Over octane just makes your bottom end worse so why throw money away? Everyone is running what the manufacturer recommends. Anymore doesn't really make sense. Lets do the math real quick: It's Actually $2.30 more right now * 4 gallons per ride * 3 rides per week = $27.60 a week * a conservative 16 weeks of riding = $442. Is that gonna break any of us in this sport probably not but It is still money I would rather have in my pocket for other things than burning av just because I like to smell it burn. The biggest thing for me personally is ease. I have to drive 30 minutes each way to get av and its not on my way riding so this has to be on a non riding day. I can fill up my 3 cans cans and mix in a couple gallons per ride and my cans will last 7-10 rides. If I mix 50/50 my cans are only going to last 3 rides which is usually one week. Obviously I could get more cans which I need to do but now I am trying to find places to store all of them. I just plan to run what the manufacturer recommends. Honestly, I bought a "pump gas" kit. Knowing that it is low boost. If I wanted to spend all my money on fuel I would have bought a kit that runs 12 lbs.
C-tec 2 pump gas turbo
- Thread starter jonmatz88
- Start date
J
Few things I just wanted to comment on...
Those who are looking for a cleaner bottom end, playing a bit with clutching will help. We are always refining the map as well. One thing to remember, if your clutches are dirty at all, or there is any slip on the bottom - it will effect your bottom end in a big way.
Another thing to consider trying, drop some boost and pull some weight. Just to see if that helps you guys at all. I often run 5psi as opposed to 7, I do this because I don't notice a massive difference up top between the two but can drop some weight and improve my bottom end snap just by running lighter clutching
Finally be absolutely positive you have no boost leaks. You'd be shocked how often there is a slight leak that inhibits bottom end response. This is why I make sure to silicone with some high temp silicone (copper) when I do my installs.
As far as the octane argument goes, all I will say is *always* over octane, never under octane. We are running very high performance 2 stroke machines in dynamic operating conditions. We often over octane on deep days, or days that are warmer. 100LL burns cool - and if you are doing 1 minute pulls up deep slopes this is cheap insurance.
Those that have it dialed - awesome. Those that are unsure, it isn't the worst idea to run more than you need. Especially at first!
Those who are looking for a cleaner bottom end, playing a bit with clutching will help. We are always refining the map as well. One thing to remember, if your clutches are dirty at all, or there is any slip on the bottom - it will effect your bottom end in a big way.
Another thing to consider trying, drop some boost and pull some weight. Just to see if that helps you guys at all. I often run 5psi as opposed to 7, I do this because I don't notice a massive difference up top between the two but can drop some weight and improve my bottom end snap just by running lighter clutching
Finally be absolutely positive you have no boost leaks. You'd be shocked how often there is a slight leak that inhibits bottom end response. This is why I make sure to silicone with some high temp silicone (copper) when I do my installs.
As far as the octane argument goes, all I will say is *always* over octane, never under octane. We are running very high performance 2 stroke machines in dynamic operating conditions. We often over octane on deep days, or days that are warmer. 100LL burns cool - and if you are doing 1 minute pulls up deep slopes this is cheap insurance.
Those that have it dialed - awesome. Those that are unsure, it isn't the worst idea to run more than you need. Especially at first!
Part of it is what you say.
And I know there are some disagreements with what I stated before, but for me a primary factor is consistency in tuning. When I mix Av gas or Race gas into my tank, each time I go out I have to tune a little to keep the sled dialed (and I like to climb and boondock so a "miss" can doom me).
When I run the same gas, 91 with 10% ethanol, plus octane booster, there is no variation in the tuning. I can pull and go and know that my sled is dialed from the first pull to the last. When I mix, I have to check things out each day...and that is a PITA. Yes, I could be more careful about my mixing ratio...but that means multiple gas cans and dealing which that stuff at -15 in the morning is not by favorite. Half a bottle of octane booster, fill the tank and go.
I won’t run a sled that i need to put anything in other than what’s at the pump. I don’t see carrying around 100+ gallons of AV gas every trip I make out west and eliminate the ability to ride beyond a tank of fuel without getting back to my pickup/home base (or carrying extra AV on the sled). Yeah, I’m sure it’d be fun, but I don’t want to be handcuffed by the logistics of it. If I lived closer than 14 hours from the mountains it might be different.
J
I can relate to those saying "I just want to run pump". I used to be that way too.
...but its snowmobiling. You have to bring oil right? You have to look for 91 non ethanol right?
With Silber's kit you can always just drop boost and run pump. Especially if you are above 4-5K. No big deal.
Out west, 25 gallons of AV will last me about 10 full tanks when I'm running 6-7 psi. That's a lot of riding for 5 5 gallon containers.
