mopar1rules
Active member
anyone try a cdi box from a viper, on a '00-'02 srx, for a little hotter timing curve? i'm sure you would have to raise the needles a 1/2 to 1 clip, to make up for the hotter midrange timing. so, has anyone tried this?
hysinthius
New member
one of the guys over at a local sled shop said he has used a 600 srx cdi said it was hotter then a 700's. I dont know myself just what i heard. It would be interesting to hear if this true or not.
j
j
600 cdi runs more advance but the 00-02 wiring harness is different. 98-99,s is strate plug & play. Just run a 2-3 degree timing key for racing.
mopar1rules
Active member
turk, how do you think a viper cdi would work on a '00-'02 srx for the trails? doesn't the viper cdi plug and play on a '00-'02 srx? so, the 600 cdi is the ticket for a '98-'99 700 srx? it works for trails too, or just racing?
I would run a timing key for racing & leave it stock for trail riding. 1 bad batch of fuel & somebodies having a bad x-mas!
I have a few questions:
what do you think you will gain by adding more timing?
do you know what timing effects in the engine, as in what all you will get or not get by advancing the timing?
what leads you to believe you need more ignition timing in your engine?
what do you think you will gain by adding more timing?
do you know what timing effects in the engine, as in what all you will get or not get by advancing the timing?
what leads you to believe you need more ignition timing in your engine?
mopar1rules
Active member
what do you think you will gain by adding more timing?
...better throttle response and more hp.
do you know what timing effects in the engine, as in what all you will get or not get by advancing the timing?
...i believe that timing can affect the pressures inside the engine during combustion and that if the timing is advanced too much at near peak rpm, top end will suffer, cause timing needs to be retarded the more rpm's the engine spins. that is what i read in one of my 2-stroke books. timing helps the low-midrange, but can make the top end feel flat.....my banshee atv has proven this. i modded the stock timing plate for +4, and the bottom-midrange improved greatly, along with the throttle response, but the top end felt flat.
what leads you to believe you need more ignition timing in your engine?
...not my viper engine, but my spare srx motor that i have, i was kicking around this idea for. i thought if the viper and srx have the same max operating rpms stock (as yamaha suggests), then the would have the same/comparable timing @ those peak rpms...but everyone says that the viper's have a hotter midrange, so i was thinking that if the viper cdi went on a srx, you would have better throttle response, little more midrange hp (like 2hp) and it would be more fun when on/off the throttle in the twisties.
so mrviper, have you ever tried this before?? would this work??
...better throttle response and more hp.
do you know what timing effects in the engine, as in what all you will get or not get by advancing the timing?
...i believe that timing can affect the pressures inside the engine during combustion and that if the timing is advanced too much at near peak rpm, top end will suffer, cause timing needs to be retarded the more rpm's the engine spins. that is what i read in one of my 2-stroke books. timing helps the low-midrange, but can make the top end feel flat.....my banshee atv has proven this. i modded the stock timing plate for +4, and the bottom-midrange improved greatly, along with the throttle response, but the top end felt flat.
what leads you to believe you need more ignition timing in your engine?
...not my viper engine, but my spare srx motor that i have, i was kicking around this idea for. i thought if the viper and srx have the same max operating rpms stock (as yamaha suggests), then the would have the same/comparable timing @ those peak rpms...but everyone says that the viper's have a hotter midrange, so i was thinking that if the viper cdi went on a srx, you would have better throttle response, little more midrange hp (like 2hp) and it would be more fun when on/off the throttle in the twisties.
so mrviper, have you ever tried this before?? would this work??
I asked because if you dont understand what extra timing does it will destroy the engine in short order and you gained nothing except holed pistons, your reasons are just "throttle response" and not what timing actually does.
when you put timing into a 2 stroke engine you add heat to the piston, retarded timing adds heat to the pipe, think about that!!
FYI- a viper has near 8 degrees more timing at 8500rpm
So I ask again why do you think you need more ignition timing? throttle response is not the answer, you can gain that by lighter clutch weights, roller secondary, or tighter heads.
there are applications where you need more timing, and applications where you dont, depends upon what the engine is being built for, distance run, rpm, alot of differnt varibles. Without knowledge of how it works and why it works, I would suggest you stay away from the engine mods, as "just trying it" will lead to a bucket full of broken parts.
when you put timing into a 2 stroke engine you add heat to the piston, retarded timing adds heat to the pipe, think about that!!
FYI- a viper has near 8 degrees more timing at 8500rpm
So I ask again why do you think you need more ignition timing? throttle response is not the answer, you can gain that by lighter clutch weights, roller secondary, or tighter heads.
there are applications where you need more timing, and applications where you dont, depends upon what the engine is being built for, distance run, rpm, alot of differnt varibles. Without knowledge of how it works and why it works, I would suggest you stay away from the engine mods, as "just trying it" will lead to a bucket full of broken parts.
srxbully
New member
also a viper cdi wont plug into a 2000 srx harness..trust me i know
mopar1rules
Active member
I asked because if you dont understand what extra timing does it will destroy the engine in short order and you gained nothing except holed pistons, your reasons are just "throttle response" and not what timing actually does. when you put timing into a 2 stroke engine you add heat to the piston, retarded timing adds heat to the pipe, think about that!!
i know that too much timing will destroy the motor, if i don't have the required octane, but i was thinking like only 2 deg or so, so i figured that would be ok. i also said hp gains too, not just throttle response...lol. i know that retarded timing puts heat into the pipe. that's why ski-doo has that red button on the 440mxzx sno-cross machines. the racers hold the button down on the start, and are able to hold the throttle down without driving/taking off. the timing gets retarded enough that the sled won't take off, and now the pipe is getting nice and toasty, so when the let go of the button and it goes into non retarded timing, they take off with a hot pipe that will make power.
