Carbed 2 stroke turbo guy's !!!

[gus bohne]

no lag issues,, forget that with a ball bearing garrett.
ar is to big. drop to .8's and be good to go to 30 psi.

comp on th eold 700 was around `12 or so, squish was horribly wide.. for booost its a poor design. re dome it.
The reed cage warrpage is due to charge heat primarliy and the clamping method too. lean backfires dont help them as they are weak in that area also. they just suck for the application
double v cages present the face of the petals at to FLAT an angle. the charge backflows and that is the issue, closing tension and full open tension are bad, but total flow area and flow volume is even worse..

just google a TSR reed program.. then you'll see the differences in flow and pressure drop.

HO cage/boot assy from the o4 is the good one.

Gus

 

[proflow]

Gus, if I get a .82 hot side housing for this turbo will I have to change the impeller also ? How to tell its a b.b. turbo ? Should I feed this thing w/my SLP single or Crankshop twins ?

Thanks for your help !----Proflow

 

[gus bohne]

If it spins freely I would suspect a ball bearing unit. Use the single as it is more HEAT consistent....and makes more power under boost due to this and overscavenge from multipipe draft effect.

Yes the impeller SHOULD need to be changed to fit.


Gus

 

[Tonysnoo]

A quick little update:

I tried a little test. I used 75% 110 VP race to 25% pump 91. It got a little warm in the "chug around through the trees" off enguagement rpm range, but the rest of the power band was good at 8 and 10 lbs of boost. Snow was pretty set up so the only full load stuff was not for real long periods of time.

Prolly going to run Av gas too, but too lazy to go get it right now. Local prices are high so it's a short road trip to the smaller valley airport, some time.

I'm working on the blow off valve spring and supply hose to get it to blow immediately after letting off and it feels real good. Hard to hear it with the hose on it. Doing this cause I had a problem with full boost to full off. The fire goes out briefly, bad juju on a steep slope. The BOV helped a decent amount. Working on some other ideas too.

Any suggestions out there?

 

[gus bohne]

Tony,, be a crazy guy and try a shortened cpc slide spring or no spring in the bov..I love it..

i have 1/2 psi spring in mine its open at idle and closed by 2500 rpm,, with a large good flowing compressor..gives you an idea of how LITTLE if any vacume is present with a larger framed compressor. . hence the istant response and boost build.

Gus

 

[Tonysnoo]

Tony,, be a crazy guy and try a shortened cpc slide spring or no spring in the bov..I love it..

i have 1/2 psi spring in mine its open at idle and closed by 2500 rpm,, with a large good flowing compressor..gives you an idea of how LITTLE if any vacume is present with a larger framed compressor. . hence the istant response and boost build.

Gus

Yeah Gus, I did shorten the BOV spring at the same time that I used a bigger carb pressure source hose. My BOV is too big around to use a carb spring, unless I drill some pockets...Hmmmmm? I did hear it a lot better, so It may not have been dumping quickly before.

Hey Gus, is there any reason you picked the mag carb for you pressure source? I have a flat on both carbs and I drilled and tapped them both and 'T'ed them together and then went to the BOV. I was planning to use just one carb for a BOV source to keep it simpler.

 

[gus bohne]

I made plastic cups so to say to index the spring locataion.

it was just the shortest route,, man..LOL

Ran the 800 rev at the goldenchild nationals yesterday in the twins power adder class.
1. 1200 f catpromod turbo 530 hp built by Glenn Hall,
1. z1 promod also built by Glenn ..

We qualified # 1 !!! with the lil CPI ktted rev !!!
a bobble in the final cost us the win but suffice to say I am very proud of the little sled and its owners first sanctioned race results..

Carbs really DOO work better than EFI !!! GOTTA LOVE IT !!
the big 1200 did have 20 mph on us at the finish but ,, that don't win drag races..LOL
1.27 60 foot time for the lil rev..@ 725lbs we had to add 90 pounds to make class weight..
1.90 of the cats,, each,,, ouch....

 

[snowlovers]

turbo stuff

Hey Gus'
Have a evo 111 20g turbo, will it work on my 800xp, some say the hot side is too big and would need a external wastegate, but reading every post in here we need bigger hot side??? thanks in advance

 

[Tonysnoo]

I made plastic cups so to say to index the spring locataion.

it was just the shortest route,, man..LOL

Ran the 800 rev at the goldenchild nationals yesterday in the twins power adder class.
1. 1200 f catpromod turbo 530 hp built by Glenn Hall,
1. z1 promod also built by Glenn ..

