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I run the head and twins on my '21 850 and I would run the same setup again no question. It works and works well?
Slp head
- Thread starter danby
- Start date
Thank you for the first hand info unfortunately I ride lower elevation 50% of the time (2200'-3500') and don't want to have to mix fuel for the twins. If I have to mix fuel and spend 3k us for the outlaw stage 2 kit I might as well buy an aftermarket turbo kit for roughly the same coin.
Bingo
Not Bingo !!! Turbos pay off at high elevation. You dont need to mix gas to increase octane on a twins and a SLP head. Danby. At 10,000 feet its a turbo. At sea level a NA 850 with 180ish HP would be great . At your elevation its a tough choice. Ive owned Silber Turbos, Boost-it Turbos, And MTNTK turbos. Ive also owned Twin pipe stock displacement and Big Bores. This years build is 850 Matryx with a SLP twin piped Powderfreaks 940. Big power NA sleds at lower elevation are a ton of fun!!! Depends what you want to do with the machine?? In saying that.. Different 2strokes for different folks.
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Fair enough and thank you for the input, I was going off what slp said for mixing gas. Below 4000' they recommend 1 gal av/race gas per 4 gal premium. I don't think the cost to run it and pay for the twins on a stock 850 is worth that price. A big bore may be worth it depending on the cost and power increase, anyone have experience with running a ported 850 ?
Hmmm.. I never ran race/av with the SLP head. 93 Shell only. Never had det once ,even at low elevation. The engine Duane at Powderfreaks is building me is a ported 940 with twins at 12.8 to 1 compression ratio. It did dyno runs at 202 HP on his dyno that clocks stock 850s pulling 171 -173HP. I rode it around his property last weekend. It rips so hard out of the hole. Still doing some finishing touches on the tune and clutching. Its pulling 74 g TRS weights with Tonys clutching. There is no doubt tuning (for Duane) was no easy task. He was having some hair pulling days. He figured it out. Sorry for derailing your thread got a little excited about the new build.
That thing sounds like a monster, should be unstoppable in the creek bottoms. It's all good info and things to think about.
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Website says 90mm pistons are used. Do you know who's 90mm pistons?
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I've had several turbos, 800 turbos (pro and axys) and axys 850 turbos. I like the SLP twins better
if youre not at 8000 ft+ this is a better setup than a turbo in my opinion
and if you feel the need to mix gas (not necessary over 5000 ft) you can add a couple oz of lucas octance booster per tank
or a splash of av gas or vp 110, its not a big deal whiners
if youre not at 8000 ft+ this is a better setup than a turbo in my opinion
and if you feel the need to mix gas (not necessary over 5000 ft) you can add a couple oz of lucas octance booster per tank
or a splash of av gas or vp 110, its not a big deal whiners
You probably like the twins better because they didn't run as bad as all your turbos ran ? Nobody is whining, just stating the gains, if any, aren't worth the hassle and money.
Chadly!! Have you personally owned a sled with twin or triple pipes ?? And ridin it in the snow not on the keyboard?
Yeah I have triples on my boost ?
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Actually a 4% increase, not sure how you get .5%. To get 4% from combustion chamber shape alone is asking a lot, unless squish is tightened and compression is raised. 165 x 1.04 = 171.6hp.