Also, one big thing, I do NOT premix my av/pump before putting it in the tank. Takes a lot of the PITA out of the equation.
...but its snowmobiling. You have to bring oil right? You have to look for 91 non ethanol right?
With Silber's kit you can always just drop boost and run pump. Especially if you are above 4-5K. No big deal.
Out west, 25 gallons of AV will last me about 10 full tanks when I'm running 6-7 psi. That's a lot of riding for 5 5 gallon containers.
Also, one big thing, I do NOT premix my av/pump before putting it in the tank. Takes a lot of the PITA out of the equation.
W
So what boost level is that? They come set at 5 psi. Drop to 2? If that’s what’s safe on pump, I don’t think I’d brag about my “pump gas turbo”
J
There is no special sauce with regard to pushing high amounts of boost on pump gas. This side of different domes or a custom built motor, there are very simple limits with respect to net manifold pressure you can have before having detonation.
You can run 7psi at 11,000 feet on pump gas. Conversely, you can run about 3psi near sea level on pump gas.
There is a reason even stock snowmobiles have det sensors, and you'll hear of people actually hitting them. Bad gas is the culprit more times than not.
If your gas is old, or just the wrong blend coming out of the pump, you *will* certainly have problems with a turbo. This is why we suggest simply bringing around some AV gas. Its cheap insurance. Especially when you can't be positive what you are getting out of the pump.
Nowhere do we advertise "pump gas turbo kit". People just want to run pump gas, which we say "go for it" (just keep boost/elevation in mind).
The cool part about a turbo like Silbers is you can add some clutch weight, throw some octane in that gas tank, and turn the boost up for those deep days. Then quickly turn it down, pull some clutch weight and you are good to go on pump.
Either way, you are getting around 30 extra horse (minimum) out of the motor. That's a lot! Find another mod that'll get you 30 horse on pump gas... don't think you can!
hard to tell due to it being more load based but I would say somewhere around 4 to 5k
primary for me is about 80 g and running 8100 at 6 psi on 30% 110 to pump 91 6 to 9k in alt
primary for me is about 80 g and running 8100 at 6 psi on 30% 110 to pump 91 6 to 9k in alt
B
I'd drop your primary weight to 78 or even 76g. 8100 is too low. Justin said target is around 8500 with his kit. Rev limiter is 9000 so your not going to hit it at 8500.
What boost and RPM did you find works best with this kit along with primary weights?
Turbo
I rode my buddies doo 850 turbo and now I'm thinking that's the way to go. For guys running this kit, how is the bottom end response (lag) on the ctec? I was thinking if you run 3-5 lbs and clutch for 8500 it should spool pretty quick and be manageable in the trees. He is set at 7lbs and it's a monster on boost but is pretty slow responce on the bottom and comes on too hard for tree riding I would like something with good bottom end response and manageable power in technical terrain
I rode my buddies doo 850 turbo and now I'm thinking that's the way to go. For guys running this kit, how is the bottom end response (lag) on the ctec? I was thinking if you run 3-5 lbs and clutch for 8500 it should spool pretty quick and be manageable in the trees. He is set at 7lbs and it's a monster on boost but is pretty slow responce on the bottom and comes on too hard for tree riding I would like something with good bottom end response and manageable power in technical terrain
this is the difference between turbo power and big bore power
turbo: 8500 alt and up you get it back and have to deal with the lack of lower end power and hard hit at the top (800 mill still has to carry turbo clutching until it is on boost)
Big bore: faster throttle response and more mid torque with nice top end power below 8500 alt. AND can carry the primary weight to gain rpm.
with turbo add race gas and the bottom end gets slower. the lower boost the less the bottom end is slow the more boost the slower the bottom and harder the top it is.
B
I run 7psi 70/30 91/AV. 78g and turn 8450 at 8000-10000ft. Justin told me that 8450 is on the low side and suggested dropping to 76g.
That's the problem I ride 10000 ft and up. I have a big bore doo and it runs good but at that elevation it's no turbo by any means
100 miles on supercharged Alpha, zero, lag, zero bog, zero race fuel. Actually runs crisper than stock. No more turbos for this guy.
Race a turbo. Then report back. You paid double so I am expecting you should at least win by a couple lengths... I think the amount of bog we are talking about is being grossly over estimated by those that don't have one. Honestly 3rd ride I was so used it I barely even noticed anymore. I just work through it with the throttle. Still hope to get it resolved but its not a show stopper. I rode a supercharged 18 last year and I would put this silber setup against it anyday for less than half the cost. That is a lot of av gas.
Similar threads
