Carbed 2 stroke turbo guy's !!!

[Wheel House Motorsports]

turbo sizing for that rev ,, 2860/2871 . aero 53 biggest they have. 66 is better.
mitsu car turbos are barley adequate for 220 hp.

i find your views interesting about the mitsu turbo's. which turbos are you speaking of, and porting or not? the exhaust side on the turbos can be a little restrictive, but with a little port work they can flow a LOT of air, just curious on your thoughs.

 

[gus bohne]

The mitsu used by cpi on the lil revs is missing much more than a little exhaust flow.
the compressor side is tiny toooooooooooo.

now for the 12-15 psi trail rider its just fine.
for me at 18 minimum it just a heater..

I realize they have larger frames ,,

The 4 sroke gets away with half the turbo needs as the 2 stroke, we leek and fire every revolution so we need big booty turbos..
like big boob jobs, no need to go in and just go up to a b cup when we can jump right into the zz's !!!!!!!!

I am just a drag racer u know.. I don't know what turbo lag is, never had it in my own sleds....ANTILAG !!!!
Gus

 

[devilrmk]

12-15 psi is plenty for most of us.

Not sure what cpi uses the Evo3 16g or a 14b. The Evo 3 is still pretty small though.


Hey Gus what kind of CFM would an 800 need at say 14psi?

Would be nice to have a ballpark idea when looking at turbo maps.

I am about a week away from my first fire on my turbo build. Getting excited.

 

[zrt1]

cpi uses the 16g evoIII

 

[Wheel House Motorsports]

the compressor side on the evo III is pretty large, but the exhuast side is definately pretty small, but they are perfect for the lower boost 4 stroke application like mine, they spool fast, but your right, starting to push up past 18 psi, especially on the 2 strokes is a lot of exhaust for that poor little thing to flow.. i definately know we like on different terms of how we like our power.. your just a big top end guy.. i like a more linear powerband.

 

[Spaarky]

how many CFM is the Garret?

 

[chevota84]

I'm really considering boosting the old kk. Has anybody had any major issues with the cat 900 on boost? I'm thinking about running 100ll with a head cut for lower compression. About how much boost do you guys think I can run? Can I run the stock carbs with the power jet mod or will they be choking it to much? Sorry for all the questions at once, thanks

 

[chevota84]

how many CFM is the Garret?

This guys ad has a compressor map.
http://cgi.ebay.com/ebaymotors/ws/e...LVI&its=I&otn=2&category=33742#ht_3724wt_1010

 

[triple7]

I'm really considering boosting the old kk. Has anybody had any major issues with the cat 900 on boost? I'm thinking about running 100ll with a head cut for lower compression. About how much boost do you guys think I can run? Can I run the stock carbs with the power jet mod or will they be choking it to much? Sorry for all the questions at once, thanks

I know that a good friend of mine ran 12, 14, 16, then finally 18 and 20 psi on his 1010 cat which is off the same bottom end as the 900...I would think with our modern technology and a good Garrett it would live well into the 18 range mountain riding.
But Bohne told me some things to watch out for on the Cat motor. I will let him post that info because I dont fully understand it. But, thinking back on it Im pretty sure we fought those issues. Something about the vibrations that motor can cause fuel delivery issue.

Jake

 

[Snowjunky]

What kind of turbo would it take to do a 1200 triple watercraft Gus. I am learning and would like to continue my research. I intend to turbo my tripple next year and figure compressor sizing is step one. The sled will be ridden at 10,000 ft. What kind of boost pressure did you find to work well and not be over kill

 

[gus bohne]

1. cat twins shake like james bonds bartender making his martini !!~
make sure the crank is trued and welded on the MAG side first.

I have no experience with them under boost so I can't do much sorry.

The triples are in need of a good single exhaust for best response to the turbo but there are ways to make them talk !!!!with triple pipes..

typically I would tell you a 1200 would like a 3082 or 3582 here at sealevel especially with multipipes.

pm me with all the engine details or call me at 603-401-8897

Gus

 

[devilrmk]

Hey gus, how about twin pipes on a polaris 800? Same deal, more resposive with the single? Really tempted to try out my twins. Of course I probably should try it with the single since I just fired it yesterday.

Question about running multiples. On the signal line to the regulator would you want to plumb it to both pipes or just one. Probably don't matter too much. If you foul a plug you are going to lose fuel pressure and boost

 

[chevota84]

1. cat twins shake like james bonds bartender making his martini !!~

I'm going to have remember that to tell my other King Cat riding buddies.

 

[gus bohne]

Hey gus, how about twin pipes on a polaris 800? Same deal, more resposive with the single? Really tempted to try out my twins. Of course I probably should try it with the single since I just fired it yesterday.

Question about running multiples. On the signal line to the regulator would you want to plumb it to both pipes or just one. Probably don't matter too much. If you foul a plug you are going to lose fuel pressure and boost

twin pipes with turbos work on the dyno but in field are slower to respond . you have to fill and heat both pipes before it makes full power. You will see the boost climb but it will feel soft at first. like it has an intake side leak.

In time I am sure it acn be made to work well just is there enough gain to justify the weight, leaks , cracks and tuning time..

I think the lines question you self answered, drop one and its moot, its still a one lunged gut shot doe,, aint going to far before its towed..LOL

Gus

 

[Snowjunky]

I am getting ready to build my WC carbs in the next few. Going to be a set of tapered 40 mikunis. Now are there any of these mods I have been reading about here that I should do for sure? Might as well do them now if I will need them later.

 

[gus bohne]

The 40's should already have 2.0 seats,, good there.
you can't vent them internally as the body and slide are not the same as the TMX race carbs I use, sorry.

Any other questions just give me a call
603-401-8897
Gus

sorry ofr the delay in answering this..
CFM is to hard to call for a 2 stroke turbo. You can see some overported versions making low power and flowing huge air amounts..
ie. 304hp @ 500 cfm. vs 312 hp @401cfm.. portiming, and exhaust choice can really screw it up.

thats when the little engine that could is putting a shamefull hurting on the overported one..

big cfm with low power output is a dead give away in turbotown..

 

[devilrmk]

Is there any time I should be getting pressure in my turbo oil tank? I placed my vent at the back of the tank(bad choice I see now) and either when on boost or when I come off boost it is pushing oil out my vent. Its getting pressure from somewhere. Is this normal?

I do not have a BOV, someone told me today on the hill that it would stop that.

Ran great other than that. Really laggy so I got to work on clutching and was only pushing 4psi boost so I got to get a boost controller.

 

[gus bohne]

Well, had a problem with the cpi unit, lowered oil level in tank to 1/2 a quart and never had a problem after, but I am on the flats.

Anytie there is boost it can blow by the bearings in the turbo and push into the tank. long venting lines and one way chaeck valves are std issue..

a bov might help some to.

Gus
boost lower than the waste gate spring pressure is leaks or too rich.. if you rode it without burning it down its rich..lol

Gus

 

[Snowjunky]

GUS
Learned alot about TMX last night. Looks like they are not hard to aquire at all. Hope to have 4 on the way very soon. What throttle cable do you use for the tripple set?

 

[gus bohne]

I would think any 38mm roundslide cable will work for you. the tmx has the std small round ball end reciever in the carb for the cable . it works with any of the small lead ends.

gus