New garret now fueling issues?

[highmark00700]

Well now that the season is almost over I finally made it out to try my new Garrett setup on my 800ho. This year I changed from the mitsu evo turbo to the garrett 2860. I went from a mechanical oil pump to a electric. I moved my afr from post turbo to pre turbo (same spot turbo performance has them in their kits). I added a cold air snorkel. I think other than some small plumbing changes of antifreeze and my charge tube routing thats all I changed.

Last season I was riding it and it melted the one piston so I decided to do some upgrades while I had it apart. With the mitsu I was running 360 mains, 15 pilots, needles in 2nd from the leanest and power jets at 2 1/4 turns out. I decided with the garrett I would bump it to 400 mains to go on the first ride. After going up the trail I couldn't believe how well it was running. Instant throttle response. It felt like riding a stocker on bottom and was pulling hard up to 1/2 throttle or so. I couldn't really go much more than 1/2 till we got on top and it opened up and it was at about 8500 ft. elevation. First run at the hill I made it maybe 50 yards at full throttle and it went way lean (around 14.5 on the afr). So I opened my power jets to 3 turns out. Made another similar pull and it dropped to 13.5. Opened them to 3 1/2 turns and it killed my throttle response in the bottom to mid but dropped my afr to about 13. I dug through my jets and my two biggest jets were 470 and 480. I threw those in and put the 17.5 pilots back in since the thing wouldnt idle with the 15's. I left my power jets a 3 turns out to test it. I was seeing about 12.3 initially but would creep to 12.5 then 12.7 in a short pull. Not wanting to smoke another piston I didnt dare keep it open very long.

It seems everyone is running in the 360 to 380 range and having good luck. What am I missing here that is making this thing need so much fuel? My fuel pressure was showing around 15-17 psi. Boost was 10 psi. The way it is now I need around 520's to be able to close my power jets a touch and get my mid range cleaned back up.

Any thoughts? Thanks in advance!

 

[swrev]

Are you using pipe reference for fuel pressure? Sounds like fuel it isn't coming up fast enough.

 

[gus bohne]

Toss the gauge first
Drop.to 360.mains
The sled told you each time you went richer that it was the wrong move.
Listen to the sled first. Check plugs and enjoy.
Make.some pulls then see what that gauge says. You.moved the sensor. The.readings.changed.

Never ever trust any meter. They are slow and.easily.fooled.
Plugs and.pistons.nevrr lie

 

[highmark00700]

Toss the gauge first
Drop.to 360.mains
The sled told you each time you went richer that it was the wrong move.
Listen to the sled first. Check plugs and enjoy.
Make.some pulls then see what that gauge says. You.moved the sensor. The.readings.changed.

Never ever trust any meter. They are slow and.easily.fooled.
Plugs and.pistons.nevrr lie

Gus I agree to an extent. I think the afr readings are different now but the egts were still hot. 1250+. How long do you need to be able to hold the thing wide open to get an accurate reading on the plugs and piston wash?

I forgot to say the thing would fall on its face after about 2 seconds under full throttle. The more fuel I threw at it the better it would run on top end. ONLY the bottom to mid suffered from the extra fuel. And for the record I was running 360 mains when I burned down last season.

I am starting to see what all the hype is about with the garrett. Just blipping the throttle loading it on the trailer it was making enough boost to pop the blow off valve. It took 5500 to 6000 rpm to get the mitsu to spool at all.

 

[highmark00700]

Are you using pipe reference for fuel pressure? Sounds like fuel it isn't coming up fast enough.

No pipe reference. Just off the airbox. Watching the boost and fuel pressure gauges together they came up at the same time. I dont think thats the problem. I would think if you went slowly from 1/2 to full throttle it would walk all the through it with no hickups, if it was to slow to build fuel pressure?