We qualified # 1 !!! with the lil CPI ktted rev !!!
a bobble in the final cost us the win but suffice to say I am very proud of the little sled and its owners first sanctioned race results..

Carbs really DOO work better than EFI !!! GOTTA LOVE IT !!
the big 1200 did have 20 mph on us at the finish but ,, that don't win drag races..LOL
1.27 60 foot time for the lil rev..@ 725lbs we had to add 90 pounds to make class weight..
1.90 of the cats,, each,,, ouch....

Congrats Gus,
David and the Goliath twins....keep grindin!

Going to put my sled to the test this coming weekend.........big long pulls in big snow.

 

[canucklehead]

I tried some really light springs in my bov and they do make it really respnsive but I couldn't make my normal boost. I believe I was blowing the diaphram open a little bit. It sucks going down in boost.

 

[Tonysnoo]

I tried some really light springs in my bov and they do make it really respnsive but I couldn't make my normal boost. I believe I was blowing the diaphram open a little bit. It sucks going down in boost.

I haven't gotten that light on the spring yet, but your pressure source hose should supply enough to the back side of the BOV to hold the diaphram or piston shut against the boost even without a spring in it??????

I'm limited with just a one inch BOV/Bypass so I was thinking I might have to have two of them bypassing back to the filter, if I really want a quick dump. Not sure in need it yet,.... it may be overkill???

 

[Tonysnoo]

Had an interesting weekend failure.

I was pulling a slope and the engine started to fall off kinda like it was ready to do a lean seize...turned it down in a quick hurry and the flame never went out. Got back to the bottom and it wouldn't run for beans.

Thought I had burned a piston or fouled a plug. Plug was very wet. They never look fouled but I changed it out. Ran for a second and fouled again.

Limped it back to the truck. After dissecting the whole dang setup looking for pipe cracks, messed up carbs, bad reeds, messed up pistons, etc, I found a carb vent/pressure line had ruptured and had an 1/8" hole in it.

I'm guessing the hose was too close to the heat shield or keeper spring and gotten gooey while under boost.........pop! Then every time I developed boost and the rising fuel pressure overcame the needle and seat and flooded the carb and fouled the plug.

Went down and got some better hose and some more shielding. Scared the stuffin out of me, cause it had been running so good.

 

[JesseIngmire]

1200wc turbo questions

I had a few questions about putting together a turbo kit for my 1200wc.Any help would be great.thanks jesse 425-577-8587

 

[Tonysnoo]

Had an interesting weekend failure.

I was pulling a slope and the engine started to fall off kinda like it was ready to do a lean seize...turned it down in a quick hurry and the flame never went out. Got back to the bottom and it wouldn't run for beans.

Thought I had burned a piston or fouled a plug. Plug was very wet. They never look fouled but I changed it out. Ran for a second and fouled again.

Limped it back to the truck. After dissecting the whole dang setup looking for pipe cracks, messed up carbs, bad reeds, messed up pistons, etc, I found a carb vent/pressure line had ruptured and had an 1/8" hole in it.

I'm guessing the hose was too close to the heat shield or keeper spring and gotten gooey while under boost.........pop! Then every time I developed boost and the rising fuel pressure overcame the needle and seat and flooded the carb and fouled the plug.

Went down and got some better hose and some more shielding. Scared the stuffin out of me, cause it had been running so good.

Fixing that popped line was golden......Ran great last weekend. We found some powder pockets on a NW facing treeline ridge. We spent all day playing in the trees and steeper open spots. Gawd.. I love the low end transistion boost on that turbo.......huge trenches, but crazy fun! I put the polyurethane line inside of a silicon line wherever they ran close to the heat shield. Spent a ton of time routing and protecting the hoses. Don't want to have a scare like that again.

Found and ran the better style Cutler carbs(still 48s) with the right side idle air screw setup. Still kinda burbly on the very bottom. I think I'm going to order another set of needles from Dale. I'm using the sea level needles and he has the same cut but with a leaner bottom end........should be the final bit of carb tuning.

