Do performance CDI's REALLY perform

[SLESTAK75]

I am sure that many have tried these nifty devices. I have read on some forums that they are not worth it. I was just wondering (before I spend) what is the general opinion of Performance CDI's.

[MASTERBATES]

Im pretty curious too. i have been eyeballing a couple different versions on amazon. i can tell u a performance coil is worth it though.it would be nice if there was a single wire u could just snip to the c.d.i to override the rev limiter (trick for hondas 450R). but i dont think its possible with these gy6s

[xlint89]

Yeah, some do work. Some advance the timing (improve accel a bit) as well as eliminate the rev limiter (allows a higher top speed, but can also cause engine damage from over-revving) With these though, I think you really do get what you pay for.

The NCY (around $40) works pretty good. Then some guys have used and like the adjustable CDI/coil combo.

[Johnny 5]

I bought 2 orange performance cdi from scrappy dog scooter for 20 bucks each. My red buggy runs good with it. After installing it I had to turn the idle down and went from a 120 main to a 122 main. The engine is a 58.5 srp higher compression kit with a mild port job done by myself. On my wifes blue dune 150 it ran better with the stock cdi. The advance in the timming will help on take off and low end . I think it is worth , I did back to back runs from stock cdi to performance and could feel a gain in take off on the red buggy.
The variator in the red buggy is a dr2 with 8/9gram rollers.
The blue buggy had a doctor pulley variator with 10gram sliders, this may have something to do with the reason why the blue buggy ran better with the stock cdi.
Also the pick up sensor on the magneto could be more advanced than the red bugggy engine causing it to have enough advance allready.
Our last trip I had to put the orange cdi in the blue buggy because it would cut out at 7200rpms. We keep some spare parts with us on the trail and I was glad that I had the orange cdi in the back pack. We were about 5 miles from camp.
So if you get a perf cdi you can keep the stock one for back up.

[SLESTAK75]

I would definitely never throw away a perfectly good part. So it seems the answer is like most others....really depends on other factors. My plan is to build a low to mid powerband and gear mildly high while tuning the CVT to shift slower. So I think ill go ahead and get an orange cdi and coil. At the very least ill have a backup. Thanks for the opinions.

[SLESTAK75]

Originally Posted by Johnny 5

I bought 2 orange performance cdi from scrappy dog scooter for 20 bucks each. My red buggy runs good with it. After installing it I had to turn the idle down and went from a 120 main to a 122 main. The engine is a 58.5 srp higher compression kit with a mild port job done by myself. On my wifes blue dune 150 it ran better with the stock cdi. The advance in the timming will help on take off and low end . I think it is worth , I did back to back runs from stock cdi to performance and could feel a gain in take off on the red buggy.
The variator in the red buggy is a dr2 with 8/9gram rollers.
The blue buggy had a doctor pulley variator with 10gram sliders, this may have something to do with the reason why the blue buggy ran better with the stock cdi.
Also the pick up sensor on the magneto could be more advanced than the red bugggy engine causing it to have enough advance allready.
Our last trip I had to put the orange cdi in the blue buggy because it would cut out at 7200rpms. We keep some spare parts with us on the trail and I was glad that I had the orange cdi in the back pack. We were about 5 miles from camp.
So if you get a perf cdi you can keep the stock one for back up.

So now I know that mine is a stock CDI kinda buggy. A lot more resposive across the board with the stock. I noticed with the perf CDI it would smoke. And when I try to adjust the carb I screw the a/f screw all the way in with no affect. In fact the crew did nothing until about 4 turns out then started really running like crap. The throttle response was way more sluggish with the perf CDI. Oh well. At least I have a spare.

[xlint89]

Which cdi did you buy?

[SLESTAK75]

I just got the orange one. While a more expensive one may work better I will just stick with stock. It actually runs really good with it. I think its like Johnny said. The pickups are inconsistantly placed so that some already have more advance than others.

[mb1134]

I for one decided to stick with the stock CDI. I tried the NCY, which they claimed was able to be used on an AC or DC buggy, but did not work on my DC buggy. The buggy seems to run great for now with the stock CDI, so im just leaving it. Everyone notices things differently when it comes to their buggy. Some prefer not to upgrade certain parts and believe the stock version works just as good. Just depends on you and your buggy.

[bear]

I agree, and thankfully, these are very easy to work on and change out!

[xlint89]

I tried one of the cheap orange CDI's and it did OK. That along with the cheap orange coil I installed at the same time, made my Yerf start and idle better/smoother.

However, it didn't take long for the coil to go bad, so I bought the Bando coil from Tom. It was around that time that I did some more research and saw one of the supporting vendors on the other site highly recommend the NCY (aluminum cased) CDI and decided to try it since they had the "Christmas sale" going on.

I found it to have a little better acceleration than the cheap orange one and have run it ever since.

For anyone that thinks any bolt on part is going to make a huge difference is sadly mistaken. But every little bit does add up to a significant gain over stock.

