What kind of mileage are guys getting with piped Vipers? We have one in the group and he's getting about 7mpg. I'm riding the same speed and getting 11.5mpg on my 02 SRX. We have Maxxium jetting in it right now which is 162.5 mains, 47.5 pilots, and 3.5 on the jet needle. Stock head gasket, SLP and MAXXimum did not recommend it for some reason? Rear cooler installed. We have a MAXX clutch kit tuned to run at 8800-8900 rpm. Power valves are cleaned and adjusted correctly. Plugs are a nice color and piston wash looks good. Now why the heck does the SRX get way better mileage? Should we go a little leaner on the needle or pilots? What about gutting airbox and or putting a couple flo-rites in the dash? Does anyone have a more agressive clutch set-up than MAXX's? It runs pretty strong but feel there is more clutching we could throw at it. What do you die-hard Viper guys think? Any help would be appreciated. THANKS!
ExpertXViper
New member
WOW thats the set up I'll be running this year. Hope I get better than that. I'll be running EGTS so I'll know if somethings to rich or lean. But still I'd rather jet once than 2 or 3 times. Prolly gunna end up with a variflow. But help us both out. Thanks
skidooboy
New member
viper with pipes best case scenario is about 10 mpg babying it. the pipe design is the flaw. yes you get gobs of power but fuel is required for the motor to survive.
the srx is a similar but different animal. the pipe, cdi, and carb brass is different and allows for great power and great fuel economy.
just because people are running egts doesnt mean you will get better mileage or protect you from damaging the motor. it is just a tool for the window of performance. what you do with the tool needs to be based on plug readings and piston wash.
lots of posts on the above in the archives. ski
the srx is a similar but different animal. the pipe, cdi, and carb brass is different and allows for great power and great fuel economy.
just because people are running egts doesnt mean you will get better mileage or protect you from damaging the motor. it is just a tool for the window of performance. what you do with the tool needs to be based on plug readings and piston wash.
lots of posts on the above in the archives. ski
ExpertXViper
New member
If Im running any where from 1200 to 1250 degrees means my jetting is correct and my motor doesnt need anymore fuel. If I run over 1300 degrees means my motor is getting to lean and shes about to burn down. Now how is this not helping me with gas mileage and my chances of burning my motor down? I know theres a spike in the Vipers CDI, but The Right Jetting and Right Heat Range= Performance
SNOWRULES
New member
Expert put some tape over your egt gauges then jet the motor using your plug readings and piston wash. after jetting with this method knowing that you're jetted properly take the tape off the gauges and see what temp your running at. you might be surprised at the temp you see. might be higher or lower than your expected 1200-1300 range. at least then you'll know your exact temp range you need to run so as not to burn it down.
Yeah I wish we had EGT's on it. We might try leaning the midrange out a little, maybe that would help. Thought about tuning for 8700 also. Might have to get him a Tour-Buddy.
skidooboy
New member
probe placement is the key, and a few mm's one way or the other will be big in terms of temps on a guage.
i have saw sleds burn down with egts at 1000-1100 and saw sleds runs awesome with egts over 1400. aluminum melts at 1350.
your only going to be as accurate as your probe placement and quality of temp probe/guage.
generally as stated above you install the egt, make sure it works. and tape off the display so you cannot read it. then do your low mid and full throttle runs to get your baseline jetting by reading plugs and pistons.
when you get to your "optimum" level. untape your egt and look at the guage performing the same tests. this is your guide to how hot you will allow your guage to get before you start worrying about hurting the motor.
just because you have an egt doesnt mean you cant hurt the motor, and it isnt the be all end all in tuning, and the guage may or may not be temperature accurate. it is only one of the tools to utilize. common sense is the key.
as for leaning on the midrange, this is where most people burn their sleds down. the mfg's make their carbs leaner in this area to get fuel mileage (because thats where most of your trail riding is done). to tamper with this without proper knowledge, testing and tools. is not a good idea.
there are alot better tuners than i on here, i am sure they will offer suggestions. ski
i have saw sleds burn down with egts at 1000-1100 and saw sleds runs awesome with egts over 1400. aluminum melts at 1350.
your only going to be as accurate as your probe placement and quality of temp probe/guage.
generally as stated above you install the egt, make sure it works. and tape off the display so you cannot read it. then do your low mid and full throttle runs to get your baseline jetting by reading plugs and pistons.
when you get to your "optimum" level. untape your egt and look at the guage performing the same tests. this is your guide to how hot you will allow your guage to get before you start worrying about hurting the motor.
just because you have an egt doesnt mean you cant hurt the motor, and it isnt the be all end all in tuning, and the guage may or may not be temperature accurate. it is only one of the tools to utilize. common sense is the key.
as for leaning on the midrange, this is where most people burn their sleds down. the mfg's make their carbs leaner in this area to get fuel mileage (because thats where most of your trail riding is done). to tamper with this without proper knowledge, testing and tools. is not a good idea.
there are alot better tuners than i on here, i am sure they will offer suggestions. ski
ExpertXViper
New member
Hey skidooboy your giving me all this info. You might wanna check your melting point of aluminum. Before saying something like that. Your well over 100 degrees on your est. . Aluminum melts at 1200 to 1220 degrees. I have lots of books and internet info that tell me so. So I'm done here I'll ask people about my question that run Yamahas.
aSRX600guy
New member
Back to the original question.
