lost rpm with pc5?

[754bigbore]

I just put a pcv on my 09 800 rmk- 155. The map I got from Jim @ dynotech is 156 hp for an all stock machine. The elevation at home is around 2700 feet. After installing the pc5 and syncing the tps I went for a ride. The sled seems to pull really hard but the rpm tops out at 8150. I am running the stock weights- 62 g. The rpm seems a little low to me. The belt to shieve side clearance was just adjusted to 20 thou and the tps was adjusted also. Before at this elevation the rpm would easily bounce to 8200 to 8300 with no pc5. I'm just wondering what will happen when I get to the mountains- usually ride between 3 to 8500 feet. I have a mbrp can on the sled too, I have heard they may not be the best for these sleds. Any insight would be great!

 

[Kraven]

I just put a pcv on my 09 800 rmk- 155. The map I got from Jim @ dynotech is 156 hp for an all stock machine. The elevation at home is around 2700 feet. After installing the pc5 and syncing the tps I went for a ride. The sled seems to pull really hard but the rpm tops out at 8150. I am running the stock weights- 62 g. The rpm seems a little low to me. The belt to shieve side clearance was just adjusted to 20 thou and the tps was adjusted also. Before at this elevation the rpm would easily bounce to 8200 to 8300 with no pc5. I'm just wondering what will happen when I get to the mountains- usually ride between 3 to 8500 feet. I have a mbrp can on the sled too, I have heard they may not be the best for these sleds. Any insight would be great!

The drop in R.P.M. may/may not be PC-5 related, sounds like you changed a few things all at once.

1st- Unplug the PC-5 when you're there on the trail, see if the R.P.M.'s increase

2nd- What do your plugs look like, piston wash, and you may have to "fine tune" the top #'s to your sled.

 

[754bigbore]

Kraven- by fine tuning the top numbers, do you mean changing the map? If you unplug the pc5, does the tps have to resynced when you plug it back in? This is all new to me, I miss my 03 mod when I could rejet as needed!

 

[Kraven]

Kraven- by fine tuning the top numbers, do you mean changing the map? If you unplug the pc5, does the tps have to resynced when you plug it back in? This is all new to me, I miss my 03 mod when I could rejet as needed!

The T.P.S. does not have to be re-synched.

Yes on changing the map (slightly on the 8000 R.P.M. #'s for now)

Thin of it this way, 5%= approx 2 main jet sizes.

Read the plugs and wash, change the #'s by 5% at a time, test ride and re-check

 

[754bigbore]

ok, sounds good, will play with it a bit, thanks!

 

[diamonddave]

I wouldn't discount the can causing lower R's. If you still have the stock can, maybe give it a try.

For whatever reason, Polaris likes the SLP can as it's the only can they will still honor engine warranty with, and from what I've been told, they actually prefer the SLP can over the stock can.

 

[machinest660]

I installed my pc5 yesterday. i was running 7900-8000 rpm without the pcv and am now at 8050-8100 with the pcv. The sled seems to pull harder and has a total different sound at the 6000-7000 rpm range then it did before, This was at 1900' with mtx68g wights with 2g in tip and 1g in the belly. What is the Target rpm with the stock pipe on these sleds????

 

[AndyL]

8450 is the target RPM. I ran the MTX 68G with 2g in the bellly and 1g in the tip and was pulling 8150 at 4000ft. I pulled all the rivets and haven't had a chance to try it yet. I had the PC5 installed with my exhaust valve plugged also.

 

[machinest660]

8450 is the target RPM. I ran the MTX 68G with 2g in the bellly and 1g in the tip and was pulling 8150 at 4000ft. I pulled all the rivets and haven't had a chance to try it yet. I had the PC5 installed with my exhaust valve plugged also.

My mistake i do have 2g in the belly and 1 tip, was out again today to do some testing and had the same results 8100-8150 rpm and 66mph track speed in about 10" of snow. I had a good 1/2 mile WOT runs and that was all i could get, i checked the plugs and they still looked a bit rich on top but its better than it was, clutches were also nice and cool after multiple pulls. it was 4deg f or - 12deg C. This was the 157 map from jim so i might try the 162hp map and see how that does, i do have the stock pipe or i would try the slp map. I will try pluging the exhaust hoses next before i try anything else. AndyL do you have a pipe on your sled and what track lenght are you running?

 

[Snowman 2001]

8450 is the target RPM. I ran the MTX 68G with 2g in the bellly and 1g in the tip and was pulling 8150 at 4000ft. I pulled all the rivets and haven't had a chance to try it yet. I had the PC5 installed with my exhaust valve plugged also.

I thought target was 8-8200 RPM...

 

[AndyL]

Nope, no pipe. I'm running the ch extreme 155" and FTX drop and roll. I would be interested in how the 162 hp map does. AKSNOWRIDER on here has been a huge help in dialing in my clutch.

 

[754bigbore]

what does plugging the exhaust vlv hoses do?

 

[Kraven]

PLUGGED EXHAUST VALVES

what does plugging the exhaust vlv hoses do?

In the sleds I've done, improved hole-shot/acceleration.

Also allows for cooler running at cruising speeds by not "holding back" exhaust with the valves closed.

There's a thread on here about it, and as usual some like it, while others don't.

For the 2 minutes it takes to plug the hoses, my advice would be for you to try it on your own sled, and make your own determination.

If you don't like it, at least you're not out any $$$$$$$$$$$$$$$ on trying it.