observations from your information:
1.) your using low octane fuel, 91 is LOW octane fuel for a "performance application" where there is high load on the engine(triple pipes,higher rpm, etc.)
2.) vipers have very high ignition timing, more ignition timing puts more heat into the piston, retarded timing puts more heat into the pipe.
3.) you have added triple pipes which run at a higher operating rpm(more load), this gives more power, along with more hp comes heat, heat is the by product of more hp(more heat in coolant,raises operating temp of coolant/engine, hence the need for rear cooler in a viper)
4.) a viper has increased compression over a srx on the mag and center cylinders of the engine, the pto is larger and less compression. Yamaha merely did this because they thought the simplistic non staggering of main jets was a big deal to consumers. Its been found thru many years of these sleds research and development that the center and mag cylinders are the 2 cylinders that consistantly blow up from low octane fuel, higher compression and increased ignition timing.
5.) when bender racing came out with their opti cool headgasket for use with their pipes, theres a reason its thicker then stock.... it reduces compression, which is a reduction in heat because they too found out that increased compression in a viper, adding triple pipes, and low octane fuel is a sure mix for detonation!
6.) you have a 2004 viper with dcs, these are sensitive to fuel quality and mods to the engine will result in the dcs going off and retarding the time, possibly going into limp mode. these engines can still burn down even with this feature. I can clutch a bone stock 2002 srx also equipped with dcs and triple pipes into making the dcs go off for nothing more then applied load to the engine....the fix...... use higher octane fuel!
I merely gave you information and opinion on what you asked for, you don't have to follow my information or reccomendations, its your sled. Just be known youll find the cost of pistons,crankshafts,cases to be quite expensive anymore and rapidly declining in availability. You can change 1cc here or there and more then likely you will not be able to tell the difference in power 1 bit, your not changing the compression by 1 point but changing the volume of the chamber by 1cc. Its not gonna be worth anything of great measure of power increase. Anything under 5hp and you cant tell a difference in riding the sled other then that your wallet is thinner.
just for FYI- When I trail port a viper engine I do not do any head work to it, by porting it, when it goes back together the compression will go down because the exhaust port is larger, this is a good thing with a viper. It aids in reliability. The aftermarket head could very well have more surface contact with the water on the domes but it wont stop detonation entirely, detonation comes from the heat in the piston top and the cylinder. If it cooled a few more degrees it could delay it slightly if the rest of cooling system over achieved but it cant stop it.
If you have ridden that sled with the pipes,jetting and 91 octane for this long with no dcs lights, and or problems don't fix what isn't broke as most guys have not been as lucky as you. Look into getting some work done on the cylinders, lightweight wristpins, mod the reed blocks, dial in the clutching to perfect, reduce parasitic drag in the rear skid with oversize idler wheels, slippery hy fax,etc. and it will be of more benefit then just the head by far!
Thank you once again Mrviper for your input! This is in line with the type of information I am looking for/ interested in.
The reason for my interest in this is because I am looking for a bit more power. And when I decide to move forward, I want to know how,why and what work is being done. Also that it is done by someone qualified. I have had my good and bad experiences with engine and chassis builders over the years drag racing. I know the importance of a qualified technician.
I have exhausted most all other options on this sled without turning back to the engine for more performance.
Clutching has been done , primary heal clicker and secondary Hauck roller , and helix. This was all set up with the help of an old racer and mechanic from Pineer motor sports. Retired now, as was my suspension years ago by Bruce from Pineer motor sports. Srx rear heat exchanger,graphite hifax, track USA 136 extension with new 11/4” ripsaw track, 108 megabite picks down the center 1.325” double backers , 4th wheel kit, over sized wheels, 2 extra wheel kits, gearing, 8 tooth drivers,CB drop brackets,transfer rod nuts, boss seat to reduce weight, Ohlins all the way around. And a few more items I am sure I am forgetting.
I have ported the reed blocks, reed spacers are in, new carbon tech reeds, SLP pipes, and I added the opti cool head gasket this year. But had no problems previously with heat. It was more preventative on my part.
Thank you by the way, I was not aware the opti cool head gasket is actually thicker than stock.
I ask questions to learn more than I currently know. I know enough to get in trouble. Lol. And trouble is where I am headed.
So with all this information I believe this is what my plans are. Keep in mind I am a racer, nothing is ever fast enough.
1 have a qualified person port jugs for trail riding,
2 add peak performance head with 23cc domes and run the opti cool gasket.
3 add a light weight brake rotor.
4 not sure about this. But thinking of heat wrapping my pipes. What are your thoughts on this?
5 take to dyno after complete to tune it all in.
At this time new Yamaha pistons rings will be installed as well as bearings and seals.
Mrviper you had mentioned lightweight wrist pins. Who carries them? Where may I purchase them?
Mr viper. I would like to kindly thank you for your input and thoughts on this. It is obvious to me that you truly care and are passionate about what you do.
Ok blast me now. Lol
