbs and swap them out until you find the one that works best. That sounds silly but it is essentially what you are doing with CDI boxes. I'm not saying you're doing anything wrong, it is your only option, I just don't understand why adjustable boxes aren't available. When hotrodding a car you make mods to get more air through the motor then rejet to get the right amount of fuel, and recurve the distributor to get the most of it all. If you can't adjust the stock distributor the way you want you buy an aftermarket distributor, or black box, that is adjustable. Not a one size fits all precalibrated unit. Those Procom boxes are cool and obviously a step above stock but there is no way they can make a box that is tuned perfectly for every bike out there.

I found a few tricks to tweak the stock distributor beyond what it was designed to do. For the average Joe those simple tweaks gave the same effect as an expensive aftermarket unit. Not quite as good, but good enough for almost no money. If I could find a simple tweak for the stock CDI that would give the average rider a little boost that would be cool. I could guess and check and guess but it makes more sense to find out what it is actually doing.

If I made an adjustable CDI it would likely be for my bike only. I tried selling the box I made for my car and it ended up not being worth my time. I don't know anything about manufacturing so they were all hand made, it took too long to be cost effective.

Funny, Redrodent mentioned starting reliability, that was actually one of the trickiest tasks in the box I built. Everything changes so fast it's hard for the proccessor to stay ahead of it. I ended up just bypassing the proccessor with a solid state relay and firing the coil with the crank sensor, when the proccessor figured out what was going on it sent a signal to the relay to turn off the bypass. Crude but effective.

Link to comment
Share on other sites
Grand Master

NateTheGreat

Posted
Posted
If it's that easy, please proceed. One of the great advantages of a better map is throttle control. I just had my first dirt ride with the Mitsubisi Yosh CDI. In the tight stuff it's an amazing difference. Instead of lurching, chugga chugga, fall over, just smooth control. If this could be reproduced, even with no increase in rev limit, it would sell like hot cakes. You need to look no further than this map. Starting reliably is the problem at this point.
Redrodent..... I swear there is a Suzuki part number for that CDI. We just havent figured it out yet..... Imagine what greif it would solve.
Link to comment
Share on other sites
Grand Master

10guy

Posted
Posted

All I'm doing is providing feedback to procom on their cdi's. Only two of those boxes are mine. Of the remaining five there are 4 that are definately different with the fifth being a duplicate. If you can come up with a way to make a user adjustable unit that can be modified for new changes to the engine and still make it cost effective then I'm all for it. The only reason I'm doing it is that for some reason these boxes don't seem to work for other people or they were not able to test them for whatever reason. I'm reporting my findings here as a service to the members of TT. I'm definately not doing it to tweak my own bike, nor would I consider it a way to reach that end. When all is said and done I'm just hoping for an aftermarket box that will allow me to use the 11K I've built my top end to endure, as far as I'm concerned the stock box is still the best bet overall.

Nate- what are the numbers on your mitsu yosh cdi? pm me a pic of it if you can please.

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Reply with:

ThumperTalk

Register a new account Sign In Now
 Share
Go to topic listing
×
×
  • Create New...
Terms of Use
Copyright
Privacy Policy