I've heard changing to a SRX CDI will improve milage and drop power a little.
the SXV also is ported more agressivly than a stock SRX
I've heard changing to a SRX CDI will improve milage and drop power a little.
the SXV also is ported more agressivly than a stock SRX
skidooboy
New member
expert x, just because my name is skidooboy doesnt mean i dont run yamaha's. i am also a moderator on here and have alittle more "seniority" than you do. maybe you should try to respect people a little more. learn about them before bashing them. yes the actual melting point of aluminum is 1220. but with cooling of the dome from fuel and oil the piston never actually gets as hot as the egt might read, up until catastrophic failure. i've ran modded sxR's srx's and vipers. and actually have a very strong running slp set up for vipers. and i have run egts as well. ski
yes always respect your elders
vipertripplexxx
New member
Vipers get crap mileage because of two reasons. Yes pipe design causes more cylinder filling, thus more compression than the stock viper pipe. This means a richer mix is needed to prevent burndown. Second, the timming is very high on a viper @ 7500-8000 rpm. I say timming is the biggest of the two evils. Some say no. Let me ask you this, How many other sleds have had aftermarket trail pipes installed, and it cut the mileage in half? None that I can think of. I would be willing to bet the bank that if you could turn down the timming in the midrange it would solve the problem. This would allow you to run the pilot much smaller. M2C.
The pipe cant add compression, engine compression is a fixed mechanical clearance between the piston and head volume,cylinder volume. The reason you see such a dramatic drop in fuel mileage is because your using MORE fuel due to the pipe design, adding a expansion chamber to each cylinder simply increases the scavenging on each cylinder, allowing more fuel mixture to travel thru that same cylinder, and the added effect of whats best described as supercharging of the cylinder from the reverse pulse from the rear cone in the pipe allows you to reburn unburnt fuel/air mixture for added cylinder filling. There is alot more to this but thats simplifing the answer, getting into pressure waves and actual reasons would not be relivant to the question.
So the easy way to understand this is ,pilot jet and needle settings is where all your mileage goes, this is where you spend 80-90 percent of your trail riding time on, clutching also goes hand in hand with fuel mileage!!!! you need such a large pilot jet because the fuel/air is traveling at a faster rate thru the engine, thus leaning out the mixture, if it moves more air thru the engine, you have to add fuel to the air, its all the same thru the entire fuel curve.
About any manufacture of a single exhaust twin or triple cylinder engine will get worse fuel mileage when pipes are added, a sx/mtn max yamaha does the same thing as a viper, its a completely differnt cdi box curve!!!! A polaris 600,700,800 twin engine, same thing, crap mileage after twin piping. All that added power in the neighborhood of 15-30hp comes at a price....................FUEL consumption!! you wanna play, ya gotta pay!!!!
So the easy way to understand this is ,pilot jet and needle settings is where all your mileage goes, this is where you spend 80-90 percent of your trail riding time on, clutching also goes hand in hand with fuel mileage!!!! you need such a large pilot jet because the fuel/air is traveling at a faster rate thru the engine, thus leaning out the mixture, if it moves more air thru the engine, you have to add fuel to the air, its all the same thru the entire fuel curve.
About any manufacture of a single exhaust twin or triple cylinder engine will get worse fuel mileage when pipes are added, a sx/mtn max yamaha does the same thing as a viper, its a completely differnt cdi box curve!!!! A polaris 600,700,800 twin engine, same thing, crap mileage after twin piping. All that added power in the neighborhood of 15-30hp comes at a price....................FUEL consumption!! you wanna play, ya gotta pay!!!!
Last edited:
ViperTom
New member
You also have to remember....one persons setup for thier Viper may not work for your Viper. Every sled needs to be tuned for the given riding conditions. If your only ever going to run 660' drag races you can jet way leaner without burning down. If your going to blast WOT accossed the lake you better be jetted rich. You will also find that a piped Viper is more sensitive to temp changes so if you tune your sled on a 25 degree day and you run her WOT on a 5 degree day you could easily melt it down. From the factory the jetting is set at a very safe setting....when you tune for performance you are taking away that safety cushion. If you are new to performance tuning a sled these are things you have to be aware of.
