Questions about TM8

[mclean]

New to the turbo world and new to the 2stroke world as well. Picking up my Twisted M8 friday and I need guidence.

I know I need to fine tune the tuning...what am I watching for? What should my A/F be at idle/WOT etc. Fuel pressure? I am thinking about 8lbs so what would be a good fuel mixture. I have 91 (of course), 112 and possibly access to 100ll

Most of my riding will be at Blueriver so 7-8000' or so...Any help or tips or info would be very much appreciated. I did search a few forums and looked back to 2009 for threads to help me but couldn't find what i was looking for.

 

[Stg2Suby]

I bought a 2009 M8 last year with Boondocker pump gas kit on it, seems to run fine but I'm nervous riding it because I don't fully understand the turbo tuning. It has no fuel pressure gauge but I've got one coming. FWIW the fuel/air gauge goes as high as 14:1 part throttle coming down the trail, as low as 10:1 getting on the throttle and generally runs 11-12 range. Mine has a manual boost controller; I bought a Boondocker EBC but don't think I'm going to install it until I get more familiar with it.

 

[mclean]

Nobody else?

Sent from my MB860 using Tapatalk

 

[catsass]

What controller do you have ? I have a CPC turbo on my M8. Not sure if the settings would be close or not.

 

[mclean]

The kit comes with the attitude controller.

I'm going with 50/50 mix to start, running 8lbs. I have been told to mix the oil 40:1 and 50:1...what has been working for all you people out there?

 

[BEGA]

Not sure if this helps but I run a 901 BB done by Linderman, I'm running 9.5 pounds of boost and 100% AV gas(100LL), running a 1:1 regulator and a Attitude controller. Pressure is at 43psi at a high idle, I run both a digatron and a A/F ratio gauge and 12.4 to 12.8 seem to be where I get the best runs. This is the first year I am using the A/F gauge and i love it. also I am still only running the single injectors, doing it in steps if I go to higher boost I can see the need of the Dual injector. down the trailer it really varies and that's when i watch the EGT's a little more but as long as I blurp it on the trail its good to go and a blast. on the trail I have my first 2 light settings up around 4,5 and that helps a lot, then once on the hill I have them at 2. What I found this weekend is that you have to really keep that thing loaded so watching your RPMS is key 8200 seemed optimal. I started at 8lbs and went to 9.5, didn't really notice a difference other than over revving, I threw quite a bit of weight to it and wow it was a different machine. I run an Areocharger 66 with a turbo pipe. I've always questioned the whole 50/50 theory, you can buy AV gas at so many airports, and some as low as 1.45/l and the highest I've seen is 1/70/l, is just added insurance and I don't feel its worth the savings when I consider the cost of the sled??

 

[MP Kid]

Sounds like you had it installed some where, they should also be helping you with your drivability\tuning questions,.... if not I'd find somewhere else to deal!

New to the turbo world and new to the 2stroke world as well. Picking up my Twisted M8 friday and I need guidence.

I know I need to fine tune the tuning...what am I watching for? What should my A/F be at idle/WOT etc. Fuel pressure? I am thinking about 8lbs so what would be a good fuel mixture. I have 91 (of course), 112 and possibly access to 100ll

Most of my riding will be at Blueriver so 7-8000' or so...Any help or tips or info would be very much appreciated. I did search a few forums and looked back to 2009 for threads to help me but couldn't find what i was looking for.

 

[mclean]

Yeah they answered a lot of my questions but it is always better to get more than one persons info and experiences I find, as well as other tips and tricks that everyone has

 

[MP Kid]

For sure!!!

 

[moyiesledhead]

If you're mixing fuel this little online octane calculator might help.

Octane Calculator - www.bazellracefuels.com

 

[snobyrd]

Go to ovs turbo web site click pure logic, read their instructions, logic and attitude are the same, even use their starting numbers , it's a base point

 

[mclean]

ill do that, thanks. I know my "cruise" setting or whatever green is, is way too high. bogs really bad on the bottom end...it is set at 8

 

[ldog]

I run a BD race gas kit and run a 50-50 110 octane with premium gas. My pre mix is 40 to1. My premium air fuel is between 11 and 12 and its very happy with 10lbs of boost once I hit higher elevations. Down low I run 6-7lbs. I put on 3500 miles last year with no major problems. Watch what you run in your turbo oil tank. I was told to run Automotive synthetic in it but as the oil tank wasn't vented properly it was sucking a little of this oil up into the charge tube and into the inter cooler thus clogging because it wouldn't burn off. So this year I put a check valve in my cap got everything cleaned and run 2 stroke synthetic which does burn off if some gets sucked up thus no clogging. BTW, I did tear it down this year before riding and rebuilt the top end. Found everything in great shape and didn't really have to rebuild it but did anyways. Few issues I did find though that effected performance was a leak in my inter cooler and reed petals that were broken. Loving it !!!!

 

[Stg2Suby]

Regarding reeds see pic of what mine looked like on my 09; one petal chipped away a bit and several were peeling back. This was with ~1000mi on the odo and assuming the previous owner was honest with the mileage. Sled seemed to be running fine so I'm curious to see if fresh reeds make any difference. I bought Boyesen turbo spec reeds but later found out the M1000 reeds work well on M8T and are cheaper as well.

 

[4mcntrls]

11.8 to 12.2 wot
13.0 to 14.0 mid
14.5 to15.5 idle
X2 with the OVS numbers as a starting point. Good luck and enjoy the boost!

 

[mclean]

11.8 to 12.2 wot
13.0 to 14.0 mid
14.5 to15.5 idle
X2 with the OVS numbers as a starting point. Good luck and enjoy the boost!

Yeah thats about what I am at, once i figured out the colors (very colour blind with red, yellow and green haha). I am only at about 5lbs and for the area I am riding this week that is all I really need. What a difference once I fine tuned the settings.

Thanks for all the helps guys

 

[fredw]

the a/f numbers for the aerocharger etec for comparsion
16- 1 idle
17 to 22-1 for mid range
12.8 to 13.5 for wot

looks like the etec runs a lot leaner

11.8 to 12.2 wot
13.0 to 14.0 mid
14.5 to15.5 idle
X2 with the OVS numbers as a starting point. Good luck and enjoy the boost!

 

[ldog]

Doubling up on stock reeds also works very well

 

[Vertical-Extreme]

here is a thread on snowest about turbo tuning, and a little cheat sheet I made up last year. Lots more turbo info over there
dobek style box tuning cheat sheet - SnoWest Snowmobile Forumappy boosting