OVS 3071 Tial M8 turbo sputter on WOT.

[flatlandsledder]

2007 M8 with OVS 3071 Tial turbo purchased last season. 11 pounds boost. 110 octane. No intercooler. Low end seems to be the same throttle response as my 2006 M7-M8 big bore. I wouldn't even call it turbo lag. It's no worse than the big bore. I'm happy with low end performance. Mid range is unreal, arm pulling monster. Wide open throttle is where the problem comes in.
If I start out with a cool engine, I can make a long pull up a hill without a sputter(but probable leaving power on the table). If boondocking or warm engine, wide open throttle will result in a on-off sputter. Letting off the throttle to half to three quarter throttle will result in running good again.
Question: I'm I fighting a heat issue thats richening up because of rising heat, or not dialed in right? Or maybe I'm fighting too much fuel on the secondary injectors (Yellow/Blue)? Or turn down the Green/Blue?

Pure Logic O2
Green 2 14.1
Yellow 2.5 13.5
Red 1 12.2

Green/Blue 3
Yellow/Blue 2
Red/Blue 7

I have the large mod rod hood vent, shock tower vent, side panel vents etc. Should be getting close to as good as mesh hood, but not quite. Boondocking will have the charge tube warm to the touch. Long uphill pulls will be hot to the touch. Thinking that a intake air snokel out the top of the hood would make a difference?
Keep in mind this is a 3071. Not the 2871 that you would normally see. The way the mid range runs, I feel I'm close to having this thing run like it should be making videos.

Forgot to metion, running down the trail with throttle wide open, I do not have an issue. Only WOT under load, climbing. Fuel pressure is set to 38 psi. Maybe 37. Hard to say for sure.

 

[9500blizzard]

Is snow getting under your hood? I have a 2871 ovs kit that was having similar issues, just made a cold air intake and its realy crisp now.

 

[Tonysnoo]

What elevation?

Are you monitoring water temp too? If so does it get pretty warm?

 

[mattymac]

Tunnel dump exhaust?

 

[WyoBoy1000]

lower your mid range numbers and try it.

 

[Tonysnoo]

lower your mid range numbers and try it.

What do you base that recomendation on? It sounds like his midrange is working.

Most of his numbers already, seem low to me, but elevations and even gauge differences could account for that.

 

[flatlandsledder]

Response to your questions

9500blizzard
I'm sure a little snow entered through the large mod rod hood vent, but I lifted the hood several times to look at the filter. Other times while making a pull there was no chance of snow entering. I was thinking the heat under the hood was making it richer the hotter it got, and if so, making a snorkel sounded like my only option. I hate to put a big hole in the hood, but if it makes it run good, then so be it.

Tonysnoo
I am not monitoring water temp. Probably should. I will say that I installed a heat soak switch, but have never had to use it. I have shut it off many of times while it would have been overly hot, and it starts right back up. If it was overheated, wouldn't it run poorly from top to bottom?
Elevation-Togwotee Wyoming. Anywhere from 8000 to 11,000 feet. I live in Iowa, but thats where I had it. Riding in almost 2 ft of fresh powder the day I left. Chest deep in the meadows.

mattymac
It is a side dump, not a tunnel dump. It would sputter even if the exhaust was out of the snow.

I would say that I can't believe how well it runs from low to midrange. I figured that was where I was going to have my problems. I rode for 3 days playing in the snow with only 1/2 to 3/4 throttle and outpowered every sled around. If I didn't mash the throttle, no one could tell I was having a problem.

The numbers do seem low on the OVS box. There isn't alot of 3071's installed on M8's. Garr told me to follow the M8 settings listed on their website.

The first day I was riding, the OVS clamp holding the pipe to the Y-pipe loosened up(even though it was doubled nutted), which caused similar issues. It would blow out through the donut when the boost was climbing. I have since blue locktited the double nuts. I think I have the springs compressed down pretty tight now. I don't think it could blow the pipe off now. Maybe I'm wrong.

I'm reading some people are running 40 psi on the fuel regulator. What would happen if I turn mine up a little? Richer or leaner?

I'm heading to Cooke City on Feb 1st. Hoping to have it diagnosed by then. Any of you guys planning a trip out there around that time?

 

[backcountryislife]

What year M8 & which ECU flash?

Btw, I ask this because when I switched to the 12 ecu flash, if I add 2 extra gallons of 116 to my mix, for some reason I get a stutter, only on the top end, that FEELS like the code 21 limitation from the <2011 flash ecu's, but I never get the OCTN code on my dash.

When I get away from the extra 116, the issue goes away instantly.

Btw straight 110 for 11psi, for 8-10k riding seems WAY too high to me. On the 12 flash I can run 11psi on pump now at 9000, 11.5 at 10,500. On a deep day with big pulls somewhere around 1.5 gallon of 110 would get me 11 safely.

What kind of temp or AFR are you seeing right before it starts having issues?