As for that 3rd generation NCY CDI stating that it works on BOTH Ac and DC I find that hard to believe. I have read that in the description on Ebay as well, but still don't believe it could work on either system.

[Johnny 5]

As for power gains from the motor the best result I have had is from the port matching and cleaning up the casting lines in the head.

As for the trans the sliders and torque spring were the best bang for the buck. All the other mods add to each other for the total package.

[Masteryota]

As far as ignition advance goes, the more modded the engine, the more effective the advanced timing is. The reason you guys are seeing minimal changes with stock, or near stock engines, is that the advanced timing has very minimal effect. High compression, high flow, high RPM engines will benefit most from advanced timing. I like the idea of the adjustable timing advance based on the idea of trial and error and fine tuning, but I know they can be quite expensive compared to simpler units.

[xlint89]

Originally Posted by Johnny 5

As for power gains from the motor the best result I have had is from the port matching and cleaning up the casting lines in the head.

.

Agreed

[SYCARMS]

OK here I go again. On the older Buggies with AC volt cdi, a performance cdi will help the performance. The newer DC volt systems will bennefit little to none. The reason is: the cdi has several functions one of which is timing advance. Its important to realise that most of all perf cdi's are designed around a much lighter scooter driving one wheel, so when the advance comes in will be totally different between a buggy and scooter. Now another function of the cdi is the spark duration. In an AC system spark duration is short by nature so added circuitry is used to boost spark duration. In a dc system the spark duration is naturally longer. There are many different perf cdi's out there. It would help greatly if specs were listed on them like where timing advance takes place as well as spark duration. I have tried several of the adjustable timing cdi's but have not yet found one that will hold that timing for the long haul, and being that the means used is from a dashpot adjuster these tend to not adjust over time due to the shoch they take. The early msd cdi's for racing atv's had the same problems. The dashpot adjustment is not for offroad punishment and the reason why msd now uses semiconductor technology using the laptop to adjust timing, which drives the cost way up. Bottom line is the older AC systems will bennifit from the perf cdi for these were scooter engines and components put into our buggies. The DC systems first off due to epa regulations have to be designed for our buggies so using a cdi from a scooter will actually hurt performance in some part of the powerband.

[SLESTAK75]

And mine is a DC model.

[Miamieddie]

Cdi makes motors rev at high rpm. If you make ur motor rev higher then recommended you will burn ur motor up!! . .... if your motor is hopped up then go ahead ...... go for it. But it still don't mean you wont burn ur motor. We all know when you start high performing motors youve taken away the reliability, ndurance, durability, reliability, of your motor. With that said if you want to play you've got to pay...... Eddie.

[xlint89]

Originally Posted by SYCARMS

OK here I go again. On the older Buggies with AC volt cdi, a performance cdi will help the performance. The newer DC volt systems will bennefit little to none. The reason is: the cdi has several functions one of which is timing advance. Its important to realise that most of all perf cdi's are designed around a much lighter scooter driving one wheel, so when the advance comes in will be totally different between a buggy and scooter. Now another function of the cdi is the spark duration. In an AC system spark duration is short by nature so added circuitry is used to boost spark duration. In a dc system the spark duration is naturally longer. There are many different perf cdi's out there. It would help greatly if specs were listed on them like where timing advance takes place as well as spark duration. I have tried several of the adjustable timing cdi's but have not yet found one that will hold that timing for the long haul, and being that the means used is from a dashpot adjuster these tend to not adjust over time due to the shoch they take. The early msd cdi's for racing atv's had the same problems. The dashpot adjustment is not for offroad punishment and the reason why msd now uses semiconductor technology using the laptop to adjust timing, which drives the cost way up. Bottom line is the older AC systems will bennifit from the perf cdi for these were scooter engines and components put into our buggies. The DC systems first off due to epa regulations have to be designed for our buggies so using a cdi from a scooter will actually hurt performance in some part of the powerband.

That's an Xlint explanation. Thanks Tom

Now it makes more sense why I noticed a gain and some guys don't. AC/DC

[SYCARMS]

Originally Posted by Miamieddie

Cdi makes motors rev at high rpm. If you make ur motor rev higher then recommended you will burn ur motor up!! . .... if your motor is hopped up then go ahead ...... go for it. But it still don't mean you wont burn ur motor. We all know when you start high performing motors youve taken away the reliability, ndurance, durability, reliability, of your motor. With that said if you want to play you've got to pay...... Eddie.

When you consider how most of us drive our buggies the hopped up motor if done correctly will be as reliable as the stock. The reliability is lessened not from building it but from the abuse we give it. When a built engine looses it's reliability for other than pure abuse weather built or stock it is due to using substandard parts or due to the way the engine was built. The same is true with cars. The people I know who race on a budget 1 never win and 2 are alway's tearing into their engine. The fact is people who build on budget actually spend more in the long run in money but mostly time which equals money. Also knowing the limits of ones buggy helps as well.

[Miamieddie]

That makes a lot of sense sycarms... thanks!!