Fireroad Express Posted March 11, 2007 Report Share Posted March 11, 2007 amongst my huge pile of parts sitting in my shop that was once a banshee ,is a boss intake. the one w/the internal cross-over. when looking down the bore you can see two intersecting pieces of aluminum that are shaped like a "plus"(+) sign. this is probably there to direct air towards the reeds but to me they look like a waste of space. has anyone ever removed/ground out, this piece from thier boss intake and if so did it have any negative effects on performance. it seems to me that without this thing,alot more air/fuel could flow through. anyone got any thoughts on this? Quote Link to comment Share on other sites More sharing options...
Washburn Posted March 11, 2007 Report Share Posted March 11, 2007 Never had them but more flow isent Always better. it all depends. That could be there to atomize the flow. Quote Link to comment Share on other sites More sharing options...
wesw Posted March 11, 2007 Report Share Posted March 11, 2007 post a pic but every boss intake i saw doesnt have the crosshairs. i know wkr makes them with them. boss is very tall, cause of the reed spacers. is your like a 1/2 in total thickness??] like said post pic will help also i would remove the crosshairs, im sure their there for a reason. if its not broken dont fix it imo. Quote Link to comment Share on other sites More sharing options...
Bansh-eman Posted March 11, 2007 Report Share Posted March 11, 2007 the + is to help create more veloicity.... and help in atomizing the fuel... do some searches on them... white knuckle and a few other do the same thing.... Quote Link to comment Share on other sites More sharing options...
jbooker82 Posted March 11, 2007 Report Share Posted March 11, 2007 My boss intake doenst have those ethier. Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 11, 2007 Report Share Posted March 11, 2007 the + is to help create more veloicity.... and help in atomizing the fuel... do some searches on them... white knuckle and a few other do the same thing.... The "cross hair" style intake is sort of pointless IMO. I understand what the person who designed them was trying to accomplish, but I think he may have been absent the day they were teaching the laws of aerodynamics. Assuming the intake charge is moving near the speed of sound, the boundary layer over the surface of the "cross hairs" is about 2mm. So if you add 2mm to every surface that air flows over in the intake, how much open area do you have to move an intake charge to the reed valve? My answer is not much. Personally, I don't believe the type on intake that we are talking about here is worth anything, but some people like them. If I were you, I would sell your intakes on eBay and buy something else. :thumbsup: Quote Link to comment Share on other sites More sharing options...
RATBIKE0130 Posted March 11, 2007 Report Share Posted March 11, 2007 The "cross hair" style intake is sort of pointless IMO. I understand what the person who designed them was trying to accomplish, but I think he may have been absent the day they were teaching the laws of aerodynamics. Assuming the intake charge is moving near the speed of sound, the boundary layer over the surface of the "cross hairs" is about 2mm. So if you add 2mm to every surface that air flows over in the intake, how much open area do you have to move an intake charge to the reed valve? My answer is not much. Personally, I don't believe the type on intake that we are talking about here is worth anything, but some people like them. If I were you, I would sell your intakes on eBay and buy something else. :thumbsup: Maybe you were absent as well because you obviously forgot Bernoulli's Principle. If the intake was designed correctly with smooth leading edges the boundary layer would not be 2mm as you assume (How did you get 2mm anyway? Just pulling numbers out of your ass or do you have modeling programs?). In reality there is a couple things going on with those crosshairs. First they do help with laminar airflow. Second they help aim the intake charge. Third they help with intake velocity. Think about this... why do V-force reeds flow more than stock style reeds or other aftermarket brands all while having lots of dividers creating these 2mm boundary layers? Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 12, 2007 Report Share Posted March 12, 2007 Maybe you were absent as well because you obviously forgot Bernoulli's Principle. If the intake was designed correctly with smooth leading edges the boundary layer would not be 2mm as you assume (How did you get 2mm anyway? Just pulling numbers out of your ass or do you have modeling programs?). In reality there is a couple things going on with those crosshairs. First they do help with laminar airflow. Second they help aim the intake charge. Third they help with intake velocity. Think about this... why do V-force reeds flow more than stock style reeds or other aftermarket brands all while having lots of dividers creating these 2mm boundary layers? First of all you can figure out how thick a boundary layer is with out a modeling program if you are willing to make an assumption about the speed of air traveling over a surface. The 2mm number I tossed out there is round up from some thin like 1.8935.................mm. I could throw together a simulation of the part in a CFD software package if necessary, but it's really not necessary. You're right that I must have been absent the day they were teaching how to not understand Bernoulli's principle. Aim the intake charge, really? That might be the most ignorant thing I have heard today and I was at a NASCAR race. I mean, obviously that's what the person who orginally designed the manifold was thinking as well. With regard to V-Force reeds out flowing all of the other reed valves, who told you that? It's not remotely accurate. In fact, from a mass air flow stand point, V-Forces are the worst reed valves. The trade off is that they have one of the best and most consistant opening profiles. Quote Link to comment Share on other sites More sharing options...