FYI- a viper has near 8 degrees more timing at 8500rpm
how do you measure/find out the timing curve, of these different cdi boxes? also, if you use '00-'02 srx heads on a viper, and both engines peak at the same rpm, why couldn't the srx motor live/benefit from the viper cdi? i was told the aaen viper pipes are just the same pipes aaen has for the 700 srx, so if it has the same pipe specs, same cc head volume, same cylinder cc volume, same porting specs (race logic template is the same for srx/viper), i still don't see why it won't work. you've delt w/these motors/timing/tuning, longer than i have, so i will take your word for it. thanks for saving me a box of scrap metal and a unhappy xmas.
So I ask again why do you think you need more ignition timing? throttle response is not the answer, you can gain that by lighter clutch weights, roller secondary, or tighter heads.
...but lighter clutch weights are just going to lead to less belt clamp and possibly belt slip (hotter primary temps).
there are applications where you need more timing, and applications where you dont, depends upon what the engine is being built for, distance run, rpm, alot of differnt varibles. Without knowledge of how it works and why it works, I would suggest you stay away from the engine mods, as "just trying it" will lead to a bucket full of broken parts.
it was just an idea i was kicking around. i wonder why +4 timing helps my banshee so much...on the low end that is? i know the top end is now kinda flat, cause of too high of cylinder pressures...imo. thanks mrviper for posting your replies and for your input. your input, as well as everyone else's, is always much appreciated. its always nice, to kick around these different ideas.
i know that too much timing will destroy the motor, if i don't have the required octane, but i was thinking like only 2 deg or so, so i figured that would be ok. i also said hp gains too, not just throttle response...lol. i know that retarded timing puts heat into the pipe. that's why ski-doo has that red button on the 440mxzx sno-cross machines. the racers hold the button down on the start, and are able to hold the throttle down without driving/taking off. the timing gets retarded enough that the sled won't take off, and now the pipe is getting nice and toasty, so when the let go of the button and it goes into non retarded timing, they take off with a hot pipe that will make power.
FYI- a viper has near 8 degrees more timing at 8500rpm
how do you measure/find out the timing curve, of these different cdi boxes? also, if you use '00-'02 srx heads on a viper, and both engines peak at the same rpm, why couldn't the srx motor live/benefit from the viper cdi? i was told the aaen viper pipes are just the same pipes aaen has for the 700 srx, so if it has the same pipe specs, same cc head volume, same cylinder cc volume, same porting specs (race logic template is the same for srx/viper), i still don't see why it won't work. you've delt w/these motors/timing/tuning, longer than i have, so i will take your word for it. thanks for saving me a box of scrap metal and a unhappy xmas.
So I ask again why do you think you need more ignition timing? throttle response is not the answer, you can gain that by lighter clutch weights, roller secondary, or tighter heads.
...but lighter clutch weights are just going to lead to less belt clamp and possibly belt slip (hotter primary temps).
there are applications where you need more timing, and applications where you dont, depends upon what the engine is being built for, distance run, rpm, alot of differnt varibles. Without knowledge of how it works and why it works, I would suggest you stay away from the engine mods, as "just trying it" will lead to a bucket full of broken parts.
it was just an idea i was kicking around. i wonder why +4 timing helps my banshee so much...on the low end that is? i know the top end is now kinda flat, cause of too high of cylinder pressures...imo. thanks mrviper for posting your replies and for your input. your input, as well as everyone else's, is always much appreciated. its always nice, to kick around these different ideas.
tedgoesfast
New member
detonation detonation and then some more dentonation is not good
mopar1rules
Active member
mrviper700 said:
mrviper, but higher compression should lead to more heat too...right? if so, that would lead to a hotter piston crown, just like w/advanced timing.
heres some learning material
http://edj.net/2stroke/jennings/2stroketunershandbook.pdf
print it, it will save you about 80 bucks, there are lots of other books but this will give you a good start.
http://edj.net/2stroke/jennings/2stroketunershandbook.pdf
print it, it will save you about 80 bucks, there are lots of other books but this will give you a good start.
short answer, yes a 02/03 viper box will work in a 01 srx only, direct bolt in(with bypassing the temp sensor) 04 viper box will fit a 02 srx(same fix is needed and not sure what goes on with the grips on this one)
advance is wayyyyyyyyyyy more. You can not run mid 8000 with this box for long periods of time unless you dump fuel in it and then it doesnt make any power.
it does however work great for a cheap drag race box. If your using a viper box with probes at 7in from piston, look for sled to burn down around 1300, with the srx box, the temps will go into the 1500 range(i never burned it down with the srx box)
advance is wayyyyyyyyyyy more. You can not run mid 8000 with this box for long periods of time unless you dump fuel in it and then it doesnt make any power.
it does however work great for a cheap drag race box. If your using a viper box with probes at 7in from piston, look for sled to burn down around 1300, with the srx box, the temps will go into the 1500 range(i never burned it down with the srx box)
mopar1rules
Active member
mrviper, thanks for the linky. i already have that one tho, but thanks again. what other books would you suggest...."stimulation and design of two-stroke engines" by gordon p blair? yeah, those 2-stroke tuners handbook, by gordon jennings, go for about $80-$90 on ebay....if you ever find one.
littlebear
New member
So, Mr.Viper, if I was to change the cdi box in my 02 viper to an 02 srx box so that the timing isn't so advanced over 8000, could I just plug it in and go?
Or do you have to bypass the temp sensor as well? Basically asking which srx cdi box to use with little or no modifications to an 02 Viper.
Thanks
Or do you have to bypass the temp sensor as well? Basically asking which srx cdi box to use with little or no modifications to an 02 Viper.
Thanks