Still building a bit of EGT temp and showing a mid 12.6 air fuel, but any richer and it's pretty flat sounding.

 

[gus bohne]

Tony,, goood to hear the newer carbs are just a little easier for you.
I suspect the needle dale has is going to be correct for you too.

just and fyi,, even though the egt and o2 look lean you might in reality be just making lots of heat in the pipe FROM being slightly rich at WOT.
Just another could be, egt's and o2's get false readings when rich and under boost with possibly slightly less than peak power timing..

When running at less than 14 degrees total timing higher readings will show due to the lateer burn still expanding and gaining heat as it exits the pipe.

its a could be, not a definite..

Gus

 

[Tonysnoo]

makes me wonder if the hugely oversquare bore needs the 2 degree key back in it. When I lean it it a bit the little motor is just an animal, but the 12.9/ 1400+ egts scare the hell out of me.....When I fatten it to just about dull sounding its definitely down on power(loses about 300rpm), but the gauges are happier.

Exhaust valves are pinned open, port timing is spot on, and the compression and squish are opened up so it's almost a function of the timing now. One other thought: That big fat monster pipe has some steep divergent cones, it might be reflecting a heck of a lot more back at the motor????

 

[Spaarky]

Alright... the thread has settled down a bit and I have been rereading some things. What I have has been working flawless. Even a rookie like me can tune the fuel in for the day in a matter of minutes or less.

Gus, Devil.. and a bunch of you guys are not running powerjets in the charge tube. This has been beat into my head over and over, that us mnt. riders have to have it to keep the bottom/midrange alive. We spend a lot of time in the bottom/mid area boondockin and tree running. Mine carb power jets are in the bell area.

Again, please forgive me if this is basic, but how are you keeping that mid/bottom alive. Like I said, what I have has been working great, but maybe there is better ways?

Also I noticed DW has his powerjets in what appears to be right through the slide... is there an advantage of that over the bell?

 

[gus bohne]

There are multiple to methods to achieving the same curve, the differences show in the throttle position of the overlap periods and how they realte to engine load.

Longer power jet tubes begin puling fuel with no load at 1/4 throttle . When under load they are adding fuel sooner but not too much.

as the throttle is opened we ( blowthru turboed ) progress from pilot to needle AND powerjet,
""this is what some overlook and miss out on dropping main and needle jet orrafice.""
as we get to half throttle the main starts to add in its fuel with needle movement.

We no longer follow the pilot, needle, main order of feeding fuel to the engine.

the pint of tip in for the powerjet is what causes rich bogs, if we address the pilot and needle jet to clean the NOW RICHER combined needle and powerjet flow the drivability came back even better.

its just different methods of getting to the same destination.

His power jets ( DW ) are 3 mm off the slide, thru the top cover..yes

closer they are the cleaner they break open and close to the throttle position making the overlap less fuzzy on either end..

Tony, I follow you, go for it..

Jesse,
Outlaws buddy has just what your building already running like a rocket.. talk to twister..

Gus

 

[Spaarky]

Gus... thanks for explaining that in simple terms... GOT IT!!!!!!! The more I spend with my sled, and Twisters edumacational skills... the more I learn. I have learned so much about fuel delivery and tunning in the last couple rides, my head is spinning. Even dealing with some of the efi's has helped me learn.

Last ride out Twister, didnt even touch my sled!!!!!! Well to tune it anyway.

The powerjet question came from a late night discussion we had.

Jesse,
Outlaws buddy has just what your building already running like a rocket.. talk to twister..

After 3 years(that number is skewed a bit, due to lack of ride time), "Sasquatch" is alive!!!!!!!!!! I watched him, pull a hill that he looked to be gaining track speed the whole way. It was incredible.

Gus if you ever get to go riding with us... Rule #1 .. dont follow Twister! Its either succuss or yardsale...

 

[Tonysnoo]

Hey Gus,

Another little update. Went to Utah this last weekend. Got in on some nice clutching advise. Tried(and bought) a reverse angle helix and a torsional setup from OVS. Pretty amazing. I thought this thing was close, but they helped me go another step....way... way up.....very cool all the help I have gotten with this project.

Now I gotta turn the boost down for spring riding. It's going to be too stupid if I don't......LOL