21' Defender Max XT HD10 at HIGH ALTITUDE

[Okstate1010]

Just wondering if anyone has much experience at higher altitudes and if they experience a noticeable power loss at 10K'+ on the newer HD10's? I had a Kawasaki Mule Pro FXT previously that didn't perform well at or above 9.5-10K'. 

 

[DirtRider]

I have a 2021 Defender Limited with the 1000cc engine in it.  It is a little soon in the year to be seeing how power is affected at 10,000 ft elevation though.  Snow still prevents you from getting above 8,000 feet around here.  By June the 10,000 ft elevation trails will be open.  Based on air density decreasing with altitude an engine should lose about 1/3 of its power at 10,000 ft, relative to what it would be at sea level though.

 

[Okstate1010]

Thanks Dirtrider, any way to prevent that 1/3 power loss or is it a simple as less oxygen = less power and no way to stop it? I heard someone mention rejetting it last time i was above 10K'.

 

[Andystoy19]

The engine is fuel injected and will compensate for altitude by reducing the fuel to keep the AF mixture in line but unfortunately unless you go Turbo or supercharged you still lose your 3%/thousand feet of elevation.

 

[DirtRider]

Less air means less power, so the way around that is to force feed the air into the engine.  Hence, the turbo or supercharger that Andystoy19 mentioned.  No carburetor to replace jets in with these engines.

 

[Coachgun]

Planning a trip to Colorado this summer to ride our YZ's that are fuel injected. Previously had Honda CRF's that were carbureted.  Certainly won't miss having to re-jet at altitude.  I'm trying to decide if I want to take the Defender or not just to have for backup but will see.

CG

 

[A hunt 2 remember]

As stated above... These rigs are electronically fuel injected and do not require rejetting for altitude. Other than turbos and such the amount of O2 you get at 10k will be all that you have to work with. So the loss is real... That being said, your HD8 will be an HD8/5.6.... LOL Hopefully there won't be an HD10/7 there..... No matter what, I'M SURE YOU'LL HAVE FUN!!!