i am lookin to buy a z400, and i am adding mods to it, and the first thing is a cdi rev box, what is a good one out there?....and wat kind of price do they have?....post a good suggestion!!!!!

 

I think the very very best cdi out there is the dyna fs programmable. They run somewhere around the $400 range, and another $100 if you want the software to reprogram them. Expensive, but you did ask for the best. You can set your own curves, rev limits, it has a tachometer output, programmable outputs for shift lights, nitrous, etc., just about anything you could want in a CDI unit.

 

I really don't understand why people like rev boxes. Unless the motor's power curve is still on the way up above the rev limiter's mark, you won't be accelerating much faster. You will be able to run gears longer but, this doesn't mean you are making better times. I'm sure there are cases where the stock rev limiter is too low.. in that case it would help but, at what risks? There could be zero risks or you could be on the edge of floating valves. Running a higher limiter should be thought as something that is there only when you need it.. not something you push hard everytime you go around the trail.. A lot of people think they are racing hard by bouncing every gear off the rev limiter.. I think it just means you really don't have enough power to be racing whoever is next to you or you just don't know when to shift. I almost never mess with rev boxes until the valves/springs are setup to run the higher Rs. I'm not saying all rev boxes are bad.. i'm just saying to make sure you know your shift points instead of hitting the rev limiter. You may find out the speeds come out the same. If you feel the motor has more power left in top gear then change your sprockets. Anyone who has let a 4 stroke rider on their Banshee for the first time knows how bad it can be to watch.


I was typing when recon99 posted.. I agree with what recon99 said. If you are looking for a full aftermarket CDI with lots of options go with the dyna. But....if you just need a rev box, it may not be worth the extra cash.

 

There's more to it than just an increased rev limit. Heck, yamaha warriors don't even have rev limiters from the factory. A rev box changes the spark timing to gain some power and throttle response. In the case of the dyna, it lets you program your own timing curves or use 4 pre-programmed ones. The most aggressive pre-programmed one is so aggressive you can't use it with stock valve springs or it'll float the valves like crazy. In my opinoin there are better mods for you money, at least until you get some more basic mods like a piston, cam, springs, etc.

 

Trust me.....The Dyna FS is worth every penny.....

 

Oh yeah.. I totally agree with having better timing curves. The Dyna does all this plus more. The problem is, I have seen shops selling hacked up CDI boxes that remove or change the rev limiter. They try to make it sound like its some magic box that will turn it into a whole new quad. And thats fine, some give you a better timing curve and remove the stock limiter (if there is one) BUT, just like you said, even the Dyna box will let you set it to the point where it is not safe on stock valve springs. Thats the point i'm trying to get across. Some riders push their rev limiter then get an aftermarket rev box in hopes of pushing the RPMS higher without knowing the problems it could cause. I have heard of riders saying the factory wouldn't have put the rev limiter in if they didn't want you to hit it each ride. I just think some bolt on parts, that need no deep knowledge of motors, are over marketed. I'm only talking about the places that market what they call "magic boxes" ..I'm not talking about the Dynatek ignition systems but, they also can cause major problems when used wrong.

 

thanks for the replys, but how is the big gun rev box, i have heard good thangs about them, but never talked to any body wiht one....?

2003* GRIZZLY
2001* PRAIRIE 300

 

We just discussed that they're not going to do much for a stock motor. The curve may add a little power, but probably not enough to feel the difference without a dyno. A higher rev limit on a stock motor just means you can blow it up easier, the peak power on a z400 is about 1000 rpm before it hits the rev limit. If you start doing mods that move the peak power to a higher rpm the rev box has more advantages.

 

mods like what...?...exhaust, or somtin....?...or like what kind of mods, the only big mods i know of is the big bore kit, make it like a 440 or somtin...

 

cam, stiffer springs, high compression piston, port work, and the basic stuff like exhaust and intake.