Dyno # for XP
- Thread starter HANDSOME
- Start date
tested stock, our 860r big bore, single pipes, y pipes, reeds, twin pipes, heads.
I was with CJ motorsports at Dynotech last December. We were the 9th 800R in a row to go on the dyno.
Jim told us that on these 800R's so far, he had to "make a run at the pipe" do warm up runs to get the pipe as hot as he could before a full pull. When the pipe temperature got near equilibrium, could not get hotter then the engine would make an honest 150 hp, then let off the throttle and do the 2nd full pull, it would make 151~153hp after a 6~9 second run.
Jim mentioned to us that for a normal trail rider who runs on the trail, he can see the pipe temperature during riding being less than what he would run there on the dyno - the engine probably won't make over 145hp. The other runs he did with cooler pipe temperatures were around 144hp.
With 91 octane on my own 08XP800, made 137hp on 1st pull and 147 after a run at the pipe.
Jim told us that on these 800R's so far, he had to "make a run at the pipe" do warm up runs to get the pipe as hot as he could before a full pull. When the pipe temperature got near equilibrium, could not get hotter then the engine would make an honest 150 hp, then let off the throttle and do the 2nd full pull, it would make 151~153hp after a 6~9 second run.
Jim mentioned to us that for a normal trail rider who runs on the trail, he can see the pipe temperature during riding being less than what he would run there on the dyno - the engine probably won't make over 145hp. The other runs he did with cooler pipe temperatures were around 144hp.
With 91 octane on my own 08XP800, made 137hp on 1st pull and 147 after a run at the pipe.
T
trinitypowder
Well-known member
Silly question...but if the hotter the pipe is the more HP the 800R produces, why is it that on the hill it feels like the sled pulls a lot harder and climbs higher if you let things cool off for a bit before hitting the hill again? Is it because the clutch is hot and shifts better when cooler ?
I have noticed this on my '02 Summit 800 & my '08 XP
As pipe temperature increases, hp increases, torque decreases.
as pipe temperature cools, hp decreases, torque increases.
Far as that "feeling" goes, I don't know. I only can recall principles from engine part vendors like rkt or bjohn, supertuner...etc.
L
LRD
Well-known member
As the engine itself gets more heatsoaked (crankcase) the air density through the engine goes down. Cold air has more oxygen in it. Pipe probably holds some heat longer as the motor cools a bit so it heat back up quicker.
Good Luck
PS Sounds like a bit of insulation might help or maybe little tighter stingers to build a bit more heat in pipe at altitude. Pipe and can Have TO BE Made Loose so they don't blow up engine at close to sea level in Alaska etc. TurboAl has a very informative thread going on pipe pressure.
Good Luck
PS Sounds like a bit of insulation might help or maybe little tighter stingers to build a bit more heat in pipe at altitude. Pipe and can Have TO BE Made Loose so they don't blow up engine at close to sea level in Alaska etc. TurboAl has a very informative thread going on pipe pressure.
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HANDSOME
Well-known member
It is your clutches cooling off and the engine a little cooler may help as well but when you are climbing your pipe is almost always hot. People used to think me and buds were nuts for pulling our hoods to make a mark ... I call it greedy.
B
badass1000
Well-known member
so what can be done to keep the pipe hotter? Say with a aftermarket single that is ceramic coated? Try to put the stock heat shields on? wrap the ceramic coated pipe with headerwrap?
when pipe temp is low peak hp is lower, not nessasarly hp, when pipe is hot peak rpm hp is higher.
hp and torque work in relation to rpm.
were tuboals post on pipe presure couldn't find it