Ya...you get crappy mileage from a piped Viper but a piped Viper sure is alot more fun!!!!
Tom
Ya...you get crappy mileage from a piped Viper but a piped Viper sure is alot more fun!!!!
Tom
ExpertXViper
New member
I'm paying to play. I dont care what the cost is more HP is always more fun. So the pipes are still going on. Gunna buy a Variflow and jet it one step richer for temp changes, thats my plan. After I get everything dailed in.
vipertripplexxx
New member
Ya know.....
When you put more air into a motor (supercharge, turbo, pipes), for the same amount of revolutions, I will guarantee that it will have higher running compression, thus have a tendencey to detonate easier. Why do you think supercharged and turbos run such a low calculated compression, and use alot of timming retard in the ignition?
Don't you think yamaha knew what they were doing when they made the timming curve for tripple piped SRX's? Nine degrees is a gigantic difference!!! The SRX curve is simply a better curve for tripple pipes on pump fuel.
And where do they burn down....Right at peak timming 8000 rpm.
If you read spark plug electrodes you would know. Do a run for at least 1/2 mile at 8000 rpm, pull your plugs and look at the tip of the electrode. You will see it has a ring about half way down. Way too much timming!
Now that I have an srx box my ring is right out at the end of the electrode.
NUFF SAID!
What you are talking about is called calculated compression, I'm taking about running compression. They are two different animals.
When you put more air into a motor (supercharge, turbo, pipes), for the same amount of revolutions, I will guarantee that it will have higher running compression, thus have a tendencey to detonate easier. Why do you think supercharged and turbos run such a low calculated compression, and use alot of timming retard in the ignition?
Don't you think yamaha knew what they were doing when they made the timming curve for tripple piped SRX's? Nine degrees is a gigantic difference!!! The SRX curve is simply a better curve for tripple pipes on pump fuel.
Actually you need a bigger pilot for two reasons. One, the timming is so far advanced that it causes the motor to run extremely hot. Two, more air =more fuel. You can't tell me that the timming curve for an srx is wrong, and the viper curve is better for tripple pipes, I'm not buy'in it!
And where do they burn down....Right at peak timming 8000 rpm.
If you read spark plug electrodes you would know. Do a run for at least 1/2 mile at 8000 rpm, pull your plugs and look at the tip of the electrode. You will see it has a ring about half way down. Way too much timming!
Now that I have an srx box my ring is right out at the end of the electrode.
NUFF SAID!
Last edited:
You would be correct in your thinking for a POWER ADDER like a turbo or supercharger, it does exactly what you described, because its forcing more air into the engine but not a pipe, it doesnt add any FORCED airflow into the intake of the engine. The intake is done soley thru the carb and via the piston/case/transfer ports. The added airflow is simply from the increased scavenging effect and the loss of the 3 into 1 pipe, creates alot of back pressure and impeded flow. The air intake remains the same, the engine can only flow "x" amount of air thru the port openings,carb opening etc., the only way to change that "x" amount of airflow is to port the cylinders, bigger carbs or a power adder which in turns adds pressure to the air intake! While a expansion chamber will add power from the reversion pulse, but its still only allowing you to burn left over fuel charge that has escaped into the pipe, and this rides solely on the effect of the rear cone of the pipe. It can not create more air intake pressure in the cylinder.This is the sole reason why a expansion chamber was a major break thru in 2 stroke engine design.
This is caused by the exh giving a double pulse action back to the engine,there is a negitive pulse and a positive pulse. The positive pulse reaches the rear diffuser cone and stinger,and part of the wave will be reflected back as a negitive wave and help to evacuate the cylinder of any old charge, by going out thru the cone and stinger, it creates a vacum signal, but the other part of the wave is reflected back at a certain speed depending upon cone angles, that helps to recover some of the lost fuel/air charge that wasnt completely burned before the piston closes the exh port, this is what increases the power and reduces fuel consumption. I am sure you know all this already.
As far as your jetting theory, If your on the pilot jet at 8000rpm....., you have issues, the timing issue that you think is causing all this is on the needles/main jet transistion period. The need for more fuel is the increased airflow thru the engine via the pipe. While yes a viper box has more timing in the first part then a srx does, this helps the engine make more power at a quicker rate, so yes......... a viper box will make more power with triple pipes on a viper then a srx box on a viper will rapidly accellarating the engine! I do know and agree with you that the box has alot of timing in the upper mid range of the box, it was obviously needed for the engine to perform with the single pipe, but it is not the SOLE reason for running large jets all the way from pilot to main, the pipe has more influence then the timing does. The added timing simply puts more heat into the piston, retarded timing puts more heat out in the pipe of the sled, you have to have both, heat in the piston and pipe to come up with a good result.