 

[gus bohne]

my bad, thought it ALL got worse, no reference to it getting better.
Now. fuel pressure must be over boost , 3 to 5 is safe

3 seconds of wide open gives a very very good plug to read. you look att he ground strap, it will have a line on it . the closer that line is to the curve the leaner you are getting. we / I stay in front of the bend..not in it or after it.

reference to pipe helps allot. having at LEAST a 1/4 inch un restriced tank vents makes a world of difference as the longer the pull the more fuel is drawn from the tank resulting more air needing to be pulled in to allow this .
He could very well be draining the bowls sure as hell sounds like it..damn.. stinger size ? is it at least stock ?

 

[swrev]

No pipe reference. Just off the airbox. Watching the boost and fuel pressure gauges together they came up at the same time. I dont think thats the problem. I would think if you went slowly from 1/2 to full throttle it would walk all the through it with no hickups, if it was to slow to build fuel pressure?

You are correct. If not coming up fast enough, you can "walk it" into full throttle. I know my sled prior to going pipe reference was a pain to build into boost smoothly unless 8 or less lbs.

I think Gus is most likely correct in this case on getting a weird reading. I chased mine all over before especially when my mains were to rich. I'd jet back down to 360 and go full rich on powerjets and then start making passes and turn it down 1/4 at a time until it runs clean. You shouldn't have to worry about a lean burn down if you do it this way. It'll give you a chance to also watch your guages and see if they match to how the sled feels.

What did your pistons look like w/ prior burn down? Do you think it was lean or just extreme heat from the mitsu that caused it?

 

[nuttyn01]

Why are you running the thing off the power jets? Jet the thing accordingly and use the power jets only if needed. The metering tools inside the carburetor are waaay more precise than an 1/8" siphon tube ever thought about. Not sure if most know this but there are different needles that can be in the power jets depending on the part number. So even at 3 turns open on the power jet you may not delivering as much fuel as you think. Let the carburetors do the work. Raising the needles will deliver more fuel on the top end also. I would not let the thing creep up in temp with the needles down that far. I would lower the clip to at least the middle if not one spot down from the middle. Make sure your fuel screws are opened up to the correct specs.

 

[nuttyn01]

Power jets are over rated. When tuned precisely you'd be surprised how little you actually use them and then wonder why you even have then.

 

[highmark00700]

my bad, thought it ALL got worse, no reference to it getting better.
Now. fuel pressure must be over boost , 3 to 5 is safe

3 seconds of wide open gives a very very good plug to read. you look att he ground strap, it will have a line on it . the closer that line is to the curve the leaner you are getting. we / I stay in front of the bend..not in it or after it.

reference to pipe helps allot. having at LEAST a 1/4 inch un restriced tank vents makes a world of difference as the longer the pull the more fuel is drawn from the tank resulting more air needing to be pulled in to allow this .
He could very well be draining the bowls sure as hell sounds like it..damn.. stinger size ? is it at least stock ?

Good to know on the plug read. Are you looking for color or just where the carbon stops on the ground strap? Ill give it a try this weekend when I go again. The tank vent is still stock but I'm not sure thats what I'm running into. The longest Ive held it open is maybe 4-5 seconds and its going lean that fast. Ill measure the stinger and post some pics so you can see it. Thanks for the help!

 

[highmark00700]

You are correct. If not coming up fast enough, you can "walk it" into full throttle. I know my sled prior to going pipe reference was a pain to build into boost smoothly unless 8 or less lbs.

I think Gus is most likely correct in this case on getting a weird reading. I chased mine all over before especially when my mains were to rich. I'd jet back down to 360 and go full rich on powerjets and then start making passes and turn it down 1/4 at a time until it runs clean. You shouldn't have to worry about a lean burn down if you do it this way. It'll give you a chance to also watch your guages and see if they match to how the sled feels.

What did your pistons look like w/ prior burn down? Do you think it was lean or just extreme heat from the mitsu that caused it?

