So I installed the Swamp XL slip-on about 2 weeks ago. The thing sounds sweet on the 850. HIGHOCTANE has a video somewhere on here that really gives you an idea the sound these things make while he is ripping up his back lawn. It's killer. But it had an off idle miss when you grabbed a bunch of throttle. I'm sure this was from a lean condition off idle. Anyway the optimizer took care of that and it made the throttle response crisp at all speeds. You can also definitely feel all of those 5 horsepower. I'm not sure my butt dyno could feel 5 HP in my car but on the quad you can certainly feel the extra power. I thought I could feel the added power before the fuel adjustments.... and maybe I did a little bit. There's no mistaking it now. These two items are worth the $.

 

Dan, being a 800 owner, can't imagine those exta ponies with the need for more? But that is just me. Are you now that fine tuned with your 850XP that you need more? What kind of riding do you do? Are these just long flat sprints or pulls?

The power on my HO 800 scares me at times more so from the boost situations Vs. running fast past 55mph on a flat open stretch. Now that I am running Mudlites I feel the rear sway a little and not as good as stock at those fast speeds - IMO But its all good, I need not to be going that fast anyways.

Good talking,

R'

 

I'd probably get shot at where I ride with one of those on!

 

Enough power, let me see..... You can't have to much power can you? The 850 XP obviously has a lot of power and it's a lot of fun to use, but it does have more power than I need. I do enjoy the long power slides that it will do. It will pretty much break the tires loose, Bighorn 2.0s, anytime you goose it. As for what kind of riding I do.. I pretty much just rip up the trails around my house and neighborhood. Now and then I will take it into the mountains and ride trails there. I have taken it out on a short stretch of dirt road to see how it pulls above 50 but there isn't enough room to hit top speed. I have a few acres to ride on around the house as well as a small subdivision that was never built in the neighborhood.
The pipe and optimizer surprised me in the way they smoothed out the power delivery. Also that it delivered enough more power that I could feel it. I guess I shouldn't be surprised that the pair delivered as advertised, it's just nice to buy something that delivers as promised.

 

If you like clean and MEAN...the sound of the HMF Swamp Series XL on the 850 is worth the price of admission all by itself! If you like quiet...keep it stock lol.