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Reddragon800
Well-known member
You can just do the new billet throttle bodies and injector relocate on an 850 and makes 15hp.
9R Build - high compression head with twins, billet throttle bodies and injector re-locate
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Reddragon800
Well-known member
Yes it would. it would be roughly 15hp
davesilb
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I have been telling people they are turning their 9R's to tight. I found adding 4 grams to my 23 9R's clutch got me at 8100 and a much better pulling machine. I also have not changed my clutch yet for the new one and have not fouled a single plug. Over 1000 miles on it.
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FlynHigh
Well-known member
Curiosity question about the upshift403 mod. Looking at my stock 850 it appears the injector shoots directly into the rear transfer port. I thought the advantage of this was that it doesn't wash the oil off the bearings so the snowmobile can use less oil. On the other hand I can see how injecting fuel through the throttle bodies would help cool the bearings down. Throttle body injection would also allow the fuel more time to vaporize. My understanding is you want cool air but actually "warm" fuel so it vaporizes and burns completely. So running fuel through the throttle bodies and hence the entire bottom end kills two birds with one stone, cools the bearings, and warms the fuel. Only down side I can see is potentially washing oil off the bearings?
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NEWDUCK
Well-known member
Interesting. I thought it was cool air and fuel made more power. It was in reference to v8s but I recall a dyno shoot out of a Port injection vs TBI vs Carb. The TBI and Carb made more power because the fuel/air ration cooled more before it hit the combustion chamber.
The tunnel ram on my boat is cool to the touch after a long pull on a hot summers day. So I think there is something to that
Transfer port injection is more efficient, although it varies a lot, depending on engine speed and load. That's because it allows you to time the injection during the intake/exhaust cycle to minimize raw fuel going out the exhaust. As I recall from some of Dan's discussions, the downside is two-fold, with the rod bearing taking it hardest. First was mentioned: the fuel in the crankcase helps keep the rod bearing cool. Second, it helps lubricate the rod bearing because there's far more lubricant (fuel/oil mix) in the case, where the rod bearing is left with what little oil can be maintained in the case. The main bearings have it a lot easier because they're fed oil directly. As for washing oil out, that's really not a problem as long as it isn't raw gas. Old school engines ran just fine (generally longer, if anything) on pre-mix. I'm not sure of the atomization part of it - it may actually be worse because fuel returns to a liquid state pretty easily. That's part of the reason automotive engines moved from TBI to port to direct injection - although the advantage is usually more in fuel efficiency than raw power.
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Anyone out there try the throttle bodies on a 850 with SLP single and SLP head? Any real world feed back?
You will probably get some feed back this weekend.
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I would be interested in hearing his thoughts on this as well. When I tried a Catalyst with that track the traction was insane. So much traction it seemed impossible to spin the track to set the sled on edge. The sled would just shoot forward…..at least it did in those conditions on that day…
When you turn the engine higher rpm you also are naturally spinning the track faster. I have done a bunch of testing with this back 12 years ago on a 350hp turbo m1000 running 20 psi boost. If i clutched it heavy it was fast but it was also pulling the belt farther down into the secondary, if i pulled some weight out of primary and spun it higher rpm it had more track speed, finally what i did was marked a black line on clutches and started gearing up so i was near 1-1 clutch ratio on a climb and the final result was 80-85 mph track speed and no blown belts once i geared up and got the clutches in the efficiency zone. I always clutch on the higher side of the rpm zone so if you get into that super deep long pull you never come off the power.
This is exactly why burandt gears up his mod boost sleds.
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Reddragon800
Well-known member
He doesn't have 350hp. Gearing up his 900 boost is losing track speed. 1-1 shift on a boost is 115kmph track speed. Even in his own video he said that the 900 boost is getting 53mph track speed, which is only 85kmph. Those are poor numbers for the amount spent on a 9R boost. A stock boost will see over 90kmph with just SRP cluthcing.
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At 2k elevation sure. (From your picture)
A screenshot can show that on a lake just as well as a hill.
Or deep vs shallow snow.
Burandt rides 10-12k
There's definitely a subjectivity to trackspeed claims that makes them apples to oranges......
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Reddragon800
Well-known member
Not at all, this is at 2077 meters (6814 feet) on a stock boost in a climb vs $67,000 900 boost in a climb at 12,000 feet. Needs to gear down. Will have more track speed. And needs better clutching… lol
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2k meters, so around 6500ft.
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What kind of track speeds should one expect from an SRP kit on a stock 850 with 155 (2.75), at 6500 in interior BC snow? Still in the first third of break-in and I have 8150rpm and 66km/h. Running 91 pump fuel on the ethanol non-premium setting.
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Reddragon800
Well-known member
typically we see a 4-5 mph increase with the 850 N/A set up.