The pistons were spi dual ring. They had 5 rides on them. Only one side went down. I'm not 100% sure why it went down but it looked like a combination of deto (I think the vp 110 at the pump wasnt very fresh) and lean. The mag side was the one that went down. The pto had signs of light deto but my bottom to mid was so rich with that setup it would wash all carbon off the pistons. I fired it up after it broke free to get off the hill it went down on so I didnt have to back down it. It washed the good piston clean. It had the chra cooled from the head port and going back to the coolant bottle. That might have contributed to it as well.

 

[Spaarky]

I would follow Swrev's plan.

Couple things stand out to me. Fuel pressure seems a tic low at 10 lbs to me. I run one of those jacked up heat makin Mits, so maybe that is showing me funky pressures. With pipe ref for fuel pressure.

Next, I am a Polaris guy, please forgive me. I don't know the comps on a stock Doo head, timing, Ect. I know they run a little hotter out of the box. On straight 110, at elevation, it's tough to burn down. No fuel, it should just run like terd. We have literally tried to burn mine down, and it just runs like crap. We just ran a 800 Doo in some snodrags. AFR in the upper 13's no problems. Plugs and wash showed what we were seeing on the gauge. I don't know if the pull length would be comparable.

Seems to me there is something else going on, that is a issue that carried over. Could be wrong, my wife will tell you it's not the first time.

 

[highmark00700]

Gus,

I did some measuring on my stinger last night. Here is some sizes. The pipe is a straightline performance with the internal stinger removed. From the pipe to the turbo it goes up an 1/8" in diameter from the outlet dia. of the pipe. The downpipe is 2 1/4" out of the flange and upsizes to 2 1/2" within 2 inches. I wanted 2 1/2" the whole downpipe but I can barely get the bolts in the flange with the 2 1/4". I think it big enough because its barely bigger than the dia. of the wheel. The used turbo that I bought was out of a boondocker kit and it had 2 1/4 all the way down.

 

[gus bohne]

Make sure it's a 82 or 84 ar hotside.
Seen a few fromnthem .64. Big no no. Too tight below 9000 feet on a doo.
Pipes is ok. Raise needles like.nickie said. Reference fuel reg to pipe and.go riding.
Tank vent issues show in 2 seconds..dont.****nwith dumb stuff.fix it before tou.saynits.notnanproblemnansnblownitnup again

 

[gus bohne]

Sent from cell. Fat fingers

 

[highmark00700]

Gus,

its definately a .86 exhaust housing. As far as the tank vent issue goes can you test that by loosening the gas cap?

 

[gus bohne]

Yes. Messy but.

 

[highmark00700]

Well I made it out on another ride over the weekend. It ran a lot better. I ended up jetting up to 600 mains with the power jets at 1 1/4 turns out and afr was reading 12.3 - 12.7. Its was very warm probably 40's. I made about a 4-5 second wot pull and shut it down to check the plugs. The pto was black just starting to change to brown. The mag had a little more brown. It was just a tad leaner than the pto. Still a little room to work but as warm as it was I'm not going to get to carried away since its going to need more fuel as it gets colder next season. Im completely dumbfounded that it needs that much fuel to run but I will give it what it likes.

 

[gus bohne]

the ONLY reason it would be having trouble PULLING fuel is a LEAK in the bowl venting.
Lower bowl pressure than boost will cause this exact problem. just as higher bowl pressure makes them go flooding rich.

dont know if you have changed the lines on all dpm connections to plug them shut or if they came like that to you but are just leaking.
ive seen it when carbs are drilled for a second boost vent fitting on the face of the carbs. when done wrong they do the same thing.. crazy leanouts..

hope you find it man.
simbatheking had same problems. poorly done carbs. we swapped to a simple single vent oem set up on his and solved his leanout issue as well..

 

[highmark00700]

Gus,

I had Bryce from t.p. set up these carbs when I switched from my old round slide setup. The only thing he did was connect the two vent lines with one piece of hose and add the power jets. I used 03 mxz carbs instead of my summit carbs not sure if that would make any difference? Ill keep looking to see if there is a hole in the vent line or something not sealing.