Carbed 2 stroke turbo guy's !!!

[papafinger1]

You know I have been meaning to say this for a week or so but have held off cuz of being new.

I need pics.
Speakin of that I might have some pics of my carbs.

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[papafinger1]

I have one more pic that is better. I have trimmed 3/4" off the rubber hose to get them closer to the carbs as well as giving better clearance to the steering post. What would be other options for the powerjets? Now the bevels from the carbs and the airbox are millimeters from touching.

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[Todd H]

Power jet location

I'm running one sled with the power jet installed in the airbox outlet (sort of like yours) and one with the power jet installed in the inlet of the carb ( drill, tap, etc) Both seem to work, it does make sense to have it as close to the slide as possible. On both sleds the power jets are hanging approx half way in the inlet / outlet. Sorry, no pictures. I will try to get some later.

 

[Fack]

Get them in the air horn of the carb as close to the slide as possible. The intake velocities are higher at this point and the flow coming in is more columnized and linear there as well. This gives you a stronger more consistant signal that results in higher control over the power jet circuit. With them in the air box as you have them the air is more turbulent and you are potentially picking up a lot of "dirty" air at the current location.

-Fack

 

[Team Voodoo]

carbs

Will these cat 38 mil carbs work on my one off doo turbo project I pick up a pair on ebay for a 100 bucks new. There is more if anyone is looking.

 

[gus bohne]

Papa,,, that airbox is a trouble spot for sure..
its to small , the area in front of the carb openings is much to tight( front to back ) .
Make yourself a box with ( depth equal to 2 times the diameter of the carb size). Put the power jets into the carb bells as Fack stated and you will be amazed at the difference in tuneability.

Even with reeds there is still a fair amount of reversion on the intake tract. the back wall being too close to the bell will over enrich at low speeds and cause pretty substantial issues at higher airspeeds and volumes..

If you have room for a deeper box get one. what is the measurement between spark plug centers ?

Might be some airboxs around that would fit so you don't need to fab one up.

those carbs are ok for boost use voodoo

Gus

 

[devilrmk]

papa, I will take a pic of mine tonight. That doesn't look nearly as bad as I was picturing.

They will affect much more of the throttle range where they are at. The closer they are to the slides the cleaner the on/off.

Not sure if its really worth it to change the location, but I think it will make it easier to tune, and a bit crisper in the low-mid range and maybe help fuel economy slightly.

Edit, I guess gus was answering while I was posting.

If you make a box like what tony has with o-rings, you can get way more room for box or post clearance. I have changed mine to that style box to better clear my steering post.

 

[papafinger1]

Papa,,, that airbox is a trouble spot for sure..
its to small , the area in front of the carb openings is much to tight( front to back ) .
Make yourself a box with ( depth equal to 2 times the diameter of the carb size). Put the power jets into the carb bells as Fack stated and you will be amazed at the difference in tuneability.

Even with reeds there is still a fair amount of reversion on the intake tract. the back wall being too close to the bell will over enrich at low speeds and cause pretty substantial issues at higher airspeeds and volumes..

If you have room for a deeper box get one. what is the measurement between spark plug centers ?

Might be some airboxs around that would fit so you don't need to fab one up.

those carbs are ok for boost use voodoo

Gus

thanks. And once again pics would be great. I am terrible at visualizing stuff. LOL! plugs are 5 1/2 in c to c. carbs bellows are 2 1/2 in outside to outside. Air box is 8 1/2" wide x 1 1/2" wide and 4" deep. Can go deeper on the air box but I only have 3 1/4" clearance from carb to steering post but once beyond the post there is plenty of room to move back.

So for better tunability the powerjets should be tapped into the bellow as close to the slide as possible on the airbox side? Just want to make sure I am getting all of this correct.

Thanks again,
wes

 

[Tonysnoo]

Hey Papa,

I might be able to help on this one. You're right, the power jets as close to the slides as possible.

On page 5 of this thread are some of the pics I posted. Pic 6 of my post shows the relationship between the airbox and the location of the powerjet. Since I'm running an M chassis, I was also limited in depth, but I was able to get the box built where it was over twice my bore size deep, except the fairly gentle tapers on the sides.

Hope this helps.

 

[papafinger1]

Hey Papa,

I might be able to help on this one. You're right, the power jets as close to the slides as possible.

On page 5 of this thread are some of the pics I posted. Pic 6 of my post shows the relationship between the airbox and the location of the powerjet. Since I'm running an M chassis, I was also limited in depth, but I was able to get the box built where it was over twice my bore size deep, except the fairly gentle tapers on the sides.

Hope this helps.

It does. My airbox is in theory quite similar to the one u have other than the fact I have about 4 more inches available to move back to the gas tank. Problem is that there would have to be a notch in the airbox to accomodate the steering post. The way it sits now I would not be able to soften the taper back on the airbox without interfering with the post. I could offset it farther to the clutch side, but would that have a altering effect on equal air flow to both carbs and have a negetive effect on correct tuning?

 

[devilrmk]

Heres mine, hard to get a camera in there with it all together.

My box has an offset in it, to clear the steering post. It only has the offset on the one side and the other is just straight. My charge box is pretty large and its fairly tall to help it flow better to the mag side carb. I plan to do some work to the box to try and make it more equal and a little smaller but it seems to work fine the way it is.

Tony, you will notice that I copied your idea with the o-ring sealing. Works good. Theres no way I would get it on without the carbs off though but they come off hooked together just fine. I just used a single o-ring and kept it pretty tight. Took my time welding it up and had to do just a very small amount of massaging to get it to fit right.

