Ducman Posted March 24, 2004 Report Share Posted March 24, 2004 I'm in the process of rebuilding my wifes blaster, modding it with the Vito's 240 kit and a new crank. Hope that livens the ol' dog up some. While at the blaster HQ I came accross and saw that a lot of people have this "riffel" mod done to their stock and aftermarket carbs. Has anyone tried this? Anyone got any knowlede of this. I haven't heard of any banshees with rifeled carbs. Seems like it would be similar to boring the carb out cause it would add more open X-sectional area to the inside of the carb with the added benifit of more turbulance so atomise the fuel and maybe cut down on the boundary layer air friction along the carb walls to help speed up the air flow. They were having a promotional short term price of $50 per carb. Boring the stock carb is usually around $80 each right? Good Idea for the banshee or no? Quote Link to comment Share on other sites More sharing options...
Ducman Posted March 24, 2004 Author Report Share Posted March 24, 2004 Oops, forgot to add a link so you could check it out Quote Link to comment Share on other sites More sharing options...
wesw Posted March 24, 2004 Report Share Posted March 24, 2004 well you can be the guinea pig and test it out for us. im guessing that would work but for 70 bucks i dont know. could spend it somewhere else. gas, beer, porn just a thought Quote Link to comment Share on other sites More sharing options...
MULLET~BOY Posted March 24, 2004 Report Share Posted March 24, 2004 i can't bealive i'm gona say this but thats is one thing that guy douse that douse work what it douse is creat a vortex witch sucks the fuel into the motor and spins the air and fuel up really good turnes it into a verry fine mist i hope your not gona let that guy port you motor though he douse alot of stupid stuff like polishes the intakes Quote Link to comment Share on other sites More sharing options...
Nighty Posted March 24, 2004 Report Share Posted March 24, 2004 Hmm thats nice.. i was thinking about making a vortex in my exhaust ports of my banshee cilinders. i see this guy has come up with the exact same thing i should have patented it Does it work? Quote Link to comment Share on other sites More sharing options...
MotulMonsta Posted March 25, 2004 Report Share Posted March 25, 2004 Dude, I don't know..They shure claim an awful lot...yet I haven't heard of ANYBODY running them. Once you do any of that shit, there's no turning back..you could f*ck up a perfectly good carb, head and cylinder. Quote Link to comment Share on other sites More sharing options...
Nightbreed Posted March 25, 2004 Report Share Posted March 25, 2004 just my two cents, i have been building race engines for years, lots of flow bench work, and dyno testing. just a little fyi, so as not to think i am a shade tree mech. lol this type of porting configuration has been tried for many years, in all aspects of the intake and exhaust systems. the idea was to introduce a swirl effect after the opening of the intake valve on for stroke style engines. for the cost, and the amount of work there are no significant gains to power, kind of like the boost bottle theory on two stroke engines. the best way do debunk the idea is, on a banshee for example there is a split intake plentum , followed by port windows in the cylinder. when you try to introduce this swirl into that configuration, when it hits these points in the intake system, any pattern that it might have been attained during the intake charge would be disrupted by the obsticals in the opening. this also would hold true in a single cylinder application. hense, the fuel that is atomizied and suspended in the air would no longer follow a clean path. the best thing that can be done to any engine is quality port work, and a intake and exhaust system that will complement the cylinder head, compression, and ridding type for each person. Quote Link to comment Share on other sites More sharing options...
MULLET~BOY Posted March 25, 2004 Report Share Posted March 25, 2004 ok this is my oppinion and beilive me or not i'm going off what builders have told me ok rifflining the exughst port = bad it couses the the charge to be sucked out witch is good but from my understanding alot of power on a 2 stroke is from the charge reentering the motor and from what i am told that riffling would not alow that to go about as easly also when riffling the exughst port it would not match up to the pipe witch would also dissrupt the charge as far as the head goes i am told it can couse detination ..... duno how true but it looks like it would screw with stuff ..... once again i am just going of what some builders have told me and i could be tottaly wrong but untill some person comes and showes me exactly why and proves to me it works better then the standerd way i'm not gona go bt what i have been told Quote Link to comment Share on other sites More sharing options...
frocashmoney24 Posted March 25, 2004 Report Share Posted March 25, 2004 well its like the vortex, ive seen thos and they seem legit to work, but then again ive seen them for sale with banshee stuff, and they are now selling htem with a combo deal with the boost bottle, so that kinda makes me iffy.. aint heard of anyone on here runnin with em, theres plenty of other things you can do to modifly the hell out of a blaster thou Quote Link to comment Share on other sites More sharing options...
