What RPM should i be seeing in climbs

[stusnow]

Been having trouble all year with getting full RPM on climbs. running around the 7700-7800 range and wont come back up unless i turn around, hit packed snow or lower grade slope

super deep days, tracked out days & even spring riding still the same.
Sled screams into bottom of climb in 8100rpm then slowly starts to drop and drop...and drop even went to 6800 at one point while other sleds are having no problem at all

dealership went over clutches etc and said all good

shouldn't the sled be able to maintain 8000-8200 RPM even on smaller climbs with tracks all over it ??

I know i'm leaving out alot of variables, but generally i would expect to see that 8200Rpm on the tack. Sled is a '13 M8 Ltd 153" stock gearing, Full SLP pipe & PC5.

and im not climbing chutes or anything crazy just usual hills in Sicamous & Revy area, 6500 - 7500 Ft
like i said the other guys are doing same stuff and hitting 8000+ RPM

 

[Joerobi1]

My sled pulls 8200 all day long

 

[rockymtnboy]

take it back to cat, if it starts out good (8100) sounds like something is binding as you shift out my m did the same thing(1200miles) and it was a bad roller. destroyed the weight. take it back and ask nicley (lol) for new clutches. as stated above, 8150 all day, all terain

 

[Insaneboltrounder/sjohns]

I bet it's the crap secondary

 

[stusnow]

Thanks guys, kinda what i was suspecting....unfortunately

 

[Suzzy-Q]

If it has been like that from day 1 of your setup have u tried dropping some weight outta the primary

 

[backcountryislife]

My sled pulls 8200 all day long

You're giving away about 8 hp being at 8200...

you're better off being 300 low than 100 high.


If you want to get a better idea how to target your sleds rpm for power, check out some dynos... being high on a cat is VERY bad. The higher rpm SOUNDS good, so our brain tells us it's making more power.

depending on which dyno you look at peak is between 8k & 8100, I'd shoot for 8050. Adjustable weights are nice, because you can get it just right, and you can see back to back pulls & see the difference from one setup to another.

 

[Joerobi1]

You're giving away about 8 hp being at 8200...

you're better off being 300 low than 100 high.


If you want to get a better idea how to target your sleds rpm for power, check out some dynos... being high on a cat is VERY bad. The higher rpm SOUNDS good, so our brain tells us it's making more power.

depending on which dyno you look at peak is between 8k & 8100, I'd shoot for 8050. Adjustable weights are nice, because you can get it just right, and you can see back to back pulls & see the difference from one setup to another.

Really I thought peak hp on these motors were 8250

 

[backcountryislife]

Really I thought peak hp on these motors were 8250

Google some dynos, don't take my word for it.

Different dynos will show different numbers, but the peak hp is what you want to look for, and more importantly the dynamic of the numbers around peak.

Look at which way drops off harder, up or down. If being 200 low costs you 1 hp, but 100 high costs you 8, you know it's better to target a bit lower.

I've never seen a dyno that is showing 8250, you're losing a decent chunk.

for me it's all about where I peak on the hill. I'm ok with losing a bit on the way high stuff, compared to over revving a bunch way down low so I don't build power & load the motor properly for the start of the climb.

 

[spoon]

shouldn't the sled be able to maintain 8000-8200 RPM even on smaller climbs with tracks all over it ??

I know i'm leaving out alot of variables, but generally i would expect to see that 8200Rpm on the tack. Sled is a '13 M8 Ltd 153" stock gearing, Full SLP
like i said the other guys are doing same stuff and hitting 8000+ RPM

Have you tried running it stock to see if same issue? Check pipe for cracks. Too rich on topend and it will do same thing under load. Are you running EGTs or just program from SLP? Some sleds need different tuning than others.

 

[WyoBoy1000]

If its starting good then loosing I would be temped to think its the belt heating up and getting sticky causing backshift issues.
What belt are you running?