Your trying to compare a srx exh system to a aftermarket system, and your comparing apples to peas. No one can or will commit the time that yamaha has put into the factory srx exh system. Talking to any aftermarket pipe builder will yield you the same results that you can not out do the factory triple pipe system on the srx on a stock engine, and unless your into a large over bore 78+mm,stroking the engine, or massive race tuning via wild porting,ultra high compression, case milling etc, then will a aftermarket set of pipes be the answer, but by doing that to the srx, its not what the factory designed the exh system for anyways.The viper was quite another story, it was a triple with a single pipe.
This is caused by the exh giving a double pulse action back to the engine,there is a negitive pulse and a positive pulse. The positive pulse reaches the rear diffuser cone and stinger,and part of the wave will be reflected back as a negitive wave and help to evacuate the cylinder of any old charge, by going out thru the cone and stinger, it creates a vacum signal, but the other part of the wave is reflected back at a certain speed depending upon cone angles, that helps to recover some of the lost fuel/air charge that wasnt completely burned before the piston closes the exh port, this is what increases the power and reduces fuel consumption. I am sure you know all this already.
As far as your jetting theory, If your on the pilot jet at 8000rpm....., you have issues, the timing issue that you think is causing all this is on the needles/main jet transistion period. The need for more fuel is the increased airflow thru the engine via the pipe. While yes a viper box has more timing in the first part then a srx does, this helps the engine make more power at a quicker rate, so yes......... a viper box will make more power with triple pipes on a viper then a srx box on a viper will rapidly accellarating the engine! I do know and agree with you that the box has alot of timing in the upper mid range of the box, it was obviously needed for the engine to perform with the single pipe, but it is not the SOLE reason for running large jets all the way from pilot to main, the pipe has more influence then the timing does. The added timing simply puts more heat into the piston, retarded timing puts more heat out in the pipe of the sled, you have to have both, heat in the piston and pipe to come up with a good result.
Your trying to compare a srx exh system to a aftermarket system, and your comparing apples to peas. No one can or will commit the time that yamaha has put into the factory srx exh system. Talking to any aftermarket pipe builder will yield you the same results that you can not out do the factory triple pipe system on the srx on a stock engine, and unless your into a large over bore 78+mm,stroking the engine, or massive race tuning via wild porting,ultra high compression, case milling etc, then will a aftermarket set of pipes be the answer, but by doing that to the srx, its not what the factory designed the exh system for anyways.The viper was quite another story, it was a triple with a single pipe.
Last edited:
shortstop20
New member
- Joined
- Mar 6, 2005
- Messages
- 1,583
- Age
- 38
- Location
- Stickney, South Dakota
- Website
- www.snowmobilefanatics.net
Just curious, can a person use a SRX CDI on a piped Viper, and get better reliability and MPG??? Or does the aftermarket pipe design and/or motor design make the SRX CDI unusable??
yes, you can run a 2001 srx cdi box on a viper, the 01 box is the only one that will work, you need to run a jumper wire to fool the temp sensor is all, Scott(betheviper) is a master doing this and knows it all off the top of his head. I know he has done the swap personally and sold a few boxs with wires to other members on here. This will help you reduce the need for such a rich needle setting, and this will make a big differance from what your used to now but you still wont ever get the fuel mileage of a srx, you will still need a fairly rich pilot and main jet due to aftermarket pipe design, a srx is like having your cake and eating it too...LOL. You may want to check with scott and ask about the jetting he was able to use with stock srx pipes converted to run on his viper, I think if memory serves me he was almost back at yamaha specs for the srx, or real close anyways.
vipertripplexxx
New member
WOW it's getting deep around here!!!
But in you first post.....
Yea and it causes detonation also.
I would like to see someone run the SRX box with Bender pipes, and give us a review! The Benders stay within the rpm range of the SRX box. I would bet they would rock out the power with good mileage too boot! Sh1t Maybe I will try it?
Shortstop, I put srx pipes on my viper , so if you need any help with what needs to be done, PM me and I will do my best. I am sure Scott has had enough questions on this, Especially from me!
Cheers, Steveo
But in you first post.....
With the simons cpr clutching and pipes, your @7800- 8000 rpm @1/4 throttle, I'd say your on the pilot bigtime.
Yea and it causes detonation also.
My point exactly! We are not talking about 2 or 4 degrees, it's a HUGE 9 degrees.
I would like to see someone run the SRX box with Bender pipes, and give us a review! The Benders stay within the rpm range of the SRX box. I would bet they would rock out the power with good mileage too boot! Sh1t Maybe I will try it?
Shortstop, I put srx pipes on my viper , so if you need any help with what needs to be done, PM me and I will do my best. I am sure Scott has had enough questions on this, Especially from me!
Cheers, Steveo
- Status
- Not open for further replies.