considering turbo cont.

[NM]

small plenums on 2 strokes lead to bad times tuning,, you can only fit a very minimal plenum in that chassis NM. its too bad it can be as good as it could...

gulp factor on a 2 stroke is throttle response.. you need a larger rather than smaller volume for response..hence the larger compressor trend so many are now trying and see for themselves...

though 'maybe' the compressor being undersized all along was the rreason they liked larger plenums ? you need to have air availible when the blade lays open,..? static volume or a larger compressor to flow that added volume quicker than waiting for a small flowing wheel to spin faster and make higher pressure to generate the flow...( supply ).

I talk to much..


Gus

Interesting theory Gus..It amazes me how much fuel our two stroke needs when you wack the throttle and boost comes on. Must mean it's getting lots of air!

 

[taylorbok]

after reading gus's last post several times and talking to some people I am going to cut back plenum size to between 2000-1800cc.

Lets try and keep posting to a minimum here so I dont have to start another thread, thanks guys.

 

[gus bohne]

it operated correctly for 15 seconds then went out again.

funny, my msd, data loggers and ams 1000 controller ALL function fine on the same sled..

gus

 

[Wheel House Motorsports]

on the turbo xp that I helped work on we built the biggest airbox we could fit in the chassis(still not terrible big. i have to say, it had one of the cleanest bottom ends of any 2stroke turbo sled i have been around... super smooth transition into boost. with the size of turbo you are putting on these things the extra few cc's are easily filled as soon as the turbo is even halfway spooling.

and this setup was with a 66 aero, so not gonna move nearly as much as your turbo.. we made the box so it was sorta hard to sutff into the chassis, a little wider then the carbs outside to outside and similarly as tall.

 

[taylorbok]

double up stock reeds or just run one?

 

[taylorbok]

and how do you mount the power jets so you can still get the airbox boots onto the carbs?

 

[Wheel House Motorsports]

we actually mounted them right in the front of the airbox in front if it.. only moved em back maybe 1/2" compared to the carbs but made it a lot easier to work on for us... you just gotta pull the lines off to take the box out. so a little bit of a pain but thats how we found was easiest to work on.

 

[swrev]

and how do you mount the power jets so you can still get the airbox boots onto the carbs?

Go right through the top of the carbs w/ a longer tube in the powerjet. Cleaner shutoff/on. Gus should be able to back me on this. I don't have my sled around to take a picture but should be easy enough to figure out. Just make sure the slides can operate freely. Have the tube come to the center of the carb intake/bellow area to allow for strongest signal. You can always shorten the tube if you want the powerjet to come on a little later in relation to throttle position.

 

[taylorbok]

Go right through the top of the carbs w/ a longer tube in the powerjet. Cleaner shutoff/on. Gus should be able to back me on this. I don't have my sled around to take a picture but should be easy enough to figure out. Just make sure the slides can operate freely. Have the tube come to the center of the carb intake/bellow area to allow for strongest signal. You can always shorten the tube if you want the powerjet to come on a little later in relation to throttle position.

do you mean go straight through the slide? that sounds to wild for me, plus i didnt get power jets long enough gonna just put them in the air box. I just doubled up my reeds and put my boot reinforcements on along with the stm valves and bolted down motor should be making air box tonight. fell behind my schedule a bit but not too bad. still waiting on wg and bov and some flanges.

is this where I tap for bov?

should I tap both at T together or just one?

 

[brycter]

yep that is the place for the bov. we have found that the efi sleds can use a smaller air box next to a carbed one. I personally think that powerjet placement and peto tube lenth make the biggest difference.

 

[nuttyn01]

carbs

Thats the spot. I taped them both and tee'd down for a little stronger signal.

do you mean go straight through the slide? that sounds to wild for me, plus i didnt get power jets long enough gonna just put them in the air box. I just doubled up my reeds and put my boot reinforcements on along with the stm valves and bolted down motor should be making air box tonight. fell behind my schedule a bit but not too bad. still waiting on wg and bov and some flanges.

is this where I tap for bov?

should I tap both at T together or just one?

 

[swrev]

do you mean go straight through the slide? that sounds to wild for me, plus i didnt get power jets long enough gonna just put them in the air box. I just doubled up my reeds and put my boot reinforcements on along with the stm valves and bolted down motor should be making air box tonight. fell behind my schedule a bit but not too bad. still waiting on wg and bov and some flanges.

is this where I tap for bov?

should I tap both at T together or just one?

That is where my blow off is hooked also. As far as the powerjets, I was meaning directly behind the slide. If the tube are too short, at least put them in the carb bellows, may be a little harder to take the airbox off and on, but it would be worth it.

 

[taylorbok]

As far as the powerjets, I was meaning directly behind the slide. If the tube are too short, at least put them in the carb bellows, may be a little harder to take the airbox off and on, but it would be worth it.

sorry behind meaning toward the motor or toward the airbox? I am kind of confused I could lengthen the power jets if I wanted to, solder on a tube extension thing. I can see having it on the motor side of the slide making it come on with throttle position but again wouldnt be able to put carbs on.

 

[swrev]

sorry behind meaning toward the motor or toward the airbox? I am kind of confused I could lengthen the power jets if I wanted to, solder on a tube extension thing. I can see having it on the motor side of the slide making it come on with throttle position but again wouldnt be able to put carbs on.

Toward the airbox. If I head to the grass drags (two weeks) I'll try and take a picture. Not sure if you could find old R&D kit pics, but this is how he had them set up. I'll see if I can come up w/ anything else in the meantime.

http://www.youtube.com/watch?v=7V1p-54Ie8o&feature=player_detailpage

If video link works, you can see my powerjets around 2:45 in the video. I've left the sled pretty close to how it was in the video. Still need to change the exhaust, but it never bogs from being plugged. You'll notice the block off's also. Neither was done by Peak (kit supplier) so it is not a very good representation of the Peak kits if people are looking. Probably going to do the Supreme valves. Did you get yours yet? Do they come with the valve itself, or do you have to remove it from the existing valve assemby?

 

[taylorbok]

ya got mine they do not come with the valve blade or what ever you must use your old one, I am very impressed with them.

Those power jets look like they are in the caps of the carbs? now I am really confused, gus chime in quick cause I know we are getting close to your reading limits. I need to look at my carbs again I think I will just put them in the airbox/ runners.

 

[swrev]

They are through the caps-sorry, didn't explain what I meant through the top of the carbs

 

[taylorbok]

I knew what you meant I couldnt figure out how it would work but now that I looked at my carbs I see what your talking about. might try that instead because it would be easier to work on/ rejet with them in the caps which will mean I have to extend the tubes, is there a problem using a larger diameter tube to extend my power jets down so they sit midway in the throat of the carb?