Srx pipes on viper engine


How much shorter are they?
When the pipe length [or distance from piston to end of cone or stinger outlet] is shortened it will raise the peak RPM the pipes make their max power at. Many years ago it was not uncommon for people to cut 1/2' off of the exhaust header pipe lengths to gain a couple hundred RPM in the power band. Without a dyno it is hard to predict the out come. I would suggest you use an SRX CDI and conservative SRX jetting for this setup and start with the shift RPM at 8500RPM and see how it runs.
JM.02c
Bob
 
01 SRX CDI will bolt right into the Viper harness

Your exhaust will not line up correctly with those adapters bolted onto the Viper cylinders and your peak RPM will be higher from the exhaust manifolds being shorter, not sure how the timing will like that... those of us that have done the SRX pipe swap have made adapters to make up for the length difference. The adapters are angled, somewhere around 2" on the bottom and 1.25" on the top, I didnt make mine so I dont know the correct number, MrViper checked them out when he ported my cylinders and made sure they were correct.

Here is a couple threads to look over, it wont all apply to you, but you will need to make the adapters...
http://www.totallyamaha.net/forums/showthread.php?t=6036
http://www.totallyamaha.net/forums/showthread.php?t=39948
 
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sideshowBob said:
How much shorter are they?
When the pipe length [or distance from piston to end of cone or stinger outlet] is shortened it will raise the peak RPM the pipes make their max power at. Many years ago it was not uncommon for people to cut 1/2' off of the exhaust header pipe lengths to gain a couple hundred RPM in the power band. Without a dyno it is hard to predict the out come. I would suggest you use an SRX CDI and conservative SRX jetting for this setup and start with the shift RPM at 8500RPM and see how it runs.
JM.02c
Bob
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Can not use the srx jetting because the cylinders are stage 2 ported. The jetting is not a big problem for me, I have alot of jets at home so that will be sorted out. Dont know for sure how much shorter they are but approx 20mm
 
viperhauck said:
And why the srx cdi?
Click to expand...


The stock SRX pipes are tuned to make power in the 8300 - 8500 RPM range hence the suggestion to run an SRX CDI that has a timing curve to match this. The Viper CDIs run a lot of advance timing right in that area. All that timing can cause high piston and combustion chamber temps resulting in destructive detonation.
With the ported Viper engine and SRX pipes you have basically put together a ported 2000 - 2002 SRX, the only difference is you have the Viper CDI.
Since you ended up with 20mm[3/4"] shorter SRX pipes you have kinda moved into uncharted waters and you have a setup that will most likely make its power at a higher RPM so now knowing this, a Viper CDI may be a possible choice as the timing curve does not fall off after 8500RPM like the SRXs do.
I believe some members have shortened SRX pipes and maybe they will chime in with suggestions/solutions to jetting/timing issues.

I have never dealt with the setup you have but "IMO" for safeties sake, I would still try a 2001 SRX CDI and jet it like a mod ported SRX...start rich and try running 8500RPM.

JM.02c
 
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So different timing on the srx cdi ok...but oem viper also work at 8500 rpm hmm. My plan was to try running at 8500-8700 with this setup and maybe make it rigt with the flanges first.
 
viperhauck said:
So different timing on the srx cdi ok...but oem viper also work at 8500 rpm hmm. My plan was to try running at 8500-8700 with this setup and maybe make it rigt with the flanges first.
Click to expand...

Yes the stock Viper does run at 8500 RPM but remember it is only making under 120hp stock...with your setup the engine will be capable of over 140hp at that same RPM, just like a 2000+ SRX does. The cylinder pressures and temps at 140+hp are a big difference compared to 120hp. Yamaha matched the SRX CDI to the stock pipes for performance + reliability.
As I have said, IMO better to be cautious.
For some insight and ideas, you may want to do a forum search for Vipers with Bender tripple pipes to get some knowledge on jetting ect as they run in the RPM band you are talking about on the Vipers.

JM.02c
 
I had bender triple on this engine in my viper before I change to cpr´s. I run that in 8700-8800 rpm
 
And one more thing. If I run it with viper cdi what is the most critical? timing or jetting? Jetting is no problem for me but I haven´t any experiance of timing
 
If you had the Benders on your Viper you must already be aware of how much richer you had to run it then stock. The timing in the CDI is fixed at the factory program so your jetting and fuel quality would be most critical, again having a piped Viper you have already "been there done that" and must be experienced at jetting for survivability with the Vipers CDI.
 
I always run with the best pumpgas and is very careful with the jetting. This engine with bender`s I have 165 main and 55 pilot. With the cpr´s I must use 172.5 main. Big? yes but it have bored carbs and mod airbox to
 
viperhauck. so wont your motor not produce as much power as it could cause the srx cdi has significantly less timing then the viper cdi? but yet will be alot more reliable and dont have to worry about detonation and better fuel milage? just wondering cause i was thinking of doing this with my bender pipes
 
ridergonwild5692 said:
viperhauck. so wont your motor not produce as much power as it could cause the srx cdi has significantly less timing then the viper cdi? but yet will be alot more reliable and dont have to worry about detonation and better fuel milage? just wondering cause i was thinking of doing this with my bender pipes
Click to expand...

What do you mean? That I get less power with viper cdi, less reliable and fuel milage? I dont worry, its my wife´s sled and she sucks ;) to ride sled. Its no WOT here just cruising on the trails and maybe a little powder to learn how to ride.
 
no im saying. does that basically detune the motor? but yet get better fuel milage and better reliability? i dont know what it does. thats y im asking
 
If your sled is running so much timing you have to doust it with fuel to keep the temps down to make the engine survive, do you really think the fuel is being converted to power. I think not.
 
I haven't done any of this but I have read about it. Betheviper did this setup and running a SRX cdi is one key to make it work with the SRX pipes but I believe their becomes some issues being the Viper has a different gauge module (digital) vs. the SRX which runs an analog gauge setup.
 
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