 

[flatlandsledder]

Response to your question- backcountryislife

backcountryislife
It's a 2007 M8. ECU flash? Never been reflashed I don't think. I believe it's stock. The kit uses a pure logic box. Programmed for 12 lbs boost.
O2 reads 12.2
It's more like 105 octane because I did have one or two gallons of 91 in the tank.

 

[Vertical-Extreme]

Check the condition of your reeds, and also check to make sure your hot start switch has not failed "on". That will make it go full rich. Your numbers don't look that much different than mine. Also check for boost leaks, you can try putting some rtv silicone on both sides of the exhaust donut.

 

[flatlandsledder]

Response to Vertical-Extreme

Are you running the 3071 Tial?
Reeds are brand new M1000's. I just installed them with the OVS reed stops. Can I start my sled and flip the switch without any ill effects?
Should I install the silicone on the outside of the pipe just to see if it leaks? I thought we turbo guys weren't supposed to use silicone to keep the little chunks out of the turbo.

 

[never satisfied]

It sounds to me like your a little rich on full throttle. I would take a little away on your yellow/blue or green/blue. If your worried to go leaner then add some first and see if it gets worse. Could also be fouled spark plugs but i would start with adjusting the yellow/blue secondary injectors first. pretty common to have a cackle wot if your a little to rich, also makes sense that it rips when cold and starts acting up when warmed up, does'nt need as much fuel warm. I'm always adjusting a half a light up or down to account for elevation or temp changes. Good Luck.

 

[Vertical-Extreme]

Are you running the 3071 Tial?
Reeds are brand new M1000's. I just installed them with the OVS reed stops. Can I start my sled and flip the switch without any ill effects?
Should I install the silicone on the outside of the pipe just to see if it leaks? I thought we turbo guys weren't supposed to use silicone to keep the little chunks out of the turbo.

I have an 07 with PL fuel control, but mine has a 2871. I would try and take the switch out of the situation, mine failed and it was acting similar to what you are describing, so i just unplugged it and haven't had trouble since, something to try, and rule out if it does not help.

 

[WyoBoy1000]

I say cut the mid because if its even a little rich when the boost fuel comes in all the sudden it studders, doesn't drop a cylinder just studders, like a det 21 but not as bad and louder. I ran the yellow/mid setting at 1.5, was told 3, but anything other than 1.5 and it would not run.

i would also shut off the red for testing, then if you think you want to fine tune turn it back on.

can't hurt to try it.

You may also want to check the torque spec on the det sensor and pipe sensor if you don't come up with anything else.

I am ruling out the warm vs cold and looking at it more like, when cold there is less fuel in the engine starting out, but after ran a minute or two its loading up on bottom but still running, then dump in the boost fuel and stutter.

 

[9500blizzard]

my sled was doing the same thing last year, all my vents were letting in snow which was heated and turned moisture. As long as your A/F is reading 12.5, try taking your hood off and making a pull see if it helps. the cold air intake i made for mine is the best thing i've done, i can send you some pics if you'd like.

 

[flatlandsledder]

Response

9500blizzard
I'd really like some pics and how to info on the cold air intake. scottyhintz@gmail.com is my email. thanks

I wouldn't call it a stutter. It's more of a blah, The power loss is like I'm droping a cylinder.

WyoBoy1000
I'm gonna try dropping the secondary (yellow-blue) to 1.5 . Garr said no lower than that. I'll also try dropping the yellow also.

Vertical-Extreme
I'll unhook the switch also. I'll probably try a little more dropping of the numbers on the pure logic box first, then out she comes.

Never satisfied
I replaced the plugs with new, but it still didn't fix it. Gonna keep leaning it out.


Also gonna add some more weight to the primary.

 

[WyoBoy1000]

Just remember, one thing at a time.


Why are you adding weight, whats the rpm

I would not change the y/b, start with the yellow, then turn off the red, then tune as close as possible with the Y/B, if you need to fine to the top end turn the red back on.
If you turn the red on start with red 1 and R/B 7.5 or 8

the
G
Y
R are your fine tune adjustment, all are non boost adjustments

the
G/B turns on boost fuel and is activated by boost - and it can kick on over the top of the other setting, I have had mine kick in on top of the G setting, so if any of the lower settings are to high when the boost fuel comes on it will go rich.
Y/B not sure but I think it turns on secondary injectors
R/B R turns this one on, if you set red at .5 it turns off the R/B and anything above .5 adds fuel, the R/B is where it adds the fuel and it goes off of load percentage, so once it hits a curtain amount of load, it adds how ever much fuel you add on the red setting. So if the fuel is already there with the G/B and Y/B and you add fuel in the red it will sputter. You have it set at 7, it may be adding to soon and going rich, if you put it up to 8 it will only add it in the high rpm at a higher load and not go rich to soon.

Check to make sure what the Y/B is though! Hate to steer you wrong.

If the Y/B is the secondary injectors, then you also have to balance between the G/B and Y/B, i e you don't want to much fuel kicking in all at once.