DCS and variflow

norwegian

norwegian

Well-known member
Joined
Nov 5, 2004
Messages
2,904
Age
45
Location
norway
I wonder if the variflow messes up the dcs?
I have one installed and I have to have it much richer than I should need to keep the dcs quiet.

at -3 c I have to have it set to -31 to keep it shut (dcs) most of the time and to the rich (-40c) to keep it completly shut

When it's colder, only -40 (rich) helps.

I have the right jets in the carbs and in the variflow (alu and brass for a 7% maximum fuel reduction). I have it also jetted correctly to the altitude.

In my opinion, the variflow set at -12,5c or the second most aggressive setting, should be more than good for -3c, but it's not, the moment I punch the throttle the light comes on. Spraying with startergas on the carb boots and pto seal revealed no air leaks.

What I am going to do next is to remove the variflow and just try stock jetting at -18 for my altitude which whould be 151 and tow times 150
 
Well, I have had A Vari-flow on mine aswell and Created the same problam on my viper. Took it off and the Dcs went away, maybe i installed it wrong but honestly i doubt it because A buddie was there showing me how to. Took it off and no sign of dcs, so yeah take it off seal up the holes and Take it for a rip and let us know if your still having Detonation.

mine went away, hopefully yours can. Them Vari-flows are Useless i think.
 
Took it off, jetted for -18c for my altitude, no sign of the dcs whatsoever. But I've only ridden in max -6c since then.

I agree on the installation aslo. What could go wrong if you follow the instructions?
 
Last edited:
Did you change the pilot jets? You need to go up at least one size, I went two, also raised the needles one washer, and the fuel mileage is still very good at the white dot setting.
 
If you understand the theory of variflow and you understand the theory of dcs, you would understand that the DCS system keeps the motor from leaning out (by retarding the timing) and DETONATING.. Why would you put a variflow system on a sled in the first place???? people get carried away with KNOBS and GADGETS thinking that they are getting SO MUCH BETTER PERFORMANCE from all of their bells and whistles!! Its an SRX or a VIPER... PLENTY FAST for the trails or the lakes!!!! the sled works JUST FINE bone stock from YAMAHA!!! It really does!!!
 
nosboy said:
If you understand the theory of variflow and you understand the theory of dcs, you would understand that the DCS system keeps the motor from leaning out (by retarding the timing) and DETONATING.. Why would you put a variflow system on a sled in the first place???? people get carried away with KNOBS and GADGETS thinking that they are getting SO MUCH BETTER PERFORMANCE from all of their bells and whistles!! Its an SRX or a VIPER... PLENTY FAST for the trails or the lakes!!!! the sled works JUST FINE bone stock from YAMAHA!!! It really does!!!
Click to expand...

If U can find a Yammi around here that doesnt have Variflow U would be lucky. I ride from 1400 feet to 10000+, never have to jet, thats why we use them.
 
make sure you follow the directions to the tee, especially the part about venting the lines either into the airbox or the atmosphere - wherever they started originally. I put one on an arctic cat and it was vented to the atmosphere, so i vented the variflow to the atmosphere as well. You have to jet to 40 below (f) and then work your reductions from there - depending on the range of operation you want, you then start putting in your fittings (brass, aluminum copper etc.) to dial in your degree of adjustability. If you vent the thing to the atmosphere, and it should be in the airbox, i beleive it has the opposite effect. Additionally, you have to place your airbox vents exactly as original - if original vents were under the first shelf, then that's where your vents have to be placed - make sure your vacuum source is good as well.
 
Glab: yes, I went to #42,5 on the pilots. The dot you’re referring to is on a tempaflow, not a variflow.

Nosboy: I understand the theory of the dcs and the variflow, and that is exactly why I put it on a dcs equipped sled, so that if something went wrong, the dcs would save me, which it did.
If I didn’t have the dcs, it would surely burn down when it was on my sled. The point of this thing (variflow) was to get the jetting closer to the ambidient (spelling) temperature. When I tried to turn the dial to something that was like 10c off, the dcs went off, proving that something was wrong. That’s why

Woolyviper: I vented the air intake of the variflow behind the airbox, outside. That is correct to my understanding. I went with the least aggressive jets on the variflow, alu and brass which would make a 7% reduction, when the dial was at the leanest. The sled was jetted for -40c and the needles were at 3,5. The only thing with the installation that I could put my finger on was that the intake was at level or even so slighly above the variflow body, because the variflow was mounted on the plastic cowl under the hood (right behind the PV motor).

The point is anyhow, that while in theory I could go closer with the jetting on the variflow, the opposite happened. Holtzman claims on their homepage that every 2% of reduction, means 11c difference in jetting

Temperature: -3c. Octane booster in fuel tank as well!

With the variflow installed I had to have the dial on “rich” which means less than 1% reduction in fuel, and when jetted to -40, it means that the sled is jetted for -35c or so with the variflow. Now I could hold the throttle to the bar.

With the dial on “position 1” which means, (with alu and brass jets), a 1,5%, using the theory on their site, would make my sled jetted to -31,75c. Now I could only hold the throttle to the bar for maybe 800 meters or half a mile. Mind this: THE SLED IS JETTED FOR -31,75 and the amb. Temp is -3! The “safety margin” is 28,75 degrees in theory. ( I know that you cannot read the decimals on your temp meter, but this is what I’ve calculated)

Dial on “position 2”, a reduction of 3,5%, or in theory, the sled is jetted for -19,25c. Now I can run only 4-500 meters (a quarter mile and then some) before the dcs goes off.

No variflow run:
Temperature: -5C, no octane booster

Sled jetted to -18C at the lowest elevation possible: or, 151,3 and 2X150. Jet needle position is 3 and needle jets are leaned down to #40. Safety margin: 13c

All runs: you can hold the throttle to the bar for as long as you like without the dcs going off!

I am not saying that the variflow doesn’t work at all, but for my application, it didn’t do its’ job properly. Yes, it did lean out when I wanted to, but it leaned too much? Somehow I got the worst of two worlds, I had to run it pig fat, and it would still detonate on top end!

I am going to send the variflow back to holtzman to see if it has mechanical flaws..
 
A good idea if you run different elevations all the time,,, a BAD IDEA if you trail ride at 600ft all the time!!!!
 
What octane booster are you running? Most actane booster does almost nothing, it usually gives 92 octane, a rating of 93, if you are lucky. usually it's 7 points, which would be 92.7 octane. Most idiots think it's 99 octane(92+7=99 wrong). Then to top it off the add something like MMT, or Methyl tert-butyl ether, this is probably your problem. It is a major oxygenate, which will lean your motor, hence the power increase, Then the consumer says "wow that stuff really works" and buys more. I'm not saying it's all of the problem, but it probably is contributing to the lean condition.
I asked if you raised your needles, this will richen the mix on top also. I know with the tempaflow you need to raise them or your DCS WILL go off.

You are talking about All of these percentages, and calculations. Well just riching the pilots and the jets isn't everything above 1/8 throttle, you still have the needles. I did all three, and it is still slightly lean 1/2 throttle. The needles also affect WOT alot.
 
I did raise all 3 of them, I did run with and without octane booster. I run on 98 research octane (sticker on sled says min 97 research).
Pilots were 42,5, needles 3,5 and mj 153,8 and 152,5? times 2
 
cacsrx1 said:
If U can find a Yammi around here that doesnt have Variflow U would be lucky. I ride from 1400 feet to 10000+, never have to jet, thats why we use them.
Click to expand...
yea the srx's are kinda a pain to rejet all the time with coolant hoses and the other stuff. mine seems t work flawlesly.
 
You must log in or register to reply here.


Back
Top