Top of hill bogging down...HELP!!!!

If you are using leaded race fuel, the fuel filter will catch some of the lead and could eventually start to block the flow of fuel.I did cut a filter apart and the element was totally black. Have you replaced the fuel filter lately?

100LL is Avgas, Low Lead 100 octane.

You are using too much avgas. I run a 13.6 head at 2200' and use 30% 110 race fuel, at 8000' i would be lucky to need 10-15% (but i do anyways).

Try reducing the avgas a little at a time as suggested above.

I have my throughts on your sled as well (mainly clutching and some other small details)

But more advice for getting good information.

Better more concise info regarding your sled, all info in one place. Also, work on less more thought out replies, I want to help you but there is WAY to much going on in this thread and there are way to many random ideas being thrown around detracting from any sort of Q@A that may help pinpoint the problem.

100LL is Avgas, Low Lead 100 octane.

You are using too much avgas. I run a 13.6 head at 2200' and use 30% 110 race fuel, at 8000' i would be lucky to need 10-15% (but i do anyways).

Try reducing the avgas a little at a time as suggested above.

Click to expand...

Gotta chime in here at the risk of getting a bit off track.
The above quote is the worst piece of advice that you can follow.
The number 1 cause of engine failures is insufficient octane for the motor.
You are running a 14-1 compression ratio. If you know someone who is into hot rods, ask them what octane they would run in their 600hp car with a 14-1 compression ratio.
Think of it like this-you have a 2 cylinder motor that makes 150 hp. An 8 cylinder engine is like 4 of your motors put together in one block. 4 x 150hp=600hp.
A car motor spins at 6000rpm tops. Your motor spins at 8000+ rpms. The car motor has nice rolling wheels and you would be hard pressed to hold it to floor for more than 10 seconds. Your sled, well, if your climbing, it can be up to a minute with way more more load on it.
You can never run too much avgas. Period. Beware of people that mix 30% avgas with such and such octane. They may ride like a granny and maybe they don't hold it the bars, ever.
Anyhoo, the advice of the head company could be right to say you can run 91 at 8000ft.
Unfortunately, you don't start out at 8000ft. You start at a much lower elevation. You will need more octane than a cheap *** mix of avgas and 91.
To try to save $10 a sled tank of fuel when you have a $15,000 sled and a $30,000-$60,000 truck is just ridiculous. Consider the fact that you could lose a day or week sledding, a rebuild is anywhere from $1000-$3500 depending on damage and spending $10 a ride for good fuel seems like chump change.
Thats my take with fuel.
Wheel house hit the nail on the head.
If your sled is a 2011 and you haven't cleaned or replaced the clutches, then there in lies your problem.
Screwing with mixing fuel isn't gonna bring you another 1000rpm.
A good tip is to take the secondary clutch off of a friends sled that is running good and put it on yours. Do this on the hill. Ride for a half hr and let him ride with your clutch. If his clutch works better, then don't give it back to him till you get back to the truck. Simple. This tells you what is or isn't wrong.
I'm gonna go take my meds now. Blood pressure meds too.

Lol, calm down. You make it sound like i told him to stop using Avgas all together!

Enjoy those meds.

I think it could be the can , not all sleds respond the same with the same mods .
Just from experience .
You can't clutch a motor that has variable inconsitant hp loss as heat builds up.

Mmmmmmmmm.......meds.

If you read the guys posts he states that at the bottom of the hill he has already hit the rev limiter....middle of the hill pulling good power....to of the hill bogs down.

The symptoms he's describing sounds like clutching to me :face-icon-small-win

DPG

The '11s were plagued with multiple problems. Electrical wiring was one. Have you checked all the simple/easy things? Not enough information here. What upgrades, yellow injectors with reflash? Have you done a leak down test? Any digital wrench hook up info. There are a ton of things to check. Even a track that is to loose will have this affect. Sounds like it isn't ridden often or maintained very well. Just my observation from the posts.