What clutch weights and did you change the secondary. what helix?

I saw a dyno that showed 7950 was peak torque and 8150 was peak hp, I've also seen tac's be off a bit also.

Only way to know is to pull clutch weight on the hill and see what gets more track speed along with the higher mark.

I'm not one to gear down, fix the clutching first, then if needed gear down. I wouldn't go lower than a top 20t. But in stiff snow with the 2.6 track it might be whats needed. But get the clutching in line first.

 

[Joerobi1]

Google some dynos, don't take my word for it.

Different dynos will show different numbers, but the peak hp is what you want to look for, and more importantly the dynamic of the numbers around peak.

Look at which way drops off harder, up or down. If being 200 low costs you 1 hp, but 100 high costs you 8, you know it's better to target a bit lower.

I've never seen a dyno that is showing 8250, you're losing a decent chunk.

for me it's all about where I peak on the hill. I'm ok with losing a bit on the way high stuff, compared to over revving a bunch way down low so I don't build power & load the motor properly for the start of the climb.

Those are the numbers for the 2010 800. I tried googling it and couldn't find any dynos for the 2012

 

[rockymtnboy]

Those are the numbers for the 2010 800. I tried googling it and couldn't find any dynos for the 2012

same motor,, i guess the airbox is different tho. how about the shape of the pipe, is it the same? both of those could change it a little.

 

[backcountryislife]

same motor,, i guess the airbox is different tho. how about the shape of the pipe, is it the same? both of those could change it a little.

Airbox is different, and pipe is SLIGHTLY different.


Without some hard numbers I see no reason to believe that peak bumped up 150-200 rpm though with no motor changes.

Again though, it all comes down to it being way better to be under than over, so when in doubt, shoot low imo.

 

[Joerobi1]

Airbox is different, and pipe is SLIGHTLY different.


Without some hard numbers I see no reason to believe that peak bumped up 150-200 rpm though with no motor changes.

Again though, it all comes down to it being way better to be under than over, so when in doubt, shoot low imo.

Guess next year ill have to double check what rpms I'm hitting during pulls and adjust if I need too. I have no idea where I thought I saw peak hp was at 8250.

 

[backcountryislife]

Guess next year ill have to double check what rpms I'm hitting during pulls and adjust if I need too. I have no idea where I thought I saw peak hp was at 8250.

If you look around you'll see people saying that peak is higher than it is very often, not sure why.
Funny, in the doo section they say peak is 7900, when on the hill, and on a dyno it's clearly around 8k to 8050.

Folks go with what feels right, rather than with real testing pretty often. If you look around here & see the dozens of threads where folks tell guys to run a 1000 at 7400 to 7450... it's unreal. You're giving up nearly TWENTY HORSE at 7450 on that sled, and people say to run it all the time. I had a buddy spinning 7600 because someone told him to... painful.

 

[DYEMAN]

Rpm dropping

Ck bushing in primary, as well as clutch spring , when you have clutch cover off ck rolls and weights ! Plus ck secondary clutch bushings& spring helix angle ect , then take the gearing down to match 2014 ! Have tach calibrated ( tach can be off 100/500 rpms off at different rpm ranges ) also your engine or clutches posibly moving out of alinement , under different load conditions &rpm ranges !stick to the really basic stuff & you find your problem . The 2012/13 some had rear motor mount issues .

 

[WyoBoy1000]

I would not gear down to '14 gearing, just me!

I change my primary spring every 500miles or less because they start to sag

 

[Suzzy-Q]

Dyno results for 2012+ 800 have less midrange and has a narrower peak power band due to slight pipe differences this new setup favors over rev way more and dropping below 7900 rpm has severe hp loss, let these proclimbs scream

 

[Suzzy-Q]

Also isn't your slp pipe suppose to run at 8300-8400 rpm ? Drop some weight and let that thing wail lol but go over clutches to make sure nothing's throwing things off good luck