278 Posted June 25, 2009 Report Posted June 25, 2009 gregrob made a post about whether the different intake manifolds are worth it... I was planning on getting one from Jeff at FAST for my 4mil. build, it's the one thats got the 4 sections inside og the intake and the built in crossover. My question is, the sectioning thing seems like it would just get in the way of flow, and they are round in the back instead of square like the stock cages, since I am going to be running my stock ported cages, so can I port the intake to make it taper outwards going towards the motor so it is a smooth transition from the carb to reeds instead of a drop? Quote
AKheathen Posted June 25, 2009 Report Posted June 25, 2009 believe it or not, leaving them will increase air velocity to the reeds Quote
gregrob Posted June 25, 2009 Report Posted June 25, 2009 believe it or not, leaving them will increase air velocity to the reeds Who says / how do you know this? Quote
AKheathen Posted June 25, 2009 Report Posted June 25, 2009 exhaust porting principals (4 stroke) the same- manipulates the pulses into a "check" effect Quote
mopar1rules Posted June 25, 2009 Report Posted June 25, 2009 Who says / how do you know this? books say and so do the guys that know their stuff w/these engines. yamaha snowmobiles come w/these reed stuffers stock......that's why they have such great throttle response. Quote
278 Posted June 25, 2009 Author Report Posted June 25, 2009 the problem is that the intake is a circle and smaller than the large rectangular reeds, I know the intake will helps smooth things out but its a big drop and that just doesn't make sense... that the drop I thought will actually reduce performance. Quote
AKheathen Posted June 26, 2009 Report Posted June 26, 2009 are you wondering about making them bigger, or smoothing out the edges to a curve? obviously, they should be large enough not to cause restriction, but the air will tend to follow any gradual slopes and curves. leaving the sharp edge will allow the incoming air to stay the tract longer. the area with the highest velocity would benefit from an even match to follow, but that usually requires some major machining and/or stuffing. that being said, there is pulses traveling both directions through the reeds which can interfere with the flow more greatly when you spread the incoming charge toward the more indirect flow areas. basically, either maintain higher velocities by using the stuffers, or leave edges that do not draw the charge out of it's path. another factor to think about is the flow delay timing, which, of course will be more conducive to an rpm range. Quote
278 Posted June 26, 2009 Author Report Posted June 26, 2009 I was just thinking that normally your suppose to match everything in the motor up so it all flows smoothly, well since im going to use the stock reeds and the intake im getting is smaller and round and designed for VF3 reeds I would think that opening the back side of the intake up and making it square so it matches my reeds. BTW AK how did your bike run out at Jim's Quote
AKheathen Posted June 26, 2009 Report Posted June 26, 2009 I was just thinking that normally your suppose to match everything in the motor up so it all flows smoothly, well since im going to use the stock reeds and the intake im getting is smaller and round and designed for VF3 reeds I would think that opening the back side of the intake up and making it square so it matches my reeds. BTW AK how did your bike run out at Jim's fuckin awesome! i love these pipes. just have to get some new silencers. these ones are trashed. had to sew my core back together with bailing wire, and the other one is about to break. Quote
278 Posted June 26, 2009 Author Report Posted June 26, 2009 Breaking the alaska way of duct tape huh haha, just kidding. You could always do like what I did with my Toomy's. I like shit loud, and figured we have no noise laws so why have to replace packing. I cut a piece of copper tubing that has an O.D. that mathces the I.D. of the silencer to fit inside each silencer that fits just enough to were when I bolt the stinger to the silencer it is tight. Might be harder to do with the PC's, I'd just take the core out and run them like that. BTW rocky mountain has Dial-a-jets, I saw them when I was looking at intakes yesterday Quote
AKheathen Posted June 26, 2009 Report Posted June 26, 2009 yah, they sound like a cammed big block, but i'm gonna rebuild them as not to hinder my precious low end, which i noticed once the packing blew out. my toomy stingers are too smal for the pcp's Quote
278 Posted June 27, 2009 Author Report Posted June 27, 2009 Nice, yeah my shee kind of sounded like a mesquito on steroids, or a sled with a can before I tore the motor down again. Quote
AKheathen Posted June 27, 2009 Report Posted June 27, 2009 that could also be lean. should have a resonant undertone to it Quote
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