Ducman Posted March 25, 2004 Author Report Share Posted March 25, 2004 Thanks for the great feedback and comments. Yeah, I'm not saying that I was planning to get this done, it just looked cool and the kids at the Blaster HQ seem to love this kind of crap. If I were to try it out, I think I would use the wifes Blaster as the Gunnie pig. Hehehehe I knew that the flow would be disrupted before it went into the intake port but I immagine that it could speed up flow through the carb itself (due to a larger x-sectional area, not so much the vortex effect) and atomise the fuel better (due to the vortex effect). Once the fuel is atomised in the air I would think it will generally stay that way. I doubt that it would be noticable though. I completely agree that the rifeling on the exhaust port is totally assanine, mabe on a 4 stroke, but on a 2 ????.... No. Also from what I remember from thermodynamics, a vortex is actually bad. You want the air velocity to be fast mainly only in the direction of the path it has to take. The faster the air moves, the more friction that is generated and you dont want to waste friction on air velocity that isn't going in the direction that is doing any good. I think that if the inside surface of the carb was dimpled like a golf ball that would help cut down on air friction from the boundary layer, this is also the same reason that you dont want the intake port polished (along with better atomization of droplets of fuel that land on the intake walls, you dont want the fuel to be able to easily run in drips along smooth walls) and the reason a golf ball has dimples. The exhaust side is polished because the expanding gasses comming out of the cylinder are in a supersonic flow and are so turbulent that they dont have a boundary flow layer. That is, if I still have any fully functioning brain cells that could ratain memory after college. Quote Link to comment Share on other sites More sharing options...
MULLET~BOY Posted March 25, 2004 Report Share Posted March 25, 2004 good points made about wanting it to go in one direction would be kinda fun to do a dyno test to see how much of a gain you would get if any ......... Quote Link to comment Share on other sites More sharing options...
Blue03 Posted March 25, 2004 Report Share Posted March 25, 2004 I had my stock carbs line bored from 26's to almost 29's and the rifled effect was a by-product. The shop that did my carbs does alot for snomobile owners, many of whom race, and the rifling is a desired option for the race crowd. I can't really say if that had much effect since the carbs draw larger amounts of air now...... to many variables between air volume and jetting changes to really say if the spiral effect had anything to do with the performance of my Banshee or not. I will say that it does have a better hit in the top end, and with more tuning I think it will pull harder through the entire range..... Quote Link to comment Share on other sites More sharing options...
99LRDblaster Posted March 31, 2004 Report Share Posted March 31, 2004 my friend "nowusheeitnowudont" is getting his stock 26 mikunis rifled by HDP. i only want him to rifle it and go up to 28mm because his engine is stock on porting and only has T5's, boyesen reeds, 2:1 filter, and soon to have the stock carbs bored to 28mm and rifled. the design works. on their message boards daputz dynoed his rifled blaster carb and it made NO more peak hp than the stock carb, HOWEVER the power was improved down low coming on quicker and stronger and better through midrange. i see no reason why this would not work on a banshee. i put a lot of trust in marc at HDP because i just had him put his port design 3 on my top end, rechamber and mill my head, and bore and rifle my stock carb to 30mm. the rifling DOES work. many companies use swirl techniques for their heads. one example is the powerstar heads for 250R's. the rifling of the exhaust port scavenges gases out of the motor which would cause oen to think of as a bad thing, however the expansion chambers holds most of the back pressure for the motor so the rifling is essentially making the motor works more efficiently and better. the polishing of the intake ports is basically a matter of opinion. some people want it for fuel and oil atomization however i beleive after the charge is rifled through the carb, pre mixed in the gas, and passes over the reed cage its basically atomized. im hoping to get my blaster together soon to see how HDP's work does . however i will give a report on its benefit on a banshee when my friend rebuilds his shee. he is getting the ridling done by HDP. also marc at HDP is looking to do banshee porting in the future. Quote Link to comment Share on other sites More sharing options...
99LRDblaster Posted March 31, 2004 Report Share Posted March 31, 2004 here is the dyno sheet. the red line is the rifled carb and the green line is the stock carb.(dont mind the HP numbers, they are low because it was just a test to see the curve on the motor not to find the most power) Quote Link to comment Share on other sites More sharing options...
MULLET~BOY Posted March 31, 2004 Report Share Posted March 31, 2004 the red curve is falling off alot earlyer then the green carb why is that i duno but when i email the holly wood dirt guy here is what i emailed him and what he emailed me back i have a couple quastions about your porting mabey you can explain to me why you do a couple things first why are you polishing intakes ? i was told that you want them ruff you dont want it smotth becasue then the gass will fall out of atomizaton , and then it will bead up on the polished part thought gas burnes better as a fine mist why are you riffling the exughst port some of the riffles apear to be bigger then the pipe if so you are slowing down flow you talk about how the riffled exast helps pull the charge out of the exaust port ....well i realy dont know if that works , but i think your forgetting 1/2 of a 2 strokes power is produced by back waves ...we need the gas to come back and refill the cylender just a couple quastions not dissing you just wanting some explination on why you are doing a couple things the way you do them his reply I would love to explain all my findings over the years, but I've told these theories so many times in the last 10 years, I'm burned out on explainations, all I can say is what we have tested and developed works, we have proven it on our race blasters, sorry I just can't sit here and type it all out any more Quote Link to comment Share on other sites More sharing options...
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