blowit Posted March 12, 2007 Report Share Posted March 12, 2007 First of all you can figure out how thick a boundary layer is with out a modeling program if you are willing to make an assumption about the speed of air traveling over a surface. The 2mm number I tossed out there is round up from some thin like 1.8935.................mm. I could throw together a simulation of the part in a CFD software package if necessary, but it's really not necessary. You're right that I must have been absent the day they were teaching how to not understand Bernoulli's principle. Aim the intake charge, really? That might be the most ignorant thing I have heard today and I was at a NASCAR race. I mean, obviously that's what the person who orginally designed the manifold was thinking as well. With regard to V-Force reeds out flowing all of the other reed valves, who told you that? It's not remotely accurate. In fact, from a mass air flow stand point, V-Forces are the worst reed valves. The trade off is that they have one of the best and most consistant opening profiles. What I want to know is where did the near mach intake flow velocity come from? You might have your intake and exhaust numbers mixed up a bit. I cannot give you exact numbers because of the type of work we do but we have employed flow sensors in the intake to give the correct data and it is not mach. One thing to look at is the "pressure" of the air. I would also have to disagree with a 2mm boundry layer. We do have aerospace engineers and that data has been well documented by us. Sorry, can't give that up either. I would say there are way too many assumptions made here in respect to flow in the intake tract. "tumble" is a standard word for 2-stroke intakes. The reason has to do with the frequency of the reeds inducing a push-pull effect in the intake. The vanes in the V-force are simply used to isolate each reed element from affecting another. All in all, the V-force has solid engineering behind it but a crosshair in the intake is reaching and for what I am not sure. They will not increase velocity. You will have to induce throttling to do that. Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 12, 2007 Report Share Posted March 12, 2007 What I want to know is where did the near mach intake flow velocity come from? You might have your intake and exhaust numbers mixed up a bit. I cannot give you exact numbers because of the type of work we do but we have employed flow sensors in the intake to give the correct data and it is not mach. One thing to look at is the "pressure" of the air. I would also have to disagree with a 2mm boundry layer. We do have aerospace engineers and that data has been well documented by us. Sorry, can't give that up either. I would say there are way too many assumptions made here in respect to flow in the intake tract. "tumble" is a standard word for 2-stroke intakes. The reason has to do with the frequency of the reeds inducing a push-pull effect in the intake. The vanes in the V-force are simply used to isolate each reed element from affecting another. All in all, the V-force has solid engineering behind it but a crosshair in the intake is reaching and for what I am not sure. They will not increase velocity. You will have to induce throttling to do that. The near mach 1 intake charge speed is pretty standard as an assumption in the automotive industry. Intake charge pressure is directly related to the intake charge speed and vice versa. You'll have to excuse me if this sounds rude, but I hear "defense contracor'ish" statements alot when we are interviewing folks, and the ones that disagree with you and cannot tell you why because it's secret are usually full of crap. I am not saying that you are full of crap, but depending on who you are taling to you may wind up coming off that way even if you are 100% correct. :thumbsup: Tumble is a term used when discussing pretty much all internal combustion engines. With reed induction two stroke engine, there isn't so much of a push-pull effect, but there is a pull-stall effect. I know what you are getting at and I think that I agree with you You are correct that there are a few other assumptions that need to be made in order to calculate the thickness of a boundary layer, but intake speed has the greatest influence on the end result out of the assumptions that I made. Other than that, I think I agree with pretty much everything else you stated. :woot: Quote Link to comment Share on other sites More sharing options...