 

[papafinger1]

Heres mine, hard to get a camera in there with it all together.




My box has an offset in it, to clear the steering post. It only has the offset on the one side and the other is just straight. My charge box is pretty large and its fairly tall to help it flow better to the mag side carb. I plan to do some work to the box to try and make it more equal and a little smaller but it seems to work fine the way it is.

Tony, you will notice that I copied your idea with the o-ring sealing. Works good. Theres no way I would get it on without the carbs off though but they come off hooked together just fine. I just used a single o-ring and kept it pretty tight. Took my time welding it up and had to do just a very small amount of massaging to get it to fit right.

Devil, if it isn't too much trouble I would like to see a pic of the whole airbox. Curious to see how it was built and how you manipulated it around the steering post. Especially since we are running the same chassis. I haven't decided what I am going to do yet, if anything but the info is worth taking a serious look at. Only so many things I am going to work on a year. It seems to be running really strong right now but I also don't know what its potential can be. I will probably wait to get it is some elevation and see how it reacts. I also don't have the capability to weld the aluminum so outsourcing the built will be an added expense that maybe better focused elsewhere.... clutching, thinking my maverick track is too soft, rear suspension, and a different tunnel.....

 

[Spaarky]

Devil... how the heck do you get your hands in there to adjust the powerjets? OMG.. you have tiny hands?????


Anyone have a good source for fittings? Like off the fuel regulator, oil, pump, turbo? Some of my fittings came from a hardware/plumbing store. Since it is running good, I want to start making things look a little nicer. Some of the fittings we used were nitrous fittings... looking for something similar. Would like to change some of the lines over to a nice braided line.

 

[heinracing]

the reason power jets are in your airbox wes is easy of selling kits..
i have ran that box with no problems of tuning and with different boxes of not noticed seat of pants performance.

moving the powerjets a 1/4 closer would not notice a difference either as there that close to the slides anyways

that airbox is a cpi it's been tested on many sleds.

 

[Tonysnoo]

Devil... how the heck do you get your hands in there to adjust the powerjets? OMG.. you have tiny hands?????


Anyone have a good source for fittings? Like off the fuel regulator, oil, pump, turbo? Some of my fittings came from a hardware/plumbing store. Since it is running good, I want to start making things look a little nicer. Some of the fittings we used were nitrous fittings... looking for something similar. Would like to change some of the lines over to a nice braided line.

Hey Outlaw,

Most of my fittings came from a hydraulic hose supply house and Napa. A few from Summit, if that helps.

Just a suggestion for adjusting the powervalves. I built a tool. It's simply a length of 1/4 aluminum rod with about 1 inch of 3/16 gas line slipped about 3/8in onto the end. I can reach down and slip the open end of the gas line on the powervalve and just start turning. The cool thing is that is will work on an angle so I don't burn my hands(or coat) anymore.

 

[Spaarky]

Hey Outlaw,

Most of my fittings came from a hydraulic hose supply house and Napa. A few from Summit, if that helps.

thanks... I might take a few pics of the fittings I am missing to see if anyone can help out. It runs like crazy, just needs a little underhood clean up.

 

[devilrmk]

Its real hard to see what the box is like with it on. But it doglegs around the shaft and follows the angle of the shaft all the way down. At the bottom of the carb the box is literally 1/4" from the edge of the carb. About in the middle of the carb is where the bend is that opens up the rest of the box. It has quite a bit of area above the carb to flow through. It isn't perfect but its about the best I could come up with at the time and still clear the post.

I work at a metal fab shop so I had all the tools necessary to do it like this.

 

[devilrmk]

Devil... how the heck do you get your hands in there to adjust the powerjets? OMG.. you have tiny hands?????


Anyone have a good source for fittings? Like off the fuel regulator, oil, pump, turbo? Some of my fittings came from a hardware/plumbing store. Since it is running good, I want to start making things look a little nicer. Some of the fittings we used were nitrous fittings... looking for something similar. Would like to change some of the lines over to a nice braided line.

The PTO side sucks, Mag side is easy. Only one ride since I changed my box, I had 3/4" more room there before, it still sucked though. I really need some remote adjusters, though I don't mess with them more than once or twice a ride so its not that big of a deal. Its still easer than swapping jets. I don't have too big of hands either, not really a big guy. 5'4"


Good idea Tony. Going to steal that one from ya too.

 

[gus bohne]

Now I see your dilema !!!

Thats the same issue had many years ago with the polaris triples,, damn column is in the way ..

Relocating the powerjets to the bell is going to make a very noticable difference. The turbulence in the mag tube to bell connection is not so much the issue as the ultra constricted opening area in front for reversion..



Good news is you can live with it as many did for years..

It will be a gurgler from time to time on one hole at low speeds but thats no big deal.

Money spent elsewhere is a good idea...

Gus

 

[papafinger1]

the reason power jets are in your airbox wes is easy of selling kits..
i have ran that box with no problems of tuning and with different boxes of not noticed seat of pants performance.

moving the powerjets a 1/4 closer would not notice a difference either as there that close to the slides anyways

that airbox is a cpi it's been tested on many sleds.

Was wondering if/when you may chime in here.

Thanks for all the new information fellas. It has been fun trying to wrap my head around all of it.
Devil that is a sweet airbox but would cost me at least $200 to have made.
Yeah gus I believe you are right. Tryin to scrounge up some pennies for a powerclaw. Really think that maverick lays over and doesn't hook up the way a track should. No point in having all this power if I can't transfer it to the ground.