I know M series like 87 Octane, but??

[jeffro]

What about if you put a pipe & can on 'em? My friend has 2 '05 M7's and an '06 M7 all with pipes. He's been running 91 Octane (highest we can get in CA) and I was wondering if 87 is OK.

It would save him a TON of cash as he lives in the mountains & pays a premium for gas due to location.

-Jeff

 

[backcountryislife]

From how I understand it, as long as you don't have a head you can still run 87, also keep in mind that octane demand goes down significantly with altitude. Our sleds run better on 85 up at 10k+ (stock)

 

[YooperScott]

On SLP's instructions it says that no boondocker is required BUT 91 octane minimum with their exhaust.

 

[jeffro]

That's what I was thinking... Especially 'cause he hasn't modified the intake either..

Thanks!

-Jeff

 

[DusterB]

My m7 runs like **** on 87. I tried it last year and will never go that route again. Not sure about CA but MT the difference on 87 & 91 fillups is about $2.00

 

[backcountryislife]

On SLP's instructions it says that no boondocker is required BUT 91 octane minimum with their exhaust.

So does a pipe create compression? how does it change the octane needs, back pressure? (serious question, not arguing the statement)

Also keep in mind that this requirement has to be based on 0 altitude in case the rider is in Wi or MN or whatever, in CO, CA... we ride higher. not sure what the formula would be for reduced octane requirement with altitude, probably based on varying air pressure?

 

[jeffro]

My m7 runs like **** on 87. I tried it last year and will never go that route again. Not sure about CA but MT the difference on 87 & 91 fillups is about $2.00

I'll take that into consideration...

Ummm. up in the mountains the difference between the 2 is about $.50 X 4 sleds for 2 days = ~ $35.00 for one weekend....

-Jeff

 

[YooperScott]

My assumption is that the pipe is leaning things down and 91 octane is going to therefore help give a little extra margin against detonation. If you added the fuel box and brought the fuel up then you would likely be safe at low octane again. That's what makes sense to me anyways. I was just pointing out since he asked the question, that SLP says 91 with pipe.

 

[Dartos]

I started to explain but I remember somthing I read several years ago and it took me a while to remember whre it was. Here is a graph to whet your appitite.

Go to this link and then you should have some answers.

Read this SLP article

Good reading from RK Tek

Let us know what you learn!!!!

Hope this helps.

 

[geo]

If a pipe makes the engine a more efficient pump (pulls in more air, stuffs back more mixture) then yes the pipe will create higher RUNNING compression.

The SLP pipe is a very efficient pipe, but the M8 is a very safe motor with it,s pipe, temp and det sensors (which is why I believe we will get a heck of a sceamer in the 800 HO next year). So you can get away with alot.

This year when I installed the SLP on my HCR (same crankimg pressures of a stock SP)after one ride. It felt way too rippy compared to the SP it just came off, so I started running premium to be safe 'till I got a baseline. Kept using the better fuel and took out a bunch of numbers from my normal Boony box settings. I feel it runs better on the premium fuel settings.

Geo

 

[WyoBoy1000]

91 octane is a lot cheaper than a top end, I wouldn't risk it.

 

[RMK_Ryder02]

M8 what grade of gas?

i have a 2008 M8 with SLP single pipe and can, reads and clutching and the elevation i ride at is about 1800 to 8000 ft.. wondering what blend of gas i should be running .. if i need to be more exact with the elevation i ride Norns and lady bird area as well as the valhala's almost same thing ... just wondering what blend of gas i shoul dbe running i run regular to be safe right now but i was wondering if i can run premium to see if there is a deference in performance thanks any help would be much apreciated

Aaron

 

[Knizer8hun]

I agree.... higher octane shouldn't be needed unless you have a higher compression ratio.

My 08 M8 has SLP's setup and clutching. It didn't mind premium (91) , but it was still plagued with that low low end grumble and bog. Tried mid grade (89 up here) and it changed it quite a bit, however that was after I wrecked an exhaust sensor. Im not sure if the mid grade and faulty sensor worked hand in hand to improve how the sled ran, but it seemed to hang on longer on climbs, and be a bit snappier off the line.

Haven't tried 87 yet, and probably wont because of what someone said about the pipe.

Seems smart to me to kind of slpit the difference between reg. and prem..... get two birds stoned at once or however that saying goes.