blowit Posted March 12, 2007 Report Share Posted March 12, 2007 The near mach 1 intake charge speed is pretty standard as an assumption in the automotive industry. Intake charge pressure is directly related to the intake charge speed and vice versa. You'll have to excuse me if this sounds rude, but I hear "defense contracor'ish" statements alot when we are interviewing folks, and the ones that disagree with you and cannot tell you why because it's secret are usually full of crap. I am not saying that you are full of crap, but depending on who you are taling to you may wind up coming off that way even if you are 100% correct. :thumbsup: Tumble is a term used when discussing pretty much all internal combustion engines. With reed induction two stroke engine, there isn't so much of a push-pull effect, but there is a pull-stall effect. I know what you are getting at and I think that I agree with you You are correct that there are a few other assumptions that need to be made in order to calculate the thickness of a boundary layer, but intake speed has the greatest influence on the end result out of the assumptions that I made. Other than that, I think I agree with pretty much everything else you stated. :woot: Sorry, I don't want to be the one the guy that is full of crap but just like some defense contractors, it called "proprietary info" so I have to decline on some data. I think there are some sharp people here so I have to watch how I present. We spend months engineering our products and we don't like it when others are too lazy to do engineering. I also try to "dumb" things down a touch because I even get peeved with other engineers' chat. Call it what it is. Also in reference to the intake flow data, and I think we know that that "indicated" value depends a bunch on where the measurement is taken. It has been a huge problem in V8s of having nice flow across the carb and then dropping to sh** in the intake and causing fuel to accumulate. The tunnel ram helped a bunch and the port injector was a biggy. Quote Link to comment Share on other sites More sharing options...
FireHead Posted March 12, 2007 Report Share Posted March 12, 2007 Sorry, I don't want to be the one the guy that is full of crap but just like some defense contractors, it called "proprietary info" so I have to decline on some data. I think there are some sharp people here so I have to watch how I present. We spend months engineering our products and we don't like it when others are too lazy to do engineering. I also try to "dumb" things down a touch because I even get peeved with other engineers' chat. Call it what it is. Also in reference to the intake flow data, and I think we know that that "indicated" value depends a bunch on where the measurement is taken. It has been a huge problem in V8s of having nice flow across the carb and then dropping to sh** in the intake and causing fuel to accumulate. The tunnel ram helped a bunch and the port injector was a biggy. No worries. I understand what you guys can and can't talk about. The new OPSEC regs. that DOD has out there basically doesn't allow you to talk about non-classified information such as websites if it has anything remotely to do with what you are working on. I can appreciate you tryin to simplify the information you were presenting as I forget to do that from time to time. It actually sounds like you have a pretty good grasp of the subject matter that we are talking about. As I said before, I made several assumptions when I worked out what a theoretical boundary layer might be across a the feature in question. There have been many different attempts to sort out even intake charge distribution across cylinders in a V style engine. So of them were actually fairly insane. The old standard of having one injector and one throttle blade per cylinder is still the best way of doing it as far as a high rpm, naturally apirated race engine is concerned. Direct injection is the latest attempt and it certainly works well (better in diesels), but it currently has several emissions related draw backs with small gasoline engines. :thumbsup: Quote Link to comment Share on other sites More sharing options...
Fireroad Express Posted March 13, 2007 Author Report Share Posted March 13, 2007 here's the intake i was talking about Quote Link to comment Share on other sites More sharing options...
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