 

[XFIRE800]

i have a 2008 M8 with SLP single pipe and can, reads and clutching and the elevation i ride at is about 1800 to 8000 ft.. wondering what blend of gas i should be running .. if i need to be more exact with the elevation i ride Norns and lady bird area as well as the valhala's almost same thing ... just wondering what blend of gas i shoul dbe running i run regular to be safe right now but i was wondering if i can run premium to see if there is a deference in performance thanks any help would be much apreciated

Aaron

running premium isnt going to hurt anything, they just claim the motor runs better stock on 87 octane. I run premium all of the time, except the last time i filled up. Now I have my slp pipe kit waiting to be put on, but im afraid i will need to have 91 for it. And there is not enough snow here to ride at the moment so i cant burn up the 87. BTW i ride at about 1500 ft at home right now.

 

[Knizer8hun]

That is very correct, in fact, if you don't need the higher octane, couldn't you expect performance that is less than par?

Im impressed with 89 octane, and maybe for the last ride of the season, give 87 a whirl, so I can get a new motor(should anything happen) over the loooong summer?

 

[Frostbite]

I'm with you guys. I run 3,500 - 7,000 feet.

The mechanic from my dealer says to run 87 octane with my 09 sled with the SLP pipe. He said they have dozens of sleds out there running 87 without issues. The 87 octane helps get rid of the bog I'm told.

While I don't doubt the mechanic from my dealer one bit but, when I called SLP they were very firm about the need to run 91 octane but wouldn't discuss the how's or why's with me at the time.

 

[WyoBoy1000]

lower octane burns faster and hotter than high octane but if you are creating more horse power you create more heat. heat alone can cause pre detonation and burn down the motor. Run what slp recommends. If your under 3000 with pipe you should have a fuel controller? As for the 09 m8 it has a det sensor and will change the timing to correct pre det but if you are retarding the timing you lose top end hp and gain more low end torque. When you raise hp you raise the compression output risking pre det, 91 oct is a fail safe and you could be risking your motor on a modded sled. My 09 m1000 stock ran the best on 89. last year I ran a 07 m1000 full slp and had pre det problems even with 91 oct. If you have egts the temps will read lower in the pipe than in the piston if it pre dets because all the heat is being created before it leaves the cylinder so don't let egts fool you. hope this helps

 

[RMK_Ryder02]

octane#'s

well i thought about this very differently i thought the higher elevation you go the higher octane you need.. and yes i did have a really bad bog with my sled on regular gas but i tightend the belt up and that got rid of the bog i had basically my sled was engaging when it should have been doing 20 KM already ... so what you guys are saying is to run premium or midgrade insted of regular for my elevation's???

 

[backcountryislife]

well i thought about this very differently i thought the higher elevation you go the higher octane you need.. and yes i did have a really bad bog with my sled on regular gas but i tightend the belt up and that got rid of the bog i had basically my sled was engaging when it should have been doing 20 KM already ... so what you guys are saying is to run premium or midgrade insted of regular for my elevation's???

Higher elevation = less air pressure, this creates less compression. A sled that pulls 150psi at 5k will pull around 120 up at 10k (around there somewhere, I never go that low!) this requires less octane since you're less likely to det. at lower compression levels. The sled has an ideal temp it wants to run at & if say you run 110 on a stock sled (ooh, race gas, must make power right?) you lose power because it runs too cool.

I don't know the science behind what the temps do (differences in scavenging, etc...) I just know what the different fuels do to a machine. Living at the extreme of altitudes our sleds run best on 85 but yet lots of people buy 91 because they think it will make their sled run better. Not so.

Run what the mfg of your sled or mods tells you to, but a blank statement like "run 91" doesn't seem too accurate to me, at what altitude?

I run 91 with a 14.5:1 head at 10k+, if I go below 7500 I have to add a gal or so of race gas for each 1000 I drop below that Kelsey said (can't remember exactly) It all depends on altitude.

 

[cappel]

Guess I can't tell...

..the difference really. I just bought an '07 M8 about a month ago and have only run 91 in it and it runs like a raped ape! Has around 900 miles on the sled now. I have run every grade, 85,87,91 in my '03 Mtn. Max and it didn't make a difference there, at least i couldn't tell. I have never heard of "AC says 87 oct. works best" myself but then again, i've only owned adn AC for a month now. I know the Max is carbed and maybe that makes a diff but really, I couldn't tell a diff. with using diff. octanes. I've run 91 in all my sleds and here in CO. it's only 20 cents difference from 85. What's that on a fill up, maybe 2 bucks. You guys really have this down to a science huh? Oh yeah, the M8 is stock besides snow eliminators and a Boss seat. The Max on the other hand has v-force 3 reeds, SLP tripple pipes and can, drilled air box and a bunch of other sh*t. I put fuel in my sleds and rip them! I run AC oil and yamalube. That's my 2 pennies.